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1
Paleontological Journal, Vol. 38, No. 1, 2004, pp. 1–9. Translated from Paleontologicheskii Zhurnal, No. 1, 2004, pp. 3–9.
Original Russian Text Copyright © 2004 by Ivantsov, Malakhovskaya, Serezhnikova.
English Translation Copyright © 2004 by
åÄIä “Nauka
/Interperiodica” (Russia).
INTRODUCTION
The present paper continues the description of new
taxa of the Late Vendian metazoans collected by the
permanent expedition of the Laboratory of Precam-
brian Organisms of the Paleontological Institute of the
Russian Academy of Sciences in the southeastern
White Sea Region. The material was collected in the
following localities: (1) the Onega Peninsula, the vicin-
ity of Severodvinsk City, left bank of the Solza River,
approximately 5 km south of the city diversion dam;
(2) the same region, left bank of the Karakhta River,
approximately 2 km upstream from the road Severod-
vinsk–Onega; and (3) Zimnii Bereg (Winter Coast) of
the White Sea near the Zimnegorsk lighthouse. The
host rock of the first and second localities is assigned to
the Ust-Pinega Formation (Grazhdankin and Bronni-
kov, 1997), the third locality displays the Mezen For-
mation of the Upper Vendian. The studied collections
(nos. 3993, 4852, and 4853) are housed at the Paleon-
tological Institute of the Russian Academy of Science,
Moscow (PIN). All specimens were found on the basal
surface of thin layers of fine-grained sandstone. The
species
Parvancorina sagitta
sp. nov.,
Solza margarita
gen. et sp. nov.,
Karakhtia nessovi
gen. et sp. nov., and
Temnoxa molliuscula
gen. et sp. nov. are represented by
counterparts, while
Vaveliksia vana
sp. nov. is repre-
sented by a positive mold.
The reconstruction of the fossils represented by
counterparts is based on two assumption, i.e., (1) in
addition to the relief of the upper surface of the ani-
mal’s body, an imprint partly reproduces some internal
structures; and (2) convex elements of imprints corre-
spond to body structures relatively less compact at the
moment of sediment lithification, while concavities
correspond to more compact structures.
Parvancorina sagitta.
Judging from the absence of
folds and rough deformations of the imprint (Pl. 1,
figs. 5–8), the body of
Parvancorina
was rather hard
and, possibly, sclerotized. The single species of
Par-
vancorina, P. minchami
Glaessner, 1958 (Fig. 1), was
Some Problematic Fossils from the Vendian of the Southeastern
White Sea Region
A. Yu. Ivantsov, Ya. E. Malakhovskaya, and E. A. Serezhnikova
Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow, 117997 Russia
e-mail: yamal@paleo.ru
Received June 4, 2002
Abstract
—Three new genera and five new species of uncertain taxonomic position, i.e.,
Solza margarita
gen.
et sp. nov.,
Parvancorina sagitta
sp. nov.,
Karakhtia nessovi
gen. et sp. nov.,
Temnoxa molliuscula
gen. et
sp. nov., and
Vaveliksia vana
sp. nov., from the Late Vendian localities of the Onega Peninsula and Zimnii Bereg
of the White Sea are described.
Key words
: Metazoa, Late Vendian, Arkhangelsk Region, White Sea, Russia.
5
50 10
10
15
mm
mm
Length
P. sagitta
Width
P. minchami
Fig. 1.
Plot of length versus width of the imprints of
Par-
vancorina sagitta
sp. nov. (Onega Peninsula, Solza River;
Ust-Pinega Formation) and
P. minchami
Glaessner from
Zimnii Bereg (Winter Coast) of the White Sea; Mezen For-
mation, “
Kimberella
Lenses” locality.
2
PALEONTOLOGICAL JOURNAL
Vol. 38
No. 1
2004
IVANTSOV
et al
.
1
Plate 1
2
3
4‡
4b
5‡
5b
6
7
8
9
10
11 12
13
14
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SOME PROBLEMATIC FOSSILS FROM THE VENDIAN 3
considered to be an arthropod (Glaessner, 1980) due to
the presence of oblique hacks on several imprints,
which were interpreted as limb remains, and general
similarity with carapaces of some Paleozoic arthropods
(Glaessner, 1980; Fedonkin, 1985; Jenkins, 1992). Our
material does not display any new arguments favoring
the arthropod affinity of
Parvancorina
. No signs of
limbs were found in specimens of
P. sagitta.
In con-
trast, the similarity of
Parvancorina
to the new fossil
form
Temnoxa molliuscula
, which lacks any arthropo-
dian features at all, casts doubt on the arthropod affinity
of
Parvancorina
.
Temnoxa molliuscula.
The bilateral symmetry of
the body suggests the mobile life style of
Temnoxa
. The
substance composing the body was rather compact but
flexible. The axial zone of the body could be inflated
and displaced laterally (Pl. 2, fig. 2). It was large and
high, so that it could enclose a large volume of internal
organs. The lateral part of the body, which is flattened
in imprints, could be the lateral margin of the foot. The
small number of preserved features do not allow us to
ascribe this fossil to any known phylum; however, in
general, the structure does not exclude a higher organi-
zation of this animal, such as the molluskan evolution-
ary level.
Solza margarita.
The imprint of
Solza
remains a
certain volume, so that its central part is slightly
inflated. Specimens of this form are usually slightly
deformed, i.e., incurved in the anterior region (Pl. 1,
fig. 4a) or inclined laterally (Pl. 1, fig. 2). Probably, the
body was elastic: not firm but not excessively soft. The
body is asymmetrical; one end is acuminate, the maxi-
mum convexity is displaced toward this end. The dorsal
side of the body bears furrows radiating from the center
of convexity, branching, and anastomosing (Fig. 3). It is
impossible to recognize whether these furrows covered
the body during the animal’s life or they were formed
postmortem above certain cavities inside the body.
Judging from the indistinct relief in the majority of
imprints, the latter assumption seems more probable.
The narrow ends of the cavities reached the body mar-
gin and were probably open outside. The pores could
also be present in the central area of the body, where the
cavities anastomose; however, they are not prominent
on the imprint. On the basis of available material, it is
Explanation of Plate 1
Figs. 1–4.
Solza margarita
sp. nov.: (1–3, 4a) latex replica from the natural specimens, (4b) imprint on the rock surface;
×
6;
(1) specimen PIN, no. 4853/55; (2) specimen PIN, no. 4853/58; (3) specimen PIN, no. 4853/61; and (4) holotype PIN, no. 4853/60;
Arkhangelsk Region, Onega Peninsula, Solza River; Upper Vendian, Ust-Pinega Formation.
Figs. 5–8.
Parvancorina sagitta
sp. nov.: (5a) imprint on the rock surface; (5b, 6–8) latex replica; (5) holotype PIN, no. 4853/89,
×
6; (6) specimen PIN, no. 4853/92,
×
6; (7) specimen PIN, no. 4853/101,
×
6; and (8) specimen PIN, no. 4853/91,
×
8; Arkhangelsk
Region, Onega Peninsula, Solza River; Upper Vendian, Ust-Pinega Formation.
Figs. 9–12.
Parvancorina minchami
Glaessner: (9–11) latex replica, (12) imprint on the rock surface; (9) specimen PIN,
no. 3993/5190,
×
8; (10) specimen PIN, no. 3993/5188,
×
6; (11) specimen PIN, no. 3993/5115,
×
3; (12) specimen PIN,
no. 3993/5187,
×
6; Arkhangelsk Region, Zimnii Bereg (Winter Coast) of the White Sea; Upper Vendian, Mezen Formation.
Figs. 13 and 14.
Karakhtia nessovi
sp. nov., imprint on the rock surface: (13) holotype PIN, no. 4852/250,
×
2; and (14) specimen
PIN, no. 4852/249,
×
1; Arkhangelsk Region, Karakhta River; Upper Vendian, Ust-Pinega Formation.
Fig. 2.
Temnoxa molliuscula
sp. nov.; schematic reconstruc-
tion, dorsal view.
Fig. 3.
Solza margarita
sp. nov., schematic reconstruction,
dorsal view (spotted area shows the system of internal ca-
nals).
4
PALEONTOLOGICAL JOURNAL
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No. 1
2004
IVANTSOV
et al
.
1
Plate 2
2
3
456
7
8910
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SOME PROBLEMATIC FOSSILS FROM THE VENDIAN 5
rather difficult to suggest the function of these cavities
(or furrows). We can only suppose that they were asso-
ciated with feeding and internal secretion. This system
could support a structure filtering suspension, microor-
ganisms, or dissolved molecules in the case that both
marginal and central pores developed. The bilateral pat-
tern of the body suggests that
Solza
led a mobile mode
of life. To date, it is impossible to ascribed this taxon to
any known phylum.
Karakhtia nessovi.
The body of
Karakhtia
was
flexible and soft. Its imprints are usually strongly crum-
pled, so that any structural details are hardly discern-
ible. Probably, certain folds were present in living ani-
mals. Only two specimens display traces of transverse
division in the central part. The pattern of body differ-
entiation suggests that
Karakhtia
is related to proartic-
ulates. Actually, this form displays the main proarticu-
late characters, i.e., bilateral symmetry of the body
composed of equal and alternating elements. The pro-
posed hypothetical reconstruction (Fig. 5) resembles
Yorgia
Ivantsov,
Podolimirus
Fedonkin,
Vendia
Keller,
and some other genera from the class Vendiamorpha.
However, the structure of the anterior and lateral parts
of
Karakhtia
is unknown; therefore, the assignment of
Karakhtia
to vendiamorphs and the phylum Proarticu-
lata is premature.
Vav eliksia vana.
Vaveliksia
is represented by irreg-
ularly oval bodies, elongated to different extents,
strongly protruding from the host sandstone (Fig. 6).
Rather often, the bodies are isolated from the host rock
by a separate layer and can easily be extracted. A circu-
lar structure having a central depression and a ringlike
marginal elevation is located near the body end, either
forming its continuation or being slightly apart (Pl. 2,
fig. 8). In the majority of imprints, the surface is divided
by a system of narrow depressions (Fig. 6). Usually,
these depressions look like longitudinal subparallel fur-
rows, more prominent in the middle part of the body
and at the end, opposing the circular structure. The con-
centric wrinkles, sometimes gradually becoming paral-
lel, are visible near the circular structure (Pl. 2, fig. 5).
Small starlike depressions are present everywhere on
Explanation of Plate 2
Figs. 1 and 2.
Temnoxa molliuscula
sp. nov., latex replica,
×
8: (1) holotype PIN, no. 4852/104 and (2) specimen PIN, no. 4852/106;
Arkhangelsk Region, Karakhta River; Upper Vendian, Ust-Pinega Formation.
Figs. 3–10.
Vaveliksia vana
sp. nov.; imprint on the rock surface: (3) specimen PIN, no. 3993/5219-1,
×
2; (4) specimen PIN,
no. 3993/5244,
×
1.5; (5) specimen PIN, no. 3993/5219-2,
×
2; (6) specimen PIN, no. 3993/5216,
×
1.5; (7) specimen PIN,
no. 3993/5224,
×
2; (8) holotype PIN, no. 3993/5217-1,
×
1.5; (9) specimen PIN, no. 3993/5222,
×
1.5; and (10) specimen PIN,
no. 3993/5218,
×
1.5; Zimnii Bereg (Winter Coast) of the White Sea near the Zimnegorsk lighthouse; Upper Vendian, Mezen For-
mation, lower part of the
Yorgia
Beds.
1
2
4
3
5
1
2
3
4
5
(a)
(b)
af
Fig. 4.
Karakhtia nessovi
sp. nov., drawing based on the photographs of (a) holotype PIN, no. 4852/250; and (b) specimen PIN,
no. 4852/249. Designations: (
af
) axial furrow isolating two rows of isomeres from each other; the numbers designate the isomeres
of the left side (on the imprint).
6
PALEONTOLOGICAL JOURNAL
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IVANTSOV
et al
.
both the imprints and adjacent rock surface. The three
mentioned types of structures are probably caused by
postmortal changes, although the furrows and wrinkles
possibly reflect some morphological features. Some
imprints are crumpled, forming wide sliding isometric
folds, especially prominent in the marginal area (Pl. 2,
figs. 6, 9). Some imprints are finely pitted in places
(Pl. 2, fig. 6). The single specimen (Pl. 2, fig. 3) bears a
large depression on the end opposing the circular struc-
ture, while the surface of the imprint is divided by more
or less regular small linear structures.
Judging from the state of preservation and the posi-
tion within the host rock, the organism was incapable of
self-motion, since no typical signs of muscular activity
nor traces of motion and sediment treatment are
observed near the imprints. All specimens, at least
those composing groups, were preserved
in situ.
One
can propose several kinds of habit for this organism.
It could be buried in sediment, lie freely on the bottom,
or be attached to some substrate and raised above the
bottom. We are inclined to accept the last version. The
characteristic circular structures can be interpreted as
attaching structures. Sometimes, the spatial orientation
of imprints can be noted (Pl. 2, fig. 10). The orientation
might be caused by the bottom water currents. The
feeding strategy of this sessile animal was most likely
filtration through the body wall, since its body surface
is relatively small and no traces of mouth-like struc-
tures are observed. If this is the case, the animal’s body
most likely contained an internal cavity or a system of
cavities increasing the internal surface area.
Thus, the general morphological pattern of
Vavelik-
sia
can be reconstructed as follows (Fig. 7). The sac-
shaped organism was attached by its basal part to the
substrate (microbial film?). The walls of the body were
soft or composed of sediment particles imbedded into
the organic matrix (in the manner of some sponges).
It can also be supposed that the walls were supported
by spicula-like structures (the small linear structures
shown in Fig. 6 can be interpreted as spicules). Super-
ficially similar, but dictionally positioned structures of
the Precambrian genus
Palaeophragmodictya
were
interpreted by Gehling and Rigby (1996) as spicules.
Since the attaching structure and saclike body differ in
the preserved relief (the first is significantly more
prominent than the second), the sucker was a rather
dense and stout structure, while the sac, judging from
its extensive postmortal rugosity, had an internal cavity
and thin walls. Another fact showing the difference
between these elements is disconnection of sac and
sucker in the burial (Pl. 2, fig. 8). Possibly, the organism
was capable of gemmation, the wide and isometric
knobby folds may be interpreted as undetached daugh-
ter individuals (Pl. 2, figs. 5, 6). Small circular struc-
tures in the marginal areas can be very tentatively inter-
preted as apertures, while small pits on the surface can
be regarded as wall perforations. Probably, sediments
got into the body through these openings. The ragged
isometric injury (Pl. 2, fig. 3) is noteworthy. It could be
a bite trace, although such traces are untypical for the
Vendian. Probably,
Vaveliksia
dwelt on the bottom and
formed small colonies composed of three or four indi-
viduals of different size (Fig. 8). Individuals found in
groups lack any communicative structures. From the
above observations and assumptions, one may propose
Fig. 5.
Karakhtia nessovi sp. nov., schematic reconstruc-
tion, dorsal view.
d
ls
p
kf
lf
cw
cs
(a) (b)
Fig. 6. The types of preservation of Vaveliksia vana sp. nov.;
drawing based on the photographs of the specimens (a) PIN,
no. 3993/5219-1 and (b) specimen PIN, no. 3993/5222.
Designations: (cs) circular structure; (cw) concentric wrin-
kles; (d) depression at the apical end of the body (possibly,
aperture); (kf) knobby folds; (lf) longitudinal furrows;
(ls) fine linear structures; and (p) pit, supposed traces of per-
foration of the wall.
PALEONTOLOGICAL JOURNAL Vol. 38 No. 1 2004
SOME PROBLEMATIC FOSSILS FROM THE VENDIAN 7
that Vaveliksia has the same level of organization as
archaeocyaths or sponges.
SYSTEMATIC PALEONTOLOGY
Genus Parvancorina Glaessner, 1958
Parvancorina sagitta Ivantsov, sp. nov.
Plate 1, figs. 5–8
Etymology. From the Latin sagitta (arrow).
Holotype. PIN, no. 4853/89, imprint on the rock
surface, Arkhangelsk Region, Onega Peninsula, Solza
River; Upper Vendian, Ust-Pinega Formation.
Description. The body is elongated oval with a
wider, tentatively anterior end. A narrow band slightly
widened anteriorly and posteriorly extends along the
margin of the body. The central part of the body is
evenly convex in small specimens, while in the larger
specimens, the central area is occupied by an anchor-
like ridge. The transverse beam of this structure is
arched, the distance between its ends is about half of the
whole length of the structure. The longitudinal beam is
straight and relatively wide.
Measurements. See Fig. 1.
Ontogenetic changes. The central structure
is almost indistinct in the smallest specimens (Pl. 1,
fig. 8). During the body growth, it becomes more prom-
inent, and, at the same time, the relative width of the
longitudinal beam decreases, while the relative width of
the transverse beam increases.
Comparison. The new species differs from
P. minchami in the elongated body, wider marginal
band, and wider longitudinal beam and narrower trans-
verse beam of the axial structure. These features are
well-pronounced even in distorted and laterally com-
pressed specimens (Pl. 1, fig. 12).
Material. Holotype and paratypes PIN, nos.
4853/36, 4853/37, 4853/39, 4853/40, 4853/47,
4853/90–93, 4853/95–101, and 4853/104–124 from the
type locality.
Genus Temnoxa Ivantsov, gen. nov.
Etymology. From the Temnoksa River.
Type species. T. molliuscula sp. nov.
Diagnosis. Body elongated oval, clearly divided
into two parts: wide crescent cephalic part and narrow
oval undivided body part. Deep depression extending
across cephalic part in parallel to anterior margin. Body
part with almost flat lateral margins and strongly con-
vex central area composing more than half of body part.
Composition. Type species.
Comparison. The new genus is somewhat simi-
lar to Parvancorina in its elongated oval body with
wide anterior end and in the presence of a wide and
long convex central structure composing more than half
of the body part. The two genera could also be similar
in the structure of the anterior end, as the convex struc-
ture of the anterior part of Temnoxa is compared to the
transverse beam of the anchorlike structure of Parvan-
corina. The difference between the genera is the divi-
sion of the Temnoxa body into two parts so that the con-
vexities of the anterior and posterior parts are isolated
from each other and the absence of the entire peripheral
band bordering the body.
Fig. 7. Reconstructed appearance of Vaveliksia vana sp. nov.
(a)
(b)
Fig. 8. A colony of Vaveliksia vana sp. nov.: (a) drawing
based on the photograph of specimen PIN, no. 3993/5217;
(b) schematic reconstruction.
8
PALEONTOLOGICAL JOURNAL Vol. 38 No. 1 2004
IVANTSOV et al.
Temnoxa molliuscula Ivantsov, sp. nov.
Plate 2, figs. 1 and 2
Etymology. From the Latin molliusculus (rather
soft).
Holotype. PIN, no. 4852/104, imprint on the
rock surface; Arkhangelsk Region, Onega Peninsula,
Karakhta River; Upper Vendian, Ust-Pinega Formation.
Description. The same as the generic diagnosis
(Fig. 2).
Measurements, in mm. Holotype length, 8.5;
holotype width at the cephalic part, 4.6; paratype
length, 6.4; paratype width at the cephalic part, 3.7.
Material. Holotype and paratype PIN,
no. 4852/106 from the type locality.
Genus Solza Ivantsov, gen. nov.
Etymology. From the Solza River.
Type species. Solza margarita sp. nov.
Diagnosis. Body low conical with flattened mar-
gin, egg-shaped in plan. Top of cone displaced toward
tapering end. Body containing system of canals, which
becoming narrower toward periphery, anastomosing in
central part, and repeatedly dichotomizing in marginal
area. Probably, canals open along body margin.
Composition. Type species.
Comparison. The features listed in the diagno-
sis are unique to the new genus.
Solza margarita Ivantsov, sp. nov.
Plate 1, figs. 1–4
Etymology. From the latinized Greek
(µαργαριτηζ) margarita (pearl).
Holotype. PIN, no. 4853/60, imprint on the rock
surface, Arkhangelsk Region, Onega Peninsula, Solza
River; Upper Vendian, Ust-Pinega Formation.
Description. The same as the generic diagnosis
(Fig. 3).
Measurements, in mm:
Material. Holotype and paratypes PIN,
nos. 4853/7, 4853/55, 4853/56, 4853/58, and 4853/61
from the type locality.
Genus Karakhtia Ivantsov, gen. nov.
Etymology. From the Karakhta River.
Type species. Karakhtia nessovi sp. nov.
Specimen PIN, no. Length Width
4853/61 7.2 5.3
4853/56 7.6 5.8
4853/58 8.6 5.9
4853/55 9 7.5
4853/60 (holotype) 10.4 8
4853/7 10.5 8
Diagnosis. Medium and large-sized, body
rounded and isometric in plan divided into two rows of
transverse elements positioned in alternating order with
reference to longitudinal axis of body. Transverse ele-
ments gradually decreasing in size from one end to
other, their lateral ends inclined in the same direction.
Margin of body covered by coarse radial folds, which
probably present in living organism.
Composition. Type species.
Comparison. Karakhtia is similar in morpho-
logical pattern to proarticulates from the class Vendi-
amorpha (Ivantsov, 2001), but it strikingly differs in the
constantly present coarse radial folds.
Karakhtia nessovi Ivantsov, sp. nov.
Plate 1, figs. 13 and 14
Etymology. In honor of the Leningrad paleon-
tologist L.A. Nessov.
Holotype. PIN, no. 4852/250, imprint on the
rock surface, Arkhangelsk Region, Onega Peninsula,
Karakhta River; Upper Vendian, Ust-Pinega Formation.
Description. The same as the generic diagnosis
(Figs. 4a, 4b).
Measurements, in mm:
Material. Holotype and paratypes PIN,
nos. 4852/249, 4852/251–254 from the type locality.
Genus Vaveliksia Fedonkin, 1983
Vaveliksia: Fedonkin, 1983, pp. 136, 137; 1985, pp. 103, 104.
Type species. Vaveliksia velikanovi Fedonkin,
1983; Podolian Dniester Region, right bank of the Dni-
ester River, Dniester hydroelectric power station; Ven-
dian, Mogilev–Podolsk Group, Mogilev Formation,
Lomozov Beds.
Diagnosis. Small saclike organisms with
monaxonix heteropolar symmetry of uncertainly large
order (terminology after Beklemishev, 1964). Organ-
ism composed of two different parts, i.e., rather convex
and massive attaching disk weakly connected to capsu-
lar body.
Composition. The type species and V. vana
sp. nov.
Comparison. The features from the diagnosis
are unique to the genus.
Remarks. In the original description of Vavelik-
sia, Fedonkin (1983) noted that “at the end opposite to
the disk, the ellipsoidal part lacks the smooth closure,
Specimen PIN, no. Length
4852/253 8
4852/252 16
4852/250 (holotype) 22
4852/254 40
4852/249 108
PALEONTOLOGICAL JOURNAL Vol. 38 No. 1 2004
SOME PROBLEMATIC FOSSILS FROM THE VENDIAN 9
but has short linear elements oriented along the long
axis that form a pectinate margin.” These structures
were interpreted as remains of tentacles. A study of
extensive material has shown that these structures are
folded walls of the body rather than tentacles.
Vaveliksia vana Serezhnikova, sp. nov.
Plate 2, figs. 3–10
Etymology. From the Latin vana (incorporeal).
Holotype. PIN, no. 3993/5217-1, natural mold;
Zimnii Bereg (Winter Coast) of the White Sea near the
Zimnegorsk lighthouse; Upper Vendian, Mezen Forma-
tion, lower part of the Yorgia Beds.
Description. The capsular sac is elongated to
different extents along the central axis (see measure-
ments). The attaching disk is 7 to 15 mm in diameter.
The walls of the body are relatively thin and probably
perforated.
Measurements, in mm:
Comparison. The new species differs from
V. velikanovi Fedonkin, 1983 in different proportions of
the saclike body and a smaller diameter and more con-
vex surface of the attaching disk.
Material. Holotype and paratypes PIN,
nos. 3993/5216–5224, 3993/5244–5246 from the type
locality.
ACKNOWLEDGMENTS
The authors are grateful to A.V. Mazin (Paleonto-
logical Institute of the Russian Academy of Sciences)
for the production of photos.
The field works were supported by the National
Geographic Society of the USA (grant no. 7131-01),
the study of fossil specimens was supported by the Rus-
sian Foundation for Basic Research, project nos. 02-05-
64658 and 00-15-98610.
REFERENCES
1. V. N. Beklemishev, Fundamentals of Invertebrate Com-
parative Anatomy (Nauka, Moscow, 1964), Vol. 1 [in
Russian].
2. M. A. Fedonkin, in Vendian of Ukraine (Nauk. Dumka,
Kiev, 1983), pp. 128–139 [in Russian].
3. M. A. Fedonkin, in Vendian System: Historical Geolog-
ical and Paleontological Substantiation (Nauka, Mos-
cow, 1985), Vol. 1, pp. 70–106 [in Russian].
4. J. G. Gehling and J. K. Rigby, J. Paleontol. 70 (2), 185
(1996).
5. M. F. Glaessner, Ann. Nat. Hist. Mus. Wien 83, 83
(1980).
6. D. V. Grazhdankin and A. A. Bronnikov, Dokl. Ross.
Akad. Nauk 357, 792 (1997).
7. A. Yu. Ivantsov, Paleontol. Zh. 42 (4), 3 (2001).
8. R. J. F. Jenkins, in Origin and Early Evolution of the
Metazoa (Plenum, New York, 1992), pp. 131–176.
Specimen PIN, no. Length Width
3993/5217 86 17
3993/5218 55 16
3993/5219 41 15
3993/5221 35 08
3993/5222 (holotype) 51 19
