Chronology of Early Cambrian biomineralization

Abstract

Data on the first appearances of major animal groups with mineralized skeletons on the Siberian Platform and worldwide are revised and summarized herein with references to an improved carbon isotope stratigraphy and radiometric dating in order to reconstruct the Cambrian radiation (popularly known as the ‘Cambrian explosion’) with a higher precision and provide a basis for the definition of Cambrian Stages 2 to 4. The Lophotrochozoa and, probably, Chaetognatha were first among protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the Deuterostomia, represented by echinoderms, appeared in the middle of Cambrian Stage 3. The fossil record of sponges and cnidarians suggests that they acquired biomineralized skeletons in the late Neoproterozoic, but diversification of both definite sponges and cnidarians was in parallel to that of bilaterians. The distribution of calcium carbonate skeletal mineralogies from the upper Ediacaran to lower Cambrian reflects fluctuations in the global ocean chemistry and shows that the Cambrian radiation occurred mainly during a time of aragonite and high-magnesium calcite seas.

Full text

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Geol. Mag.: page 1 of 31. c
Cambridge University Press 2011 1
doi:10.1017/S0016756811000720
Chronology of early Cambrian biomineralization
ARTEM KOUCHINSKY∗†, STEFAN BENGTSON∗, BRUCE RUNNEGAR‡,
CHRISTIAN SKOVSTED∗, MICHAEL STEINER§ & MICHAEL VENDRASCO¶
∗Department of Palaeozoology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
‡Department of Earth and Space Sciences, University of California Los Angeles, CA 90095-1567, USA
§Department of Earth Sciences, Freie Universität Berlin, Malteserstrasse 74-100, Haus D, Berlin, 12249, Germany
¶Department of Biological Science (MH-282), California State University, Fullerton, P.O. Box 6850 Fullerton,
CA 92834-6850
(Received 16 September 2010; accepted 5 February 2011)
Abstract – Data on the first appearances of major animal groups with mineralized skeletons on the
Siberian Platform and worldwide are revised and summarized herein with references to an improved
carbon isotope stratigraphy and radiometric dating in order to reconstruct the Cambrian radiation
(popularly known as the ‘Cambrian explosion’) with a higher precision and provide a basis for
the definition of Cambrian Stages 2 to 4. The Lophotrochozoa and, probably, Chaetognatha were
first among protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the
Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of
the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the
Deuterostomia, represented by echinoderms, appeared in the middle of Cambrian Stage 3. The fossil
record of sponges and cnidarians suggests that they acquired biomineralized skeletons in the late
Neoproterozoic, but diversification of both definite sponges and cnidarians was in parallel to that
of bilaterians. The distribution of calcium carbonate skeletal mineralogies from the upper Ediacaran
to lower Cambrian reflects fluctuations in the global ocean chemistry and shows that the Cambrian
radiation occurred mainly during a time of aragonite and high-magnesium calcite seas.
Keywords: Cambrian, radiation, biomineralization, evolution, stratigraphy.
1. Introduction
The term ‘Cambrian radiation’ (popularly known as
the ‘Cambrian explosion’) is embedded in modern
scientific literature and was coined for the early Cam-
brian geologically rapid diversification of metazoans.
Most of these early Cambrian metazoans appear to
represent members of the stem lineage of extant
clades. The first appearances of these groups are
clustered geochronologically by higher-rank phylogeny
(Budd, 2003; Landing & Westrop, 2004; Li et al.
2007). Budd (2003) and Budd & Jensen (2000,
2003) argued that this clustering reflects the true
sequence of divergence of these high-ranking groups
and implies rather late origins, probably near the
Precambrian–Cambrian boundary, followed by their
rapid evolutionary radiation in the early Cambrian.
This event is marked in the fossil record by the first
appearances and increase in diversity and abundance
of many groups of animals, accompanied by the
independent acquisition of mineralized skeletons in
many lineages.
Skeletal biomineralization was likely an epiphen-
omenon of the general radiation of body plans and
tissues (Bengtson, 2004). Skeletal elements are con-
sidered principal aspects of many body plans, and their
origin and diversification are thought to have helped
spur evolutionary radiation in the Cambrian. Skeletons
†Author for correspondence: artem.kouchinsky@nrm.se
certainly diversified along with the taxa that obtained
them, with 80 % of modern skeletal morphotypes
present by the middle Cambrian (Thomas, Sherman
& Stewart, 2000). The diversity of minerals employed
in early skeletalized animals suggests a limit to
the role of ocean geochemistry in the emergence
of skeletons, although the primary acquisition of
particular skeletal carbonate mineralogies was likely
driven by the ocean geochemistry (Zhuravlev, 1993;
Bengtson, 1994, 2004; Ushatinskaya & Zhuravlev,
1994; Hardie & Stanley, 1997; Stanley & Hardie, 1998;
Porter, 2007; Zhuravlev & Wood, 2008; Kiessling,
Aberhan & Villier, 2008). Mineralized skeletal parts
are only one of many strategies to escape predation,
since skeletonized species constitute a minority in
modern and ancient marine ecosystems (e.g. Conway
Morris, 1986). However, it was probably the anti-
predatory selective advantage of mineral skeletons that
drove early evolution in many clades (Bengtson, 1994,
2004). Further diversification of predators and their
increased pressure on epibenthos in the Cambrian may
well have triggered the early Cambrian rapid evolu-
tionary radiation in different clades (Bengtson, 1994,
2004).
In order to understand in detail the fossil re-
cord of early Cambrian skeletal biomineralization
and structure of the Cambrian radiation, a better-
resolved sequence of first appearances of mineralized
skeletons in the early Cambrian class-to-phylum-
level animal groups is presented herein. Our study

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
2A. KOUCHINSKY & OTHERS
Figure 1. Schematic palaeogeographic map for the early
Cambrian with crustal units discussed in this paper (adapted
from Fatka, Kraft & Szabad, 2011 and Álvaro et al. in press).
incorporates a new carbon isotope chemostratigraphy
of the northern Siberian Platform, where a continuous
isotopic and fossil record is known from mainly
carbonate sections of the Cambrian System (online
Fig. S1 at http://journals.cambridge.org/geo). The
Siberian data are stratigraphically correlated with
those from other well-known units of the Cam-
brian world, such as Western Mongolia, Kazakhstan,
South China, Iran and India, Australia, Avalonia, the
Mediterranean region of West Gondwana, Laurentia
and Baltica (Fig. 1; online Appendices 1 & 2 at
http://journals.cambridge.org/geo). This record, sup-
ported by available chemostratigraphy and radiometric
dating, allows us to constrain the timing of the
first appearances of skeletonization in various animal
groups (Fig. 2).
2. Stratigraphical setting
The traditional three-fold subdivision of the Cambrian
System into Lower, Middle and Upper Cambrian
series has been abandoned recently in favour of a
subdivision into four series of ten stages (Babcock
et al. 2005; Babcock & Peng, 2007). The uppermost
two series of the revised Cambrian timescale more or
less correspond to the traditional Middle and Upper
Cambrian series, while the former Lower Cambrian
is subdivided into two series. The new Cambrian
timescale begins with the Fortunian Stage of the
Terreneuvian Series, the base of which is defined as the
first occurrence of the trace fossil Treptichnus pedum
Figure 2. Global first appearances of mineralized skeletons in animals during the Cambrian radiation. Question marks indicate
uncertainty in first appearance or place within higher-ranked group; affinities of chancelloriids to the Lophotrochozoa and
hyolithelminths to the Cnidaria are uncertain (see main text and online Appendix 1 at http://journals.cambridge.org/geo). Cambroclavids
(with paracarinachitids included) are tentatively attributed to the Lophotrochozoa. Vertical dashed lines for sponges reflect
sporadic occurrence of their presumably biomineralized spicules in the Precambrian (see main text and online Appendix 1 at
http://journals.cambridge.org/geo). ECC – Ediacaran calcified cnidariomorphs; Ch – Chaetognatha; D – Deuterostomia.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 3
Figure 3. Correlation chart of the major crustal units discussed in this paper. It is formally accepted that the Purella Zone corresponds
to the entire upper part of the Nemakit–Daldynian Stage (e.g. Rozanov et al. 2008). According to the chemostratigraphic record (e.g.
Kaufman et al. 1996; see also Fig. 4 herein), a hiatus of disputed duration exists, however, at the base of the Tommotian Stage in
its stratotype in the southeastern Siberian Platform. The Purella Zone is shown herein to cover its duration, since the missing record
exists in the northern part of the Platform. The first occurrences of trilobites are highlighted by thick horizontal lines within the Stage
3 interval. The Atdabanian Stage is subdivided into three parts (lower, middle and upper): 1 – Profallotaspis jakutensis and Repinaella
zones; 2 – Delgadella anabara Zone; 3 – Judomia Zone. SSF4 =Sinosachites flabelliformis–Tannuolina zhangwentangi Assemblage
Zone. Absolute ages for the Precambrian–Cambrian boundary after Bowring et al. 2007; Cambrian Series 2–Series 3 boundary after
Ogg, Ogg & Gradstein, 2008. Absolute ages of the lower and upper boundaries of the Tommotian Stage are based on data from
Morocco (see main text and Maloof et al. 2005, 2010a,b). The fossiliferous Watsonella crosbyi Zone in China is older than 526.5 ±
1.1 Ma (after Compston et al. 2008) and its lower boundary in Avalonia is shown to be older than 530.7 ±0.9 Ma (Isachsen et al.
1994) or 528.1 ±0.9 Ma (Compston et al. 2008). That boundary is, however, younger than 535.2 ±1.7 Ma, a combined depositional
ageforBed5(shownas<535 Ma in figure) from the upper Anabarites trisulcatus–Protohertzina anabarica Zone (Zhu et al. 2009;
see main text for discussion).
at Fortune Head in Newfoundland (Landing et al.
2007). It is anticipated that the base of Cambrian
Series 2 and Stage 3 will coincide with the first
appearance of trilobites (Babcock & Peng, 2007),
here interpreted to correlate with the base of the
Atdabanian Stage in Siberia (Fig. 3). The remaining
boundaries within Series 1–2 are less certain. In the
present work, we will provisionally correlate the base
of Cambrian Stage 2 of the Terreneuvian Series with
the base of the Watsonella crosbyi Zone of Avalonia
and South China (see Landing et al. 2007; Li et al.
2007) and the base of Cambrian Stage 4 with the
lower Botoman Stage in Siberia (Fig. 3). The base of
Cambrian Series 3, Stage 5 is presently highly debated,
but is here correlated with the first occurrence of the
trilobite Oryctocephalus indicus, which more or less
coincides with the traditional Lower–Middle Cambrian
boundary in many areas. The further development
of the chronostratigraphy of Cambrian Series 1 and
2 is directly related to our precision in dating and
correlation of the first appearances of diverse skeletal
fossils in principal Cambrian sequences.
The age of the Precambrian–Cambrian boundary,
marked worldwide by a negative carbon isotope anom-
aly, is dated in the well-constrained section in Oman
to 542 ±0.3 Ma (Amthor et al. 2003), later revised to
541 ±0.13 Ma (Bowring et al. 2007). An associated
biotic crisis is inferred from the disappearance of
the Ediacaran biota (e.g. Kimura & Watanabe, 2001;
Narbonne, 2005). As recognized herein, the Cambrian
radiation event (‘Cambrian explosion’) occurred within
a period of c. 25 Ma. The Cambrian radiation began
with the diversification of skeletonized bilaterians
following this negative anomaly and concluded with the
Botoman–Toyonian biotic crisis (Zhuravlev & Wood,
1996; Zhuravlev, 2001; Li et al. 2007), which was
the first mass extinction episode in the Phanerozoic
(Signor, 1992). The onset of the crisis on the Siberian

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
4A. KOUCHINSKY & OTHERS
Figure 4. First appearances of skeletal fossil groups on the Siberian Platform (S1–S13, see Appendix 1 for details) in the key
sections correlated with the δ13C chemostratigraphy (after Brasier, Khomentovsky & Corfield, 1993; Brasier et al. 1994b; Kouchinsky
et al. 2001). Zones: Ns –Nochoroicyathus sunnaginicus;Dr –Dokidocyathus regularis;Dl –Dokidocyathus lenaicus–Tumuliolynthus
primigenius;Rz –Retecoscinus zegebarti;C. pinus –Carinacyathus pinus;Nk –Nochoroicyathus kokoulini;Fl –Fansycyathus
lermontovae;Pj –Profallotaspis jakutensis;R–Repinaella;D. anabara –Delgadella anabara;Bm –Bergeroniellus micmacciformis;
Bg –Bergeroniellus gurarii;Ba –Bergeroniellus asiaticus. Numbers in brackets are projections of the corresponding first appearances
in the Atdabanian Stage of the Anabar Uplift onto the Lena-Aldan reference scale.
Platform (Sinsk event), is marked by decreasing δ13C
values above peak VII of the Siberian reference scale
(Brasier et al. 1994a,b; Zhuravlev & Wood, 1996; Li
et al. 2007; Fig. 4).
The Cambrian radiation interval shows prominent
and frequent oscillations of the carbon isotope ratio
(e.g. Brasier et al. 1994a,b; Brasier & Sukhov, 1998;
Figs 4, 5). An overall rising trend in δ13C values charac-
terizes the sedimentary sequence of the Fortunian Stage
in Siberia, Mongolia, China and Western Gondwana.
SHRIMP U–Pb zircon analyses from the lower part
of this trend in South China provide a revised age
of 539.4 ±2.9 Ma (Compston et al. 2008), whereas
secondary ion mass spectrometry (SIMS) of the same
tuffite (Bed 5 of the Meishucun section) resulted in a
c. 533 Ma estimate (Brooks et al. 2006). Nano-SIMS
measurements by Sawaki et al. (2008) provided an age
estimate of 536.5 ±2.5 Ma for Bed 5, whereas SIMS
analyses by Zhu et al. (2009) yielded an age of 536.7 ±
3.9 Ma. A combined depositional age for Bed 5 was
calculated as 535.2 ±1.7 Ma by Zhu et al. (2009). The
fauna known from below Bed 5 is considered herein
to be older than 535 Ma (Figs 2, 3). The dated bed is
situated in the upper part of the Anabarites trisulcatus–
Protohertzina anabarica (SSF1) Assemblage Zone of
the lower Meishucunian Stage.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 5
Figure 5. First appearances of skeletal fossil groups in the
Tsagan Oloom and Bayan Gol formations of Western Mongolia
(M1–M7, see Appendix 2 for details) (after Brasier et al. 1996,
fig. 6), in the Tsagan Gol, Bayan Gol and Salany Gol sections
composite. Features of the δ13C curve, from W to C after Brasier
et al. (1996, fig. 5) and from D to F after fig. 7 therein; adapted
for unit thickness of the Bayan Gol Formation in Brasier et al.
1996, fig. 6a. Zones after Brasier et al. (1996). A – correlation
with Siberia, after Voronin et al. (1982), Astashkin et al. (1995),
Khomentovsky & Gibsher (1996) and Esakova & Zhegallo
(1996); B – chemostratigraphic correlation, after Brasier et al.
(1996).
The rising trend of δ13C values continues into
the Cambrian Stage 2, where several highly positive
peaks preceding the Tommotian Stage in Siberia top it
(Fig. 4). A single preserved prominent positive peak
from the same rising trend is present in the Watsonella
crosbyi (SSF3) Assemblage Zone of the Middle
Meishucunian Stage in South China and is older than
526.5 ±1.1 Ma (after Compston et al. 2008). The lower
boundary of the Cambrian Stage 2 and Watsonella
crosbyi Zone has been preliminarily estimated to be
close to 530 Ma (Landing et al. 2007). The estimate is
based on the absolute age of 530.7 ±0.9 Ma obtained
from the Watsonella crosbyi Zone in Avalonia (Isachsen
et al. 1994), but the date was revised to 528.1 ±0.9 Ma
by Compston et al. (2008, p. 417). The uppermost
peak in the rising trend of δ13C values within Stage
2 is dated in Morocco to 525.4 ±0.5 Ma (Maloof
et al. 2005), later revised to 525.343 ±0.088 Ma
(Maloof et al. 2010a,b). The high-resolution succes-
sions of δ13C peaks in Morocco and Siberia (Brasier
et al. 1994b; Kouchinsky et al. 2007) proved to be
very similar, and their correlation resulted in a c.
525 Ma estimate of the age of the Nemakit–Daldynian–
Tommotian boundary dated in Morocco to 524.837 ±
0.092 Ma (Maloof et al. 2010a,b). Chemostratigraphic
δ13C correlation with radiometrically dated sections of
Morocco allows dating of the lower boundary of the
Atdabanian Stage in Siberia to a maximum age of
520.93 ±0.14 Ma (Maloof et al. 2010a,b), thereby
providing an estimate of c. 521 Ma for the upper
boundary of Stage 2 and the Terreneuvian Series.
A recalculated age of 515.56 ±1.16 Ma attributed
to the upper Antatlasia gutta-pluviae Zone of the
Moroccan Banian Stage (originally 517.0 ±1.5 Ma
by Landing et al. 1998) can be correlated with the
Botoman Stage (probably, the Bergenellious asiaticus
Zone) of Siberia and the Bonnia–Olenellus Zone
of Laurentia (Zhuravlev, 1995; Landing et al. 1998;
Maloof et al. 2010a). The conclusion of the Cambrian
radiation and the onset of the Botoman–Toyonian biotic
crisis are, therefore, dated herein to be c. 515 Ma
(Figs 2, 3). The upper boundary of the Cambrian
Series 2 is estimated to be c. 510 Ma (Ogg, Ogg
& Gradstein, 2008), because it is somewhat younger
than the estimated age of 511 ±1 Ma for the upper
Branchian Series of Avalonia (Landing et al. 1998).
2.a. Siberia
The former Lower Cambrian includes on the Siberian
Platform and in the Altai-Sayan Folded Area the Tom-
motian, Atdabanian, Botoman and Toyonian stages,
in ascending order (Rozanov & Sokolov, 1984;
Rozanov et al. 2008; Varlamov et al. 2008). The
lowermost Cambrian strata (approximately, Fortunian
Stage equivalent) were recognized on the Platform as
the Nemakit–Daldynian (or Manykayan Stage by some
authors, e.g. Missarzhevsky, 1982, 1989; Val’kov, 1982,
1987; see discussion in Khomentovsky & Karlova,
2002, 2005). The Nemakit–Daldynian Stage is now
subdivided into the Anabarites trisulcatus and Purella
antiqua zones, in ascending order (Khomentovsky &
Karlova, 1993, 2002). In the Lena-Aldan and Uchur-
Maya regions of the southeastern Siberian Platform, the
first appearances of taxa are reported from the Ust’-
Yudoma Formation (Nemakit–Daldynian Stage) and
from the overlying Pestrotsvet Formation (Tommotian–
Atdabanian stages) (Figs 4, 6). In the northern part
of the Platform, the regional first occurrences are re-
corded from the Manykay, Medvezh’ya and Emyaksin

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
6A. KOUCHINSKY & OTHERS
Figure 6. Map of the Siberian Platform with localities
referred to in the main text and online Appendix 1 at
http://journals.cambridge.org/geo. The localities are indicated
by circles with the following numbers: 1 – Sukharikha River,
middle reaches; 2 – Kotuj River (between the Sergej-Koril-
Uoran rapids and mouth of the Kugda Brook) and the lowermost
reaches of the Kotujkan River; 3 – Bol’shaya Kuonamka River,
lower reaches; 4 – Olenyok River at the mouth of the Erkeket
River and Khorbosuonka River at the mouth of the Mattajya
River; 5 – Lena River, lower reaches, sections Chekurovka and
at the mouth of the Ulakhan-Ald’yarkhaj Brook; 6 – Lena River,
middle reaches, between sections Isit’ and Achchagyi-Kyyry-
Taas; 7 – Aldan River, between sections ‘Dvortsy’ and Ulakhan-
Sulugur; 8 – Uchur-Maya region, sections along the Uchur River,
between the Gonam and Selinde rivers, including the Mount
1291 m, Mount Konus, Nemnekey, and Selinde localities.
formations of the Anabar Uplift (Nemakit–Daldynian–
Atdabanian stages), upper Turkut and Kessyuse forma-
tions of the Olenyok Uplift (Nemakit–Daldynian–lower
Tommotian), and uppermost Sukharikha–lower Krasny
Porog formations abutting the lower Tommotian bound-
ary on the northwestern margin of the Platform (Figs
4, 6). Detailed biostratigraphy and carbon isotope
chemostratigraphy was obtained throughout these units
and provides the basis for global correlations used
herein (Fig. 4).
2.b. Western Mongolia
Ediacaran and lower Cambrian beds in Mongolia are
better studied in sections of the Khasagt-Khairkhan
Ridge in Western Mongolia, where carbon isotope
chemostratigraphy and sequence stratigraphy are also
available (Brasier et al. 1996; Esakova & Zhegallo,
1996). This region represented an isolated Zavkhan
Terrane that separated from Eastern Gondwana and
collided with Siberia during the Ediacaran–Early
Palaeozoic interval (Ruzhentsev & Mossakovsky,
1995; Debrenne, Maidanskaya & Zhuravlev, 1999;
Kheraskova et al. 2003). The chemostratigraphic
record from this region is fragmentary because of thick
intercalations of siliciclastic sediment from which the
δ13Ccarb values cannot be read (Brasier et al. 1996).
A composite section through the uppermost Tsagan
Oloom and Bayan Gol formations in Western Mongolia
is provided herein (Fig. 5).
2.c. Kazakhstan
The region was situated in proximity to East Gondwana
and embraces Kazakhstanian terranes (Holmer et al.
2001; Popov et al. 2009). Among them, sections in
the Lesser Karatau Range that include the Kyrshabakty
and Chulaktau formations and the Shabakty Group in
ascending order are the best studied and most continu-
ous lower Cambrian sequences in Kazakhstan (Missar-
zhevsky & Mambetov, 1981; Holmer et al. 2001). The
Kyrshabakty and Chulaktau formations are biostrati-
graphically correlated, respectively, with the Nemakit–
Daldynian and upper Nemakit–Daldynian–Tommotian
stages of Siberia (Missarzhevsky & Mambetov, 1981;
Mambetov, 1993). First occurrences in members of
the lower Shabakty Group are biostratigraphically
correlated with the upper Atdabanian–Botoman stages
of Siberia (Missarzhevsky & Mambetov, 1981; Holmer
et al. 2001).
2.d. South China, India and Iran
From the Yangtze Platform (South China), a set of
the oldest first appearances of bilaterian taxa with
mineralized skeletons is described herein mainly from
the Zhujiaqing Formation of Yunnan and Maidiping
Formation of Sichuan. They are correlated bio- and
chemostratigraphically with the Nemakit–Daldynian
Stage of Siberia (Qian et al. 2002; Li, Zhang &
Zhu, 2001; Li et al. 2007, 2009; Li & Xiao, 2004;
Steiner et al. 2007) and comprise in ascending
order the assemblage zones Anabarites trisulcatus–
Protohertzina anabarica (SSF1) of the lower Meishu-
cunian Stage, Paragloborilus subglobosus–Purella
squamulosa (SSF2) and Watsonella crosbyi (SSF3) of
the middle Meishucunian Stage (Steiner et al. 2007)
(Fig. 3). The upper Meishucunian strata comprise the
Sinosachites flabelliformis–Tannuolina zhangwentangi
Assemblage Zone (SSF4) and directly underlie the
trilobitic interval of the Cambrian in the shallow water
realm of the Yangtze Platform. The first occurrences of
skeletonized bilaterians within the Parabadiella and
Eoredlichia–Wutingaspis zones of the Qiongzhusian
Stage are biostratigraphically correlated (but not
directly constrained by chemostratigraphy) with the
middle–upper Atdabanian and upper Atdabanian–
lower Botoman stages of Siberia, respectively (Qian
et al. 2002; Li, Zhang & Zhu, 2001; Li et al.
2007; Li & Xiao, 2004; Steiner et al. 2007; Fig. 3).
This interval of earliest trilobitic zones is also more
coarsely resolved by the Pelagiella subangulata Taxon
Range Zone (SSF5) in the shallow water realm, roughly

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 7
correlative with the Ninella tarimensis–Cambroclavus
fangxianensis Assemblage Zone and the Rhombocor-
niculum cancellatum Taxon Range Zone at the northern
margin of the Yangtze Platform. First appearances
of skeletal fossils from sections of the upper Krol
and lower Tal formations in the Lesser Himalayas of
India and lower Soltanieh Formation in the Elburz
Mountains of Iran are correlated with SSF1 of South
China (Hamdi, Brasier & Jiang, 1989; Hamdi, 1995;
Hughes et al. 2005). The three regions belonged to
East Gondwana (Fig. 1).
2.e. Australia
The first appearances of skeletal fossils in East
Gondwana are also derived from South Australia. In
the Arrowie Basin, first occurrences are documented
herein from the lower Wilkawillina and Ajax Lime-
stones, Wirrapowie Limestone and lower Mernmerna
Formation, and the Moorowie Formation. These first
appearances span the reportedly pre-trilobitic interval
and Abadiella huoi–Pararia janeae zones, correlated
biostratigraphically with the Atdabanian–Botoman
stages of Siberia (Bengtson et al. 1990; Gravestock
et al. 2001; Jago, Sun & Zang, 2002; Jago et al. 2006;
Skovsted, Brock & Paterson, 2006; Topper et al. 2010,
2011). In the Stansbury Basin, the earliest skeletal
fossils are derived from the Mount Terrible and Winulta
formations, broadly correlated with the Nemakit–
Daldynian–Tommotian stages of Siberia (Daily, 1976,
1990; Gravestock & Shergold, 2001; Jago, Sun & Zang,
2002; Jago et al. 2006). Other first occurrences from the
overlying Kulpara Formation and Parara Limestone are
reported from pre-trilobitic beds and Abadiella huoi–
Pararia janeae zones (Bengtson et al. 1990; Gravestock
et al. 2001; Jago, Sun & Zang, 2002; Jago et al. 2006).
2.f. Mediterranean region
Several blocks now in North Africa and Western Europe
were situated along the western margin of Gondwana
(Fig. 1). Among these, first occurrences from the
Corduban Series of central Spain are discussed herein.
Based on biostratigraphic correlation with Morocco
and chemostratigraphy, the Corduban Series represents
a sub-trilobitic part of the lower Cambrian of Western
Gondwana (Geyer & Landing, 2004; Fig. 3). The
first appearances from the lower Ovetian Stage in W
Europe (Spain, France, Germany, Sardinia) are cor-
related biostratigraphically with those from the lower
Issendalenian Stage in the Anti-Atlas Mountains of
Morocco (Geyer & Landing, 2004). The base of the Is-
sendalenian Stage in Morocco correlates chemostrati-
graphically with the Delgadella anabara Zone of the
Atdabanian Stage of Siberia (Kirshvink et al. 1991;
Maloof et al. 2005, 2010a,b). First appearances of
skeletal fossils from the upper Ludwigsdorf limestones
of the Saxothuringian microcontinent (Germany)
are correlated with the Atdabanian–Botoman stages of
Siberia and the upper Qiongzhusian–lower Canglang-
puian stages of South China (Elicki, 1994; Geyer &
Elicki, 1995).
2.g. Avalonia
The region formed a relatively small terrane of West
Gondwanan affinity. In its portion represented by SE
Newfoundland, the oldest first appearances are located
within the Quaco Road Member of the upper Chapel
Island Formation, within the Ladatheca cylindrica
Zone of the Fortunian Stage and Watsonella crosbyi
Zone of the Cambrian Stage 2 (Landing, 2004; Landing
& Westrop, 1998; Landing et al. 1989, 2007). Other
important first occurrences are reported from the
upper Cuslett and lower Fosters Point formations
(Camenella baltica Zone, correlated with the lower–
middle Atdabanian Stage), as well as from the basal part
of the overlying Brigus Formation (Callavia broeggeri
Zone, correlated with the upper Atdabanian–Botoman
stages) (Shergold & Geyer, 2003; Fig. 3). In the
portion of Avalonia represented by South Britain, the
first occurrences regarded herein are from the Home
Farm Member, Lower Comley Sandstone and Comley
Limestone (Camenella baltica and Callavia zones).
2.h. Laurentia
In the Northwest Territories of Canada the first ap-
pearances are reported from the Ingta Formation of the
Wernecke Mountains, correlated with the basal Cam-
brian Anabarites–Protohertzina Zone (Pyle et al. 2006)
and underlain by the Precambrian–Cambrian boundary
negative excursion (Narbonne, Kaufman & Knoll,
1994; Pyle et al. 2004), and from the Sekwi Form-
ation of the Mackenzie Mountains and basal Rosella
Formation of the Cassiar Mountains, correlated with
the Fallotaspis and Nevadella zones (Voronova et al.
1987; Dillard et al. 2007). In Greenland, important first
occurrences are reported from the lower Buen Forma-
tion, biostratigraphically correlated with the Nevadella
Zone and upper Atdabanian Stage (Conway Morris et
al. 1987; Conway Morris, 1989; Debrenne & Reitner,
2001; Conway Morris & Peel, 2008, 2010), and from
the upper Bastion–Ella Island formations, correlated
with the Bonnia–Olenellus Zone and Botoman Stage
(Skovsted, 2003, 2004, 2006). First occurrences in Cali-
fornia and Nevada are from the Campito Formation,
from the Fritzaspis,Fallotaspis and Nevadella zones
(Durham, 1971; Hollingsworth, 2005, 2007; Fig. 3).
2.i. Baltica
The earliest skeletal fauna (Mobergella fauna) on the
Baltic Shield known from the Kalmarsund Sandstone
and subsurface deposits in southern Sweden is correl-
ated with the Schmidtiellus mickwitzi Zone (Bengtson,
1968, 1970, 1977). First appearances from the Zaw-
iszyn Beds of the upper Klimontovian Stage in Poland
(Lendzion, 1972, 1978; 1983; Bengtson, 1977), Lükati
Formation and lower part of the Tiskre Formation in

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
8A. KOUCHINSKY & OTHERS
northern Estonia are also attributed to the Schmidtiellus
mickwitzi Zone of the Dominopol’ Stage (Bergström,
1973; Mens & Pirrus, 1977; Moczydłowska, 2002).
These beds are broadly correlated with the Atdabanian
Stage of Siberia (Moczydłowska, 2002). The oldest
regional first occurrences are reported from the Lontova
Formation in Estonia, Platysolenites antiquissimus
Zone, broadly correlated with the Terreneuvian Series
(Fig. 3).
3. First appearances of mineralized skeletal parts
in animal groups
3.a. Sponges and spongiomorphs
The oldest fossils attributed to sponges are reported
from the Cryogenian Period. One of the earliest lines
of evidence for sponges comes from well-preserved
molecular biomarkers of demosponges from strata of
the Neoproterozoic Huqf Supergroup of the South
Oman Salt Basin pre-dating the termination of the
Marinoan glaciation and having a minimum age of
c. 635 Ma (McCaffrey et al. 1994; Love et al. 2006,
2009). Fossils interpreted as sponge-grade metazoans
are also found in the pre-Marinoan Trezona Formation
of South Australia with a maximum age of 659.7 ±
5.3 Ma (Maloof et al. 2010c). Palaeophragmodictya
reticulata Gehling & Rigby, 1996, from the Ediacaran
Rawnsley Quartzite in South Australia, was interpreted
as a hexactinellid (Gehling & Rigby, 1996; Debrenne &
Reitner, 2001), or a stem-group sponge (Mehl, 1998),
but later it was reinterpreted as an attachment disc
of a problematic organism of uncertain affinity to
sponges or cnidarians (Serezhnikova, 2007). The Late
Ediacaran Fedomia mikhaili Serezhnikova & Ivantsov,
2007 and Vaveliksia vana Ivantsov, Malahovskaya &
Serezhnikova, 2004, from the White Sea coast, are
likely sponges (Ivantsov, Malahovskaya & Serezh-
nikova, 2004; Serezhnikova, 2007; Serezhnikova &
Ivantsov, 2007).
3.a.1. Demosponges and hexactinellids
The earliest reported sponge spicules from c. 750 Ma
strata in Nevada were attributed to demosponges
(Reitner & Wörheide, 2002; Müller et al. 2007). Mon-
axonous thin-walled and hollow spicules of possible
hexactinellids derive from Alaska (Allison & Awramik,
1989; Debrenne & Reitner, 2001), from beds inferred
by chemostratigraphy to be Neoproterozoic, most likely
pre-Varangerian (Kaufman, Knoll & Awramik, 1992).
Skeletal remains of sponges found in thin-sections
from the Doushantuo Formation on the South China
Platform are interpreted as demosponges, because they
consist exclusively of siliceous monaxonal spicules (Li,
Chen & Hua, 1998). Their maximum age is c. 580 Ma
(Condon et al. 2005). These latter, however, were
regarded as possible pseudofossils (inorganic crystals)
by Zhou, Yuan & Xue (1998). Spicule-like objects
of hexactinellid habit from the Ediacaran Doushantuo
and Dengying formations of Hubei Province were
observed in thin-section (Tang, Zhang & Jiang, 1978;
Zhao et al. 1988; Steiner et al. 1993), but these
might also be pseudofossils composed of inorganic
crystals (Zhou, Yuan & Xue, 1998) or might instead
represent acanthomorphic acritarchs (Zhang, Yuan &
Yin, 1998). Spicules with demosponge affinities are
known from Cloudina reefs of Namibia (Reitner &
Wörheide, 2002), with an age of c. 550 Ma (after Wood,
Grotzinger & Dickson, 2002; Grotzinger, Adams &
Schröder, 2005). Disarticulated and clustered tetracts,
pentacts, hexacts and polyactines attributed to upper
Ediacaran hexactinellids are preserved in iron oxides
in chert layers of the upper Tsagan Oloom Formation of
Western Mongolia (Brasier et al. 1996; Brasier, Green
& Shields, 1997), but the stratigraphic position of strata
yielding these spicules requires further age constraint.
Hexactiniellid and/or demospongiid siliceous spicules
were mentioned but not illustrated by Brasier & Singh
(1987, p. 326), Mazumdar & Banerjee (1998) and
Tiwari (1999). These fossils were recovered from the
lowermost Cambrian basal Chert-Phosphate Member
of the lower Tal Group, in the Mussoorie, Garwhal
and Korgai synclines of the Lesser Himalayas and
from the lower part of the Gangolihat Dolomite
(Deoban Formation) of the Inner Kumaun Lesser
Himalayas (inner carbonate belt) (Tiwari, Pant &
Tewari, 2000), correlated with the lowermost Cambrian
(lower Meishucunian) based on the occurrence of
protoconodonts (Azmi & Paul, 2004).
Abundant and extraordinarily preserved hexactinel-
lids and demosponges (including articulated speci-
mens) are well documented from the early Cambrian
deep basinal settings of the Yangtze Platform, from the
Niutitang black shales of Hunan (Ding & Qian, 1988;
Steiner et al. 1993) and Hetang black shales of Anhui
(Yuan et al. 2002). Hexactinellid sponge spicules occur
in chert beds of the basal member of the Niutitang
Formation of Hunan Province (Steiner et al. 1993: p. 6,
figs 2–4) and of equivalent strata in Zhejiang Province
(Steiner et al. 2004a, fig. 2h), of which the ages are
constrained to the lower Meishucunian Stage owing
to the occurrence of Kaiyangites. Megasters are not
rare in the lower Meishucunian of Shaanxi Province
(Steiner et al. 2007). By contrast, there are no remains
interpreted as sponge spicules from the Meishucunian
Stage in its stratotype area of eastern Yunnan (Rigby &
Hou, 1995), where the first spicules and sponge body
fossils occur in the basal Yu’anshan Formation of the
Qiongzhusian Stage (Steiner et al. 2001).
In Siberia, siliceous spicules attributed to the
Hexactinellida are known from the lowermost Tom-
motian Nochorojcyathus sunnaginicus Zone (Sokolov
& Zhuravleva, 1983; Pel’man et al. 1990; Rozanov
& Zhuravlev, 1992) and traditionally referred to as
Protospongia sp. (Protospongia Salter, 1864). Similar
fossils have also been reported by Khomentovsky,
Val’kov & Karlova (1990) and Khomentovsky
& Karlova (1993) (but not illustrated) from the
pre-Tommotian part of the lower Cambrian, from

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 9
the upper Ust’-Yudoma Formation (Fig. 4; on-
line Appendix 1 at http://journals.cambridge.org/geo).
The earliest spicules of demosponges occur in
the Fansycyathus lermontovae Zone of the up-
per Atdabanian Stage in northern Siberia (Fedorov
in Shabanov et al. 1987; online Appendix 1 at
http://journals.cambridge.org/geo). The earliest artic-
ulated hexactinellids and demosponges in Siberia
occur in the lower Botoman Sinsk lagerstätten (Gory-
ansky, 1977; Ivantsov et al. 2005; Ponomarenko,
2005; Rozanov et al. 2010; online Appendix 1 at
http://journals.cambridge.org/geo).
3.a.2. Calcareans
The earliest calcarean sponge spicules of Dodecaact-
inella sp. occur in the lower Dokidocyathus regularis
Zone of Siberia (Kruse, Zhuravlev & James, 1995;
Fig. 2). Pentactines of Sulugurella sulugurica Fedorov
in Pel’man et al. 1990 were originally attributed to
the Calcarea and reported from the Nochorojcyathus
sunnaginicus Zone of the Tommotian (Pel’man et al.
1990) and from the probably slightly older upper-
most Sukharikha Formation of the Sukharikha River
section (Rowland et al. 1998), but their hexactinellid
affinity is more plausible (A. Zhuravlev, pers. comm.,
2008). Calcarean spicules are also known from the
Atdabanian–Botoman-equivalent strata of Mongolia,
Western Gondwana, Australia and Laurentia (online
Appendix 1 at http://journals.cambridge.org/geo). The
first articulated calcarean Gravestockia pharetronen-
sis Reitner, 1992 occurs in Australian beds cor-
related with the Atdabanian Stage (Reitner 1992;
Debrenne & Reitner, 2001; online Appendix 1
at http://journals.cambridge.org/geo). According to
Zhuravlev & Wood (2008), spicules of first repres-
entatives of calcarean sponges are probably high-
magnesium calcitic in original composition. Stem-
group sponges, which may combine mineralogy and
morphology of calcarean and hexactinellid spicules,
are also reported from the Cambrian Series 2 (Bot-
ting & Butterfield, 2005; Harvey, 2010; see also
Eiffelia Walcott, 1920 in online Appendix 1 at
http://journals.cambridge.org/geo).
3.a.3. Archaeocyaths and other probable aspicular sponges
First archaeocyaths are known from the lowermost
Tommotian Stage of the Siberian Platform (e.g.
Rozanov et al. 1969, 1992, 2008; Shabanov et al.
2008; Riding & Zhuravlev, 1995; Kruse, Zhuravlev &
James, 1995). Among them, an undetermined form is
reported from the uppermost Ust’-Yudoma Formation
(Rozanov et al. 1992; Shabanov et al. 2008), while
several species occur in the basal Pestrotsvet Formation
of the Lena-Aldan region (online Appendices 1
& 2 at http://journals.cambridge.org/geo; Fig. 2).
Archaeocyaths were also reported from the basal
Pestrotsvet Formation at Selinde in the southeastern
Siberian Platform (Korshunov, Repina & Sysoev,
1969; Khomentovsky & Karlova, 2002) and the
uppermost Sukharikha Formation in the Igarka region
of the northwestern margin of the Siberian Platform
(Rozanov et al. 1969, but see Luchinina et al. 1997
and Rowland et al. 1998). In the latter two localities,
carbonates display δ13C oscillations with high positive
peaks characteristic of the lower Tommotian boundary
beds, although the position of these peaks with respect
to this boundary has been questioned (Kouchinsky et
al. 2001, 2005, 2007). The skeleton of archaeocyaths
is thought to have been originally mineralized
with high-magnesium calcite (Zhuravlev & Wood,
2008). The radiocyaths and cribricyaths are thought
to be different groups of aspicular sponges with,
respectively, aragonitic and high-magnesium calcitic
biomineralization (Zhuravlev & Wood, 2008). The
radiocyaths first appear in the upper Tommotian of
the Siberian Platform (Rozanov & Zhuravlev, 1992),
whereas the oldest cribricyaths are known from
the Altai-Sayan Folded Area in the first half of the
Atdabanian Stage (Rozanov & Zhuravlev, 1992).
3.b. Cnidariomorphs and problematic tubular forms
Fossils that can be reasonably interpreted as
diploblastic-grade metazoans with biomineralized
skeletons are represented by a few but locally abundant
forms in the upper Ediacaran strata (Grant, 1990;
Grotzinger, Watters & Knoll, 2000; Grotzinger, Adams
& Schröder, 2005; Wood, Grotzinger & Dixon,
2002; Amthor et al. 2003; online Appendix 1 at
http://journals.cambridge.org/geo). There is also a
variety of mineralized solitary and modular calcareous
corallomorphs in the lower Cambrian (Debrenne,
Lafuste & Zhuravlev, 1990). For convenience, all
of these fossils are herein collectively termed cnid-
ariomorphs, including such accretionarily growing
mineralized solitary tube-like forms as anabaritids
and protoconulariids. Hyolithelminths and ‘coleolids’
have a more uncertain biological affinity, and their
interpretation as bilaterian organisms (such as annelids)
cannot be excluded.
3.b.1. Ediacaran calcified cnidariomorphs
The earliest biomineralizing cnidariomorph fossils
are represented by such solitary calcareous (probably
aragonitic or high-magnesium calcite) tubular forms as
Cloudina and Namacalathus (ECC in online Appendix
2 at http://journals.cambridge.org/geo and Fig. 2).
Their lowermost occurrence is documented from the
Nama Group in Namibia (Germs, 1972; Grant, 1990)
and coincides with a pronounced positive carbon
excursion reaching 8 ‰and dated 548.8 ±1Ma
(Grotzinger et al. 1995; Grotzinger, Watters & Knoll,
2000; Condon et al. 2005; Grotzinger, Adams &
Schröder, 2005; Zhuravlev et al. 2011). Namapoikia
rietoogensis Wood, Grotzinger & Dixon, 2002 (a
calcareous, probably aragonitic, modular form with
a robust biomineralized but aspicular skeleton) is of

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
10 A. KOUCHINSKY & OTHERS
uncertain affinity to sponges or cnidarians and occurs
in the Nama Group of Namibia (Wood, Grotzinger &
Dixon, 2002) in the uppermost Ediacaran beds of the
same estimated age.
3.b.2. Corallomorphs
The earliest solitary calcareous corallomorph, Cysti-
cyathus tunicatus Zhuravleva, 1955, appears in the
lower Dokidocyathus regularis Zone of the Tommotian
Stage of the Siberian Platform, whereas the oldest
modular corallomorphs are the khasaktiids Vittia
Sayutina and Khasaktia Sayutina (Sayutina, 1980) from
the upper Tommotian of Siberia (Rozanov & Zhuravlev,
1992; Kruse, Zhuravlev & James, 1995; online
Appendices 1, 2 at http://journals.cambridge.org/geo).
Khasaktiids are reconstructed as originally high-
magnesium calcitic (Zhuravlev & Wood, 2008). The
oldest known korovinellid- or khasaktiid-like struc-
tures described from the uppermost Krol Formation
(near the Precambrian–Cambrian boundary) of In-
dia (Flügel & Singh, 2003; online Appendix 1 at
http://journals.cambridge.org/geo) were interpreted as
sponges/stromatoporoids (Flügel & Singh, 2003), but
their microbial origin was also suggested (Debrenne,
Gangloff & Zhuravlev, 1990).
3.b.3. Anabaritids
Anabaritids are a problematic early Cambrian group
with originally calcareous, probably aragonitic, skelet-
ons that typically had triradiate symmetry (Kouchinsky
et al. 2009). Anabaritids mark the basal Cambrian strata
in Siberia, Mongolia, Kazakhstan, China, India, Iran
and Laurentia, but may also occur in the uppermost
Ediacaran of Siberia (Karlova & Vodanyuk, 1985;
Karlova, 1987; Knoll et al. 1995) and Western Mon-
golia (Brasier et al. 1996; Esakova & Zhegallo, 1996;
Khomentovsky & Gibsher, 1996; online Appendices 1,
2 at http://journals.cambridge.org/geo; Fig. 2).
3.b.4. Protoconulariids
Protoconulariids have a disputed affinity with Palaeo-
zoic conulariids, a group most convincingly placed
within the Cnidaria (Van Iten, Zhu & Li, 2010).
Calcium phosphatic protoconulariids first appear in the
upper Anabarites trisulcatus–Protohertzina anabarica
Assemblage Zone of the lower Meishucunian Stage of
China. They are represented by Arthrochites emeishan-
ensis Chen, 1982, Hexangulaconularia formosa He in
Xing et al. 1984 and probably related forms, such
as Carinachites spp. and Emeiconularia trigemme
Qian et al. 1997 (Brasier, 1989a; Qian, 1989, 1999;
Qian & Bengtson, 1989; Conway Morris & Chen,
1992; Qian, Li & Zhu, 2001; Zhu et al. 2001; Qian
et al. 2002; Steiner et al. 2004a). Hexangulaconu-
laria formosa is also known from the Anabarites
trisulcatus–Protohertzina anabarica Assemblage Zone
of the Lesser Himalayas (Brasier & Singh, 1987;
Hughes et al. 2005). A probably coeval occurrence
of Carinachites sp. is described from the upper Ingta
Formation in northwestern Canada (Laurentia), also
assigned to the Anabarites trisulcatus–Protohertzina
anabarica Zone (Pyle et al. 2006; online Appendices
1, 2 at http://journals.cambridge.org/geo; Fig. 2).
3.b.5. Hyolithelminths
Hyolithelminths have calcium phosphatic tubes that are
circular (Hyolithellus Billings, 1871) or oval (Torellella
Holm, 1893) in cross-section. They are similar to
Sphenotallus Hall, 1847 and Byronia Matthew, 1899
also known from the Cambrian Series 2 and may be
cnidarians as well, but do not show budding typical of
the Cnidaria (Neal & Hannibal, 2000; Van Iten, Zhu &
Collins, 2002; Van Iten et al. 2005; Peng et al. 2005).
Hyolithelminths are alternatively compared to annelid
tubes (Fisher, 1962; Sokolov & Zhuravleva, 1983; Kiel
& Dando, 2009; Johnston et al. 2009; Skovsted &
Peel, 2011). Hyolithelminths are well known from the
lower Tommotian Stage of Siberia (Rozanov et al.
1969; Sokolov & Zhuravleva, 1983). Their first
representatives are reported, but not illustrated, from the
upper Purella Zone of the Nemakit–Daldynian Stage
(Khomentovsky et al. 1983; Khomentovsky, Val’kov
& Karlova, 1990; Khomentovsky & Karlova, 1993;
Varlamov et al. 2008). Probably the earliest hyol-
ithelminths are represented by Hyolithellus spp. from
the Anabarites trisulcatus–Protohertzina anabarica
Assemblage Zone of South China (Brasier, 1989a; Qian
& Bengtson, 1989; Qian, 1999; Qian et al. 2002), Ingta
Formation of Laurentia (Pyle et al. 2006) and Lower
Tal Formation of India (Brasier & Singh, 1987; online
Appendices 1, 2 at http://journals.cambridge.org/geo;
Fig. 2).
3.b.6. Problematic tubular forms
Other widespread tubular problematics are repres-
ented by calcareous, probably aragonitic forms Co-
leolella Missarzhevsky in Rozanov et al. 1969,
Coleoloides Walcott, 1889 and, possibly, Coleolus
Hall, 1876 (to which ‘Coleolus’trigonus Sysoev,
1962 is attributed; see online Appendix 1 at
http://journals.cambridge.org/geo; Fig. 2). Coleoloides
trigeminatus,Coleolella billingsi (Sysoev, 1962) and
‘Coleolus’trigonus Sysoev, 1962 are reported from the
lowermost Tommotian N. sunnaginicus Zone (Sokolov
& Zhuravleva, 1983) of Siberia. They also occur in
probably older beds, where carbonates display high
positive δ13C peaks, whose position with respect to
the lower Tommotian boundary has been questioned
(Kouchinsky et al. 2005, 2007). C.typicalis is known
from the Tiksitheca licis Zone of Western Mongolia
and Watsonella crosbyi Zone of Avalonia (Landing
et al. 1989). Coleoloides is also reported from the
Anabarites trisulcatus–Protohertzina anabarica Zone
of India (Brasier & Singh, 1987), but the material
requires further revision.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 11
3.c. Protoconodonts
The protoconodonts are a group of phosphatic simple-
cone-shaped sclerites with a deep cavity, lamellar and
often longitudinally fibrous wall, and with accretionary
growth on the inner side and basal margin (Bengtson,
1976, 1977, 1983). Protoconodonts are microstructur-
ally different from para- and euconodonts (see Section
3.q); finds of animals with grouped protoconodonts in
the Chengjiang fossil lagerstätte (Chen & Huang, 2002;
Vannier et al. 2007) and partially articulated protocon-
odont apparatuses of lower Meishucunian species Mon-
golodus longispinus (Vannier et al. 2007) demonstrate
their affinity with chaetognathans (Szaniawski, 1982,
2002; Hamdi, Brasier & Jiang, 1989; Azmi, 1996;
McIlroy & Szaniawski, 2000; Doguzhaeva, Mapes
& Mutve, 2002; Azmi & Paul, 2004; Qian et al.
2004; Pyle et al. 2006; Vannier et al. 2007; see
also Remarks in section ‘Protoconodonts’ in online
Appendix 1 at http://journals.cambridge.org/geo). The
primary nature of phosphatization in protoconodonts
has been questioned, however, because microstructures
rather suggest that in analogy with grasping hooks
of modern chaetognaths the protoconodonts had an
organic composition, i.e. of hardened chitin (Steiner
& Li, 2010).
Among these fossils, Protohertzina anabarica and P.
unguliformis (probably morphotypes within the same
species collectively referred to as the Protohertzina
anabarica group, e.g. by Brasier, 1989b) represent the
earliest skeletal remains attributed to protoconodonts
and, probably, bilaterian animals in general (Qian &
Bengtson, 1989). The first protoconodonts of the P.
anabarica group appear in the Anabarites trisulcatus
Zone of the Nemakit–Daldynian Stage on the Siberian
Platform and in roughly contemporaneous beds
in South China, India, Iran, Laurentia and probably
Western Mongolia and Kazakhstan (online Appendices
1 & 2 at http://journals.cambridge.org/geo; Fig. 2).
With the resolution of stratigraphic correlation
available, it is not possible to warrant, however, their
earlier appearance than the first calcareous sclerites
and shells (see next Section).
3.d. Molluscs, hyoliths, halwaxiids and chancelloriids
Coiled, conical or cyrtoconic shells occur frequently
in lower Cambrian faunas worldwide. These fossils
resemble shells of undisputed molluscs in overall
form and shell microstructure. It is largely accepted,
therefore, that they are the earliest representatives of the
Phylum Mollusca, falling more likely within its stem
group (e.g. Peel, 1991; Budd, 2001). Univalved shells
with solid walls (not composed of sclerites) presumably
represent complete and adult external skeletons (but
see Martí Mus, Palacios & Jensen, 2008) and are con-
sidered herein to be molluscs. Some other problematic
shells or plates, probably parts of multiplated chiton-
like exoskeletons, may also belong to this group or to
the Halwaxiida (see Section 3.k; online Appendices 1
& 2 at http://journals.cambridge.org/geo).
The complete exoskeleton of hyoliths consists of a
conical shell (conch), apertural lid (operculum) and
may include a pair of curved retractable appendages
(helens) protruding between the conch and operculum.
These fossils are usually classified either within the
Phylum Mollusca or Annelida, or in a separate phylum-
level group (e.g. Runnegar et al. 1975; Runnegar, 1980;
Kouchinsky, 2000).
The Halwaxiida Conway Morris & Caron, 2007 is
an apparently monophyletic group that includes biom-
ineralizing calcareous scale-bearing siphogonuchitids
and halkieriids. Their compound scleritomes (=full
set of sclerites of one individual, after Bengtson, 1985)
could also contain conical shells (Bengtson, 1992a).
Determining whether specific early Cambrian mollusc-
like shells represent the complete skeleton or only a
part of the scleritome is not always straightforward (see
Section 3.k and ‘Other fossils’ in online Appendix 1
at http://journals.cambridge.org/geo). Representatives
of the Halwaxiida have been united with sedentary
Chancelloriida in the problematic Coeloscleritophora,
whose members share possession of hollow calcareous
sclerites secreted at a fixed size by internal soft tissue
and a similar skeletal microstructure (Bengtson &
Missarzhevsky, 1981; Bengtson & Conway Morris
1992; Conway Morris & Peel, 1995; Bengtson, 2005;
Porter, 2008). Halwaxiids can be considered to be
stem-group lophotrochozoans, while the general body
morphology and affinity of chancelloriids is more
problematic (Bengtson & Hou, 2001; Janussen, Steiner
& Zhu, 2002; Randell et al. 2005; Bengtson, 2005;
Sperling, Pisani & Peterson, 2007; Porter, 2008).
These four groups (molluscs, hyoliths, halwaxiids
and chancelloriids) appeared in the geological record
at about the same time. Their evolutionary radiation in
the earliest Cambrian was an important early step for
metazoans, which gave rise to numerous forms typical
of the lower Cambrian strata worldwide and dominated
most of the pre-trilobitic bilaterian fossil assemblages.
With the current fidelity of stratigraphic correlation
available it is not yet possible to further resolve the
relative order of first appearances of molluscs, hyoliths
and coeloscleritophorans (Fig. 2).
The oldest such fossils occur at the same level in
the upper Anabarites trisulcatus–lower Purella zones
of the Nemakit–Daldynian Stage of the southeastern
Siberian Platform (Khomentovsky, Val’kov & Karlova,
1990) correlated with the lowermost part of the rising
trend in the lower Cambrian δ13C values, around feature
Z of the Siberian δ13C reference scale (Brasier, Kho-
mentovsky & Corfield, 1993; Fig. 4). The fossils are
represented by mollusc-like shells, such as cyrtoconic
planispiral Oelandiella Vostokova, 1962 and sinistrally
coiled Barskovia Golubev, 1976, conchs of hyoliths,
siphogonuchitid sclerites and scaly shells of Purella
Missarzhevsky, 1974. The earliest hyoliths are also de-
scribed from the probably time-equivalent basal Purella
Zone of Western Mongolia (Khomentovsky & Gibsher,
1996), SSF1 of South China (Qian & Bengtson, 1989;
Steiner et al. 2004a) and India (Brasier & Singh,

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
12 A. KOUCHINSKY & OTHERS
1987; Hughes et al. 2005). Siphogonuchitid sclerites
and shells of Maikhanella Zhegallo in Voronin et al.
1982 are also reported from SSF1 beds of South China
(Qian & Bengtson, 1989; Steiner et al. 2004a), whereas
Purella defines the base of the Purella Zone in Western
Mongolia (Khomentovsky & Gibsher, 1996; Fig. 5).
The earliest confirmed appearance of Chancelloria
is represented by articulated sclerites from the Purella
Zone of the Nemakit–Daldynian Stage of Siberia
(Khomentovsky, Val’kov & Karlova, 1990) and correl-
ated with a trough between Siberian isotopic features
Z and I (Brasier, Khomentovsky & Corfield, 1993;
Fig. 4). Identification of fossils reported as single rays
of Chancelloria sp. from the Anabarites trisulcatus and
basal Purella zones of the Nemakit–Daldynian Stage
of the southeastern Siberian Platform (Khomentovsky,
Val’kov & Karlova, 1990; Khomentovsky & Karlova,
2005; Brasier, Khomentovsky & Corfield, 1993) is
questionable (Zhuravlev et al. 2011). Likewise, the
occurrence of Chancelloriidae in SSF1 of South
China (Qian & Bengtson, 1989) has not been con-
firmed (M. Steiner, unpub. obs.; Online Appendix
1 at http://journals.cambridge.org/geo). Single-rayed
sclerites of Cambrothyra are known, however, from
SSF1. This organism is treated as closely related to,
but outside the Chancelloridae sensu stricto (Steiner
et al. 2004a, fig. 2; Moore etal. 2010).
3.e. Cambroclavids and paracarinachitids
Cambroclaves are originally calcareous (probably
aragonitic) sclerites without concentrically arranged
growth increments and consist of a basal hollow
shield usually bearing a spine (Qian, 1978; Mambetov
& Repina, 1979; Bengtson et al. 1990; Conway
Morris & Chen, 1991; Conway Morris et al. 1997;
Elicki & Wotte, 2003). Paracarinachitids are probably
related forms, but were formed by overlapping growth
increments (Qian & Bengtson, 1989). These fossils
are regarded as protective sclerites of bilaterally
symmetrical animals without reliable systematic po-
sition (Bengtson et al. 1990). They were alternat-
ively interpreted as receptaculitids (algae or sponges)
(Dzik, 1994), protoconodonts (Mambetov & Repina,
1979), acanthocephalans (Qian & Yin, 1984) or such
ecdysozoan groups as priapulids (Conway Morris et al.
1997) and lobopodians (Qian, 1999; Liu et al. 2007).
A fragment of an articulated body covered with
cambroclavid-type sclerites was reported from the
Sirius Passet fauna and has been tentatively assigned
to the Ecdysozoa (Conway Morris & Peel, 2010). The
fibrous ultrastructure of the wall in cambroclavids and
paracarinachitids (Qian & Bengtson, 1989; Conway
Morris & Chen, 1991), typical of the other calcareous
fossils discussed above, such as molluscs, hyoliths, hal-
waxiids and chancelloriids, are nevertheless compatible
with a lophotrochozoan affinity.
The first sclerites of cambroclavids (Zhijinites
Qian, 1978) and paracarinachitids (Paracarinachites
Qian & Jiang in Luo et al. 1982) are known from
the Yangtze Platform, Paragloborilus subglobosus–
Purella squamulosa Assemblage Zone (SSF2) of the
middle Meishucunian Stage, marked by a rising trend
in the carbon isotope record below a prominent positive
peak ZHUCE (Qian, 1999; Qian et al. 2002; Qian &
Bengtson, 1989; Bengtson, 1992b; Steiner et al. 2007;
online Appendices 1 & 2 at http://journals.cambridge.
org/geo; Fig. 2).
3.f. Tommotiids
Tommotiids are represented by calcium phosphate
sclerites with evidence of basal marginal accretionary
growth. These fossils have been interpreted as sclerites
of larger scleritomes of problematic animals (Bengtson,
1970, 2004; Holmer et al. 2008; Skovsted et al. 2008,
2009b). The taxonomy of tommotiids was discussed by
Landing (1984, 1995), Bengtson (1986), Laurie (1986),
Bengtson et al. (1990), Conway Morris & Chen (1990),
Esakova & Zhegallo (1996) and Skovsted et al. (2009a).
Based on the organophosphatic shell composition
and morphological similarities, tommotiids have been
regarded as closely related to brachiopods (Williams
& Holmer, 2002). Recent discoveries of articulated
tommotiids show distinct affinities to lophophorates,
including a sessile habit and brachiopod-like shells
within the scleritome (Skovsted et al. 2008, 2009b;
Holmer et al. 2008).
Classical tommotiids, such as Camenella Missar-
zhevsky in Rozanov & Missarzhevsky, 1966, occur in
the basal Tommotian Stage deposits of the southeastern
Siberian Platform (Rozanov et al. 1969). Without
description or illustration, they are also reported
from apparently older beds of the northern Siberian
Platform (Fedorov & Shishkin, 1984; Khomentovsky
& Karlova, 1993; Luchinina et al. 1997; Meshkova
et al. 1976; Rozanov et al. 1969). These beds contain
pre-Tommotian prominent positive carbon isotopic
peaks (Kouchinsky et al. 2001, 2007; Fig. 4; online Ap-
pendices 1 & 2 at http://journals.cambridge.org/geo).
Probably the earliest appearance of Camenella is that
reported from Western Mongolian beds at the begin-
ning of the rising trend towards positive peak D (Brasier
et al. 1996, fig. 9; Fig. 5), which may correspond to the
rising trend towards Siberian peaks I or I(Fig. 4).
Porcauricula hypsilippis (Jiang, 1980) is known
from lower SSF2 beds (Qian & Bengtson, 1989), in the
rising trend towards a prominent positive peak ZHUCE
in China (Brasier et al. 1990; Li et al. 2009). Lap-
worthella ludvigseni Landing, 1984 and Eccentrotheca
kanesia Landing, Nowlan & Fletcher, 1980 occur in the
lower Watsonella crosbyi Zone of SE Newfoundland
(Landing et al. 1989). Hence, the first tommotiids
reported from Western Mongolia, South China and
Avalonia are probably older than those from the base of
the Tommotian Stage in its stratotype in the southeast-
ern part of the Siberian Platform (online Appendices 1
& 2 at http://journals.cambridge.org/geo; Fig. 2).
3.g. Tianzhushanellids
Tianzhushanellids are bivalved and probably origin-
ally aragonitic shelly fossils assigned to the Family

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 13
Tianzhushanellidae Conway Morris in Bengtson
et al. 1990 with uncertain higher-rank taxonomy
(see ‘Other fossils’ in Online Appendix 1 at
http://journals.cambridge.org/geo). They were referred
to molluscs (Parkhaev, 1998), but have more recently
been regarded as the best candidates for calcitic-
shelled stem-group brachiopods (Balthasar, 2008; Li,
2009). New articulated material of Apistoconcha from
strata correlative with the Cambrian Stage 3 in
Australia seems to support its stem-group brachiopod
position (Skovsted et al. 2010). The earliest undoubted
representatives of the group are known from the SSF3
of China (Qian, 1999; Li & Chen, 1992; Steiner et
al. 2007) and occur at near the peak of the positive
carbon isotope excursion ZHUCE in Sichuan (Brasier
et al. 1990, fig. 6; online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Fig. 2).
3.h. Brachiopods
The earliest reported brachiopod species with a calcium
phosphate (organophosphatic) shell is the paterinid
Aldanotreta sunnaginensis Pel’man, 1977. It first
appears on the Siberian Platform in the N. sunnaginicus
Zone of the Tommotian Stage (Bengtson et al.
1987; Ushatinskaya & Malakhovskaya, 2001; online
Appendices 1 & 2 at http://journals.cambridge.org/geo;
Figs 2, 4). The earliest Siberian brachiopod with a
calcareous shell is Nochoroiella isitica Pel’man in
Grigor’eva, Melnikova & Pel’man, 1983 (assigned
to obolellids, although its affinity with brachiopods
was questioned: see online Appendices 1 & 2 at
http://journals.cambridge.org/geo) and Obolella sp.
from the D. lenaicus Zone of the Tommotian Stage
(Figs 2, 4). Chemostratigraphic correlation with Siberia
(cf. Brasier et al. 1996) suggests that these occurrences
are likely pre-dated by Khasagtina primaria Ushatin-
skaya, 1987 from Western Mongolia. The latter fossil
is originally assigned to kutorginids, but its affinity to
brachiopods needs revision (online Appendices 1 & 2
at http://journals.cambridge.org/geo; Figs 2, 5).
3.i. Stenothecoids
Stenothecoids, a group of probably low-magnesium
calcite (Zhuravlev & Wood, 2008) enigmatic bivalved
organisms with serial paired imprints sometimes
present, occur in Cambrian Series 1–3 (Aksarina,
1968; Yochelson, 1969; Runnegar & Pojeta, 1974;
Rozov, 1984; Pel’man, 1985; online Appendices 1
& 2 at http://journals.cambridge.org/geo). In Siberia,
the first reliable stenothecoids appear in the late
Tommotian Stage of the Altai-Sayan Folded Area
(Pel’man et al. 1992; Rozanov & Zhuravlev, 1992),
but the earliest stenothecoids overall (Stenothecoides
sp. and S. yochelsoni) are reported respectively from
Western Mongolia (Voronin et al. 1982; Khomentovsky
& Gibsher, 1996, fig. 13; Fig. 5; online Appendices 1
& 2 at http://journals.cambridge.org/geo) and the SSF3
Zone of South China (Yu, 1996; online Appendices 1 &
2 at http://journals.cambridge.org/geo). Voronin et al.
(1982) defined the Stenothecoides Zone in Western
Mongolia at a level correlated chemostratigraphically
(cf. Brasier et al. 1996; Fig. 5) with prominent positive
peaks of the uppermost Nemakit–Daldynian Stage of
the Siberian Platform. Consequently, like brachiopods,
the first stenothecoids are reported from Cambrian
Stage 2, probably below the lower Tommotian bound-
ary (Fig. 2).
3.j. Mobergellids
Mobergellids are low conical or disc-shaped cal-
cium phosphate problematic fossils with evidence of
accretionary growth and paired radiating (possibly,
muscular) imprints on the interior side (Bengtson,
1968; Conway Morris & Chapman, 1997; Skovsted,
2003; Dzik, 2010). The first occurrence of Mobergella
sibirica Skovsted, 2003 (formerly Mobergella ra-
diolata Bengtson, 1968) in Siberia is known from the
lower Dokidocyathus lenaicus–Tumuliolynthus primi-
genius Zone of the Tommotian Stage (Rozanov et al.
1969; Sokolov & Zhuravleva, 1983; Rozanov &
Sokolov, 1984; Missarzhevsky, 1989; Rozanov &
Zhuravlev, 1992; online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Fig. 4). Mobergella
sp. is also reported from the upper D. regu-
laris Zone of the Tommotian Stage (Repina et al.
1974), but was not illustrated. Fossils described
as Mobergella, but without characteristic radiating
imprints, are known from the middle Meishucunian
Stage of China (Li et al. 2007; online Appendix 1
at http://journals.cambridge.org/geo), although no def-
inite record of mobergellids exists from China (Qian &
Bengtson, 1989; Streng & Skovsted, 2006). The most
reliable first appearance of the group is thus in the lower
D. lenaicus Zone of the Tommotian Stage (upper part of
the Cambrian Stage 2), within the carbon isotope trough
between peaks III and IV of the Siberian reference scale
(Brasier et al. 1994a,b; online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Figs 2, 4).
3.k. Other problematic shells and sclerites
Besides shells assigned herein to molluscs, hyoliths,
halwaxiids, brachiopods, mobergellids, stenothecoids
and tianzhushanellids, there are shells or plates
of a calcareous or unknown original composition,
often with evidence of accretionary growth. Some
of these may represent parts of scleritomes similar
to those of halkieriids or chitons (Conway Morris,
McIlroy & Rushton, 1998; Vendrasco et al. 2009; see
‘Molluscs’ and ‘Other fossils’ in online Appendix 1 at
http://journals.cambridge.org/geo). A number of such
problematic shells are reported from China, where
they are found in beds of the middle Meishucunian
Stage (Bengtson, 1992b;Liet al. 2007). Most of
them are treated as problematic molluscs by Bengtson
(1992b) and Li et al. (2007), but some forms among

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
14 A. KOUCHINSKY & OTHERS
them are alternatively regarded as ‘brachiopod-like’ or
‘problematic brachiopods’ by Qian, Li & Zhu (2001).
An array of problematic sclerites from Cambrian
Series 1–2 is known from Siberia and elsewhere,
and some of the sclerites can be assigned to larger
groups discussed herein, such as protoconodonts, chan-
celloriids, halwaxiids, tommotiids and cambroclavids
or to ecdysozoan cuticular sclerites and fragments
of carapaces, but the others are more problematic
(see Bengtson, 1992b; Qian et al. 2004; Li et al.
2007; see ‘Other fossils’ in online Appendix 1 at
http://journals.cambridge.org/geo).
3.l. Trilobites
The Class Trilobita are advanced arthropods (Phylum
Arthropoda) with calcareous (low-magnesium cal-
cite) carapaces (Wilmot & Fallick, 1989). The first
occurrences of trilobites in the world (highlighted
by thick horizontal lines within Stage 3 interval
in Fig. 3) post-date or are estimated to be no
earlier than those on the Siberian Platform, where
their first undoubted appearance is just above the
base of the Atdabanian Stage (Lieberman, 2002;
Hollingsworth, 2005, 2007, 2008; online Appendices
1 & 2 at http://journals.cambridge.org/geo; Fig. 2).
The earliest trilobites (Family Archaeaspididae, Order
Redlichiida) are represented by Profallotaspis Repina
in Khomentovsky & Repina, 1965 from Siberia and
Fritzaspis Hollingsworth, 2007 from Laurentia.
3.m. Bradoriids
Bradoriids known from Cambrian to lower Ordovician
rocks worldwide have originally weakly or second-
arily mineralized (phosphatized) carapaces (Jones &
McKenzie, 1980; Landing, 1980; Butterfield, 2003;
Zhang, 2007; Zhang, Dong & Maas, 2011). These
arthropods are represented by the Order Bradoriida
Raymond, 1935 (Bradoriida sensu stricto) and Phos-
phatocopida Müller, 1964 (Hou et al. 2002; Maas
& Waloszek, 2005; Williams et al. 2007; Zhang,
2007). The former are regarded at present as stem-
group crustaceans, whereas the latter are considered
by some to be crown-group crustaceans (Hou et al.
1996, 2010; Shu et al. 1999). Although other stem-
group crustaceans represented by non-mineralizing
Isoxys zhurensis Ivantsov, 1990 are known as early
as the middle Profallotaspis jakutensis Zone of
the Atdabanian Stage on the southeastern Siberian
Platform (Ivantsov, 1990), the first bradoriid Cambria
Neckaja & Ivanova, 1956 is reported in Siberia from the
middle Atdabanian Delgadella anabara Zone (online
Appendices 1 & 2 at http://journals.cambridge.org/geo;
Figs 2, 4). Coeval first occurrences of bradoriids are
also known from South China (Hou et al. 2002),
Gondwana (Hinz-Schallreuter, Gozalo & Liñán, 2008;
Topper et al. 2011), Avalonia (Brasier, 1989c) and
Baltica (Streng, Ebbestad & Moczydłowska, 2008).
3.n. Lobopodians
Lobopodians have been considered a Cambrian stem
group of the Panarthropoda, including such phyla
as Onychophora, Tardigrada and Arthropoda (see
Budd, 1997; Liu et al. 2007; Edgecombe, 2009).
These animals were similar to modern onychophorans
and are often regarded as members of the Phylum
Lobopodia Snodgrass, 1938 (Hou & Bergström, 1995)
or Tardipolypoda Chen & Zhou, 1997. Exceptionally
preserved in the Chengjiang fossil lagerstätte, they are
elongate animals with paired limbs and sclerites (trunk
plates) situated along each side of the body (Chen,
Hou & Lu, 1989; Chen, Zhou & Ramsköld, 1995;
Ramsköld & Hou, 1991; Bergström & Hou, 2001;
Hou et al. 2004). The sclerites are thought to be of
an original calcium phosphatic composition, although
their biomineralization has been doubted by Steiner
et al. (2007).
The first sclerites of Microdictyon sp. in Siberia
are reported herein from the Emyaksin Formation of
the Bol’shaya Kuonamka River, from beds correlated
by carbon isotope chemostratigraphy with the upper
Delgadella anabara Zone of the Atdabanian Stage
(Kouchinsky et al., unpub. data; online Appendices
1 & 2 at http://journals.cambridge.org/geo; Fig. 2).
This occurrence is somewhat older than the previ-
ously reported occurrence from the upper Atdabanian
Fansycyathus lermontovae Zone of Lena River
(Varlamov et al. 2008). It is correlated chemostrati-
graphically (Dillard et al. 2007; online Appendices
1 & 2 at http://journals.cambridge.org/geo) with the
regional first occurrence of Microdictyon sp. and
Microdictyon cf. rhomboidale Bengtson, Matthews &
Missarzhevsky, 1986 in the lower Nevadella Zone
of Laurentia (Bengtson, Matthews & Missarzhevsky,
1986; Voronova et al. 1987; Fig. 3) and, probably, with
the first occurrence of M. sphaeroides Hinz, 1987 in the
Camenella baltica Zone of Avalonia (Hinz, 1987) and
Microdictyon depressum Bengtson in Bengtson et al.
1990 in the Abadiella huoi Zone of Australia. The first
soft-bodied lobopodians with remains of sclerites are
already diverse and well known from the Chengjiang
fossil lagerstätte, which is time-equivalent with the
upper Atdabanian Stage of Siberia.
3.o. Palaeoscolecids
The Class Palaeoscolecida Conway Morris & Robison,
1986 is known from the Cambrian Series 2 to the
Upper Silurian. These fossils are morphologically
similar to nematomorphs (Hou & Bergström, 1994)
and priapulids (Conway Morris, 1997). They are
broadly considered as a stem group of the Priapulida
(Harvey, Dong & Donoghue, 2010) or Cycloneuralia
(Budd, 2001; Conway Morris & Peel, 2010). Complete
preservation of their worm-like bodies is known, but
far more often they occur as disarticulated calcium
phosphate cuticular sclerites. The first palaeoscolecids,
represented by the biomineralized trunk sclerites

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 15
Hadimopanella apicata Wrona, 1982 are reported
herein from the middle Nochoroicyathus kokoulini
Zone (lower Judomia Zone) of northern Siberia
(Kouchinsky et al., unpub. data; online Appendices 1 &
2 at http://journals.cambridge.org/geo; Figs 2, 4). The
earliest soft-bodied preservation of palaeoscolecids
is known from the Sirius Passet fauna of Laurentia
(Greenland; Conway Morris & Peel, 2010; online
Appendices 1 & 2 at http://journals.cambridge.org/geo)
and the Chengjiang fossil lagerstätte of South China
(Hu, 2005), which are time-equivalent with the upper
Atdabanian of Siberia.
3.p. Echinoderms
The earliest fossils of the phylum Echinodermata
are disarticulated and presumably originally high-
magnesium calcite plates (Dickson, 2002, 2004).
Some of these plates derive from brachiole-bearing
echinoderms and thus can be assigned to eocrinoids.
The ‘class’ Eocrinoidea Jaekel, 1918 is paraphyl-
etic and comprises stem-groups of other blastozoan
clades (e.g. Sprinkle, 1973). The earliest echino-
derm plates like these are reported herein from the
upper Delgadella anabara Zone of the Atdabanian
Stage from Siberia (Kouchinsky et al., unpub. data;
Zamora et al. in press; online Appendices 1 &
2 at http://journals.cambridge.org/geo; Figs 2, 4).
First echinoderm plates from the lower part of the
Nevadella Zone of Laurentia are chemostratigraphic-
ally correlated with the upper part of the Delgadella
anabara Zone of Siberia (Dillard et al. 2007; Fig. 3).
The earliest isolated echinoderm plates occur in lower
Ovetian beds of West Gondwana (Spain) broadly
correlated with the Delgadella anabara Zone of Siberia
and also appear contemporaneously in South China and
Australia (Zamora et al. in press).
3.q. Chordates (paraconodonts and agnathans)
Conodonts (including para- and euconodonts) are char-
acterized by calcium phosphatic dental structures with
dentin-like tissue (but see Kemp, 2002a,b). They are
regarded as the earliest known biomineralized chord-
ates (Donoghue, Forey & Aldridge, 2000; Donoghue,
Sansom & Downs, 2006). There is a microstructural
similarity between the two sub-groups as well as a his-
tological and morphological transition from paracon-
odonts to euconodonts, and therefore they are united as
conodonts (Szaniawski & Bengtson, 1993, 1998).
The oldest paraconodonts from Siberia are Wester-
gaardodina cf. tricuspidata Müller, 1959 and Furnish-
ina sp. from the Paibian Stage-equivalent Kutugunian
Horizon, which contains the upper Cambrian (Furong-
ian Series) SPICE carbon isotope excursion (online
Appendices 1 & 2 at http://journals.cambridge.org/geo;
Shabanov et al. 2008). Furnishina and Westergaar-
dodina are known, however, from the Drumian Stage
(within the Cambrian Series 3, or traditional Middle
Cambrian) in most other crustal units. The oldest
paraconodonts, represented by Furnishina sp. and
Westergaardodina sp., are reported respectively from
the Triplagnostus gibbus Zone of the uppermost part of
Cambrian Stage 5 (lower Series 3) in Sweden (Müller,
1959, 1971; Dong, 2004) and from Stage 5 deposits
of Alaska (Dutro et al. 1984), but the former is much
better preserved and constrained stratigraphically.
The earliest vertebrates with ossification in the
dermal skeleton, that contains dentin-like tissue (Smith,
Sansom & Repetski, 1996; Karatajute-Talimaa, 1997),
are similar to the Ordovician agnathans and represented
by disarticulated calcium phosphatic plates of Anato-
lepis sp. from the mid-Sunwaptan Stage of Laurentia
(Smith & Sansom, 1995; Smith, Sansom & Cochrane,
2001) corresponding to the upper part of the Cambrian
Stage 9 (Furongian Series).
4. Discussion
There is no unambiguous evidence of the existence of
bilaterian superphyla in the Precambrian (Budd, 2008;
Budd & Jensen, 2000, 2003), although some bilaterally
symmetrical forms from the late Ediacaran, younger
than 555 Ma, are interpreted as their representatives
(e.g. Fedonkin & Waggoner, 1997). On the other hand,
Ediacara-type fossils have repeatedly been reported
from the Early Palaeozoic (Conway Morris, 1993;
Jensen, Gehling & Droser, 1998; Samuelson, Van Roy
& Vecoli, 2001; Zhang & Babcock, 2001), but none of
those is comparable with typical Ediacaran vendobionts
in their structure, symmetry and growth pattern
(Antcliffe & Brasier, 2008; Zhuravlev et al. 2011).
The general succession of first appearances of biom-
ineralized skeletal parts during the Cambrian radiation
includes two main sets clustered geochronologically
by high-rank phylogeny and reflects two successive
phases of diversification of bilaterians (Fig. 2). Such a
pulsed diversification accompanied a general increase
in generic diversity of the biota towards the early
Botoman maximum preceding the Botoman–Toyonian
biotic crisis (Brasier et al. 1994a; Zhuravlev & Wood,
1996; Zhuravlev, 2001; Li et al. 2007).
The first phase recognized herein is marked by a
set of first appearances of biomineralization in the
Terreneuvian Epoch (c. 541–521 Ma), mainly within
the Fortunian Age. The latter embraces the first c.10 Ma
of the Cambrian Period (Fig. 2). During the Terren-
euvian Epoch such major skeletal groups as protocon-
odonts, halwaxiids, chancelloriids, hyoliths, molluscs,
tommotiids, brachiopods, tianzhushanellids, stenothec-
oids, cambroclavids–paracarinachitids and mobergel-
lids first appeared and diversified, as well as other forms
with problematic affinities to these groups (online
Appendices 1 & 2 at http://journals.cambridge.org/geo;
Fig. 2). All of them, except protoconodonts and
possibly chancelloriids, can be comfortably placed
within the total-group Lophotrochozoa. Among them,
such extant biomineralizing lophotrochozoan phyla
as Mollusca and Brachiopoda can be recognized.
Annelida does not have undisputed biomineralized

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
16 A. KOUCHINSKY & OTHERS
representatives during the Cambrian radiation (Conway
Morris & Peel, 2008), but such problematic groups
as hyolithelminths, hyoliths and halwaxiids may share
that affinity (see Section 3 and remarks in online
Appendix 1 at http://journals.cambridge.org/geo). By
contrast, Bryozoa certainly appear relatively late, in
the uppermost Cambrian, at the onset of the Ordovician
radiation (Landing, English & Keppie, 2010).
Protoconodonts were among the first bilaterians to
acquire hardened (probably mineralized calcium phos-
phatic) skeletal parts (presumably for active predation).
These have been interpreted as grasping spines of
the Chaetognatha, a protostomian phylum close to
the Lophotrochozoa, but most likely its sister-group
(Halanych, 2004; Dunn et al. 2008). They appeared
in the fossil record at about the same time as the
first calcareous sclerites of coeloscleritophorans, shells
of molluscs and hyoliths. The majority of bilaterian
skeletal fossils of the Terreneuvian Series belong to
these latter groups. Their first appearances occurred
in beds younger than the Precambrian–Cambrian
boundary and the carbon isotope negative anomaly
associated with this boundary (Narbonne, Kaufman &
Knoll, 1994; Brasier et al. 1996; Kimura et al. 1997; Li
et al. 2009), but not younger than those with Siberian
δ13C feature Z and attributed to the upper Anabarites
trisulcatus–lower Purella zones of the Nemakit–
Daldynian Stage (Brasier, Khomentovsky & Corfield,
1993; Brasier, et al. 1994a,b). These first appearances
can be correlated with the Anabarites trisulcatus–
Protohertzina anabarica (SSF1) Assemblage Zone of
the lower Meishucunian Stage of South China, where
all of them except shells of molluscs occur in beds
older than the tuffite with a combined depositional age
of 535.2 ±1.7 Ma (Zhu et al. 2009).
Calcium phosphatic sclerites of tommotiids, prob-
ably members of the stem group of organophosphatic
brachiopods, have a younger first appearance associ-
ated with the same rising trend, but still below highly
positive peaks of the lower part of the Cambrian
Stage 2. The first reported appearance of tommotiids
is older than the estimated c. 530 Ma base of the
Cambrian Stage 2 in Avalonia (Landing et al. 2007).
Such groups as cambroclavids–paracarinachitids, other
problematic shells with affinities close to molluscs
or halwaxiids, and some problematic sclerites also
appear during this interval (online Appendices 1 &
2 at http://journals.cambridge.org/geo; Fig. 2).
Brachiopods, apparently related to tommotiids, are
another major group of lophotrochozoan animals with
their first appearance in the Cambrian Stage 2. Together
with tianzhushanellids, which probably represent stem-
group calcareous brachiopods, and stenothecoids, their
first occurrences are registered from Stage 2 strata
older than or coeval with the Nemakit–Daldynian–
Tommotian boundary of c. 525 Ma (Maloof et al.
2010a,b). Mobergella,Rhombocorniculum and some
other problematic sclerites appeared during the upper
part of Cambrian Stage 2 (online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Fig. 2).
Biomineralization in ecdysozoans and deuterosto-
mians did not apparently occur during the first phase
of the early Cambrian bilaterian radiation, but these
events mark the second phase. Non-biomineralized
ecdysozoans, however, existed before, as evidenced
by: (1) fossilized embryos of Markuelia secunda
Val’kov from the basal Tommotian Stage in Siberia,
having already a sclerotized cuticle and representing
the Scalidophora, a sub-group of the Cycloneuralia
(Bengtson & Yue, 1997; Dong et al. 2004, 2005, 2010);
embryos and possibly related larvae of Pseudooides
prima from the lower Meishucunian Stage of South
China, considered as possible stem-group arthropods
(Steiner et al. 2004b) and (2) the arthropod-type trace
fossils in pre-trilobitic strata (Crimes, 1987; Weber &
Zhu, 2003; Weber, Steiner & Zhu, 2007).
The second phase of the early Cambrian bilaterian
radiation is thus marked by the first appearances
of biomineralization in the Superphylum Ecdysozoa
within Cambrian Stage 3, during <5 Ma (Fig. 2). The
earliest undoubted and widespread event in the second
phase is the appearance of calcification in carapaces
of trilobites at the base of Stage 3, succeeded by
the first appearances of calcium phosphate carapaces
of bradoriids (Phylum Arthropoda), sclerites of lobo-
podians (Phylum Tardipolypoda) and palaeoscolecids
(?Phylum Priapulida) in that order, in the early and
middle parts of Stage 3 (online Appendices 1 &
2 at http://journals.cambridge.org/geo; Fig. 2). The
diversity of ecdysozoans and their dominance in the
Burgess Shale-type fossil communities in upper Stage
3, by the conclusion of the Cambrian radiation, is
well documented in such fossil lagerstätten as the
Sirius Passet of north Greenland and the roughly time-
equivalent Chengjiang of South China (e.g. Conway
Morris & Peel, 2008, 2010).
The second phase also involves the Superphylum
Deuterostomia, Phylum Echinodermata. The earliest
biomineralizing representatives of echinoderms appear
in the middle of Stage 3. Among them eocrinoids,
members of the stem-group Echinodermata, can be
recognized. The origin of their high-magnesium calcite
stereom skeleton is the first documented skeletal
biomineralization event among deuterostomians. Tu-
nicates (Phylum Chordata) may have also existed at
that time (Chengjiang fauna, Chen et al. 2003, but
see Bergström, 2010), and some of them may have
produced biomineralized spicules (see Bengtson et al.
1990). Non-mineralizing representatives of the Phylum
Chordata were also present during the Cambrian
radiation: hagfish-like fossils from Chengjiang are
most likely the first vertebrates, but without traces of
biomineralization (Shu et al. 1999; Conway Morris,
2006; Bergström, 2010). The first appearances of cal-
cium phosphatic dental mineralization in problematic
chordates/conodonts (i.e. paraconodonts) in the upper
part of Cambrian Stage 5 (Donoghue, 2002; Donoghue
& Sansom, 2002; Kemp, 2002a,b; online Appendices
1 & 2 at http://journals.cambridge.org/geo) and dermal
biomineralization in agnathan-like chordates by the end

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 17
of the Cambrian (Cambrian Stage 9) (Smith & Sansom,
1995; Smith, Sansom & Cochrane, 2001; Young, 2009)
post-date both the Cambrian radiation and the first
fossils interpreted as chordates by c. 10 and 25 Ma,
respectively.
The fossil record of sponges and cnidarians sug-
gests that they acquired skeletal biomineralization
in the Precambrian (online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Fig. 2), but it was
not until diverse bilaterian groups become abundant
in the fossil record that radiation among skeletonized
non-bilaterians like these occurred. Although solitary
tubular forms with questionable affinities to cnidarians
are already diverse during the first phase of the
early Cambrian bilaterian radiation, biomineralized
remains of sponges and spongiomorphs are sporadic
until the Cambrian Stage 2, where corallomorphs also
entered the fossil record (online Appendices 1 & 2 at
http://journals.cambridge.org/geo; Fig. 2).
Distribution of calcium carbonate skeletal min-
eralogies from upper Ediacaran to lower Cambrian
(Fig. 2) are shown to reflect fluctuations in the
magnesium/calcium ratio in the ocean (Zhuravlev,
1993; Ushatinskaya & Zhuravlev, 1994; Porter, 2007;
Zhuravlev & Wood, 2008). First appearances of animal
groups with aragonite skeletons occur mainly during
the Fortunian Age. A few rare and speculative cases of
low-magnesium calcite (LMC) biomineralization have
been attributed to the Cambrian Stage 2, including
Khasagtina primaria (kutorginid brachiopod?) and
the earliest stenothecoids (Zhuravlev & Wood, 2008;
Fig. 2), but their mineralogy is only suggested from
the inferred composition of younger forms, and hence
alternative carbonate mineralogies cannot be excluded.
The second phase of the early Cambrian bilaterian
radiation occurred after one of the major perturbances
in the carbon cycle in the Phanerozoic Earth history,
marked with a c.10
‰negative shift in δ13C
record in the middle of Stage 2 (online Fig. S1
at http://journals.cambridge.org/geo). The upper part
of Stage 2, generally correlated herein with the
Tommotian Stage of Siberia, represents a transitional
interval with first appearances of high-magnesium
calcite (HMC) skeletons, a transition that probably
corresponds to decreasing Mg/Ca ratio of the ocean.
The second phase, marked by the first appearance of
trilobites (Fig. 2), is characterized by the onset of the
LMC biomineralization in trilobites and brachiopods
and a short-term switch to the calcite sea in the early
Atdabanian (Zhuravlev & Wood, 2008). Based on
distribution of inorganic precipitates and the relative
abundance of genera with aragonite and HMC v. LMC
skeletal mineralogies, the remaining part of the second
phase is characterized, however, as a reappearance of
the aragonite sea (Zhuravlev & Wood, 2008). Hence,
despite an increasing number of genera with LMC
skeletons during the second phase, the Cambrian
radiation interval was generally aragonite and HMC
favourable.
Acknowledgements. Artem Kouchinsky acknowledges
support from the NASA Astrobiology Institute and the
Swedish Research Council (Grant No. 621-2001-1751 to
Stefan Bengtson and Grant No. 623-2003-207 to Artem
Kouchinsky) at the initial stage of work in 2002–2005. Artem
Kouchinsky was also supported later from the NordCEE
(Nordic Centre for Earth Evolution) project (Danish National
Research Foundation (Danmarks Grundforskningsfond))
grant to Prof. Donald Canfield. Igor Korovnikov (Institute
of Oil-and-Gas Geology and Geophysics, Novosibirsk,
Russia) and John Malinky are acknowledged for useful
personal communication. We also thank Andrej Zhuravlev
(Universidad de Zaragoza, Spain) for invaluable information
and critical revision of this work. Ed Landing and Martin
Brasier provided detailed reviews of the manuscript.
References
AKSARINA, N. A. 1968. Probivalvia-novyy klass drevney-
shikh mollyuskov. [Probivalvia-a new class of ancient
molluscs.] In Novye dannye po geologii i poleznym
iskopaemym Zapadnoy Sibiri. [New data on geology
and natural resources of western Siberia.] (ed. G.
A. Selyatitskiy), pp. 77–86. Tomsk: Tomsk University
Press (in Russian).
ALLISON,C.W.&AWRAMIK, S. M. 1989. Organic-walled
microfossils from earliest Cambrian or latest Proterozoic
Tindir Group rocks, northwest Canada. Precambrian
Research 43, 253–94.
ÁLVA R O ,J.J.,AHLBERG,P.,BABCOCK,L.E.,BORDONARO,
O. L., CHOI,D.K.,COOPER,R.A.,ERGALIEV,G.
K., GAPP,I.W.,POUR,M.G.,HUGHES,N.C.,JAGO,
J. B., KOROVNIKOV,I.,LAURIE,J.R.,LIEBERMAN,
B. S., PATERSON,J.R.,PEGEL,T.V.,POPOV,L.
E., RUSHTON,A.W.A.,SUKHOV,S.S.,TORTELLO,
M. F., ZHOU,Z.& ˙
ZYLI ´
NSKA, A. In press. Global
Cambrian trilobite palaeobiogeography assessed using
parsimony analysis of endemicity. In Early Palaeozoic
Palaeography and Biogeography (eds D. Harper &
T. Servais). Geological Society of London, Special
Publication.
AMTHOR,J.E.,GROTZINGER,J.P.,SCHRÖDER,S.,BOWRING,
S. A., RAMEZANI,J.,MARTIN,M.W.&MATTER,A.
2003. Extinction of Cloudina and Namacalathus at the
Precambrian–Cambrian boundary in Oman. Geology
31, 431–4.
ANTCLIFFE,J.B.&BRASIER, M. D. 2008. Charnia
at 50: developmental models for Ediacaran fronds.
Palaeontology 51, 11–26.
ASTASHKIN,V.A.,PEGEL’, T. V., REPINA,L.N.,BELYAEVA,
G. A., ESAKOVA,N.V.,ROZANOV,A.YU., ZHURAVLEV,
A. YU., OSADCHAYA,D.V.&PAKHOMOV, N. N. 1995.
The Cambrian System of the Foldbelts of Russia and
Mongolia. International Union of Geological Sciences
publication no. 32, 132 pp.
AZMI, R. J. 1996. Evidence for soft tissue basal support in
earliest Cambrian protoconodonts from the Lesser Him-
alaya: conodont function and affinity. In Contributions
to the XV Indian Colloqium on Micropaleontology and
Stratigraphy (eds J. Pandey, R. J. Azmi, A. Bhandari &
A. Dave), pp. 457–61. Dehra Dun.
AZMI,R.J.&PAUL, S. K. 2004. Discovery of Precambrian–
Cambrian boundary protoconodonts from the Gango-
lihat Dolomite of Inner Kumaun Lesser Himalaya:
implication on age and correlation. Current Science 86,
1653–60.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
18 A. KOUCHINSKY & OTHERS
BABCOCK,L.E.&PENG, S. 2007. Cambrian chronostrati-
graphy: current state and future plans. Palaeogeography,
Palaeoclimatology, Palaeoecology 254, 62–6.
BABCOCK,L.E.,PENG,S.C.,GEYER,G.&SHERGOLD,J.H.
2005. Changing perspectives on Cambrian chronostrati-
graphy and progress toward subdivision of the Cambrian
System. Geoscience Journal 9, 101–6.
BALTHASAR, U. 2008. Mummpikia gen. nov. and the origin of
calcitic-shelled brachiopods. Palaeontology 51, 263–79.
BENGTSON, S. 1968. The problematic genus Mobergella from
the Lower Cambrian of the Baltic area. Lethaia 1, 325–
51.
BENGTSON, S. 1970. The Lower Cambrian fossil Tommotia.
Lethaia 3, 363–92.
BENGTSON, S. 1976. The structure of some Middle Cambrian
conodonts, and the early evolution of conodont structure
and function. Lethaia 9, 185–206.
BENGTSON, S. 1977. Aspects of problematic fossils in
the early Palaeozoic. Acta Universitatis Upsaliensis.
Abstracts of Uppsala Dissertations from the Faculty of
Science 415, 1–71.
BENGTSON, S. 1983. The early history of the Conodonta.
Fossils and Strata 15, 5–19.
BENGTSON, S. 1985 Taxonomy of disarticulated fossils.
Journal of Paleontology 59, 1350–8.
BENGTSON, S. 1986. A new Mongolian species of the
Lower Cambrian genus Camenella and the problem
of scleritome-based taxonomy of the Tommotiida.
Paläontologische Zeitschrift 60(1–2), 45–55.
BENGTSON, S. 1992a. The cap-shaped Cambrian fossil
Maikhanella and the relationship between coeloscler-
itophorans and molluscs. Lethaia 25, 401–20.
BENGTSON, S. 1992b. Proterozoic and earliest Cambrian
skeletal metazoans. In The Proterozoic Biosphere: A
multidisciplinary study (eds J. W. Schopf & C. Klein),
pp. 397–435. Cambridge: Cambridge University Press.
BENGTSON, S. 1994. The advent of animal skeletons. In
Early Life on Earth. Nobel Symposium 84 (ed. S.
Bengtson), pp. 412–25. New York: Columbia University
Press.
BENGTSON, S. 2004. Early skeletal fossils. In
Neoproterozoic–Cambrian Biological Revolutions
(eds J. H. Lipps & B. M. Waggoner), pp. 67–77. The
Paleontological Society Papers 10. The Paleontological
Society.
BENGTSON, S. 2005. Mineralized skeletons and early animal
evolution. In Evolving Form and Function: Fossils and
development (ed. D. E. G. Briggs), pp. 101–24. New
Haven: Yale Peabody Museum.
BENGTSON,S.&CONWAY MORRIS, S. 1992. Early radiation
of biomineralizing phyla. In Origin and Early Evolution
of the Metazoa (eds J. H. Lipps & P. W. Signor),
pp. 447–81. New York: Plenum Press.
BENGTSON,S.,CONWAY MORRIS,S.,COOPER,B.J.,JELL,
P. A . & R UNNEGAR, B. N. 1990. Early Cambrian fossils
from South Australia. Memoirs of the Association of
Australasian Palaeontologists 9, 1–364.
BENGTSON,S.,FEDOROV,A.B.,MISSARZHEVSKY,V.V.,
ROZANOV,A.YU., ZHEGALLO,E.A.&ZHURAVLEV,
A. YU. 1987. Tumulduria incomperta and the case for
Tommotian trilobites. Lethaia 20, 361–70.
BENGTSON,S.&HOU, X. 2001. The integument of Cambrian
chancelloriids. Acta Palaeontologica Polonica 46, 1–22.
BENGTSON,S.,MATTHEWS,S.C.&MISSARZHEVSKY,V.
V. 1986. The Cambrian netlike fossil Microdictyon.In
Problematic Fossil Taxa (eds A. Hoffman & M. H.
Nitecki), pp. 97–115. New York: Oxford University
Press.
BENGTSON,S.&MISSARZHEVSKY, V. V. 1981. Coeloscler-
itophora – a major group of enigmatic Cambrian
metazoans. In Short Papers for the Second International
Symposium on the Cambrian System (ed. M. E. Taylor),
pp. 19–21.
BENGTSON,S.&YUE, Z. 1997. Fossilized metazoan embryos
from the earliest Cambrian. Science 277, 1645–8.
BERGSTRÖM, J. 1973. Classification of olenellid trilobites
and some Balto-Scandian species. Norsk Geologisk
Tidsskrift 53, 283–314.
BERGSTRÖM, J. 2010. The earliest arthropods and other
animals. In Darwin’s Heritage Today. Proceedings of
the Darwin 200 International Conference (ed. M. Long),
pp. 29–42. Beijing: Higher Education Press.
BERGSTRÖM,J.&HOU, X. 2001. Cambrian Onychophora or
Xenusians. Zoologischer Anzeiger 240, 237–45.
BILLINGS, E. 1871. On some new species of Palaeozoic
fossils. Canadian Naturalist 6, 213–223, 240.
BOTTING,J.P.&BUTTERFIELD, N. J. 2005. Reconstructing
early sponge relationships by using the Burgess Shale
fossil Eiffelia globosa, Walcott. Proceedings of the
National Academy of Sciences 102, 1554–9.
BOWRING,S.,GROTZINGER,J.,CONDON,D.,RAMEZANI,
J., NEWALL,M.&ALLEN, P. 2007. Geochronologic
constraints of the chronostratigraphic framework of the
Neoproterozoic Huqf Supergroup, Sultanate of Oman.
American Journal of Science 307, 1097–145.
BRASIER, M. D. 1989a. China and the Palaeotethyan belt
(India, Pakistan, Iran, Kazakhstan, and Mongolia).
In The Precambrian–Cambrian Boundary (eds J. W.
Cowie & M. D. Brasier), pp. 40–74. Oxford: Clarendon
Press.
BRASIER, M. D. 1989b. Towards a biostratigraphy of the
earliest skeletal biotas. In The Precambrian–Cambrian
Boundary (eds J. W. Cowie & M. D. Brasier), pp. 117–
65. Oxford: Clarendon Press.
BRASIER, M. D. 1989c. Sections in England and their
correlation. In The Precambrian–Cambrian Boundary
(eds J. W. Cowie & M. D. Brasier), pp. 82–104. Oxford:
Clarendon Press.
BRASIER,M.D.,CORFIELD, R. M., DERRY,L.A.,ROZANOV,
A. YU.&ZHURAVLEV,A.YU. 1994a. Multiple δ13C
excursions spanning the Cambrian explosion to the
Botomian crisis in Siberia. Geology 22, 455–8.
BRASIER,M.D.,GREEN,O.&SHIELDS, G. 1997. Ediacarian
sponge spicule clusters from southwestern Mongolia
and the origins of the Cambrian fauna. Geology 25,
303–6.
BRASIER,M.D.,KHOMENTOVSKY,V.V.&CORFIELD,R.M.
1993. Stable isotopic calibration of the earliest skeletal
fossil assemblages in eastern Siberia (Precambrian–
Cambrian boundary). Ter ra N o v a 5, 225–32.
BRASIER,M.D.,MAGARITZ, M., CORFIELD,R.,LUO,H.,
WU,X.,OUYANG,L.,JIANG,Z.,HAMDI,B.,HE,T.&
FRAZIER, A. G. 1990. The carbon- and oxygen-isotopic
record of the Precambrian–Cambrian boundary interval
in China and Iran and their correlation. Geological
Magazine 127, 319–32.
BRASIER,M.D.,ROZANOV,A.YU., ZHURAVLEV,A.
YU., CORFIELD,R.M.&DERRY, L. A. 1994b.A
carbon isotope reference scale for the Lower Cambrian
succession in Siberia: report of IGCP project 303.
Geological Magazine 131, 767–83.
BRASIER,M.D.,SHIELDS,G.,KULESHOV,V.N.&
ZHEGALLO, E. A. 1996. Integrated chemo- and
biostratigraphic calibration of early animal evolution:
Neoproterozoic–early Cambrian of southwest Mongo-
lia. Geological Magazine 133, 445–85.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 19
BRASIER,M.D.&SINGH, P. 1987. Microfossils
and Precambrian–Cambrian boundary stratigraphy at
Maldeota, Lesser Himalaya. Geological Magazine 124,
323–45.
BRASIER,M.D.&SUKHOV, S. S. 1998. The falling amplitude
of carbon isotopic oscillations through the Lower to
Middle Cambrian: northern Siberia data. Canadian
Journal of Earth Sciences 35, 353–73.
BROOKS, B.-G., CROWLEY,J.,BOWRING,S.,CERVATO,C.
&J
IN, Y. 2006. A new U/Pb date for the basal
Meishucun section and implications for the timing of the
Cambrian explosion. The Palaeontological Association
Annual Meeting, University of Sheffield, Programme
with abstracts, p. 18.
BUDD, G. E. 1997. Stem-group arthropods from the Lower
Cambrian Sirius Passet fauna of North Greenland.
In Arthropod Relationships (eds R. A. Fortey &
R. H. Thomas), pp. 125–38. London: Chapman and
Hall.
BUDD, G. E. 2001. Tardigrades as ‘stem-group arthropods’:
The evidence from the Cambrian fauna. Zoologischer
Anzeiger 240, 265–79.
BUDD, G. E. 2003. The Cambrian fossil record and the origin
of the phyla. Integrative and Comparative Biology 43,
157–65.
BUDD, G. E. 2008. The earliest fossil record of the animals
and its significance. Philosophical Transactions of the
Royal Society B 363, 1425–34.
BUDD,G.E.&JENSEN, S. 2000. A critical reappraisal of the
fossil record of the bilaterian phyla. Biological Reviews
75, 253–95.
BUDD,G.E.&JENSEN, S. 2003. The limitations of the fossil
record and the dating of the origin of the Bilateria. In
Telling the Evolutionary Time: Molecular Clocks and
the Fossil Record (eds P. C. J. Donoghue & M. P. Smith),
pp. 166–89. London: Taylor and Francis.
BUTTERFIELD, N. J. 2003. Exceptional fossil preservation and
the Cambrian Explosion. Integrative and Comparative
Biology 43, 166–77.
CHEN, M.-G. 1982. [The new knowledge of the fossil
assemblages from Maidiping section, Emei County,
Sichuan with reference to the Sinian-Cambrian
boundary]. Scientia Geologica Sinica 1982, 253–62 (in
Chinese).
CHEN,J.-Y.,HOU, X.-G. & LU, H. 1989. Early Cambrian
netted scale-bearing worm-like sea animal. Acta Palae-
ontologica Sinica 28(1), 12–27.
CHEN,J.-Y.&HUANG, D.-Y. 2002. A possible Lower
Cambrian chaetognath (arrow worm). Science 298,
187.
CHEN,J.-Y.&HUANG,D.-Y.,PENG,Q.-Q.,CHI, H.-M.,
WANG,X.-Q.&FENG, M. 2003. The first tunicate from
the Early Cambrian of South China. Proceedings of the
National Academy of Sciences 100, 8314–18.
CHEN,J.-Y.&ZHOU, G.-Q. 1997. Biology of the Chengjiang
fauna. Bulletin of the National Museum of Natural
History (Taichung, Taiwan, China) 10, 11–105.
CHEN,J.-Y.,ZHOU,G.-Q.&RAMSKÖLD, L. 1995. The
Cambrian lobopodian Microdictyon sinicum.Bulletin of
the National Museum of Natural Science 5, 1–93.
COMPSTON,W.,ZHANG,Z.,COOPER,J.A.,MA,G.&
JENKINS, R. J. F. 2008. Further SHRIMP geochronology
on the early Cambrian of South China. American Journal
of Science 308, 399–420.
CONDON,D.,ZHU, M., BOWRING,S.,WANG,W.,YANG,
A. & JIN, Y. 2005. U–Pb ages from the Neoprotero-
zoic Doushantuo Formation, China. Science 308, 95–
8.
CONWAY MORRIS, S. 1986. The community structure of
the middle Cambrian phyllopod bed (Burgess Shale).
Palaeontology 29, 423–67.
CONWAY MORRIS, S. 1989. South-eastern Newfoundland and
adjacent areas (Avalon Zone). In The Precambrian–
Cambrian Boundary (eds J. W. Cowie & M. D. Brasier),
pp. 7–39. Oxford: Clarendon Press.
CONWAY MORRIS, S. 1993. Ediacaran-like fossils in Cam-
brian Burgess shale-type faunas of North America.
Palaeontology 36, 593–635.
CONWAY MORRIS, S. 1997. The cuticular structure of the 495-
Myr-old type species of the fossil worm Palaeoscolex,
P. piscatorum (?Priapulida). Zoological Journal of the
Linnean Society 119, 69–82.
CONWAY MORRIS, S. 2006. Darwin’s dilemma: the realities
of the Cambrian “explosion”. Philosophical Transac-
tions of the Royal Society of London B 361, 1069–
83.
CONWAY MORRIS,S.&CARON, J. B. 2007. Halwaxiids and
the early evolution of the Lophotrochozoans. Science
315, 1255–8.
CONWAY MORRIS,S.&CHAPMAN, A. J. 1997. Mobergellans
from the Lower Cambrian of Mongolia, Sweden, and the
United States: molluscs or opercula of incertae sedis?
Journal of Paleontology 71, 968–85.
CONWAY MORRIS,S.&CHEN, M. 1990. Tommotiids
from the Lower Cambrian of South China. Journal of
Paleontology 64, 169–84.
CONWAY MORRIS,S.&CHEN, M. 1991. Cambroclaves and
paracarinachitids, early skeletal problematica from the
Lower Cambrian of South China. Palaeontology 34,
357–97.
CONWAY MORRIS,S.&CHEN, M. 1992. Carinachitids,
hexangulaconulariids, and Punctatus: problematic meta-
zoans from the early Cambrian of South China. Journal
of Paleontology 66, 384–406.
CONWAY MORRIS,S.,CRAMPTON,J.S.,XIAO,B.&
CHAPMAN, A. J. 1997. Lower Cambrian cambroclaves
(incertae sedis) from Xinjiang, China, with comments on
the morphological variability of sclerites. Palaeontology
40, 167–89.
CONWAY MORRIS,S.,MCILROY,D.&RUSHTON, A. W. 1998.
Lower Cambrian halkieriids from Oxfordshire, U.K.
Geological Magazine 135, 501–8.
CONWAY MORRIS,S.&PEEL, J. S. 1995. Articulated
halkieriids from the Lower Cambrian of North Green-
land and their role in early protostome evolution.
Philosophical Transactions of the Royal Society of
London B 347, 305–58.
CONWAY MORRIS,S.&PEEL, J. S. 2008. The earliest
annelids: Lower Cambrian polychaetes from the Sirius
Passet Lagerstätte, Peary Land, North Greenland. Acta
Palaeontologica Polonica 53, 137–48.
CONWAY MORRIS,S.&PEEL, J. S. 2010. New palaeoscol-
ecidan worms from the lower Cambrian: Sirius Passet,
Latham Shale and Kinzers Shale. Acta Palaeontologica
Polonica 55, 141–56.
CONWAY MORRIS,S.,PEEL,J.S.,HIGGINS,A.K.,SOPER,N.
J. & DAV I S , N. C. 1987. A Burgess shale-like fauna from
the Lower Cambrian of North Greenland. Nature 326,
181–3.
CONWAY MORRIS,S.&ROBISON, R. A. 1986. Middle
Cambrian Priapulids and other soft-bodied fossils from
Utah and Spain. Paleontological Contributions from the
University of Kansas Papers 117, 1–22.
CRIMES, T. P. 1987. Trace fossils and correlation of late
Precambrian and early Cambrian strata. Geological
Magazine 124, 97–119.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
20 A. KOUCHINSKY & OTHERS
DAILY, B. 1976. Novye dannye ob osnovanii kembriya
v Yuzhnoy Avstralii. [New data on the base of the
Cambrian in South Australia.] Izvestiya Akademii
Nauk SSSR, Seriya Geologicheskaya 1976(3), 45–
52.
DAILY, B. 1990. Cambrian stratigraphy of Yorke Peninsula.
Geological Society of Australia, Special Publication 16,
215–29.
DEBRENNE,F.,GANGLOFF,R.A.&ZHURAVLEV,A.YU.
1990. Archaeocyatha from the Krol-Tal succession
(Lesser Himalaya): an invalid record. Geological
Magazine 127, 361–2.
DEBRENNE, F. M., LAFUSTE,J.&ZHURAVLEV,A.YU.
1990. Coralomorphes et spongiomorphes à l’aube du
Cambrien. Bulletin du Muséum National d’Histoire
Naturelle 12, 17–39.
DEBRENNE, F. M., MAIDANSKAYA,I.D.&ZHURAVLEV,
A. YU. 1999. Faunal migrations of archaeocyaths and
early Cambrian plate dynamics. Bulletin de la Société
Géologique de France 170, 189–94.
DEBRENNE,F.M.&REITNER, J. 2001. Sponges, cnidarians,
and ctenophores. In The Ecology of the Cambrian
Radiation (eds A. Yu. Zhuravlev & R. Riding), pp. 301–
325. New York: Columbia University Press.
DICKSON, J. A. D. 2002. Fossil echinoderms as monitor of
the Mg/Ca ratio of Phanerozoic oceans. Science 298,
1222–4.
DICKSON, J. A. D. 2004. Echinoderm skeletal preservation:
Calcite-aragonite seas and the Mg/Ca ratio of Phan-
erozoic oceans. Journal of Sedimentary Research 74,
355–65.
DILLARD,K.A.,POPE,M.C.,CONIGLIO, M., HASIOTIS,S.T.
&L
IEBERMAN, B. S. 2007. Stable isotope geochemistry
of the lower Cambrian Sekwi Formation, Northwest
Territories, Canada: implications for ocean chemistry
and secular curve generation. Pala e o geog ra p h y, Pa l a eo-
climatology, Palaeoecology 256, 174–94.
DING,W.&QIAN, Y. 1988. Late Sinian to Early Cambrian
small shelly fossils from Yangjiaping, Shimen, Hunan.
Acta Micropalaeontologica Sinica 5(1), 39–55 (in
Chinese).
DOGUZHAEVA,L.A.,MAPES,R.H.&MUTVEI,H.
2002. Chaetognath grasping spines from the Upper
Mississippian of Arkansas (USA). Acta Palaeontologica
Polonica 47, 421–30.
DONG, X.-P. 2004. On the evolution and histology of some
Cambrian protoconodonts, paraconodonts and primitive
euconodonts. Science in China, Series D, Earth Sciences
47(7), 577–84.
DONG,X.-P.,BENGTSON,S.,GOSTLING,N.J.,CUNNINGHAM,
J. A., WALOSSEK,D.,HARVEY,T.H.P.,KOUCHINSKY,
A., VAL’KOV,A.K.,REPETSKI,J.E.,STAMPANONI,M.
&D
ONOGHUE, P. C. J. 2010. The anatomy, taphonomy,
taxonomy and systematic affinity of Markuelia:Early
Cambrian to Early Ordovician scalidophorans. Palae-
ontology 53, 1291–314.
DONG,X.-P.,DONOGHUE,P.C.J.,CHENG,H.&LIU, J. 2004.
Fossil embryos from the Middle and Late Cambrian
Period of Hunan, south China. Nature 427, 237–
40.
DONG,X.-P.,DONOGHUE,P.C.J.,CUNNINGHAM,J.A.,
LIU,J.&CHENG, H. 2005. The anatomy, affinity, and
phylogenetic significance of Markuelia.Evolution &
Development 7, 468–82.
DONOGHUE, P. C. J. 2002. Evolution of development of
the vertebrate dermal and oral skeletons: unraveling
concepts, regulatory theories, and homologies. Pal e o -
biology 28, 474–507.
DONOGHUE,P.C.J.,FOREY,P.L.&ALDRIDGE, R. J. 2000.
Conodont affinity and chordate phylogeny. Biological
Reviews 75, 191–251.
DONOGHUE,P.C.J.&SANSOM, I. J. 2002. Origin and early
evolution of vertebrate skeletonization. Microscopy
Research and Technique 59, 352–72.
DONOGHUE,P.C.J.,SANSOM,I.J.&DOWN S,J.P.
2006. Early evolution of vertebrate skeletal tissues and
cellular interactions, and the canalization of skeletal
development. Journal of Experimental Zoology, Part B:
Molecular and Developmental Evolution 306B, 278–94.
DUNN,C.W.,HEJNOL,A.,MAT U S ,D.Q.,PANG,K.,
BROWNE,W.E.,SMITH,S.A.,SEAVER,E.,ROUSE,
G. W., OBST, M., EDGECOMBE,G.D.,SØRENSEN,M.V.,
HADDOCK,S.H.D.,SCHMIDT-RHAESA,A.,OKUSU,A.,
KRISTENSEN, R. M., WHEELER,W.C.,MARTINDALE,
M. Q. & GIRIBET, G. 2008. Broad phylogenomic
sampling improves resolution of the animal tree of life.
Nature 452, 745–9.
DURHAM, J. W. 1971. The fossil record and the origin of
the Deuterostomata. Proceedings of the North American
Paleontological Convention, Part H, 1104–32.
DUTRO,J.T.JR., PALMER,A.R.,REPETSKI,J.E.&BROSGÉ,
W. P. 1984. Middle Cambrian fossils from the Doonerak
Anticlinorium, Central Brooks Range, Alaska. Journal
of Paleontology 58, 1364–71.
DZIK, J. 1994. Evolution of “small shelly fossils” as-
semblages of the Early Paleozoic. Acta Palaeontologica
Polonica 39, 247–313.
DZIK, J. 2010. Brachiopod identity of the alleged monoplaco-
phoran ancestors of cephalopods. Malacologia 52, 97–
113.
EDGECOMBE, G. D. 2009. Palaeontological and molecular
evidence linking Arthropods, Onychophorans, and other
Ecdysozoa. Evolution: Education and Outreach 2, 178–
90.
ELICKI, O. 1994. Lower Cambrian carbonates from eastern
Germany: palaeontology, stratigraphy and palaeogeo-
graphy.Neues Jahrbuch für Geologie und Paläontologie,
Abhandlungen 191/1, 69–93.
ELICKI,O.&WOTTE, T. 2003. Cambroclaves from the
Cambrian of Sardinia (Italy) and Germany: con-
straints for the architecture of western Gondwana and
the palaeogeographical and palaeoecological potential
of cambroclaves. Palaeogeography, Palaeoclimatology,
Palaeoecology 195, 55–71.
ESAKOVA,N.V.&ZHEGALLO, E. A. 1996. Biostratigrafiya
i fauna nizhnego kembriya Mongolii. [Biostratigraphy
and fauna of the Lower Cambrian of Mongolia.] In
Transactions of the Joint Russian-Mongolian Paleon-
tological Expedition 46 (ed. A. Yu. Rozanov), 216 pp.
(in Russian).
FATKA,O.,KRAFT,P.&SZABAD, M. 2011. Shallow-water
occurrence of Wiwaxia in the middle Cambrian of the
Barrandian area (Czech Republic). Acta Palaeontolo-
gica Polonica doi:10.4202/app.2009.0052.
FEDONKIN,M.A.&WAGGONER, B. M. 1997. The Vendian
fossil Kimberella: The oldest mollusk. Nature 388, 868–
71.
FEDOROV, A. B. 1986. Novye trubchatye problematiki iz
stratotipa tommotskogo yarusa. [New tubular prob-
lematics from stratotype of the Tommotian Stage].
Paleontologicheskij Zhurnal 1986(3), 110–2. (English
translation: Paleontological Journal 20(3), 103–5.)
FEDOROV,A.B.&SHISHKIN, B. B. 1984. Nizhnyaya
granitsa kembriya na severe Sibirskoj platformy. [Lower
boundary of the Cambrian in north of the Siberian
Platform.] In Problemy yarusnogo raschleneniya sistem

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 21
fanerozoya Sibiri. [Problems of Stage subdivision of
Phanerozoic Systems of Siberia](ed.V.I.Krasnov),
pp. 5–14. Novosibirsk: SNIIGGiMS (in Russian).
FISHER, D. W. 1962. Other small conoidal shells. In Treatise
on Invertebrate Paleontology. Miscellanea (ed. R. C.
Moore), W98–W143. Lawrence: Geological Society of
America and University of Kansas Press.
FLÜGEL,E.&SINGH, I. B. 2003. Stromatoporoid-grade and
other sponge fossils from the upper Krol Formation of
the Lesser Himalaya (India): implications for the biotic
evolution around the Precambrian-Cambrian boundary
interval. Facies 49, 351–72.
GEHLING,J.&RIGBY, J. K. 1996. Long expected sponges
from the Neoproterozoic Ediacara fauna of South
Australia. Journal of Paleontology 70, 185–95.
GERMS, G. L. 1972. New shelly fossils from the Nama Group,
South West Africa. American Journal of Science 272,
752–61.
GEYER,G.&ELICKI, O. 1995. The Lower Cambrian trilobites
from the Görlitz Synclinorium (Germany) – review and
new results. Paläontologische Zeitschrift 69(1/2), 87–
119.
GEYER,G.&LANDING, E. 2004. A unified Lower–Middle
Cambrian chronostratigraphy for West Gondwana. Acta
Geologica Polonica 54, 179–218.
GOLUBEV, S. N. 1976. Ontogenetic changes and evolutionary
trends in Early Cambrian spiral gastropods of the su-
perfamily Pelagiellacea. Paleontological Journal 10(2),
143–9.
GORYANSKY, V. Y. 1977. Pervaya nakhodka ostatkov
gubki v nizhnem kembrii vostochnoj Sibiri. [The first
find of sponge remains in the Lower Cambrian of
eastern Siberia]. Ezhegodnik Vsesoyuznogo Paleontolo-
gicheskogo Obschestva 20, 274–6.
GRANT, S. W. F. 1990. Shell structure and distribution
of Cloudina, a potential index fossil for the terminal
Proterozoic. American Journal of Science 290(A), 261–
94.
GRAVESTOCK,D.I.&SHERGOLD, J. H. 2001. Australian
Early and Middle Cambrian sequence biostratigraphy
with implications for species diversity and correlation.
In The Ecology of the Cambrian Radiation (eds A.
Yu. Zhuravlev & R. Riding), pp. 105–136. New York:
Columbia University Press.
GRAVESTOCK,D.I.,ALEXANDER, E. M., DEMIDENKO,
YU.E.,ESAKOVA,N.V.,HOLMER,L.E.,JAGO,J.
B., LIN,T.,MELNIKOVA, L. M., PARKHAEV,P.YU.,
ROZANOV,A.YU., USHATINSKAYA,G.T.,ZANG,W.,
ZHEGALLO,E.A.&ZHURAVLEV,A.YU. 2001. The
Cambrian biostratigraphy of the Stansbury Basin,
South Australia. Transactions of the Palaeontological
Institute 282. Moscow: IAPC Nauka/Interperiodica,
344 pp.
GRIGOR’EVA,N.V.,MELNIKOVA,L.M.&PEL’MAN,YU.
L. 1983. Brakhiopody, ostrakody (bradoriidy) i prob-
lematika iz stratotipicheskogo rajona yarusov nizhnego
kembriya. [Brachiopods, ostracods (bradoriids) and
problematics from the stratotype region of Lower Cam-
brian Stages]. Paleontologicheskij Zhurnal 1983(3), 54–
8. (English translation: Paleontological Journal 17(3),
51–6).
GROTZINGER,J.P.,ADAMS,E.&SCHRÖDER, S. 2005.
Microbial-metazoan reefs of the terminal Proterozoic
Nama Group (ca. 550–543 Ma), Namibia. Geological
Magazine 142, 499–517.
GROTZINGER,J.P.,BOWRING,S.A.,SAYLOR,B.Z.&
KAUFMAN, A. J. 1995. Biostratigraphic and geochrono-
logic constraints on early animal evolution. Science 270,
598–604.
GROTZINGER,J.P.,WATTERS,W.A.&KNOLL, A. H. 2000.
Calcified metazoans in thrombolite-stromatolite reefs
of the terminal Proterozoic Nama Group, Namibia.
Paleobiology 26, 334–59.
HALANYCH, K. M. 2004. The new view of animal phylogeny.
Annual Review of Ecology, Evolution and Systematics
35, 229–56.
HALL, J. 1847. Paleontology of New-York. Volume I.
Containing descriptions of the organic remains of the
Lower Division of the New-York system (equivalent to
the Lower Silurian rocks of Europe).Albany:C.Van
Benthuysen, 338 pp.
HALL, J. 1876. Illustrations of Devonian Fossils: Gas-
teropoda, Pteropoda, Cephalopoda, Crustacea and
Corals of the Upper Helderberg, Hamilton and
Chemung Groups. 39 pls. Albany: Weed, Parsons and
Company.
HAMDI, B. 1995. Precambrian–Cambrian deposits in Iran.
In Treatise on the Geology of Iran vol. 20 (ed. A.
Hushmandzadeh). Tehran: Geological Survey of Iran,
535 pp. (In Persian)
HAMDI,B.,BRASIER,M.D.&JIANG, Z. 1989. Earliest
skeletal fossils from Precambrian–Cambrian boundary
strata, Elburz Mountains, Iran. Geological Magazine
126, 283–9.
HARDIE,L.A.&STANLEY, S. M. 1997. Secular bi-
otic trends in skeletal secretion and sedimentary
carbonate production resulting from oscillations in
seawater chemistry driven by plate tectonics. Eos
(Transactions of the American Geophysical Union) 78,
S179.
HARVEY, T. H. P. 2010. Carbonaceous preservation of
Cambrian hexactinellid sponge spicules. Biology Letters
6, 834–7.
HARVEY,T.H.P.,DONG,X.&DONOGHUE, P. C. J. 2010.
Are palaeoscolecids ancestral ecdysozoans? Evolution
& Development 12, 177–200.
HINZ, I. 1987. The Lower Cambrian microfauna of Comley
and Rushton, Shropshire/England. Palaeontographica
A,198(1–3), 41–100.
HINZ-SCHALLREUTER,I.,GOZALO,R.&LIÑÁN, E. 2008.
New bradorid arthropods from the Lower Cambrian of
Spain. Micropalaeontology 53, 497–510.
HOLLINGSWORTH, J. S. 2005. The earliest occurrence of
trilobites and brachiopods in the Cambrian of Laurentia.
Palaeogeography, Palaeoclimatology, Palaeoecology
220, 153–65.
HOLLINGSWORTH, J. S. 2007. Fallotaspidoid trilobite as-
semblage (Lower Cambrian) from the Esmeralda Basin
(western Nevada, U.S.A.): the oldest trilobites from
Laurentia. Memoirs of the Australasian Association of
Palaeontologists 32, 123–40.
HOLLINGSWORTH, J. S. 2008. The first trilobites in Laurentia
and elsewhere. In Advances in Trilobite Research (eds
I. Rábano, R. Gozalo & D. García-Bellido), pp. 171–
7. Cuadernos del Museo Geominero no. 9. Madrid:
Instituto Geológico y Minero de España.
HOLM, G. 1893. Sveriges Kambrisk-Siluriska Hyolithidae
och Conularidae. Sveriges Geologiska Undersökning.
Afhandlingar och Uppsatser 112, 1–172.
HOLMER,L.E.,POPOV,L.E.,KONEVA,S.P.&BASSETT,M.
G. 2001. Cambrian-early Ordovician brachiopods from
Malyi Karatau, the western Balkhash region, and Tien
Shan, central Asia. Special Papers in Palaeontology 65,
1–180.
HOLMER,L.E.,SKOVSTED,C.B.,BROCK,G.A.,VALENTINE,
J. & PATERSON, J. R. 2008. The origin of linguliform
brachiopods from sessile Early Cambrian tannuolinids.
Biology Letters 4, 724–8.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
22 A. KOUCHINSKY & OTHERS
HOU, X.-G. & BERGSTRÖM, J. 1994. Palaeoscolecid worms
may be nematomorphs rather than annelids. Lethaia 27,
11–7.
HOU, X.-G. & BERGSTRÖM, J. 1995. Cambrian lobopodians-
ancestors of extant onychophorans? Zoological Journal
of the Linnean Society 114, 3–19.
HOU, X.-G., MA,X.-Y.,ZHAO,J.&BERGSTRÖM, J. 2004.
The lobopodian Paucipodia inermis from the Lower
Cambrian Chengjiang fauna, Yunnan, China. Lethaia
37, 235–44.
HOU, X.-G., SIVETER,D.J.,WILLIAMS,M.&FENG,X.
H. 2002. A monograph of the bradoriid arthropods
from the Lower Cambrian of SW China. Transactions
of the Royal Society of Edinburgh: Earth Sciences
92, 347–409 (reprinted in 93, Part 1, with improved
illustrations).
HOU, X.-G., SIVETER,D.J.,WILLIAMS, M., WALOSSEK,D.
&B
ERGSTRÖM, J. 1996. Appendages of the arthropod
Kunmingella from the Early Cambrian of China: its
bearing on the systematic position of the Bradoriida
and the fossil record of the Ostracoda. Philosophical
Transactions of the Royal Society of London B 351,
1131–45.
HOU, X.-G., WILLIAMS, M., SIVETER,D.J.,SIVETER,D.J.,
ALDRIDGE,R.J.&SANSOM, R. S. 2010. Soft-part
anatomy of the Early Cambrian bivalved arthropods
Kunyangella and Kunmingella: significance for the
phylogenetic relationships of Bradoriida. Proceedings
of the Royal Society B 277, 1835–41.
HU, S. 2005. Taphonomy and palaeoecology of the Early
Cambrian Chengjiang Biota from Eastern Yunnan,
China. Berliner Paläobiologische Abhandlungen 7,1–
197.
HUGHES,N.C.,PENG,S.,BHARGAVA,O.N.,AHLUWALIA,
A. D., WALIA,S.,MYROW,P.M.&PARCHA,S.K.
2005. Cambrian biostratigraphy of the Tal Group, Lesser
Himalaya, India, and early Tsanglangpuan (late early
Cambrian) trilobites from the Nigali Dhar syncline.
Geological Magazine 142, 57–80.
ISACHSEN,C.E.,BOWRING,S.A.,LANDING,E.&SAMSON,
S. D. 1994. New constraint on the division of Cambrian
time. Geology 22, 496–8.
IVANTSOV,A.YU. 1990. Pervye nakhodki fillokarid v
nizhnem kembrii Yakutii. [First finds of phyllocarids
in the Lower Cambrian of Yakutia]. Paleontologicheskij
Zhurnal 1990, 130–132.
IVANTSOV,A.YU., MALAHOVSKAYA,YA.E.&SEREZH-
NIKOVA, E. A. 2004. Some problematic fossils from
the Vendian of Southeastern White Sea Region. Pal e -
ontological Journal 38, 1–9 (translated from Paleonto-
logicheskij Zhurnal 2004(1), 3–9).
IVANTSOV,A.YU., ZHURAVLEV,A.YU., LEGUTA,A.V.,
KRASILOV,V.A.,MELNIKOVA,L.M.&USHATINSKAYA,
G. T. 2005. Palaeoecology of the Early Cambrian Sinsk
biota from the Siberian Platform. Palaeogeography,
Palaeoclimatology, Palaeoecology 220, 69–88.
JAEKEL, O. 1918. Phylogenie und System der Pelmatozoen.
Paläontologische Zeitschrift 3, 1–128.
JAGO,J.B.,SUN,X.&ZANG, W. 2002. Correlation within
early Palaeozoic basins of eastern South Australia.
South Australia. Department of Primary Industries and
Resources. Report Book 2002/033, 22 pp.
JAGO,J.B.,ZANG,W.,SUN,X.,BROCK,G.A.,PATERSON,J.
R. & SKOVSTED, C. B. 2006. A review of the Cambrian
biostratigraphy of South Australia. Pal a e owor ld 15,
406–23.
JANUSSEN,D.,STEINER,M.&ZHU, M.-Y. 2002. New
well-preserved scleritomes of Chancelloriidae from the
Early Cambrian of Yuanshan Formation (Chengjiang,
China) and the Middle Cambrian Wheeler Shale (Utah,
USA) and paleobiological implications. Journal of
Paleontology 76, 596–606.
JENSEN,S.,GEHLING,J.&DROSER, M. 1998. Ediacara-type
fossils in Cambrian sediments. Nature 393, 567–9.
JIANG, Z. 1980. [The Meishucun Stage and fauna of
the Jinning County, Yunnan.] Bulletin of the Chinese
Academy of Geological Sciences, Series I 2:1, 75–92.
(In Chinese with an English summary)
JOHNSTON,P.A.,JOHNSTON,K.J.,COLLOM,C.J.,POWELL,
W. G . & P OLLOCK, R. J. 2009. Palaeontology and
depositional environments of ancient brine seeps in
the Middle Cambrian Burgess Shale at The Monarch,
British Columbia, Canada. Pala e ogeog ra p h y, Pa l aeo-
climatology, Palaeoecology 277, 86–105.
JONES,P.J.&MCKENZIE, K. G. 1980. Queensland Middle
Cambrian Bradoriida (Crustacea): new taxa, palaeobi-
ogeography and biological affinities. Alcheringa 4, 203–
25.
KARATAJUTE-TALIMAA, V. 1997. Taxonomy of loganiid
thelodonts. Modern Geology 21(1/2), 1–15.
KARLOVA, G. A. 1987. First findings of skeletal fauna in
the Turkut Formation of the Olenyok uplift. Doklady
Akademii Nauk SSSR 292, 204–5.
KARLOVA,G.A.&VODANYUK, S. A. 1985. Novye dannye
o perekhodnykh k kembriyu otlozheniyakh bassejna
r. Khorbosuonki (Olenyokskoe podnyatie). [New data
on the deposits transitional to the Cambrian from
the Khorbosuonka River basin (Olenyok Uplift)]. In
Stratigrafiya pozdnego dokembriya i rannego paleozoya
Sibiri. Vend i rifej. [Stratigraphy of the late Precambrian
and early Paleozoic of Siberia. Vendian and Riphean.]
(ed. V. V. Khomentovsky), pp. 3–13. Novosibirsk:
Institut geologii i geofiziki SO AN SSSR (in Russian).
KAUFMAN,A.J.,KNOLL,A.H.&AWRAMIK, S. M. 1992.
Biostratigraphic and chemostratigraphic correlation of
Neoproterozoic sedimentary successions: Upper Tindir
Group, northwestern Canada, as a test case. Geology 20,
181–5.
KAUFMAN,A.J.,KNOLL,A.H.,SEMIKHATOV,M.A.,
GROTZINGER,J.P.,JACOBSEN,S.B.&ADAMS, W. 1996.
Integrated chronostratigraphy of Proterozoic–Cambrian
boundary beds in the western Anabar region, northern
Siberia. Geological Magazine 133, 509–33.
KEMP, A. 2002a. Amino acid residues in conodont elements.
Journal of Paleontology 76, 518–28.
KEMP, A. 2002b. Hyaline tissue of thermally unaltered
conodont elements and the enamel of vertebrates.
Alcheringa 26, 23–36.
KHERASKOVA,T.N.,DIDENKO,A.N.,BUSH,V.A.&VOLOZH,
YU. A. 2003. The Vendian–early Paleozoic history
of the continental margin of eastern Paleogondwana,
Paleoasian ocean, and Central Asian foldbelt. Russian
Journal of Earth Sciences 5, 165–84.
KHOMENTOVSKY,V.V.&GIBSHER, A. S. 1996. The
Neoproterozoic–lower Cambrian in northern Govi-
Altay, western Mongolia: regional setting, lithostrati-
graphy and biostratigraphy. Geological Magazine 133,
371–90.
KHOMENTOVSKY,V.V.&KARLOVA, G. A. 1991. Novye
dannye po korrelyatsii vend-kembrijskikh otlozhenij
vostochnoj i perekhodnoj fatsial’nykh oblastej yuzhnoj
Yakutii. [New data on correlation of the Vendian-
Cambrian deposits of eastern and transitional facial
belts of southern Yakutia.] In Pozdnij dokembrij i rannij
paleozoj Sibiri. Sibirskaya platforma i ee obramle-
nie. [Late Precambrian and early Palaeozoic of

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 23
Siberia. Siberian Platform and its margins.](ed.V.V.
Khomentovsky), pp. 3–44. Novosibirsk: OIGGM SO
AN SSSR Publishing House (in Russian).
KHOMENTOVSKY,V.V.&KARLOVA, G. A. 1993. Biostrati-
graphy of the Vendian–Cambrian beds and lower
Cambrian boundary in Siberia. Geological Magazine
130, 29–45.
KHOMENTOVSKY,V.V.&KARLOVA, G. A. 2002. Granitsa
nemakit-daldynskogo i tommotskoga yarusov (vend–
kembrij) Sibiri. [The boundary between Nemakit-
Daldynian and Tommotian stages (Vendian–Cambrian)
of Siberia.] Stratigraphy and Geological Correlation 10,
13–34.
KHOMENTOVSKY,V.V.&KARLOVA, G. A. 2005. The
Tommotian Stage base as the Cambrian lower boundary
in Siberia. Stratigraphy and Geological Correlation 13,
21–34.
KHOMENTOVSKY,V.V.&REPINA, L. N. 1965. The Lower
Cambrian Stratotype Section of Siberia.Moscow:
Nauka, 200 pp.
KHOMENTOVSKY,V.V.,VAL’KOV,A.K.&KARLOVA,
G. A. 1990. Novye dannye po biostratigrafii perek-
hodnykh vend-kembrijskikh sloev v bassejne srednego
techeniya r. Aldan. [New data on the biostratigraphy
of transitional Vendian–Cambrian strata in the middle
reaches of the River Aldan.] In Pozdnij dokembrij i
rannij paleozoj Sibiri. Voprosy regional’noj stratigrafii.
[Late Precambrian and early Palaeozoic of Siberia.
Problems in regional stratigraphy.](edsV.V.Kho-
mentovsky & A. S. Gibsher), pp. 3–57. Novosibirsk:
Institut geologii i geofiziki SO AN SSSR (in Russian).
KHOMENTOVSKY,V.V.,VAL’KOV,A.K.,KARLOVA,G.A.
&N
UZHNOV, S. V. 1983. Opornyj razrez dokembrijsko-
kembrijskikh otlozhenij r. Gonam. [Key-section of the
Precambrian-Cambrian deposits of River Gonam]. In
Pozdnij dokembrij i rannij paleozoj Sibiri. Vendskie
otlozheniya. [Late Precambrian and early Palaeozoic
of Siberia. Vendian deposits.] (eds V. V. Khomentovsky,
M. S. Yakshin & G. A. Karlova), pp. 29–44. Novos-
ibirsk: Institut geologii i geofiziki SO AN SSSR (in
Russian).
KIEL,S.&DANDO, P. R. 2009. Chaetopterid tubes from
vent and seep sites: implications for fossil record and
evolutionary history of vent and seep annelids. Acta
Palaeontologica Polonica 54, 443–8.
KIESSLING,W.,ABERHAN,M.&VILLIER, L. 2008. Phan-
erozoic trends in skeletal mineralogy driven by mass
extinctions. Nature Geoscience 1, 527–30.
KIMURA,H.&WATANABE, Y. 2001. Oceanic anoxia at the
Precambrian-Cambrian boundary. Geology 29, 995–8.
KIMURA,H.,MATSUMOT O ,R.,KAKUWA,Y.,HAMDI,B.&
ZIBASERESHT, H. 1997. The Vendian–Cambrian δ13 C
record, North Iran: evidence for overturning of the ocean
before the Cambrian explosion. Earth and Planetary
Science Letters 147, E1–E7.
KIRSCHVINK,J.L.,MAGARITZ, M., RIPPERDAN,R.L.,
ZHURAVLEV,A.YU.&ROZANOV,A.YU. 1991. The
Precambrian–Cambrian boundary: magnetostratigraphy
and carbon isotopes resolve correlation problems
between Siberia, Morocco, and South China. GSA Today
1, 69–71, 87, 91.
KNOLL,A.H.,GROTZINGER,J.P.,KAUFMAN,A.J.&
KOLOSOV, P. 1995. Integrated approaches to terminal
Proterozoic stratigraphy: an example from the Olenek
Uplift, northeastern Siberia. Precambrian Research 73,
251–70.
KORSHUNOV,V.I.,REPINA,L.N.&SYSOEV, V. A. 1969.
K stroeniyu pestrotsvetnoj svity vostoka Aldanskoj
anteklizy. [To the structure of the Pestrotsvet Formaton
of eastern Aldan anticline.] Geologiya i Geofizika 10,
18–21.
KOUCHINSKY, A. 2000. Skeletal microstructures of hyoliths
from the Early Cambrian of Siberia. Alcheringa 24, 65–
81.
KOUCHINSKY,A.,BENGTSON,S.,FENG,W.,KUTYGIN,R.
&V
AL’KOV, A. K. 2009. The Lower Cambrian fossil
Anabaritids: affinities, occurrences and systematics.
Journal of Systematic Palaeontology 7, 241–98.
KOUCHINSKY,A.,BENGTSON,S.,MISSARZHEVSKY,V.V.,
PELECHATY,S.,TORSSANDER,P.&VAL’KOV,A.K.
2001. Carbon isotope stratigraphy and the problem of a
pre-Tommotian Stage in Siberia. Geological Magazine
138, 387–96.
KOUCHINSKY,A.,BENGTSON,S.,PAV L O V ,V.,RUNNEGAR,B.,
VAL’KOV,A.K.&YOUNG, E. 2005. Pre-Tommotian age
of the lower Pestrotsvet Formation in the Selinde section
on the Siberian platform: carbon isotopic evidence.
Geological Magazine 142, 319–25.
KOUCHINSKY,A.,BENGTSON,S.,PAVLOV,V.E.,RUNNEGAR,
B., TORSSANDER,P.,YOUNG,E.&ZIEGLER,K.
2007. Carbon isotope stratigraphy of the Precambrian–
Cambrian Sukharikha River section, northwestern
Siberian platform. Geological Magazine 144, 1–10.
KRUSE,P.D.,ZHURAVLEV,A.YU.&JAMES, N. P. 1995.
Primordial metazoan-calcimicrobial reefs: Tommotian
(Early Cambrian) of the Siberian Platform. Palaios 10,
291–321.
LANDING, E. 1980. Late Cambrian–Early Ordovician mac-
rofaunas and phosphatic microfaunas, St. John Group,
New Brunswick. Journal of Paleontology 54, 752–
61.
LANDING, E. 1984. Skeleton of lapworthellids and the
suprageneric classification of tommotiids (Early and
Middle Cambrian phosphatic problematica). Journal of
Paleontology 58, 1380–98.
LANDING, E. 1995. Upper Placentian–Branchian Series of
Mainland Nova Scotia (Middle–Upper Lower Cam-
brian): faunas, paleoenvironments, and stratigraphic
revision. Journal of Paleontology 69, 475–95.
LANDING, E. 2004. Precambrian–Cambrian boundary inter-
val deposition and the marginal platform of the Avalon
microcontinent. Journal of Geodynamics 37, 411–35.
LANDING,E.,BOWRING,S.A.,DAV I D E K ,K.L.,WESTROP,
S. R., GEYER,G.&HELDMAIER, W. 1998. Duration
of the Early Cambrian: U–Pb ages of volcanic ashes
from Avalon and Gondwana. Canadian Journal of Earth
Sciences 35, 329–38.
LANDING,E.,ENGLISH,A.&KEPPIE, J. D. 2010. Cambrian
origin of all skeletalized metazoan phyla-discovery of
Earth’s oldest bryozoans (Upper Cambrian, southern
Mexico). Geology 38, 547–50.
LANDING,E.,MYROW, P. M., BENUS,A.&NARBONNE,
G. M. 1989. The Placentian Series: appearance of the
oldest skeletalized faunas in southeastern Newfound-
land. Journal of Paleontology 63, 739–69.
LANDING,E.,NOWLAN,G.S.&FLETCHER, T. P. 1980.
A microfauna associated with Early Cambrian faunas
of the Callavia Zone, northern Antigonish Highlands,
Nova Scotia. Canadian Journal of Earth Sciences 17,
400–18.
LANDING,E.,PENG,S.,BABCOCK,L.E.,GEYER,G.&
MOCZYDLOWSKA-VIDAL, M. 2007. Global Standard
names for the lowermost Cambrian series and stage.
Episodes 30, 287–9.
LANDING,E.&WESTROP, S. R. 1998. Revisions in strati-
graphic nomenclature of the Cambrian of Avalonian

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
24 A. KOUCHINSKY & OTHERS
North America and comparisons with Avalonian Britain.
In Avalon 1997 – The Cambrian Standard. Third
International Field Conference of the Cambrian Chro-
nostratigraphy Working Group and I.G.C.P. Project 366
(Ecological Aspects of the Cambrian Radiation) (eds E.
Landing E. & S. R. Westrop), pp. 76–87. New York State
Museum Bulletin 492.
LANDING,E.&WESTROP, S. R. 2004. Environmental
patterns in the origin and evolution and diversification
loci of Early Cambrian skeletalized Metazoa: evidence
from the Avalon microcontinent. In Neoproterozoic–
Cambrian Biological Revolutions (eds J. H. Lipps &
B. M. Waggoner), pp. 93–105. Paleontological Society
Papers 10. The Paleontological Society.
LAURIE, J. R. 1986. Phosphatic fauna of the Early Cambrian
Todd River Dolomite, Amadeus Basin, central Australia.
Alcheringa 10, 431–54.
LENDZION, K. 1972. Stratigrafia kambru dolnego na obszarze
Podlasia. Institut Geologiczny, Biuletyn 233. Z badan
stratigraficzno-paleontologicznych w Polsce, t. VI, 69–
157.
LENDZION, K. 1978. Charakterystyka stratygraficzno-
litologiczna wendu i kambru dolnego. In Wybrane
problemy stratigrafii i litologii wendu i dolnego kambru
na platformie prekambryjskiej w Polsce. Prace Instytutu
Geologicznego 90, 36–41.
LENDZION, K. 1983. Trilobita. In Upper Precambrian and
Cambrian Paleontology of East-European Platform (eds
N. A. Volkova, M. B. Gnilovskaya, K. Lendzion, V. V.
Kirjanov, V. M. Palij, L. T. Pashkyavichene, L. V. Piskun,
E. Posti, A. Yu. Rozanov, A. Urbanek, M. A. Fedonkin
& T. V. Yankauskas), pp. 95–102. Moscow: Nauka.
LI, G. 2009. Early Cambrian stem-group brachiopods from
South China. In An International Conference on the
Cambrian Explosion – Banff, Alberta, August 3–8, 2009,
Abstract Volume (eds M. Smith, L. O’Brien & J.-B.
Caron). Toronto: Burgess Shale Consortium (available
online at: http://burgess-shale.info/abstract/li).
LI,G.&CHEN, J. 1992. [Early Cambrian cap-shaped
lathamellids: their microstructures and systematics].
Acta Palaeontologica Sinica 31, 467–80. (in Chinese)
LI,C.-W.,CHEN,J.-Y.&HUA, T.-E. 1998. Precambrian
sponges with cellular structures. Science 279, 879–
82.
LI,D.,LING,H.-F.,JIANG,S.-Y.,PAN,J.-Y.,CHEN,Y.-Q.,
CAI,Y.-F.&FENG, H.-Z. 2009. New carbon isotope
stratigraphy of the Ediacaran–Cambrian boundary inter-
val from SW China: implications for global correlation.
Geological Magazine 146, 465–84.
LI,G.,STEINER, M., ZHU, M., ZHU,X.&ERDTMANN,
B.-D. 2007. Early Cambrian fossil record of metazoans
in South China: generic diversity and radiation patterns.
Palaeogeography, Palaeoclimatology, Palaeoecology
254, 226–46.
LI,G.&XIAO, S. 2004. Tannuolina and Micrina (Tan-
nuolinidae) from the Lower Cambrian of eastern Yun-
nan, South China, and their scleritome reconstruction.
Journal of Paleontology 78, 900–13.
LI,G.,ZHANG, J.-M. & ZHU, M. 2001. Litho- and
biostratigraphy of the Lower Cambrian Meishucunian
Stage in the Xiaotan section, Eastern Yunnan. Acta
Palaeontologica Sinica 40(Supplement), 40–53.
LIEBERMAN, B. S. 2002. Phylogenetic analysis of some basal
Early Cambrian trilobites, the biogeographic origins of
the Eutrilobita, and the timing of the Cambrian radiation.
Journal of Paleontology 76, 692–708.
LINDSAY,J.F.,BRASIER,M.D.,DORNJAMJAA,D.,KRUSE,
P. , G OLDRING,R.&WOOD, R. A. 1996. Facies
and sequence controls on the appearance of the
Cambrian biota in southwestern Mongolia: implications
for the Precambrian–Cambrian boundary. Geological
Magazine 133, 417–28.
LIU,J.,SHU,D.,HAN,H.,ZHANG,Z.&ZHANG, X. 2007.
Origin, diversification, and relationships of Cambrian
lobopods. Gondwana Research 14(1–2), 277–83.
LOVE ,G.D.,FIKE,D.A.,GROSJEAN,E.,STA LVIES ,
C., GROTZINGER,J.,BRADLEY,A.S.,BOWRING,S.,
CONDON,D.&SUMMONS, R. E. 2006. Constraining
the timing of basal metazoan radiation using molecular
biomarkers and U–Pb isotope dating. Goldschmidt
Conference Abstracts 2006, A371.
LOVE ,G.D.,GROSJEAN,E.,STALVI ES,C.,FIKE,D.A.,
GROTZINGER,J.,BRADLEY,A.S.,KELLY,A.E.,BHATIA,
M., MEREDITH,W.,SNAPE,C.E.,BOWRING,S.,
CONDON,D.&SUMMONS, R. E. 2009. Fossil steroids
record the appearance of Demospongiae during the
Cryogenian Period. Nature 457, 718–22.
LUCHININA,V.A.,KOROVNIKOV,I.V.,SIPIN,D.P.&
FEDOSEEV, A. V. 1997. Upper Vendian–Lower Cam-
brian biostratigraphy of the Sukharikha River section
(Siberian Platform). Russian Geology and Geophysics
38(8), 1385–97.
LUO,H.,JIANG,Z.,WU,X.,SONG,X.,OUYANG, L. 1982. The
Sinian–Cambrian Boundary in Eastern Yunnan, China.
Kunming: Yunnan People’s Publishing House, 265 pp.
(in Chinese, with an English summary).
MAAS,A.&WALOSZEK, D. 2005. Phosphatocopina –
ostracode-like sister group of Eucrustacea. Hydrobio-
logia 538, 139–52.
MALOOF,A.C.,PORTER, S. M., MOORE,J.L.,DUDÁS,F.Ö.,
BOWRING,S.A.,HIGGINS,J.A.,FIKE,D.A.&EDDY,
M. P. 2010a. The earliest Cambrian record of animals
and ocean geochemical change. Geological Society of
America Bulletin 122, 1731–74.
MALOOF,A.C.,RAMEZANI,J.,BOWRING,S.A.,FIKE,D.
A., PORTER,S.M.&MAZOUAD, M. 2010b. Constraints
on early Cambrian carbon cycling from the duration
of the Nemakit-Daldynian-Tommotian boundary δ13C
shift, Morocco. Geology 38, 623–6.
MALOOF,A.C.,ROSE,C.V.,BEACH,R.,SAMUELS,B.M.,
CALMET,C.C.,ERWIN,D.H.,POIRIER,G.R.,YAO ,N.
&S
IMONS, F. J. 2010c. Possible animal-body fossils in
pre-Marinoan limestones from South Australia. Nature
Geoscience 3, 653–9.
MALOOF,A.C.,SCHRAG,D.P.,CROWLEY,J.L.&BOWRING,
S. A. 2005. An expanded record of Early Cambrian
carbon cycling from the Anti-Atlas Margin, Mo-
rocco. Canadian Journal of Earth Sciences 42, 2195–
216.
MAMBETOV, A. M. 1993. Drevnejshie skeletnye ostatki
i zonal’naya stratigrafiya verkhnego dokembriya –
kembriya Severnogo Tyan-Shanya. [The earliest skel-
etonized fossils and zonal stratigraphy of the upper
Precambrian–Lower Cambrian of North Tien Shan]. In
Novye dannye po biostratigrafii dokembriya i paleozoya
Kyrgyzstana. [New data on biostratigraphy of the
Precambrian and Palaeozoic of Kyrgyzstan.](ed.A.M.
Mambetov), pp. 15–23. Bishkek: Ilim (in Russian).
MAMBETOV,A.M.&REPINA, L. N. 1979. Nizhnij kembrii
talasskogo Ala-Too i ego korrelyatsiya s razrezami
Malogo Karatau i Sibirskoj platformy. [Lower Cambrian
of the Talass Ala-Too and its correlation with sections
of the Lesser Karatau and Siberian Platform.] In
Biostratigrafiya i paleontologiya nizhnego kembriya
Sibiri. [Biostratigraphy and palaeontology of the Lower
Cambrian of Siberia.] (ed. I. T. Zhuravleva), pp. 98–138.
Trudy Instituta geologii i geofiziki SO AN SSSR 406.
Novosibirsk: Nauka.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 25
MATTHEW, G. F. 1899. Studies on Cambrian faunas, no.
3: Upper Cambrian fauna of Mt. Stephen, British
Columbia. Transactions of the Royal Society of Canada,
Series 2,5, 39–66.
MARTÍ MUS, M., PALACIOS,T.&JENSEN, S. 2008. Size of
the earliest mollusks: did small helcionellids grow to
become large adults? Geology 36, 175–8.
MAZUMDAR,A.&BANERJEE, D. M. 1998. Siliceous
sponge spicules in the Early Cambrian Chert-phosphate
Member of the Lower Tal Formation, Krol belt, Lesser
Himalaya. Geology 26, 899–902.
MCCAFFREY,M.A.,MOLDOWAN, J. M., LIPTON,P.A.,
SUMMONS,R.E.,PETERS,K.E.,JEGANATHAN,A.&
WATT , D. S. 1994. Paleoenvironmental implications of
novel C30 steranes in Precambrian to Cenozoic age
petroleum and bitumen. Geochimica et Cosmochimica
Acta 58, 529–32.
MCILROY,D.&SZANIAWSKI, H. 2000. A lower Cambrian
protoconodont apparatus from the Placentian of south-
eastern Newfoundland. Lethaia 33, 95–102.
MEHL, D. 1998. Porifera and Chancelloriidae from the
Middle Cambrian of the Georgina basin, Australia.
Palaeontology 41, 1153–82.
MENS,K.&PIRRUS, E. A. 1977. Stratotypicheskie
razrezy kembriya Estonii. [Stratotype sections of the
Cambrian of Estonia]. Tallinn: Valgus, 68 pp. (in
Russian).
MESHKOVA,N.P.,NIKOLAEVA,I.V.,KULIKOV,P.YU.,
ZHURAVLEVA,I.T.,LUCHININA,V.A.,MUSATOV,D.I.
&S
IDORAS, S. D. 1976. Stratigrafiya pogranichnykh
otlozhenij dokembriya i kembriya severa Anabarskogo
podnyatiya. [Stratigraphy of transitional Precambrian–
Cambrian deposits of northern Anabar Uplift]. In
Stratigrafiya i paleontologiya nizhnego i srednego
kembriya SSSR. [Stratigraphy and palaeontology of the
Lower and Middle Cambrian of the USSR.](ed.I.T.
Zhuravleva), pp. 3–22. Novosibirsk: Nauka.
MISSARZHEVSKY, V. V. 1974. Novye dannye o drevnejshikh
okamenelostyakh rannego kembriya Sibirskoj plat-
formy. [New data on the oldest fossils of the early
Cambrian of the Siberian Platform.] In Biostratigrafiya
i paleontologiya nizhnego kembriya Evropy i severnoj
Azii. [Biostratigraphy and palaeontology of the Lower
Cambrian of Europe and northern Asia.](edsI.T.
Zhuravleva & A. Yu. Rozanov), pp. 179–89. Moscow:
Nauka (in Russian).
MISSARZHEVSKY, V. V. 1982. Raschlenenie i korrelyatsiya
pogranichnykh tolsch dokembriya i kembriya po neko-
torym drevnejshim gruppam skeletnykh organizmov.
[Subdivision and correlation of the Precambrian–
Cambrian boundary beds using some groups of the
oldest skeletal organisms.] Byulleten’ Moskovskogo
obschestva ispytatelej prirody, Otdelenie geologii 57(5),
52–67 (in Russian).
MISSARZHEVSKY, V. V. 1989. Drevnejshie skeletnye okame-
nelosti i stratigrafiya pogranichnykh tolshch dokembriya
i kembriya. [The oldest skeletal fossils and stratigraphy
of the Precambrian-Cambrian boundary beds.] Trudy
Geologicheskogo Instituta AN SSSR 443, 237 pp. (in
Russian)
MISSARZHEVSKY,V.V.&MAMBETOV, A. M. 1981.
Stratigrafiya i fauna pogranichnykh sloev kembriya i
dokembriya Malogo Karatau. [Stratigraphy and fauna
of the Cambrian and Precambrian boundary beds of
the Lesser Karatau Range.] Trudy Geologicheskogo
Instituta AN SSSR 326, 92 pp. (in Russian)
MOCZYDŁOWSKA, M. 2002. Early Cambrian phytoplankton
diversification and appearance of trilobites in the
Swedish Caledonides with implications for coupled
evolutionary events between primary producers and
consumers. Lethaia 35, 191–214.
MOORE,J.L.,PORTER, S. M., STEINER,M.&LI, G. 2010.
Cambrothyra ampulliformis, an unusual coeloscerito-
phoran from the lower Cambrian of Shaanxi Province,
China. Journal of Paleontology 84, 1040–60.
MÜLLER, K. J. 1959. Kambrische Conodonten. Zeitschrift
der Deutschen Geologischen Gesellschaft 111, 434–
85.
MÜLLER, K. J. 1964. Ostracoda (Bradoriina) mit phos-
phatischen Gehäusen aus dem Oberkambrium von
Schweden. Neues Jahrbuch für Geologie und Paläon-
tologie, Abhandlungen 121, 1–46.
MÜLLER, K. J. 1971. Cambrian conodont faunas. Geological
Society of America Memoir 127, 5–20.
MÜLLER,W.E.G.,LI,J.,SCHRÖDER,H.C.,QIAO,L.
&W
ANG, X. 2007. The unique skeleton of siliceous
sponges (Porifera; Hexactinellida and Demospongiae)
that evolved first from the Urmetazoa during the
Proterozoic: a review. Biogeosciences 4, 219–32.
NARBONNE, G. M. 2005. The Ediacara biota: Neoproterozoic
origin of animals and their ecosystems. Annual Review
of Earth and Planetary Sciences 33, 421–42.
NARBONNE, G. M., KAUFMAN,A.J.&KNOLL,A.H.
1994. Integrated chemostratigraphy and biostratigraphy
of the Windermere Supergroup, northwestern Canada:
implications for Neoproterozoic correlations and the
early evolution of animals. Geological Society of
America Bulletin 106, 1281–92.
NEAL,M.L.&HANNIBAL, J. T. 2000. Paleoecologic
and taxonomic implications of Sphenothallus and
Sphenothallus-like specimens from Ohio and areas
adjacent to Ohio. Journal of Paleontology 74, 369–80.
NECKAJA,A.I.&IVANOVA, V. A. 1956. Pervaya nakhodka
ostrakod v nizhnem kembrii Vostocjnoj Sibiri. [First find
of ostracods in the Lower Cambrian of eastern Siberia.]
Doklady AN SSSR 111(5), 1095–97.
OGG,J.G,OGG,G.&GRADSTEIN, F. M. 2008. The
Concise Geologic Time Scale. Cambridge, New York,
Melbourne: Cambridge University Press, 177 pp.
PARKHAEV,YU. P. 1998. Siphonoconcha – novyj klass
rannekembriyskikh dvustvorchatykh organizmov.
[Siphonoconcha – a new class of early Cambrian
bivalved organisms.] Paleontologicheskiy zhurnal
1998(1), 3–16.
PEEL, J. S. 1991. The classes Tergomya and Helcionelloida,
and early molluscan evolution. Bulletin Grønlands
Geologiske Undersøgelse 161, 11–65.
PEL’MAN,YU. L. 1977. Ranne- i srednekembrijskie
bezzamkovye brakhiopody Sibirskoj platformy. [Early
and Middle Cambrian inarticulate brachiopods of the
Siberian Platform.] Trudy Instituta Geologii i Geofiziki
SO AN SSSR 316. Novosibirsk: Nauka, 168 pp.
PEL’MAN,YU. L. 1985. Novye stenotekoidy iz nizhnego
kembriya Zapadnoj Mongolii [New stenothecoids from
the Lower Cambrian of western Mongolia.] Trudy
Instituta Geologii i Geofiziki SO AN SSSR 632, 103–
14. Novosibirsk: Nauka.
PEL’MAN,YU.L.,ERMAK,V.V.,FEDOROV,A.B.,LUCHININA,
V. A . , Z HURAVLEVA,I.T.,REPINA,L.N.,BONDAREV,
V. I . & B ORODAEVSKAYA, Z. V. 1990. Novye dannye
po stratigrafii i paleontologii verkhnego dokembriya
i nizhnego kembriya r. Dzhandy (pravyj pritok r.
Aldan). [New data on stratigraphy and palaeontology
of the upper Precambrian and lower Cambrian of
river Dzhandy (right tributary of river Aldan).] In
Biostratigrafiya i paleontologiya kembriya Severnoj

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
26 A. KOUCHINSKY & OTHERS
Azii. [Biostratigraphy and palaeontology of the Cam-
brian of northern Asia.] (ed. L. N. Repina), pp. 3–32.
Novosibirsk: Nauka (in Russian).
PEL’MAN,YU.L.,AKSARINA,N.A.,KONEVA,S.P.,POPOV,
L. YE., SOBOLEV,L.P.&USHATINSKAYA, G. T. 1992.
Drevneyshie brakhiopody territorii severnoy Evrazii.
[The oldest brachiopods from the territory of northern
Eurasia.] Novosibirsk: OIGGiM RAN, 145 pp.
PENG,J.,ZHAO,Y.-L.,WU,Y.,YUA N,J.-L.&TAI, T.-S. 2005.
The Balang Fauna – a new early Cambrian Fauna from
Kaili City, Guizhou Province. Chinese Science Bulletin
50, 1159–62.
PONOMARENKO, A. G. (ed.) 2005. Unikal’nye sinskiye
mestonakhozhdeniya rannekembriyskikh organizmov
(Sibirskaya platforma). [Unique Sinsk localities of
Early Cambrian organisms (Siberian Platform).] Trudy
Paleontologicheskogo Instituta 284, 143 pp.
POPOV,L.E.,BASSETT,M.G.,ZHEVCHUZHNIKOV,V.G.,
HOLMER,L.E.&KLISHEVICH, I. A. 2009. Gondwanan
faunal signatures from Early Palaeozoic terranes of
Kazakhstan and Central Asia: evidence and tectonic
implications. In Early Palaeozoic Peri-Gondwana Ter-
ranes: New Insights from Tectonics and Biogeography
(ed. M. G. Bassett), pp. 23–64. Geological Society of
London, Special Publication no. 325.
PORTER, S. M. 2007. Seawater chemistry and early carbonate
biomineralization. Science 316, 1302.
PORTER, S. M. 2008. Skeletal microstructure indicates
chancelloriids and halkieriids are closely related. Pa-
laeontology 51, 865–79.
PYLE,L.J.,NARBONNE, G. M., JAMES,N.P.,DALRYMPLE,
R. W. & KAUFMAN, A. J. 2004. Integrated Ediacaran
chronostratigraphy, Wernecke Mountains, northwestern
Canada. Precambrian Research 132, 1–27
PYLE,L.J.,NARBONNE, G. M., NOW LAN,G.S.,XIAO,S.&
JAMES, N. P. 2006. Early Cambrian metazoan eggs, em-
bryos, and phosphatic microfossils from northwestern
Canada. Journal of Paleontology 80, 811–25.
QIAN, Y. 1978. The early Cambrian hyolithids in central and
southwest China and their stratigraphical significance.
Memoirs of Nanjing Institute of Geology and Palaeon-
tology 11, 1–43 (in Chinese with English summary).
QIAN, Y. 1989. Early Cambrian small shelly fossils of
China with special reference to the Precambrian-
Cambrian boundary. Stratigraphy and Palaeontology of
Systemic Boundaries in China, Precambrian–Cambrian
Boundary (2). Nanjing: Nanjing University Publishing
House, 342 pp.
QIAN, Y. (ed.) 1999. Taxonomy and Biostratigraphy of Small
Shelly Fossils in China. Beijing: Science Press, 247 pp.
(in Chinese with English summary).
QIAN,Y.&BENGTSON, S. 1989. Palaeontology and
biostratigraphy of the Early Cambrian Meishucunian
Stage in Yunnan Province, South China. Fossils and
Strata 24, 1–156.
QIAN,Y.,LI,G.&ZHU, M. 2001 The Meishucunian Stage
and its small shelly fossil sequence in China. Acta
Palaeontological Sinica 40(Supplement), 54–62.
QIAN,Y.,LI, G.-X., ZHU, M.-Y., STEINER,M.&ER-
DTMANN, B.-D. 2004. Early Cambrian protoconodonts
and conodont-like fossils from China: taxonomic revi-
sions and stratigraphic implications. Progress in Natural
Science 14(2), 173–80.
QIAN,Y.,VAN ITEN,H.,COX,R.S.,ZHU, M.-Y.
&Z
HUO, E.-J. 1997. A brief account of Emeiconularia
trigemme, a new genus and species of protoconu-
lariid. Acta Micropalaeontologica Sinica 14, 475–
88.
QIAN,Y.&YIN, G. 1984. Zhijinitae and its stratigraphical
significance. Acta Palaeontologica Sinica 23, 216–
23.
QIAN,Y.,ZHU, M., LI,G.,JIANG,Z.&VAN ITEN, H. 2002. A
supplemental Precambrian-Cambrian boundary global
stratotype section in SW China. Acta Palaeontologica
Sinica 41, 19–26.
RAMSKÖLD,L.&HOU, X. 1991. New early Cambrian animal
and onychophoran affinities of enigmatic metazoans.
Nature 351, 225–8.
RANDELL,R.D.,LIEBERMAN,B.S.,HASIOTIS,S.T.
&P
OPE, M. C. 2005. New chancelloriids from the
Early Cambrian Sekwi Formation with a comment on
chancelloriid affinities. Journal of Paleontology 79,
987–96.
RAYMOND, P. E. 1935. Leanchoilia and other mid-Cambrian
Arthropoda. Bulletin of the Museum of Comparative
Zoology, Harvard 46, 202–30.
REITNER, J. 1992. Coralline spongien der versuch
einer phylogenetisch-taxonomischen Analyse. Berliner
Geowissenshaftliche Abhandlungen E 1, 352 pp.
REITNER,J.&WÖRHEIDE, G. 2002. Non-Lithistid fossil
Demospongiae – origins of their palaeobiodiversity
and highlights in history of preservation. In Systema
Porifera: A guide to the classification of sponges (eds J.
N. A. Hooper & R. van Soest), pp. 52–68. New York:
Kluwer.
REPINA,L.N.,LAZARENKO,N.P.,MESHOVA,N.P.,
KORSHUNOV,V.T.,NIKIFOROV,N.T.&AKSARINA,N.A.
1974. Biostratigraphy and fauna of the Lower Cambrian
of the Kharulakh (Tuora-Sis Ridge). Moscow: Nauka,
299 pp.
RIDING,R.&ZHURAVLEV,A.YU. 1995. Structure and
diversity of oldest sponge-microbe reefs: Lower Cam-
brian, Aldan River, Siberia. Geology 23, 649–52.
RIGBY,J.K.&HOU, X.-G. 1995. Lower Cambrian
demosponges and hexactinellid sponges from Yunnan,
China. Journal of Paleontology 69, 1009–19.
ROWLAND, S. M., LUCHININA,V.A.,KOROVNIKOV,I.V.,
SIPIN,D.P.,TARLETSKOV,A.&FEDOSEEV, A. V. 1998.
Biostratigraphy of the Vendian–Cambrian Sukharikha
River section, northwestern Siberian Platform. Cana-
dian Journal of Earth Sciences 35, 339–52.
ROZANOV,A.YU., KHOMENTOVSKY,V.V.,SHABANOV,YU.
YA., KARLOVA,G.A.,VARLAMOV,A.I.,LUCHININA,V.
A., PEGEL’, T. V., DEMIDENKO,YU.E.,PARKHAEV,P.
YU., KOROVNIKOV,I.V.&SKORLOTOVA, N. A. 2008. To
the problem of stage subdivision of the Lower Cambrian.
Stratigraphy and Geological Correlation 16(1), 1–19.
ROZANOV,A.YU.&MISSARZHEVSKY, V. V. 1966.
Biostratigrafiya i fauna nizhnikh gorizontov kembriya.
[Biostratigraphy and fauna of the lower horizons of the
Cambrian.]. Trudy Geologicheskogo Instituta AN SSSR
148, 1–125 (in Russian).
ROZANOV,A.Y.,MISSARZHEVSKY,V.V.,VOLKOVA,N.
A., VORONOVA,L.C.,KRYLOV,I.N.,KELLER,B.
M., KOROLYUK,I.K.,LENDZION,K.,MICHNIAK,R.,
PYKHOVA,N.G.&SIDOROV, A. D. 1969. Tommotskij
jarus i problema nizhnej granizty kembrija. [The
Tommotian Stage and the Cambrian lower boundary
problem.] Trudy Geologicheskogo Instituta AN SSSR
206, 1–380. (In Russian; English edition: 1981, 359 pp.
New Delhi: Amerind Publishing Co.).
ROZANOV,A.YU., PARKHAEV,P.YU., DEMIDENKO,YU.E.,
KARLOVA,G.A.,KOROVNIKOV,I.V.,SHABANOV,YU.
YA., IVANTSOV,A.YU., LUCHININA,V.A.,MALAK-
HOVSKAYA,YA.E.,MEL’NIKOVA, L. M., NAIMARK,
E. B., PONOMARENKO,A.G.,SKORLOTOVA,N.A.,

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 27
SUNDUKOV, V. M., TOKAREV,D.A.,USHATINSKAYA,G.
T. & KIPRIYANOVA, L. D. 2010. Iskopaemye stratotipov
yarusov nizhnego kembriya. [Fossils from the Lower
Cambrian Stage stratotypes.] Moscow: PIN RAN,
228 pp.
ROZANOV,A.YU., REPINA,L.N.,APOLLONOV,M.K.,
SHABANOV,YU.YA., ZHURAVLEV,A.YU., PEGEL’, T.
V. , F EDOROV,A.B.,ASTASHKIN,V.A.,ZHURAVLEVA,
I. T., EGOROVA,L.I.,CHUGAEVA,M.N.,DUBININA,
S. V., ERMAK,V.V.,ESAKOVA,N.V.,SUNDUKOV,V.V.,
SUKHOV,S.S.&ZHEMCHUZHNIKOV, V. G. 1992. Kembrij
Sibiri. [The Cambrian of Siberia]. Novosibirsk: Nauka,
135 pp.
ROZANOV,A.YU.&SOKOLOV, B. S. (eds.) 1984. Stage
Subdivision of the Lower Cambrian. Stratigraphy.
Moscow: Nauka (in Russian).
ROZANOV,A.YU.&ZHURAVLEV,A.YU. 1992. The Lower
Cambrian fossil record of the Soviet Union. In Origin
and Early Evolution of the Metazoa (eds.J.H.Lipps&
P. W. Signor), pp. 205–82. New York: Plenum.
ROZOV, S. N. 1984. Morfologiya, terminologiya, i sis-
tematicheskoe polozhenie stenotekoid. [Morphology,
terminology, and systematic affinity of stenothecoids.]
Trudy Instituta Geologii i Geofiziki SO AN SSSR 597,
117–33.
RUNNEGAR, B. 1980. Hyolitha: status of the phylum. Lethaia
13, 21–5.
RUNNEGAR,B.&POJETA, J. 1974. Molluscan phylogeny: the
paleontological viewpoint. Science 186, 311–17.
RUNNEGAR,B.,POJETA,J.,MORRIS,N.J.,TAYLOR,J.D.,
TAYLOR,M.E.&MCCLUNG, G. 1975. Biology of the
Hyolitha. Lethaia 8, 181–91.
RUZHENTSEV,S.V.&MOSSAKOVSKY, A. A. 1995. Geodin-
amika i tektonikoe razvitie paleozoid tsentral’noy Azii
kak rezul’tat vzaimodeystviya Tikhookeanskogo i Indo-
Atlanticheskogo segmentov Zemli. [Geodynamics and
tectonic evolution of the Central Asian paleozoids as
a result of interaction between the Pacific and Indo-
Atlantic segments of Earth]. Geotektonika 1995(4), 29–
47.
SALTER, J. W. 1864. On some new fossils from the Lingula
flags of Wales. Quarterly Journal of the Geological
Society of London 20, 233–41.
SAMUELSON,J.,VAN ROY,P.&VECOLI, M. 2001. Mi-
cropalaeontology of a Moroccan Ordovician deposit
yielding soft-bodied organisms showing Ediacara-like
preservation. Geobios 34, 365–73.
SAWAKI,Y.,NISHIZAWA, M., SUO,T.,KOMIYA,T.,HIRATA,
T., TAKAHATA,N.,SANO,Y.,HAN,J.,KON,Y.&
MARUYAMA, S. 2008. Internal structures and U-Pb
ages of zircons from a tuff layer in the Meishucunian
formation, Yunnan Province, South China. Gondwana
Research 14(1–2), 148–58.
SAYUTINA, T. A. 1980. Rannekembrijskoe semejstvo Kha-
saktiidae fam. nov. – vozmozhnye stromatoporaty. [The
Lower Cambrian family Khasaktiidae fam. nov. –
probable stromatoporates]. Paleontologicheskij Zhurnal
1980(4), 13–28. (English translation: Paleontological
Journal 14(4), 13–30.)
SEMIKHATOV,M.A.&SEREBRYAKOV, S. N. 1983. The
Siberian hypostratotype of the Riphean. Trudy Geolo-
gischeskogo Instituta AN SSSR 210, 1–207.
SEREZHNIKOVA, E. A. 2007 Palaeophragmodictya spinosa
sp. nov., a bilateral benthic organism from the Vendian
of the southeastern White Sea region. Paleontological
Journal 41(4), 360–69.
SEREZHNIKOVA,E.A.&IVANTSOV,A.YU. 2007. Fedomia
mikhaili – a new spicule-bearing organism of sponge
grade from the Vendian (Ediacaran) of the White Sea,
Russia. Pala e oworl d 16(4), 319–24.
SHABANOV,YU.YA., ASTASHKIN,V.A.,PEGEL,T.V.,
EGOROVA,L.I.,ZHURAVLEVA,I.T.,PEL’MAN,YU.L.,
SUNDUKOV, V. M., STEPANOVA,M.V.,SUKHOV,S.S.,
FEDOROV,A.B.,SHISHKIN,B.B.,VAGANOVA,N.V.,
ERMAK,V.I.,RYABUKHA,K.V.,YADRENKINA,A.G.,
ABAIMOVA,G.P.,LOPUSHINSKAYA,T.V.,SYCHEV,O.
V. & M OSKALENKO, T. A. 1987. Nizhnij paleozoj yugo-
zapadnogo sklona Anabarskoj anteklizy (po materialam
bureniya). [Lower Palaeozoic of SW slope of the Anabar
anticline (drill core material).] Novosibirsk: Nauka,
208 pp.
SHABANOV,YU.YA., KOROVNIKOV,I.V.,PERELADOV,V.S.
&F
EFELOV, A. F. 2008. Excursion 1a. The traditional
Lower–Middle Cambrian boundary in the Kuonamka
Formation of the Molodo River section (the southeastern
slope of the Olenek Uplift of the Siberian Platform)
proposed as a candidate for GSSP of the lower boundary
of the Middle Cambrian and its basal (Molodian) stage,
define by the FAD of Ovatoryctocara granulata.In
The Cambrian System of the Siberian Platform. Part 2:
North-east of the Siberian Platform (eds A. Yu. Rozanov
& A. I. Varlamov). Moscow: PIN RAN and Novosibirsk,
140 pp.
SHERGOLD,J.&GEYER, G. 2003. The Subcommission on
Cambrian stratigraphy: the status quo. Geologica Acta
1(1), 5–9.
SHU,D.G.,LUO,H.L.,CONWAY MORRIS,S.,ZHANG,X.
L., HU, S.-X., CHEN,L.,HAN,J.,ZHU, M., LI,Y.&
CHEN, L.-Z. 1999. Lower Cambrian vertebrates from
south China. Nature 402, 42–6.
SHU,D.,VANNIER,J.,LUO,H.-L.,CHEN,L.-Z.,ZHANG,X.-L.
&H
U, S.-X. 1999 Anatomy and lifestyle of Kunmingella
(Arthropoda, Bradoriida) from the Chengjiang fossil La-
gerstätte (Lower Cambrian, southwest China). Lethaia
32, 279–98.
SIGNOR, P. W. 1992. Evolutionary and tectonic implications
of Early Cambrian faunal endemism. In The History of
Water: Eastern Sierra Nevada, Owens Valley, White-
Inyo Mountains (eds C. A. Hall, Jr., V. Doyle-Jones
& B. Widawski), pp. 1–13. White Mountain Research
Station Symposium, vol. 4. Los Angeles: Regents of the
University of California.
SKOVSTED, C. B. 2003. Mobergellans (Problematica) from
the Cambrian of Greenland, Siberia and Kazakhstan.
Paläontologische Zeitschrift 77, 429–43.
SKOVSTED, C. B. 2004. The mollusc fauna of the Early
Cambrian Bastion Formation of North-East Greenland.
Bulletin of the Geological Society of Denmark 51, 11–
37.
SKOVSTED, C. B. 2006. Small Shelly fauna from the upper
Lower Cambrian Bastion and Ella Island formations,
north-east Greenland. Journal of Paleontology 80,
1087–112.
SKOVSTED,C.B.,BALTHASAR,U.,BROCK,G.A.&
PATERSON, J. R. 2009a. The tommotiid Camenella
reticulosa from the lower Cambrian of South Australia,
scleritome reconstructions and tommotiid phylogeny.
Acta Palaeontologica Polonica 54, 525–40.
SKOVSTED,C.B.,BROCK,G.A.&PATERSON,J.R.
2006. Bivalved arthropods from the Lower Cambrian
Mernmerna Formation of South Australia and their
implications for the identification of Cambrian “small
shelly fossils”. Memoirs of the Association of Aus-
tralasian Palaeontologists 32, 7–41.
SKOVSTED,C.B.,BROCK,G.A.,PATERSON,J.R.,HOLMER,
L. E. & BUDD, G. E. 2008. The scleritome of

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
28 A. KOUCHINSKY & OTHERS
Eccentrotheca from the Lower Cambrian of South
Australia: lophophorate affinities and implications for
tommotiid phylogeny. Geology 36, 171–4.
SKOVSTED,C.B.,HOLMER,L.E.,LARSSON, C. M.,
HÖGSTRÖM,A.E.S.,BROCK,G.A.,TOPPER,T.P.,
BALTHASAR,U.,PETTERSON STOLK,S.&PATERSON,
J. P. 2009b. The scleritome of Paterimitra:anEarly
Cambrian stem group brachiopod from South Australia.
Proceedings of the Royal Society of London B 276,
1651–6.
SKOVSTED,C.B.,HOLMER,L.E.,TOPPER,T.P.&BROCK,
G. A. 2010. Brachiopod affinity of the Lower Cam-
brian problematic bivalve Apistoconcha.International
Palaeontological Congress, London, June, 28–July, 3,
Abstracts with prog ram me , p. 356.
SKOVSTED,C.B.&PEEL, J. S. 2011. Hyolithellus in life
position from the lower Cambrian of North Greenland.
Journal of Paleontology 85, 37–47.
SMITH,M.P.&SANSOM, I. J. 1995. The affinity of Anatolepis.
Geobios 28(Supplement 2), 61–3.
SMITH,M.P.,SANSOM,I.J.&COCHRANE,K.D.
2001. The Cambrian origin of vertebrates. In Major
Events in Early vertebrate Evolution – Palaeontology,
phylogeny, genetics, and development (ed. P. E. Ahl-
berg), pp. 67–84. The Systematics Association Special
Volume 61.
SMITH,M.P.,SANSOM,I.J.&REPETSKI, J. E. 1996. Histology
of the first fish. Nature 380, 702–4.
SNODGRASS, R. E. 1938. Evolution of the Annelida, Ony-
chophora, and Arthropoda. Smithsonian Miscellaneous
Collections 97(6), 1–159.
SOKOLOV,B.S.&ZHURAVLEVA, I. T. (eds) 1983. Yarusnoe
raschlenenie nizhnego kembriya Sibiri. Atlas okame-
nelostej. [Stage subdivision of the Lower Cambrian
of Siberia. Atlas of fossils.] Trudy Instituta Geologii
i Geofiziki SO AN SSSR 558, 1–216.
SPERLING,E.A.,PISANI,D.&PETERSON, K. J. 2007.
Poriferan paraphyly and its implications for Precambrian
palaeobiology. In The Rise and Fall of the Ediacaran
Biota (eds P. Vickers-Rich & P. Komarower), pp. 355–
68. Geological Society of London, Special Publication
no. 286.
SPRINKLE, J. 1973. Morphology and Evolution of Blastozoan
Echinoderms. Harvard University Museum of Compar-
ative Zoology, Special Publication, 283 pp.
STANLEY,S.M.&HARDIE, L. A. 1998. Secular oscillations in
the carbonate mineralogy of reefbuilding and sediment-
producing organisms driven by tectonically forced shifts
in seawater chemistry. Palaeogeography, Palaeoclimato-
logy, Palaeoecology 144, 3–19.
STEINER,M.&LI, G. 2010. Cambrian Small Shelly
Fossils and the taphonomic phosphatization window.
International Palaeontological Congress, London, June,
28–July, 3, Abstracts with programme, p. 363.
STEINER, M., LI,G.,QIAN,Y.&ZHU, M. 2004a.Lower
Cambrian Small Shelly Fossils of northern Sichuan
and southern Shaanxi (China), and their biostratigraphic
importance. Geobios 37, 259–75.
STEINER, M., LI, G.-X., QIAN,Y.,ZHU, M.-Y. & ERDTMANN,
B.-D. 2007. Neoproterozoic to Early Cambrian Small
Shelly assemblages of the Yangtze Platform (China) and
their potential for regional and international correlation.
Palaeogeography, Palaeoclimatology, Palaeoecology
254, 67–99.
STEINER, M., MEHL,D.,REITNER,J.&ERDTMANN,
B.-D. 1993. Oldest entirely preserved sponges and
other fossils from the lowermost Cambrian and a new
facies reconstruction of the Yangtze platform (China).
Berliner Geowissenschaftlich Abhandlungern E 9, 293–
329.
STEINER, M., ZHU, M., LI,G.,QIAN,Y.&ERDTMANN,
B.-D. 2004b. New Early Cambrian bilaterian embryos
and larvae from China.Geology 32, 833–36.
STEINER, M., ZHU, M., WEBER,B.&GEYER, G. 2001.
The Lower Cambrian of Eastern Yunnan: trilobite-based
biostratigraphy and related faunas. Acta Palaeontolo-
gica Sinica 40(Supplement), 63–79.
STRENG, M., EBBESTAD,J.O.R.&MOCZYDŁOWSKA,M.
2008. A Walcottella-like bradoriid (Arthropoda) from
the lower Cambrian of Sweden. GFF 130, 11–9.
STRENG,M.&SKOVSTED, C. B. 2006. A new mobergellan
(small shelly fossils) from the early Middle Cambrian
of Morocco and its significance. Paläontologische
Zeitschrift 80/3, 209–20.
SYSOEV, V. A. 1962. Khiolity kembriya severnogo sklona
Aldanskogo shchita. [Cambrian hyolithids from the
northern slope of the Aldan shield.] Yakutian Filial of
SO AN SSSR, 66 pp.
SZANIAWSKI, H. 1982. Chaetognath grasping spines re-
cognized among Cambrian protoconodonts. Journal of
Paleontology 56, 806–10.
SZANIAWSKI, H. 2002. New evidence for the protoconodont
origin of chaetognaths. Acta Palaeontologica Polonica
47, 405–19.
SZANIAWSKI,H.&BENGTSON, S. 1993. Origin of euconodont
elements. Journal of Paleontology 67, 640–54.
SZANIAWSKI,H.&BENGTSON, S. 1998. Late Cambrian
euconodonts from Sweden. In Proceedings of the Sixth
European Conodont Symposium (ECOS VI) (ed. H.
Szaniawski). Palaeontologia Polonica 58, 7–29.
TANG,T.,ZHANG,J.&JIANG, X. 1978. Discovery and
significance of the Late Sinian fauna from western
Hunan and Hubei. Acta Stratigraphica Sinica 2, 32–45.
THOMAS,R.D.K.,SHERMAN,R.M.&STEWART, C. W. 2000.
Evolutionary exploitation of design options by the first
animals with hard skeletons. Science 288, 1239–42.
TIWARI, M. 1999. Organic-walled microfossils from the
Chert-Phosphate Member, Tal Formation, Precambrian–
Cambrian boundary, India. Precambrian Research 97,
99–113.
TIWARI, M., PANT,C.C.&TEWARI, V. C. 2000. Neoprotero-
zoic sponge spicules and organic-walled microfossils
from the Gangolihat Dolomite, Lesser Himalaya, India.
Current Science 79(5), 651–4.
TOPPER,T.P.,BROCK,G.A.,SKOVSTED,C.B.&PATERSON,
J. R. 2010. Palaeoscolecid scleritome fragments with
Hadimopanella plates from the early Cambrian of South
Australia. Geological Magazine 147, 86–97.
TOPPER,T.P.,SKOVS TE D,C.B.,BROCK,G.A.&PATERSON,
J. R. 2011. The oldest bivalved arthropods from
the early Cambrian of East Gondwana: systematics,
biostratigraphy and biogeography. Gondwana Research
19, 310–26.
USHATINSKAYA, G. T. 1987. Neobychnye bezzamkovye
brakhiopody iz nizhnego kembriya Mongolii. [Unusual
inarticulate brachiopods from the Lower Cambrian of
Mongolia.] Paleontologicheskij Zhurnal 1987(2), 62–
8. (English translation: Paleontological Journal 21(2),
59–66.)
USHATINSKAYA,G.T.&MALAKHOVSKAYA,YA. E. 2001.
Origin and development of the Cambrian brachiopod
biochores. Stratigraphy and Geological Correlation
9(6), 540–56.
USHATINSKAYA,G.T.&ZHURAVLEV,A.YU. 1994. K prob-
leme mineralizatsii skeleta (na primere brakhiopod). [To
the problem on skeletal biomineralization (exemplified

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 29
by brachiopods).] Doklady Akademii Nauk 337(2), 231–
4 (in Russian).
VAL’KOV, A. K. 1982. Biostratigrafiya nizhnego kembriya
vostoka Sibirskoj platformy (Uchuro-Majskij rajon).
[Biostratigraphy of the Lower Cambrian of eastern
Siberian platform (Utchur-Maya region)]. Moscow:
Nauka, 91 pp. (in Russian)
VAL’KOV, A. K. 1987. Biostratigrafijanizhnego kembrija vos-
toka Sibirskoj platformy (Yudoma-Oleniokskij region).
[Biostratigraphy of the Lower Cambrian of eastern
Siberian Platform (Yudoma-Oleniok region)]. Moscow:
Nauka, 136 pp. (in Russian)
VAN ITEN,H.,VYHLASOVA,Z.,ZHU, M.-Y. & QIAN,Y.
2005. Widespread occurrence of microscopic pores in
conulariids. Journal of Paleontology 79, 400–7.
VAN ITEN,H.,ZHU, M.-Y. & COLLINS, D. 2002. First report
of Sphenothallus Hall, 1847 in the Middle Cambrian.
Journal of Paleontology 76, 902–5.
VAN ITEN,H.,ZHU, M.-Y. & LI, G. 2010. Redescription
of Hexaconularia He and Yang, 1986 (Lower Cam-
brian, South China): implications for the affinities of
conulariid-like small shelly fossils. Palaeontology 53,
191–9.
VANNIER,J.,STEINER, M., RENVOISE,E.,HU, S.-X. &
CASANOVA, J.-P. 2007. Early Cambrian origin of modern
food webs: evidence from predator arrow worms.
Proceedings of the Royal Society B 274, 627–33.
VARLAMOV,A.I.,ROZANOV,A.YU., KHOMENTOVSKY,V.
V. , S HABANOV,YU.YA., ABAIMOVA,G.P.,DEMIDENKO,
YU.E.,KARLOVA,G.A.,KOROVNIKOV,I.V.,LUCHININA,
V. A . , M ALAKHOVSKAYA,YA.E.,PARKHAEV,P.YU.,
PEGEL,T.V.,SKORL OTOVA,N.A.,SUNDUKOV, V. M.,
SUKHOV,S.S.,FEDOROV,A.B.&KIPRIYANOVA,L.D.
2008. The Cambrian System of the Siberian Platform.
Part 1: The Aldan-Lena region. Moscow-Novosibirsk:
PIN RAN, 300 pp.
VENDRASCO,M.J.,LI,G.,PORTER,S.M.&FERNANDEZ,
C. Z. 2009. New data on the enigmatic Ocruranus-
Eohalobia group of early Cambrian small skeletal
fossils. Palaeontology 52, 1373–96.
VORONIN,Y.I.,VORONOVA,L.G.,GRIGOR’EVA,N.V.,
DROZDOVA,N.A.,ZHEGALLO,E.A.,ZHURAVLEV,
A. YU., RAGOZINA,A.L.,ROZANOV,A.YU., SAY-
UTINA,T.A.,SYSOEVA,V.A.&FONIN, V. D. 1982.
Granitsa dokembriya i kembriya v geosinklinal’nykh
oblastyakh (opornyj razrez Salany-Gol, MNR). [The
Precambrian-Cambrian boundary in the geosynclinal
regions (reference section Salany-Gol, MNR).] Trudy
Sovmestnoj sovetsko-mongol’skoj paleontologicheskoj
ehkspeditsii.Volume 18. Moscow: Nauka, 150 pp. (in
Russian)
VORONOVA,L.G.,DROSDOVA,N.A.,ESAKOVA,N.V.,
ZHEGALLO,E.A.,ZHURAVLEV,A.YU., ROZANOV,
A. YU., SAYUTINA,T.A.&USHATINSKAYA,G.T.
1987. Iskopaemye nizhnego kembriya gor Makkenzi
(Kanada). [Lower Cambrian fossils from the Macken-
zie Mountains (Canada).] Trudy Paleontologicheskogo
Instituta AN SSSR 224, 88 pp. (in Russian)
VOSTOKOVA, V. A. 1962. Kembrijskie gastropody Sibrskoj
platformy i Tajmyra. [The Cambrian gastropods from
Siberia and Tajmyr.] Trudy Nauchno-Issledovatel’skogo
Instituta Geologii Arktiki 28, 51–74 (in Russian).
WALCOTT, C. D. 1889. Stratigraphic position of the Olenellus
fauna in North America and Europe. American Journal
of Science 38, 374–92.
WALCOTT, C. D. 1920. Middle Cambrian Spongiae. Smith-
sonian Miscellaneous Collections 67, 261–364.
WEBER,B.,STEINER,M.&ZHU, M. 2007. Precambrian–
Cambrian trace fossils from the Yangtze Platform (South
China) and the early evolution of bilaterian lifestyles.
Palaeogeography, Palaeoclimatology, Palaeoecology
254, 328–49.
WEBER,B.&ZHU, M. 2003. Arthropod trace fossils from
the Zhujiaqing Formation (Meishucunian, Yunnan) and
their palaeobiological implications. Progress in Natural
Science 13(10), 795–800.
WILMOT,N.V.&FALLICK, A. E. 1989. Original mineralogy
of trilobite exoskeletons. Palaeontology 32, 297–304.
WILLIAMS,A.&HOLMER, L. E. 2002. Shell structure and
inferred growth, functions and affinities of the sclerites
of the problematic Micrina.Palaeontology 45, 845–73.
WILLIAMS, M., SIVETER,D.J.,POPOV,L.E.&VANNIER,
J. M. C. 2007 Biogeography and affinities of the
bradoriid arthropods: cosmopolitan microbenthos of the
Cambrian seas. Palaeogeography, Palaeoclimatology,
Palaeoecology 248, 202–32.
WOOD,R.A.,GROTZINGER,J.P.&DICKSON, J. A. D. 2002.
Proterozoic modular biomineralized metazoan from the
Nama Group, Namibia. Science 296, 2383–6.
WRONA, R. 1982. Early Cambrian phosphatic microfossils
from southern Spitsbergen (Horsund region). Palaeon-
tologia Polonica 43, 9–16.
XING,Y.,DING,Q.,LUO,H.,HE,T.&WANG, Y. 1984
(but data on cover is 1983). The Sinian-Cambrian
boundary of China. Bulletin of the Institute of Geology,
Chinese Academy of Geological Sciences 10, 262 pp.
(in Chinese)
YOCHELSON, E. L. 1969. Stenothecoida, a proposed new class
of Cambrian Mollusca. Lethaia 2, 49–62.
YOUNG, G. C. 2009. An Ordovician vertebrate from
western New South Wales, with comments on Cambro-
Ordovician vertebrate distribution patterns. Alcheringa
33, 79–89.
YU, W. 1996. Early Cambrian stenothecoid molluscs from
China. Records of the Western Australian Museum 18,
209–17.
YUAN ,X.,XIAO,S.,PARSLEY,R.L.,ZHOU,C.,CHEN,
Z. & HU, J. 2002. Towering sponges in an Early
Cambrian Lagerstätte: disparity between nonbilaterian
and bilaterian epifaunal tiers at the Neoproterozoic–
Cambrian transition. Geology 30, 363–6.
ZAMORA,S.,LEFEBVRE,B.,ÁLVA R O ,J.J.,CLAUSEN,
S., ELICKI,O.,FATKA,O.,JELL,P.,KOUCHINSKY,
A., LIN,J.-P.,NARDIN,E.,PARSLEY,R.,ROZHNOV,
S., SPRINKLE,J.,SUMRALL,C.D.,VIZCAÏNO,D.
&S
MITH, A. B. In press. Cambrian echinoderm
diversity and palaeobiogeography. In Early Palaeozoic
Palaeography and Biogeography (eds.D.Harper&
T. Servais). Geological Society of London, Special
Publication.
ZHANG, X.-G. 2007. Phosphatized bradoriids (Arthropoda)
from the Cambrian of China. Palaeontographica, Ab-
teilung A 281, 93–173.
ZHANG,W.&BABCOCK, L. E. 2001. New extraordinarily
preserved enigmatic fossils, possibly with Ediacaran
affinities, from the Lower Cambrian of Yunnan, China.
Acta Palaeontologica Sinica 40(Supplement), 201–13.
ZHANG,H.,DONG,X.-P.&MAAS, A. 2011. Hesslandona
angustata (Phosphatocopida, Crustacea) from the Upper
Cambrian of western Hunan, South China, with com-
ments on phosphatocopid phylogeny. Neues Jahrbuch
für Geologie und Paläontologie 259, 157–75.
ZHANG,Y.,YUA N,X.&YIN, L. 1998. Interpreting Late
Precambrian microfossils. Science 282, 1783.
ZHAO,Z.,XING,Y.,DING,Q.,LIU,G.,ZHAO,Y.,ZHANG,
S., MENG,X.,YIN,C.,NING,B.&HAN, P. 1988. The
Sinian System of Hubei. Wuhan: China University of
Geosciences Press, 205 pp.

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
30 A. KOUCHINSKY & OTHERS
ZHOU,C.,YUA N,X.&XUE, Y. 1998. Sponge spicule-
like pseudofossils from the Neoproterozoic Toushantou
Formation in Weng’an, Guizhou, China. Acta Micropa-
laeontologica Sinica 15, 380–4.
ZHU,R.-X.,LI, X.-H., HOU,X.,PAN, Y.-X., WANG,F.,DENG,
C.-L. & HE, H.-Y. 2009. SIMS U-Pb zircon age of a
tuff layer in the Meishucun section, Yunnan, southwest
China: constraint on the age of the Precambrian-
Cambrian boundary. Science in China, Series D-Earth
Sciences 52(9), 1385–92.
ZHU, M., LI,G.,ZHANG,J.,STEINER, M., QIAN,Y.&JIANG,
Z. 2001 Early Cambrian stratigraphy of east Yunnan,
southwest China: a synthesis. Acta Palaeontologica
Sinica 40(Supplement), 4–39.
ZHURAVLEV,A.YU. 1993. Early Cambrian steps of biom-
ineralization: mineralogy. 7th International Symposium
on Biomineralization, Monaco. Biomineralization 93,
p. 103.
ZHURAVLEV,A.YU. 1995. Preliminary suggestions of the
global Early Cambrian Zonation. Beringeria Special
Issue 2, 147–60.
ZHURAVLEV,A.YU. 2001. Biotic diversity and structure
during the Neoproterozoic–Ordovician transition. In
The Ecology of the Cambrian Radiation (eds A. Yu.
Zhuravlev & R. Riding), pp. 173–99. New York:
Columbia University Press.
ZHURAVLEV,A.YU., LIÑÁN,E.,GÁMEZ VINTANED,J.A.,
DEBRENNE,F.&FEDOROV, A. B. 2011. New finds
of skeletal fossils in the terminal Neoproterozoic of
the Siberian Platform and Spain. Acta Palaeontologica
Polonica, doi: 10.4202/app.2010.0074.
ZHURAVLEV,A.YU.&WOOD, R. A. 1996. Anoxia as the
cause of the mid-Early Cambrian (Botomian) extinction
event. Geology 24, 311–4.
ZHURAVLEV,A.YU.&WOOD, R. A. 2008. Eve of biominer-
alization: controls on skeletal mineralogy. Geology 36,
923–6.
ZHURAVLEVA, I. T. 1955. K poznaniyu archeotsiat Sibiri.
[To the understanding of archaeocyaths from Siberia.]
Doklady AN SSSR 104(4), 626–9.
Appendix 1
Siberian first appearances in the Nemakit–Daldynian
Stage(seeFig.4)
S1. Sclerites of protoconodonts Protohertzina anabarica
and P.unguliformis (Nemnekey; Khomentovsky & Karlova,
1991, 1993; projected onto the Siberian δ13C reference scale
by Brasier, Khomentovsky & Corfield, 1993).
Remarks. Anabaritids are also reported from this level
and below the Precambrian-Cambrian boundary negative
excursion (see data in online Appendix 1 at http://
journals.cambridge.org/geo, not shown in Fig. 4).
S2.Shellymolluscs Oelandiella sp. and Barskovia sp., hal-
waxiids Purella cristata,Siphogonuchites aff. triangularis,
and orthothecid hyoliths Lophotheca socialis (Mt Konus;
Khomentovsky, Val’kov & Karlova, 1990; projected onto the
Siberian δ13C reference scale by Brasier, Khomentovsky &
Corfield, 1993).
Remarks.Spiculesofhexactinellids Protospongia sp. and
?sclerites of chancelloriids Chancelloria sp. are also
reported from that level (Gonam; Khomentovsky & Karlova,
1993; projected herein onto the Siberian δ13C reference
scale in accordance with Brasier, Khomentovsky & Corfield,
1993).
S3. Tubes of hyolithelminths Hyolithellus sp., scler-
ites of chancelloriids Chancelloria sp., problematic
sclerites of Fomitchella cf. infundibuliformis (Gonam;
Semikhatov & Serebryakov, 1983; Khomentovsky et al.
1983; Khomentovsky & Karlova, 1993; projected herein onto
the Siberian δ13C reference scale in accordance with Brasier,
Khomentovsky & Corfield, 1993).
Siberian first appearances in the Tommotian Stage
(see Fig. 4)
S4.Tommotiid Sunnaginia imbricata,archaeocyaths, sili-
ceous stauracts and pentacts of the hexactinellid sponges
(Aldan; Sokolov & Zhuravleva, 1983; Rozanov & Sokolov,
1984; Shabanov et al. 2008); problematic tubes Tommo-
totubulus savitzkyi Fedorov, 1986 (Aldan; Khomentovsky,
Val’kov & Karlova, 1990).
S5.Calcium-phosphate brachiopods Aldanotreta
sunnaginensis (Aldan; Sokolov & Zhuravleva, 1983;
Rozanov & Sokolov, 1984; Bengtson et al. 1987;
Ushatinskaya & Malakhovskaya, 2001); problematic
sclerites Tumulduria incomperta (Aldan; Sokolov &
Zhuravleva, 1983; Rozanov & Sokolov, 1984; Bengtson
et al. 1987; Rozanov et al. 1992) and Archaeopetasus sp.
(as opercula of Coleolella billingsi in Rozanov et al. 1969,
pl. 7) (Aldan; Rozanov et al. 1969; Bengtson et al. 1990;
Dzik, 1994); problematic tubes Coleolella billingsi (Sysoev,
1962) (Aldan; Rozanov et al. 1969; Sokolov & Zhuravleva,
1983), ‘Coleolus’ trigonus Sysoev, 1962 (Aldan; Sysoev,
1962; Rozanov et al. 1969), and Coleoloides trigeminatus
Missarzhevsky in Rozanov et al. 1969 (Aldan; Sokolov &
Zhuravleva, 1983).
S6. Spicules of the calcarean sponge Dodecaactinella sp.
and thecae of corallomorph Cysticyathus tunicatus (Middle
Lena; Kruse, Zhuravlev & James, 1995).
S7.Mobergella sibirica Skovsted, 2003 (formerly
Mobergella radiolata Bengtson, 1968) (Aldan; Rozanov
et al. 1969; Sokolov & Zhuravleva, 1983; Rozanov &
Sokolov, 1984; Missarzhevsky, 1989; Rozanov & Zhuravlev,
1992).
S8.Calcium-carbonate brachiopods Nochoroiella isitica
and Obolella sp. (Middle Lena; Grigor’eva, Melnikova &
Pel’man, 1983; Sokolov & Zhuravleva, 1983; Rozanov &
Sokolov 1984; Pel’man et al. 1992;
S9. Problematic sclerites Rhombocorniculum insolutum
(Middle Lena; Sokolov & Zhuravleva, 1983; Rozanov &
Sokolov, 1984; Brasier, 1989b; Rozanov & Zhuravlev, 1992.
Bol’shaya Kuonamka; Kouchinsky et al., unpub. data and
herein).
Siberian first appearances in the Atdabanian Stage
(see Fig. 4)
S10.Trilobites Profallotaspis sp. (Middle Lena; Rozanov &
Sokolov, 1984).
S11.Microdictyon sp. (Bol’shaya Kuonamka; Kouchinsky
et al., unpub. data and herein).
S12.Eocrinoidea indet. (Bol’shaya Kuonamka; Kouchinsky
et al., unpub. data and herein).
S13.Hadimopanella apicata (Bol’shaya Kuonamka;
Kouchinsky et al., unpub. data and herein).
Appendix 2
Mongolian first appearances (see Fig. 5)
M1.Hexactinellid spicules (Brasier et al. 1996, fig. 5;
Braiser, Green & Shields, 1997); anabaritids A. trisulcatus
and C. decurvatus (Brasier et al. 1996; Esakova & Zhegallo,

http://journals.cambridge.org Downloaded: 30 Aug 2011 IP address: 130.242.24.193
Chronology of early Cambrian biomineralization 31
1996; Khomentovsky & Gibsher, 1996) or Anabarites sp.
(Esakova & Zhegallo, 1996).
M2.Protoconodonts Protohertzina unguliformis; scaly
shells of halwaxiids Purella sp.; orthothecid? hyoliths
Pseudorthotheca bicostata Qian (indicated as P. bistriata in
Khomentovsky & Gibsher, 1996, fig. 13, p. 386) (Brasier et
al. 1996, fig. 9; Khomentovsky & Gibsher, 1996, fig. 13).
M3.Tommotiids Camenella applanata and Camenella sp.
(Khomentovsky & Gibsher, 1996, fig. 3 on p. 386; Brasier
et al. 1996), Camenella cf. baltica (Voronin et al. 1982);
problematic tubes Hyolithellus cf. vladimirovae (Brasier
et al. 1996) or Hyolithellus sp. (Voronin et al. 1982) and
Coleolella billingsi (Brasier et al. 1996, figs 6, 7).
M4. Shelled molluscs Obtusoconus honorabilis and Grano-
conus trematus (Khomentovsky & Gibsher, 1996).
M5. Sclerites of chancelloriids Chancelloria sp. (Voronin
et al. 1982).
M6. Calcium carbonate-shelled brachiopod? Khasagtina
primaria Ushatinskaya, 1987 (described as Kundatella sp.
by Voronin et al. 1982).
M7.Stenothecoides sp. (Voronin et al. 1982;
Khomentovsky & Gibsher, 1996, fig. 13).