Biodiversity and taphonomy of the Early Cambrian Guanshan biota, eastern Yunnan
Abstract and Figures
The Guanshan biota from eastern Yunnan (Cambrian Series 2, early Stage 4) is a Burgess Shale-type fossil biota with abundant
exceptionally preserved soft-bodied fossils after the discovery of the well-known Cambrian Chengjiang fauna and Kaili biota
in South China. The geological settings, sedimentology, taphonomy, and the fossil assemblage of the Guanshan biota are briefly
summarized here. The Guanshan biota consists of about 60 taxa belonging to more than 10 metazoan groups and algae, among which
the lobopods, eldonids, hyolithids with helens, and green algae are reported for the first time. The common occurrence of
soft-bodied preservation in many groups, notably the trilobites and brachiopods, makes the Guanshan biota a significant fossil
lagerstätte for understanding the metazoan evolution during Cambrian explosion and taphonomy of the Burgess Shale-type fossils.
Keywordssoft-bodied fossils-Guanshan biota-Cambrian-Cambrian Explosion-Burgess Shale-type preservation
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... The knowledge on Cambrian arthropods is essential for resolving the phylogenetic relationships and evolutionary history of extinct and extant arthropods (Yang et al. 2013;Daley et al. 2018;Giribet and Edgecombe 2019). Euarthropods are the most diverse group among the typical Burgess Shale-type Cambrian-aged Guanshan Biota (Hu et al. 2010(Hu et al. , 2013. There are many euarthropods (e.g., trilobites, radiodonts, and bivalved euarthropods) described from this famous biota (Hu et al. 2010(Hu et al. , 2013Liu et al. 2012;Chen et al. 2019;Jiao et al. 2021a, b). ...
... Euarthropods are the most diverse group among the typical Burgess Shale-type Cambrian-aged Guanshan Biota (Hu et al. 2010(Hu et al. , 2013. There are many euarthropods (e.g., trilobites, radiodonts, and bivalved euarthropods) described from this famous biota (Hu et al. 2010(Hu et al. , 2013Liu et al. 2012;Chen et al. 2019;Jiao et al. 2021a, b). Except the above mentioned groups there are only a few other taxa reported (Hu et al. 2010(Hu et al. , 2013Zhao et al. 2020;Jiao et al. 2021aJiao et al. , 2022, i.e., Guangweicaris spinatus, Panlongia tetranodusa, Longquania bispinosa, Leanchoilia sp., Sinoburius sp., the unnamed naraoiid, Alacaris? ...
... There are many euarthropods (e.g., trilobites, radiodonts, and bivalved euarthropods) described from this famous biota (Hu et al. 2010(Hu et al. , 2013Liu et al. 2012;Chen et al. 2019;Jiao et al. 2021a, b). Except the above mentioned groups there are only a few other taxa reported (Hu et al. 2010(Hu et al. , 2013Zhao et al. 2020;Jiao et al. 2021aJiao et al. , 2022, i.e., Guangweicaris spinatus, Panlongia tetranodusa, Longquania bispinosa, Leanchoilia sp., Sinoburius sp., the unnamed naraoiid, Alacaris? sp., Lihuacaris ferox, and Bailongia longicaudata. ...
A new small euarthropod Astutuscaris bispinifer gen. et sp. nov. is described from the early Cambrian Stage 4 Guanshan
Biota in Yunnan, China. This new euarthropod possesses a wide head shield, a pair of possible eyes, paired frontalmost
appendages located antero-medially, 11 imbricated tergites most of which have backward-directed tergopleura ending in
almost posteriorly oriented spines, and two well-marked wide spines. The affinity of Astutuscaris among euarthropods is
uncertain because of the undefined nature of its frontalmost appendages, the incomplete head shield, the anterior trunk
tergites, and the limbs. There are about 24 species of non-trilobite euarthropods reported from the Guanshan Biota to
date, the documentation of this new taxon expands the biological diversity of euarthropods from this important biota in
Yunnan, China.
... Radiodonts, a large soft-bodied stem group of euarthropods [1,2] with a cosmopolitan distribution from Cambrian to Ordovician, have been viewed as giant apex predators [3,4] All specimens were gathered from yellowish-to-greenish mudstones interbedded by thin-bedded siltstone and sandstone [33,43,46]. Some were further prepared with fine needles under high magnification using stereomicroscopes. ...
... A recently reported amplectobeluid of indeterminable species from the Fandian biota in South China was deposited in a similar setting with the Chengjiang biota [66]. Guanshancaris is preserved in the Guanshan biota, deposited in an offshore transition between the fair-weather wave base and the storm wave base [33,46]. Amplectobelua is a widely distributed species of amplectobeluids, which occurs from the outer shelf adjacent to a carbonate ramp (Wheeler Formation, UT, USA, [67]; Burgess Shale, British Columbia, Canada, [3]; Kinzer Formation, PA, USA, [8]) to a lower shoreface setting (Chengjiang biota, Yunnan, South China, [64]; Niutitang Formation, Guizhou, South China, [65,68]). ...
Radiodonta, an extinct stem-euarthropod group, has been considered as the largest predator of Cambrian marine ecosystems. As one of the radiodont-bearing Konservat-Lagerstätten, the Guanshan biota (South China, Cambrian Stage 4) has yielded a diverse assemblage of soft-bodied and biomineralized taxa that are exclusive to this exceptional deposit. "Anomalocaris" kunmingensis, the most abundant radiodont in the Guanshan biota, was originally assigned to Anomalocaris within the Anomalocarididae. Despite this taxon being formally assigned to the family Amplectobeluidae more recently, its generic assignment remains uncertain. Here, we present new materials of "Anomalocaris" kunmingensis from the Guanshan biota, and reveal that the frontal appendages possess two enlarged endites; all endites bear one posterior auxiliary spine and up to four anterior auxiliary spines; three robust dorsal spines and one terminal spine protrude from the distal part. These new observations, allied with anatomical features illustrated by previous studies, allow us to assign this taxon to a new genus, Guanshancaris gen. nov. Brachiopod shell bearing embayed injury and incomplete trilobites, associated with frontal appendages in our specimens, to some extent confirm Guanshancaris as a possible durophagous predator. The distribution of amplectobeluids demonstrates that this group is restricted to Cambrian Stage 3 to Drumian, and occurs across South China and Laurentia within the tropics/subtropics belt. Moreover, the amount and abundance of amplectobeluids evidently decreases after the Early-Middle Cambrian boundary, which indicates its possible preference for shallow water, referring to its paleoenvironmental distribution and may be influenced by geochemical, tectonic, and climatic variation.
... These specimens derive from several mudstone layers within the upper Wulongqing Formation at the Gaoloufang section in Kunming City, Yunnan Province, SW China (Fig. 1). The depositional environment for the unit is interpreted via sedimentological evidence as lower shoreface to offshore (Chen et al. 2021), and is taken to represent an offshore transition (Hu et al. 2010). ...
... nov. (Figs 2-4, Supplementary material Figs S1-S9) occurs alongside a diverse and exceptionally preserved fossil assemblage that includes algae, sponges, chancellorids, cnidarians, brachiopods, molluscs, hyoliths, arthropods, lobopods and anomalocaridids (Hu et al. 2010). The fossil-bearing mudstone layers show fining-upward micro-graded laminae of 0.5-2 cm thickness, with sharp and erosive bases. ...
Guangweia cheni gen. et sp. nov. is an exceptionally preserved frond-like fossil from the early Cambrian Guanshan Biota of SW China, which shares morphological similarities with some characteristic late Ediacaran frondose organisms in comprising a leaf-like frond attached via a stem to a discoidal structure resembling a holdfast. Plausible evidence for tissue differentiation and bilateral symmetry in G. cheni implies a eumetazoan affinity. However, G. cheni profoundly differs from Ediacaran frondose taxa in several morphological characters, including its possession of an unusual wedge-shaped apical structure. These observations preclude direct phylogenetic relationships with known Ediacaran forms. Instead, G. cheni may record convergent evolution of a frondose bodyplan: a possibility that should be entertained for other purported Cambrian frondose taxa.
Thematic collection: This article is part of the Advances in the Cambrian Explosion collection available at: https://www.lyellcollection.org/topic/collections/advances-in-the-cambrian-explosion
Supplementary material: https://doi.org/10.6084/m9.figshare.c.6294893
... This study reported on Tuzoia from the Guanshan Biota (Wulongqing Formation, Cambrian Series 2, Stage 4), a representative Burgess Shale-type biota from southwestern China that included several categories of soft-bodied metazoans (Luo et al., 2005;Li et al., 2006;Luo et al., 2006;Hu et al., 2007;Luo et al., 2007;Yang et al., 2008.;Hu et al., 2010a;Hu et al., 2010b;Liu et al., 2012;Hu et al., 2013;Liu et al., 2015;Liu et al., 2016;Li et al., 2017;Yang et al., 2018;Wu and Liu. 2019;Chen et al., 2020;Zhao et al., 2020). More than 60 taxa have been described from this biota, belonging to more than ten animal groups and algae, including arthropods, brachiopods, vetulicolians, lobopodia ...
... this biota, belonging to more than ten animal groups and algae, including arthropods, brachiopods, vetulicolians, lobopodians, sponges, eocrinoid echinoderms, hyolithids, polychaetes, priapulids, chancelloriids, eldonoids, and problematic fossils (Luo et al., 2005;Li et al., 2006;Luo et al., 2006;Hu et al., 2007;Luo et al., 2007;Yang et al., 2008.;Hu et al., 2010a;Hu et al., 2010b;Liu et al., 2012;Hu et al., 2013;Liu et al., 2015;Liu et al., 2016;Li et al., 2017;Yang et al., 2018;Zhao et al., 2018;Wu and Liu. 2019;Chen et al., 2020;Zhao et al., 2020). Among the large bivalved arthropods from the Wulongqing Formation, Tuzoia ranked second, after Isoxys. ...
The Guanshan Biota (Cambrian Series 2, Stage 4) is a typical Burgess Shale-type biota and is one of the most significant Cambrian Konservat-Lagerstätten from China. Tuzoia is a relatively common non-biomineralized bivalved arthropod from the Guanshan Biota and, stratigraphically, ranges from Cambrian Series 2 through the Miaolingian Series. Based on new specimens from the Longbaoshan Section of the Wulongqing Formation, this study distinguished and described in detail the Tuzoia in the Guanshan Biota. Supplemental details about the larval stage of Tuzoia tylodesa were obtained, and the ontogenetic pattern of T. tylodesa was revised. The confirmation of the presence of Tuzoia retifera and the first report of Tuzoia cf. canadensis in the Guanshan biota, as well as the confirmation of the presence of T. retifera and the first report of T. cf. canadensis out of Laurentia (in Gondwana), indicated that species communication between paleogeographic plates is possible.
... Other important biotas are exemplified by Sirius Passet in Greenland (Harper et al. 2019), the Emu Bay Shale in Australia (Paterson et al. 2016), the Spence Shale and several others in the USA (Kimmig et al. 2019), the Souss biota in Morocco (Geyer & Landing 2021), and a rapidly growing number of biotas from the Yangtze Platform, southern China (e.g. Zhang & Hua 2005;Hu et al. 2010;Liu et al. 2012;Fu et al. 2019;Du et al. 2020) and North China (Sun et al. 2022). These sites, termed Konservat-Lagerstätten, provide a significantly more complete view of the biodiversity and relative abundance of organisms than seen in ordinary shelly deposits (Seilacher 1970;Briggs 2014). ...
The Skyberg Biota is a new early Cambrian Konservat-Lagerstätte, documented from a 7.5-m-thick succession of the Skyberg Member, Ringstranda Formation, in the classical Mjøsa area of Norway. It displays a high species diversity and contains: algae; sponges; brachiopods; hyoliths; bivalved arthropods; trilobites; palaeoscolecids and other vermi-form organisms; weakly sclerotized fragments of unknown affinity; several tubicolous fossils; the enigmatic genus Lapworthella; and a number of additional problematica together with infrequent trace fossils consisting of burrows and faecal pellets. This novel macro-biota encloses the most diverse fossil assemblage known from the Cambrian Series 2 locally in the Mjøsa area, and regionally in Baltoscandia, and currently includes around 50 species of 10 major animal groups and macro-algae. The Skyberg Biota con-tains taxa previously unknown from Norway, several are new to Baltoscandia and also includes a range of new species. The Skyberg biota offers a rare glimpse into the biodiver-sity of Baltoscandia just prior to the large faunal turnover at the late–middle Cambrian transition. □ Cambrian Stage 4, Ringstranda Formation, Konservat-Lagerstätte, shelly fossils, algae, biodiversity, problematica.
... In terms of environmental setting, the Fezouata Lagerstätte is more comparable to the Guanshan and Chengjiang Lagerstätten (Hu, 2005;Hu et al., 2010;McKenzie et al., 2015), although the prevailing environmental conditions in Chengjiang remain controversial (Zhao et al., 2012) and were probably slightly different from those in the Fezouata Shale. The most detailed and recent palaeoenvironmental analysis of the Chengjiang Lagerstätte suggests relatively shallow, unstable conditions in a deltaic environment, influenced both by storms and rivers floods (Saleh et al. 2022b). ...
... Gangtoucunia aspera is a problematic, annulated, tubular and phosphatic fossil from the Guanshan Lagerstätte (Cambrian Stage 4) from eastern Yunnan Province, China, which is broadly morphologically similar to hyolithelminths and Byronia. The affinities of Gangtoucunia have been little explored since it was described, but it has been interpreted as some kind of 'worm' among scalidophorans (see [23] and electronic supplementary material, table S1 [24]), as a member of Lophophorata [25] or a problematic taxon [26]. Here, we describe new specimens of G. aspera, which reveal its originally phosphatic tube (figure 1) and exceptionally preserved internal soft tissues for the first time (figures 2 and 3), shedding new light on its phylogenetic position and evolutionary significance. ...
Exoskeletal dwelling tubes are widespread among extant animals and early fossil assemblages. Exceptional fossils from the Cambrian reveal independent origins of tube dwelling by several clades including cnidarians, lophophorates, annelids, scalidophorans, panarthropods and ambulacrarians. However, most fossil tubes lack preservation of soft parts, making it difficult to understand their affinities and evolutionary significance. Gangtoucunia aspera (Wulongqing Formation, Cambrian Stage 4) was an annulated, gradually expanding phosphatic tube, with occasional attachments of multiple, smaller juveniles and has previously been interpreted as the dwelling tube of a 'worm' (e.g. a scalidophoran), lophophorate or problematicum. Here, we report the first soft tissues from Gangtoucunia that reveal a smooth body with circumoral tentacles and a blind, spacious gut that is partitioned by septa. This is consistent with cnidarian polyps and phylogenetic analysis resolves Gangtoucunia as a total group medusozoan. The tube of Gangtoucunia is phenotypically similar to problematic annulated tubular fossils (e.g. Sphenothallus, Byronia, hyolithelminths), which have been compared to both cnidarians and annelids, and are among the oldest assemblages of skeletal fossils. The cnidarian characters of G. aspera suggest that these early tubular taxa are best interpreted as cnidarians rather than sessile bilaterians in the absence of contrary soft tissue evidence.
Diverse chancelloriids from two sections of the Kaili Biota (Cambrian Wuliuan Stage) in Guizhou Province, China, are systematically described. A total of 25 complete individuals were collected from calcareous silty mudstones of the Cambrian Kaili Formation and are assigned to 3 genera and 6 species, including Archiasterella anchoriformis sp. nov., Chancelloria zhaoi sp. nov., C. eros, Allonnia erjiensis, Al. phrixothrix, and Al. sp. The new species Ar. anchoriformis with sclerites characterised by a large angle between two marginal-lateral rays and an obvious apical tuft represents the first unambiguous Archiasterella scleritome in South China. The C. zhaoi is dominated by a series of bilaterally symmetrical, rosette-like sclerites that composed of five or six lateral rays and a central ray. Moreover, based on a careful survey of the spatialtemporal distribution of chancelloriids (including both scleritome and isolated sclerite fossils) in South China, two flourishing ages, though may be related to preservational bias, of this metazoan group are recognised: 1) a significant diversification in the upper Stage 2 to Stage 3 and 2) a thriving in the Wuliuan Stage.
The Guanshan Fauna is a soft-bodied fauna dominated by arthropods (including trilobites, trilobitoides, Tuzoia, Isoxys, and bradorids) in association with priapulids, brachiopods, anomalocaridids, vetulicoliids, sponges, chancellorids, and echinoderms. This paper reports and describes a new arthropod from the yellowish green mudstone at the lower part of the Wulongqing Formation, Canglangpuan Stage, Lower Cambrian in Kunming, Yunnan, China. The stratigraphic and geographic distribution, classification, fossil preservation, life style of this new arthropod and comparisons with other fossil arthropods are also discussed in details. The discovery and research of the non-mineralized arthropod, Guangweicaris Luo, Fu et Hu gen. nov. from the Guanshan Fauna adds new members to the taxonomic list and provides new information to the evolution of early arthropods. Furthermore, this study would shed new light into the "Cambrian Explosion" and the evolution of early life.
The Sinsk Lagerstatten from Yakutia (middle reashes of the Lena River) represent one of the oldest Cambrian Lagerstatten. They contain Early Cambrian fossils of an extraordinary preservation and are restricted to the Sinsk Formation of the Botoman Stage. Lithologic and taphonomic features of the Lagerstatten are scrutinised. Palaeontological descriptions of cyanobacteria and algae (including 4 new genera and species), sponges (1 new family, 1 genus, and 3 species), cnidarians (1 new species), cephalorhynchs (2 new families, 3 genera, and 3 species), tardipolypodians, trilobites (1 new subgenus and 3 species), bradoriids and other arthropods, brachiopods, and eldonioideans are described. [Only plates, explanations to them, and English summary are present here.]
This is a brief report of a new occurrence of eocrinoids from the Early Cambrian Wulongqing Formation in Yunnan, China. The
eocrinoids from the Guanshan fauna are among the earliest known eocrinoids. Different from many other Early and Middle Cambrian
eocrinoids, the Guanshan eocrinoids are characterized by the absence of sutural pores and epispires, the long and spiral brachioles,
the extremely long stalk, and the ratio of the length of the stalk versus that of the calyx. The discovery of the eocrinoids
from the Guanshan fauna not only provides new information to the investigation of the early evolution of this animal group,
but also shed new light on the occurrence and migration of early eocrinoids.
This study provides evidence for the existence of filamentous (cyano-) bacteria forming sediment-stabilizing mats in shelf environments at 2.9 Ga---the oldest known occurrence of microbial mats in siliciclastic rocks. The Mesoarchean Mozaan Group, South Africa, features fine-grained quartzites of an ancient shallow-shelf environment. These sandstones contain wrinkle structures, which in thin section reveal filamentous textures forming carpet-like microbial mat fabrics. The textures resemble the trichomes of modern cyanobacteria, chloroflexi, or sulfur-oxidizing proteobacteria. Mineralogical, geochemical, and isotopic analyses are consistent with a biological origin of the filament-like textures. Carbon filaments with biogenic isotopic signatures (delta13C = -24.20/00 ± 0.50/00) are closely associated with hematite, goethite, and chert minerals, which may derive from the former presence of oxygen within the microbial mats. Detrital quartz, zircon, and rutile in the mats could indicate baffling, trapping, and binding of the bacterial communities.
This paper summarizes the recent advances in the study of the Early Cambrian Guanshan fauna in the Kunming area. It briefly describes the research history, stratigraphic horizon, assemblage features of the Guanshan fauna and its research significance. The authors for the first time found the Vetulicoliid Vetulicola gangtoucunensis Luo, Fu et Hu, Tuzoia sp. nov., Palaeoscolex sp. nov. and the brachiopod Heliomedusa sp. nov., as well as some new taxa of trilobitomorphs and sponges. The Guanshan fauna is a Burgess shale-type fauna composed of diverse groups of soft-body metazoans and its age is placed between those of the Chengjiang fauna Kaili fauna. This fauna plays a role of linking the previous fauna with the succeeding fauna and has great significance in the study of the explosion of the Cambrian lives and Early Cambrian biotic evolution.
Givetian through middle Famennian brachiopods of Hunan are used to define five biozones, comprising, in ascending order, the
Stringocephalus Abundance Zone, the Ambocoeliid-Leiorhynchid Assemblage Zone, the Cyrtospiriferid Assemblage Zone, the Yunnanellina-Sinospirifer Assemblage Zone, and the Yunnanella-Hunanospirifer Assemblage Zone. They correspond approximately to the Po. hemiansatus Zone to Po. varcus Zone, S. hermanni Zone to Pa. punctata Zone, Pa. hassi Zone to Pa. linguiformis Zone, Pa. triangularis Zone to Upper Pa. crepida Zone, and Uppermost Pa. crepida Zone to Pa. marginifera Zone, respectively. Intensified rifting activity in South China during the Devonian began in the middle of the Lower Po. varcus Zone (a level marked by the first appearance of Po. rhenanus), which is consistent with the Lower-Middle Givetian substage boundary suggested by the International Subcommission on Devonian
Stratigraphy (SDS). This assumed that rifting activity in the Lower Po. varcus Zone was signified by the deposition of the Baqi Formation in Guangxi and was marked largely by the extensive deposition
of the Qiziqiao Formation in central Hunan, which probably led to an opposite pattern of relative sea level change-rising
in deeper water trough areas and lowering in carbonate platform areas. The previously recognized S. hermanni Zone sea level rise in platform margin areas of Guangxi can be identified not only in the trough areas but also in platform
areas, which probably indicates an overall marine transgression at this time, rather than tectonically induced sea level change.
Similarly, this level coincides with the Middle-Upper Givetian substage boundary suggested by the SDS. Although the sea level
rise may have occurred in the deeper water trough areas of South China towards the end of the Givetian, platformal areas experienced
uplifting at various degrees, especially in the central and northern regions of Hunan where Early Frasnian deposits were apparently
absent in many places. Similarly, the end-Frasnian regression led to exposure of many places and absence of early Famennian
deposits, which probably accounts for the restricted distribution of the Yunnanellina brachiopod fauna.
The sandy lower supratidal zone, called ``Westplate,'' of Mellum Island (southern North Sea) is colonized by epipsammic cyanobacteria. The microbes form habitats of different stages of development adjacent to each other (biofilms: initial stages; mats: mature stages). Whereas biofilms do not contribute much to cohesion of sedimentary grains, mats significantly stabilize the supratidal surface, which leads to local conservation of a former physically shaped surface relief at microbially overgrown sites. In fall, the Westplate is covered by variously orientated ripple marks, termed ``multidirected ripple marks.'' Field measurements and investigations on the epipsammon revealed that ripple marks of similar orientations were covered by microbial assemblages of similar stages of development. The results permit the following interpretation. The sediments of the Westplate are reworked by high-water spring tide flood currents, the directions of which are frequently changed by strong winds. Because the water depth of the flood current is very shallow, some parts of the uneven sedimentary surface are more affected by hydrodynamic stress than others. At sites of calmer hydrodynamic conditions, predominantly filamentous cyanobacteria settle in time, forming mats. Constant physical reworking of slightly deeper parts of the supratidal surface, however, only permits the development of less-sediment stabilizing biofilms composed mainly of coccoid cyanobacteria. After the supratidal area drains, the deeper parts are also colonized by mat-constructing cyanobacteria, and the ripple marks become consolidated by the organic layer. Repetition of these interactive processes of physical reworking and microbial colonization is documented by the patchy ripple structure of the supratidal surface.