My current interest is about the problematic fossils from the Chengjiang Biota, their morphology, affinity and autecology. Address: Yunnan University
No. 2, North Cuihu Rd. Kunming, China
Aspiculate demosponges are rarely described in geological history due to the absence of spicules ... more Aspiculate demosponges are rarely described in geological history due to the absence of spicules that are stable and resistant to degradation. One exception is the exquisite preservation of sponges without any mineralized skeletons discovered in Lagerstätten (e.g. the Burgess Shale). The Chengjiang Biota, an early example of a Burgess Shale-type biota in South China (Cambrian Series 2, Stage 3), is one of the only examples of convincing aspiculate sponges until now. Here, we describe Vauxia pregracilenta sp. nov. and V. paraleioia sp. nov., as well as two poorly preserved vauxiid specimens (Vauxia sp.) in open nomenclature, from the Chengjiang Biota. Vauxia pregracilenta has a fan-like holdfast and branches in various sizes, as well as a typical two-layered net-like skeleton, without spicules. The endosomal layer is hexagonal, while the dermal layer is sub-rectangular. Vauxia paraleioia is characterized by a two-layered subconical skeleton, with the dermal layer ornamented with vert...
New material of the rare arthropod <i>Acanthomeridion</i>, including <i>Acantho... more New material of the rare arthropod <i>Acanthomeridion</i>, including <i>Acanthomeridion anacanthus</i> sp. nov., is described from the lower Cambrian Chengjiang biota, Yunnan Province, China. The material includes a specimen with paired gut diverticulae along the length of the mid-gut that resemble structures in other artiopodan arthropods such as naraoiids. Previous phylogenetic analyses have indicated a petalopleuran/xandarellid affinity for <i>Acanthomeridion</i>, but our analysis resolves <i>Acanthomeridion</i> outside the main subclades of the Artiopoda (Aglaspidida + Trilobita, Nektaspida, Cheloniellida + Xenopoda, Conciliterga, Petalopleura (including Xandarellida)) as the most basal artiopodan. http://zoobank.org/urn:lsid:zoobank.org:pub:3563C327-EF9C-4A49-B200-417CE5D95D60
Extant cnidarians are a disparate phylum of non-bilaterians and their diploblastic body plan repr... more Extant cnidarians are a disparate phylum of non-bilaterians and their diploblastic body plan represents a key step in animal evolution. Anthozoans (anemones, corals) are benthic polyps, while adult medusozoans (jellyfishes) are dominantly pelagic medusae. A sessile polyp is present in both groups and is widely conceived as the ancestral form of their last common ancestor. However, the nature and anatomy of this ancestral polyp, particularly of medusozoans, are controversial, owing to the divergent body plans of both groups in the extant lineages and the rarity of medusozoan soft tissues in the fossil record. Here we redescribe the enigmatic Conicula striata Luo et Hu from the early Cambrian Chengjiang biota, south China, which has previously been interpreted as a polyp, lophophorate or deuterostome. We show that C. striata possessed features of both anthozoans and medusozoans. Its stalked polyp and fully encasing conical, annulated organic skeleton (periderm) are features of medusoz...
Chancelloriids are an extinct group of spiny Cambrian animals of uncertain phylogenetic position.... more Chancelloriids are an extinct group of spiny Cambrian animals of uncertain phylogenetic position. Despite their sponge-like body plan, their spines are unlike modern sponge spicules, but share several features with the sclerites of certain Cambrian bilaterians, notably halkieriids. However, a proposed homology of these 'coelosclerites' implies complex transitions in body plan evolution. A new species of chancelloriid, <i>Allonnia nuda</i>, from the lower Cambrian (Stage 3) Chengjiang Lagerstätte is distinguished by its large size and sparse spination, with modified apical sclerites surrounding an opening into the body cavity. The sclerite arrangement in <i>A. nuda</i> and certain other chancelloriids indicates that growth involved sclerite addition in a subapical region, thus maintaining distinct zones of body sclerites and apical sclerites. This pattern is not seen in halkieriids, but occurs in some modern calcarean sponges. With scleritome assembly consistent with a sponge affinity, and in the absence of cnidarian- or bilaterian-grade features, it is possible to interpret chancelloriids as sponges with an unusually robust outer epithelium, strict developmental control of body axis formation, distinctive spicule-like structures and, by implication, minute ostia too small to be resolved in fossils. In this light, chancelloriids may contribute to the emerging picture of high disparity among early sponges.
Here, we report the earliest fossil record to our knowledge of surface fouling by aggregates of s... more Here, we report the earliest fossil record to our knowledge of surface fouling by aggregates of small vermiform, encrusting and annulated tubular organisms associated with a mobile, nektonic host, the enigmatic Cambrian animal Vetulicola. Our material is from the exceptionally preserved early Cambrian (Epoch 2, Age 3), Chengjiang biota of Yunnan Province, southwest China, a circa 518 million-year old marine deposit. Our data show that symbiotic fouling relationships between species formed a component of the diversification of animal-rich ecosystems near the beginning of the Phanerozoic Eon, suggesting an early escalation of intimate ecologies as part of the Cambrian animal radiation.
Abstract Eocrinoids are scarce in the Guanshan Biota (Cambrian Series 2, Stage 4), Yunnan Provinc... more Abstract Eocrinoids are scarce in the Guanshan Biota (Cambrian Series 2, Stage 4), Yunnan Province, southwest China. Here, we introduce a new gogiid: Kunmingeocrinus cupuliformis n. gen. n. sp. which is characterized by a short stalk and a well-developed attachment disc. Preservation may indicate a weakly biomineralized body for the new taxon. Morphological similarities between the new taxon and other eocrinoids with attachment discs from Cambrian Lagerstatten of Guizhou Province (Series 2, Stage 4 and Miaolingian, Wuliuan) might suggest a similar mode of life. The eocrinoids from the Guanshan Biota possibly utilized different attachment modes.
Bryozoa are colonial, aquatic, generally sessile coelomate metazoans, with a retractable lophopho... more Bryozoa are colonial, aquatic, generally sessile coelomate metazoans, with a retractable lophophore and U-shaped digestive tract. They are widely distributed and highly diverse in extant marine and freshwater environments. Current confident fossils of the earliest bryozoan only occur in the Early Ordovician, although molecular estimation date their origin in or prior to the early Cambrian, rendering the origin and early evolution of bryozoans are intensely debated. Here, we describe two cyclostomes, Panpipora yunnanensis gen. et. sp. nov. and Corynotrypa sp., having been recovered from the Cambrian Chengjiang Biota (~ 518 m.y.) in Southwest China. The bryozoans represent the earliest fossils of Bryozoa, predating the record of the phylum by more than 30 million years. Our finding reveals that the Bryozoa, as all other skeletonised metazoans, first evolved during the Cambrian Explosion, and it is congruent with estimation of molecular clock that the cyclostomes is the earliest biomin...
Vetulicolians are a group of exclusively Cambrian animals characterized by an anterior section wi... more Vetulicolians are a group of exclusively Cambrian animals characterized by an anterior section with lateral pouches and a posterior section that appears segmented. The precise phylogenetic affinity of vetulicolians is debated because there is a lack of consensus regarding the interpretation of their anatomical features. Their disparate morphology might even cause one to question whether this is a monophyletic taxon. In total, there are 15 species grouped into three families included in vetulicolians. Here we focus on new specimens of Yuyuanozoon magnificissimi Chen, Feng, and Zhu in Chen et al., 2003, a species that was first described from only a single specimen from the Chengjiang Biota (Cambrian Series 2, Stage 3, Eoredlichia-Wutingaspis trilobite Biozone), Yunnan Province, China. The species is notable in being exceptionally large (up to 20 cm long). Morphological observations on the new specimens clarify the nature of the wide circular opening at the presumed anterior end of th...
The euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjia... more The euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjiang biota, Cambrian Series 2, Stage 3, of Yunnan Province, China. Phylogenetic analysis recovers a xandarellid affinity for L. deletres, representing only the fifth described species of this clade. L. deletres possesses a head shield that is about one-fifth of the total body length and a trunk with 30 tergites, the reduced anterior-most tergite and terminal three tergites lacking pleural elongations. Anteriorly situated notches in the head shield are associated with stalked eyes, in contrast to the more posterior, enclosed eye slits present in Xandarella. Posterior to the antennae there are at least 11 pairs of biramous appendages preserved, including three pairs in the head. The morphology of the midline gut of L. deletres, in which lateral, unbranched diverticula are wider towards the front of the body, is a characteristic also found in various trilobites. The dorsoventrally flattened e...
Aspiculate demosponges are rarely described in geological history due to the absence of spicules ... more Aspiculate demosponges are rarely described in geological history due to the absence of spicules that are stable and resistant to degradation. One exception is the exquisite preservation of sponges without any mineralized skeletons discovered in Lagerstätten (e.g. the Burgess Shale). The Chengjiang Biota, an early example of a Burgess Shale-type biota in South China (Cambrian Series 2, Stage 3), is one of the only examples of convincing aspiculate sponges until now. Here, we describe Vauxia pregracilenta sp. nov. and V. paraleioia sp. nov., as well as two poorly preserved vauxiid specimens (Vauxia sp.) in open nomenclature, from the Chengjiang Biota. Vauxia pregracilenta has a fan-like holdfast and branches in various sizes, as well as a typical two-layered net-like skeleton, without spicules. The endosomal layer is hexagonal, while the dermal layer is sub-rectangular. Vauxia paraleioia is characterized by a two-layered subconical skeleton, with the dermal layer ornamented with vert...
New material of the rare arthropod <i>Acanthomeridion</i>, including <i>Acantho... more New material of the rare arthropod <i>Acanthomeridion</i>, including <i>Acanthomeridion anacanthus</i> sp. nov., is described from the lower Cambrian Chengjiang biota, Yunnan Province, China. The material includes a specimen with paired gut diverticulae along the length of the mid-gut that resemble structures in other artiopodan arthropods such as naraoiids. Previous phylogenetic analyses have indicated a petalopleuran/xandarellid affinity for <i>Acanthomeridion</i>, but our analysis resolves <i>Acanthomeridion</i> outside the main subclades of the Artiopoda (Aglaspidida + Trilobita, Nektaspida, Cheloniellida + Xenopoda, Conciliterga, Petalopleura (including Xandarellida)) as the most basal artiopodan. http://zoobank.org/urn:lsid:zoobank.org:pub:3563C327-EF9C-4A49-B200-417CE5D95D60
Extant cnidarians are a disparate phylum of non-bilaterians and their diploblastic body plan repr... more Extant cnidarians are a disparate phylum of non-bilaterians and their diploblastic body plan represents a key step in animal evolution. Anthozoans (anemones, corals) are benthic polyps, while adult medusozoans (jellyfishes) are dominantly pelagic medusae. A sessile polyp is present in both groups and is widely conceived as the ancestral form of their last common ancestor. However, the nature and anatomy of this ancestral polyp, particularly of medusozoans, are controversial, owing to the divergent body plans of both groups in the extant lineages and the rarity of medusozoan soft tissues in the fossil record. Here we redescribe the enigmatic Conicula striata Luo et Hu from the early Cambrian Chengjiang biota, south China, which has previously been interpreted as a polyp, lophophorate or deuterostome. We show that C. striata possessed features of both anthozoans and medusozoans. Its stalked polyp and fully encasing conical, annulated organic skeleton (periderm) are features of medusoz...
Chancelloriids are an extinct group of spiny Cambrian animals of uncertain phylogenetic position.... more Chancelloriids are an extinct group of spiny Cambrian animals of uncertain phylogenetic position. Despite their sponge-like body plan, their spines are unlike modern sponge spicules, but share several features with the sclerites of certain Cambrian bilaterians, notably halkieriids. However, a proposed homology of these 'coelosclerites' implies complex transitions in body plan evolution. A new species of chancelloriid, <i>Allonnia nuda</i>, from the lower Cambrian (Stage 3) Chengjiang Lagerstätte is distinguished by its large size and sparse spination, with modified apical sclerites surrounding an opening into the body cavity. The sclerite arrangement in <i>A. nuda</i> and certain other chancelloriids indicates that growth involved sclerite addition in a subapical region, thus maintaining distinct zones of body sclerites and apical sclerites. This pattern is not seen in halkieriids, but occurs in some modern calcarean sponges. With scleritome assembly consistent with a sponge affinity, and in the absence of cnidarian- or bilaterian-grade features, it is possible to interpret chancelloriids as sponges with an unusually robust outer epithelium, strict developmental control of body axis formation, distinctive spicule-like structures and, by implication, minute ostia too small to be resolved in fossils. In this light, chancelloriids may contribute to the emerging picture of high disparity among early sponges.
Here, we report the earliest fossil record to our knowledge of surface fouling by aggregates of s... more Here, we report the earliest fossil record to our knowledge of surface fouling by aggregates of small vermiform, encrusting and annulated tubular organisms associated with a mobile, nektonic host, the enigmatic Cambrian animal Vetulicola. Our material is from the exceptionally preserved early Cambrian (Epoch 2, Age 3), Chengjiang biota of Yunnan Province, southwest China, a circa 518 million-year old marine deposit. Our data show that symbiotic fouling relationships between species formed a component of the diversification of animal-rich ecosystems near the beginning of the Phanerozoic Eon, suggesting an early escalation of intimate ecologies as part of the Cambrian animal radiation.
Abstract Eocrinoids are scarce in the Guanshan Biota (Cambrian Series 2, Stage 4), Yunnan Provinc... more Abstract Eocrinoids are scarce in the Guanshan Biota (Cambrian Series 2, Stage 4), Yunnan Province, southwest China. Here, we introduce a new gogiid: Kunmingeocrinus cupuliformis n. gen. n. sp. which is characterized by a short stalk and a well-developed attachment disc. Preservation may indicate a weakly biomineralized body for the new taxon. Morphological similarities between the new taxon and other eocrinoids with attachment discs from Cambrian Lagerstatten of Guizhou Province (Series 2, Stage 4 and Miaolingian, Wuliuan) might suggest a similar mode of life. The eocrinoids from the Guanshan Biota possibly utilized different attachment modes.
Bryozoa are colonial, aquatic, generally sessile coelomate metazoans, with a retractable lophopho... more Bryozoa are colonial, aquatic, generally sessile coelomate metazoans, with a retractable lophophore and U-shaped digestive tract. They are widely distributed and highly diverse in extant marine and freshwater environments. Current confident fossils of the earliest bryozoan only occur in the Early Ordovician, although molecular estimation date their origin in or prior to the early Cambrian, rendering the origin and early evolution of bryozoans are intensely debated. Here, we describe two cyclostomes, Panpipora yunnanensis gen. et. sp. nov. and Corynotrypa sp., having been recovered from the Cambrian Chengjiang Biota (~ 518 m.y.) in Southwest China. The bryozoans represent the earliest fossils of Bryozoa, predating the record of the phylum by more than 30 million years. Our finding reveals that the Bryozoa, as all other skeletonised metazoans, first evolved during the Cambrian Explosion, and it is congruent with estimation of molecular clock that the cyclostomes is the earliest biomin...
Vetulicolians are a group of exclusively Cambrian animals characterized by an anterior section wi... more Vetulicolians are a group of exclusively Cambrian animals characterized by an anterior section with lateral pouches and a posterior section that appears segmented. The precise phylogenetic affinity of vetulicolians is debated because there is a lack of consensus regarding the interpretation of their anatomical features. Their disparate morphology might even cause one to question whether this is a monophyletic taxon. In total, there are 15 species grouped into three families included in vetulicolians. Here we focus on new specimens of Yuyuanozoon magnificissimi Chen, Feng, and Zhu in Chen et al., 2003, a species that was first described from only a single specimen from the Chengjiang Biota (Cambrian Series 2, Stage 3, Eoredlichia-Wutingaspis trilobite Biozone), Yunnan Province, China. The species is notable in being exceptionally large (up to 20 cm long). Morphological observations on the new specimens clarify the nature of the wide circular opening at the presumed anterior end of th...
The euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjia... more The euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjiang biota, Cambrian Series 2, Stage 3, of Yunnan Province, China. Phylogenetic analysis recovers a xandarellid affinity for L. deletres, representing only the fifth described species of this clade. L. deletres possesses a head shield that is about one-fifth of the total body length and a trunk with 30 tergites, the reduced anterior-most tergite and terminal three tergites lacking pleural elongations. Anteriorly situated notches in the head shield are associated with stalked eyes, in contrast to the more posterior, enclosed eye slits present in Xandarella. Posterior to the antennae there are at least 11 pairs of biramous appendages preserved, including three pairs in the head. The morphology of the midline gut of L. deletres, in which lateral, unbranched diverticula are wider towards the front of the body, is a characteristic also found in various trilobites. The dorsoventrally flattened e...
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