The finding of pharyngeal teeth and circumoral mouthparts in fossils of the Cambrian lobopodian a... more The finding of pharyngeal teeth and circumoral mouthparts in fossils of the Cambrian lobopodian animal Hallucigenia
sparsa improves our understanding of the deep evolutionary links between moulting animals
Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodo... more Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodonta) have provoked intense debate about their affinities within the moulting-animal clade that includes Arthropoda. Current alternatives identify anomalocaridids as either stem-group euarthropods1, 2, 3, crown-group euarthropods near the ancestry of chelicerates4, or a segmented ecdysozoan lineage with convergent similarity to arthropods in appendage construction5. Determining unambiguous affinities has been impeded by uncertainties about the segmental affiliation of anomalocaridid frontal appendages. These structures are variably homologized with jointed appendages of the second (deutocerebral) head segment, including antennae and ‘great appendages’ of Cambrian arthropods, or with the paired antenniform frontal appendages of living Onychophora and some Cambrian lobopodians. Here we describe Lyrarapax unguispinus, a new anomalocaridid from the early Cambrian Chengjiang biota, southwest China, nearly complete specimens of which preserve traces of muscles, digestive tract and brain. The traces of brain provide the first direct evidence for the segmental composition of the anomalocaridid head and its appendicular organization. Carbon-rich areas in the head resolve paired pre-protocerebral ganglia at the origin of paired frontal appendages. The ganglia connect to areas indicative of a bilateral pre-oral brain that receives projections from the eyestalk neuropils and compound retina. The dorsal, segmented brain of L. unguispinus reinforces an alliance between anomalocaridids and arthropods rather than cycloneuralians. Correspondences in brain organization between anomalocaridids and Onychophora resolve pre-protocerebral ganglia, associated with pre-ocular frontal appendages, as characters of the last common ancestor of euarthropods and onychophorans. A position of Radiodonta on the euarthropod stem-lineage implies the transformation of frontal appendages to another structure in crown-group euarthropods, with gene expression and neuroanatomy providing strong evidence that the paired, pre-oral labrum is the remnant of paired frontal appendages1.
The assumption that amongst internal organs of early arthropods only the digestive system withsta... more The assumption that amongst internal organs of early arthropods only the digestive system withstands fossilization is challenged by the identification of brain and ganglia in early Cambrian fuxianhuiids and megacheirans from southwest China. Here we document in the 520-million-year-old Chengjiang arthropod Fuxianhuia protensa an exceptionally preserved bilaterally symmetrical organ system corresponding to the vascular system of extant arthropods. Preserved primarily as carbon, this system includes a broad dorsal vessel extending through the thorax to the brain where anastomosing branches overlap brain segments and supply the eyes and antennae. The dorsal vessel provides segmentally paired branches to lateral vessels, an arthropod ground pattern character, and extends into the anterior part of the abdomen. The addition of its vascular system to documented digestive and nervous systems resolves the internal organization of F. protensa as the most completely understood of any Cambrian arthropod, emphasizing complexity that had evolved by the early Cambrian.
A fossil priapulid, Eximipriapulus globocaudatus new genus new species, is described from the Cam... more A fossil priapulid, Eximipriapulus globocaudatus new genus new species, is described from the Cambrian Chengjiang Lagerstätte of Yunnan, China. The exceptional preservation of the animal reveals morphological details that allow direct comparison with extant priapulids. The body is divisible into a partially eversible pharynx, a smooth collar, a scalid-bearing introvert, a neck with triangular scalids, an unsegmented trunk with annulations, and a distinctly expanded terminal region. Several specialized regions of the alimentary canal are recognized: a pharynx (lined by cuticle and bearing teeth), esophagus, midgut, hindgut, and a terminal anus. The sample includes a putative juvenile. The animal is inferred to have been an active burrower using a double-anchor strategy, practicing both deposit feeding and carnivory. Inclusion of Eximipriapulus in the most recent character matrix for cladistic analysis of fossil and Recent priapulids resolves the new genus within the priapulid crown group.
Cambrian lobopodians have attracted much attention in that they are considered to have close affi... more Cambrian lobopodians have attracted much attention in that they are considered to have close affinities with the origin of arthropods, and recent studies agree that they sample the stem-groups of both Arthropoda and Onychophora. A new lobopodian species, Diania cactiformis Liu et al., 2011, was recently reported from the Chengjiang Lagerstätte (southwest China; Cambrian Series 2). This animal was interpreted as bearing arthropod-like articulated appendages and was resolved as the sister taxon to Arthropoda in a cladistic analysis. A reanalysis of the published dataset did not reproduce the phylogenetic placement of D. cactiformis, and the interpretation of its appendage morphology is controversial. New observations on D. cactiformis are made using newly collected material, rejecting the evidence for sclerotized, segmented and articulated appendages; instead the appendages compare more closely to lobopods. The criteria for defining arthropodized appendages are further discussed through comparative studies among fossil lobopodians, anomalocaridids and arthropods. Our study challenges the previous description of anteroposterior orientation, terminal claws and trunk tagmosis as expressed by differentiated anterior and posterior appendages. A synthesis of four recent datasets for lobopodians and stem-group arthropods is used to revisit the phylogeny of stem arthropods. Irrespective of how characters are weighted, D. cactiformis is resolved at a much more basal position to arthropods, indicating that the morphology of this animal's appendages does not fundamentally inform on the evolution of arthropodization.
Alcheringa: An Australasian Journal of Palaeontology, 2013
García-Bellido, D.C., Edgecombe, G.D., Paterson, J.R. & Ma, X. 2013. A ‘Collins’ monster’-type lo... more García-Bellido, D.C., Edgecombe, G.D., Paterson, J.R. & Ma, X. 2013. A ‘Collins’ monster’-type lobopodian from the Emu Bay Shale Konservat-Lagerstätte (Cambrian), South Australia. Alcheringa 37, 1–5. ISSN 0311-5518.A distinctive group of lobopodians known from Cambrian Stage 5 in western Laurentia includes Acinocricus Conway Morris & Robison, 1988, from the Spence Shale in Utah, and an unnamed species from the Burgess Shale, British Columbia, popularly known as ‘Collins’ monster’. The temporal gap from their closest relative, the Chengjiang lobopodian Luolishania, is bridged by a single, incomplete specimen of a Collins’ monster-type lobopodian from the Emu Bay Shale (Cambrian Series 2, Stage 4), Kangaroo Island, South Australia, the first lobopodian discovered in this Konservat-Lagerstätte. Pending formal description of the Burgess Shale species, the Australian specimen is left unassigned to a genus. Diego C. García-Bellido [[email protected]], Sprigg Geobiology Centre, School of Earth and Environmental Sciences, University of Adelaide, South Australia 5005, Australia and South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia; Gregory D. Edgecombe [[email protected]], Xiaoya Ma [[email protected]], Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; John R. Paterson [[email protected]], Division of Earth Sciences, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia. Received 8.1.2013; revised 28.3.2013; accepted 2.4.2013.
Visual organs are widely distributed throughout the animal kingdom and exhibit a great diversity ... more Visual organs are widely distributed throughout the animal kingdom and exhibit a great diversity of morphologies. Compound eyes consisting of numerous visual units (ommatidia) are the oldest preserved visual systems of arthropods, but their origins are obscure and hypothetical models for their evolution have been difficult to test in the absence of unequivocal fossil evidence. Here we reveal the detailed eye structures of well-preserved Early Cambrian lobopodians Luolishania longicruris and Hallucigenia fortis from the Chengjiang Lagerstätte, China. These animals possess a pair of eyes composed of at least two visual units, interpreted as pigment cups. Contrary to previous suggestions that Cambrian lobopodians possessed ocellus-like eyes comparable to those of extant onychophorans, this multi-component structure is more similar to the lateral eyes of arthropods. Morphological comparison and phylogenetic analyses indicate that these lobopodian eyes may represent an early stage in the evolution of the ancestral visual system of euarthropods.► Exceptionally well-preserved eyes in Cambrian lobopodian animals (ca 525 Myr). ► Eyes of Luolishania and Hallucigenia are composed of multiple visual units. ► They may represent an early stage in the development of arthropod eyes. ► This study provides direct fossil evidence of evolutionary innovation.
The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in e... more The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail, which provide a unique window into the origin and early evolution of different vermiform phyla. This article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far, and specifically comments on the phylogeny, modes of life, evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian phyla. This article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology, including taphonomy and shape change caused by vermiform movement, as well as proposing that Anningvermis multispinosa and Corynetis brevis are synonymous. Chengjiang vermiform animals displayed a great diversity of morphologies and ecological roles, which is significant for understanding the origin and evolution of early metazoans; the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy, geochemistry, cladistics, and genetics.
New material of the lobopodian Luolishania longicruris has been recovered from the Lower Cambrian... more New material of the lobopodian Luolishania longicruris has been recovered from the Lower Cambrian Chengjiang Lagerstä tte, southwest China. The specimens throw new light on several morphological features of the species, including the paired antenniform outgrowths, eyes, head shield, setae and other cuticular projections, as well as the differentiated sclerites, appendages, claws, and lobopod interspaces. L. longicruris shows well developed tagmosis: a distinct head and a trunk divided into two sections. The new data allow a revised comparison with other lobopodians. Miraluolishania haikouensis Liu et al., 2004 is considered to be a junior synonym of L. longicruris Hou and Chen, 1989. Evidence from gut filling and specialized morphological characters indicates that L. longicruris may have had a filter feeding lifestyle. A new cladistic analysis suggests that fossil lobopodians are paraphyletic or even polyphyletic and L. longicruris may be an important representative of the stem lineage leading to arthropods.
Cheungkongella , was interpreted as a urochordate. regarded the genus to be a junior synonym of P... more Cheungkongella , was interpreted as a urochordate. regarded the genus to be a junior synonym of Phlogites , and to represent a type of tentaculate similar to entoprocts. We agree with the latter interpretation. However, we have a different interpretation of the tentacles and add to the understanding of general morphology and anatomy. While accepting the similarities to tentaculates such as entoprocts and bryozoans, we believe that they are mainly the results of parallel achievements of ciliary feeding through paedomorphosis. Additional similarities, such as the presence of a stiff periderm, may indicate that the separate origins should be sought for among interrelated worm groups, presumably gnathiferans. Phlogites therefore seems to represent a separate phylum, for which we introduce the name Dendrobrachia.
The group Cnidaria includes ‘jellyfish’, soft-bodied anemone and anemone-like forms and calcified... more The group Cnidaria includes ‘jellyfish’, soft-bodied anemone and anemone-like forms and calcified corals. These diploblastic organisms have a fossil record extending back to the earliest metazoans of the Neoproterozoic; however certain cnidarians of the subclass Zoantharia, characterized by soft-bodied anemone-like forms, are absent or poorly represented in the fossil record. Despite the paucity of fossils, it is thought that calcification by soft anemone-like animals was responsible for producing the skeleton that allowed the preservation of the first corals. We report discovery of an abundant assemblage of in situ soft-bodied polyps with tissues. They are preserved in exquisite detail and come from the well-known Lower Cambrian Chengjiang biota of Yunnan, China. The soft-bodied polyps display a simple anatomy that is comparable to some extant anemones of the order Actinaria. The new fossils are assigned to Archisaccophyllia kunmingensis n. gen. et n. sp. Their simple and conservative form suggests that these fossils may represent some kind of ancestral rootstock. The preserved life assemblage provides a unique snapshot of Lower Cambrian anemone life and provides clues for relationships with extant actiniarians as well as calcified corals.
New specimens of Paucipodia inermis Chen, Zhou & Ramsköld, 1995, are described from the Lower Cam... more New specimens of Paucipodia inermis Chen, Zhou & Ramsköld, 1995, are described from the Lower Cambrian Chengjiang Lagerstätte in Haikou, Kunming. Details not previously seen in the Chengjiang material appear to be caused by early diagenetic processes. Some features not previously observed in Palaeozoic lobopodians include details of the dermomuscular sac, body cavities, contents of the gut, possible paired ventral nerve ganglia, and a rasping or biting apparatus with teeth. The latter implies a fundamental difference from onychophorans and rules out an ancestral position for Palaeozoic lobopodians. The supposed tail is shown to be the head, and it is shown that this animal possessed nine pairs of lobopods rather than six, as originally stated. The family Paucipodiidae n. fam. is introduced.
The finding of pharyngeal teeth and circumoral mouthparts in fossils of the Cambrian lobopodian a... more The finding of pharyngeal teeth and circumoral mouthparts in fossils of the Cambrian lobopodian animal Hallucigenia
sparsa improves our understanding of the deep evolutionary links between moulting animals
Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodo... more Despite being among the most celebrated taxa from Cambrian biotas, anomalocaridids (order Radiodonta) have provoked intense debate about their affinities within the moulting-animal clade that includes Arthropoda. Current alternatives identify anomalocaridids as either stem-group euarthropods1, 2, 3, crown-group euarthropods near the ancestry of chelicerates4, or a segmented ecdysozoan lineage with convergent similarity to arthropods in appendage construction5. Determining unambiguous affinities has been impeded by uncertainties about the segmental affiliation of anomalocaridid frontal appendages. These structures are variably homologized with jointed appendages of the second (deutocerebral) head segment, including antennae and ‘great appendages’ of Cambrian arthropods, or with the paired antenniform frontal appendages of living Onychophora and some Cambrian lobopodians. Here we describe Lyrarapax unguispinus, a new anomalocaridid from the early Cambrian Chengjiang biota, southwest China, nearly complete specimens of which preserve traces of muscles, digestive tract and brain. The traces of brain provide the first direct evidence for the segmental composition of the anomalocaridid head and its appendicular organization. Carbon-rich areas in the head resolve paired pre-protocerebral ganglia at the origin of paired frontal appendages. The ganglia connect to areas indicative of a bilateral pre-oral brain that receives projections from the eyestalk neuropils and compound retina. The dorsal, segmented brain of L. unguispinus reinforces an alliance between anomalocaridids and arthropods rather than cycloneuralians. Correspondences in brain organization between anomalocaridids and Onychophora resolve pre-protocerebral ganglia, associated with pre-ocular frontal appendages, as characters of the last common ancestor of euarthropods and onychophorans. A position of Radiodonta on the euarthropod stem-lineage implies the transformation of frontal appendages to another structure in crown-group euarthropods, with gene expression and neuroanatomy providing strong evidence that the paired, pre-oral labrum is the remnant of paired frontal appendages1.
The assumption that amongst internal organs of early arthropods only the digestive system withsta... more The assumption that amongst internal organs of early arthropods only the digestive system withstands fossilization is challenged by the identification of brain and ganglia in early Cambrian fuxianhuiids and megacheirans from southwest China. Here we document in the 520-million-year-old Chengjiang arthropod Fuxianhuia protensa an exceptionally preserved bilaterally symmetrical organ system corresponding to the vascular system of extant arthropods. Preserved primarily as carbon, this system includes a broad dorsal vessel extending through the thorax to the brain where anastomosing branches overlap brain segments and supply the eyes and antennae. The dorsal vessel provides segmentally paired branches to lateral vessels, an arthropod ground pattern character, and extends into the anterior part of the abdomen. The addition of its vascular system to documented digestive and nervous systems resolves the internal organization of F. protensa as the most completely understood of any Cambrian arthropod, emphasizing complexity that had evolved by the early Cambrian.
A fossil priapulid, Eximipriapulus globocaudatus new genus new species, is described from the Cam... more A fossil priapulid, Eximipriapulus globocaudatus new genus new species, is described from the Cambrian Chengjiang Lagerstätte of Yunnan, China. The exceptional preservation of the animal reveals morphological details that allow direct comparison with extant priapulids. The body is divisible into a partially eversible pharynx, a smooth collar, a scalid-bearing introvert, a neck with triangular scalids, an unsegmented trunk with annulations, and a distinctly expanded terminal region. Several specialized regions of the alimentary canal are recognized: a pharynx (lined by cuticle and bearing teeth), esophagus, midgut, hindgut, and a terminal anus. The sample includes a putative juvenile. The animal is inferred to have been an active burrower using a double-anchor strategy, practicing both deposit feeding and carnivory. Inclusion of Eximipriapulus in the most recent character matrix for cladistic analysis of fossil and Recent priapulids resolves the new genus within the priapulid crown group.
Cambrian lobopodians have attracted much attention in that they are considered to have close affi... more Cambrian lobopodians have attracted much attention in that they are considered to have close affinities with the origin of arthropods, and recent studies agree that they sample the stem-groups of both Arthropoda and Onychophora. A new lobopodian species, Diania cactiformis Liu et al., 2011, was recently reported from the Chengjiang Lagerstätte (southwest China; Cambrian Series 2). This animal was interpreted as bearing arthropod-like articulated appendages and was resolved as the sister taxon to Arthropoda in a cladistic analysis. A reanalysis of the published dataset did not reproduce the phylogenetic placement of D. cactiformis, and the interpretation of its appendage morphology is controversial. New observations on D. cactiformis are made using newly collected material, rejecting the evidence for sclerotized, segmented and articulated appendages; instead the appendages compare more closely to lobopods. The criteria for defining arthropodized appendages are further discussed through comparative studies among fossil lobopodians, anomalocaridids and arthropods. Our study challenges the previous description of anteroposterior orientation, terminal claws and trunk tagmosis as expressed by differentiated anterior and posterior appendages. A synthesis of four recent datasets for lobopodians and stem-group arthropods is used to revisit the phylogeny of stem arthropods. Irrespective of how characters are weighted, D. cactiformis is resolved at a much more basal position to arthropods, indicating that the morphology of this animal's appendages does not fundamentally inform on the evolution of arthropodization.
Alcheringa: An Australasian Journal of Palaeontology, 2013
García-Bellido, D.C., Edgecombe, G.D., Paterson, J.R. & Ma, X. 2013. A ‘Collins’ monster’-type lo... more García-Bellido, D.C., Edgecombe, G.D., Paterson, J.R. & Ma, X. 2013. A ‘Collins’ monster’-type lobopodian from the Emu Bay Shale Konservat-Lagerstätte (Cambrian), South Australia. Alcheringa 37, 1–5. ISSN 0311-5518.A distinctive group of lobopodians known from Cambrian Stage 5 in western Laurentia includes Acinocricus Conway Morris & Robison, 1988, from the Spence Shale in Utah, and an unnamed species from the Burgess Shale, British Columbia, popularly known as ‘Collins’ monster’. The temporal gap from their closest relative, the Chengjiang lobopodian Luolishania, is bridged by a single, incomplete specimen of a Collins’ monster-type lobopodian from the Emu Bay Shale (Cambrian Series 2, Stage 4), Kangaroo Island, South Australia, the first lobopodian discovered in this Konservat-Lagerstätte. Pending formal description of the Burgess Shale species, the Australian specimen is left unassigned to a genus. Diego C. García-Bellido [[email protected]], Sprigg Geobiology Centre, School of Earth and Environmental Sciences, University of Adelaide, South Australia 5005, Australia and South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia; Gregory D. Edgecombe [[email protected]], Xiaoya Ma [[email protected]], Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; John R. Paterson [[email protected]], Division of Earth Sciences, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia. Received 8.1.2013; revised 28.3.2013; accepted 2.4.2013.
Visual organs are widely distributed throughout the animal kingdom and exhibit a great diversity ... more Visual organs are widely distributed throughout the animal kingdom and exhibit a great diversity of morphologies. Compound eyes consisting of numerous visual units (ommatidia) are the oldest preserved visual systems of arthropods, but their origins are obscure and hypothetical models for their evolution have been difficult to test in the absence of unequivocal fossil evidence. Here we reveal the detailed eye structures of well-preserved Early Cambrian lobopodians Luolishania longicruris and Hallucigenia fortis from the Chengjiang Lagerstätte, China. These animals possess a pair of eyes composed of at least two visual units, interpreted as pigment cups. Contrary to previous suggestions that Cambrian lobopodians possessed ocellus-like eyes comparable to those of extant onychophorans, this multi-component structure is more similar to the lateral eyes of arthropods. Morphological comparison and phylogenetic analyses indicate that these lobopodian eyes may represent an early stage in the evolution of the ancestral visual system of euarthropods.► Exceptionally well-preserved eyes in Cambrian lobopodian animals (ca 525 Myr). ► Eyes of Luolishania and Hallucigenia are composed of multiple visual units. ► They may represent an early stage in the development of arthropod eyes. ► This study provides direct fossil evidence of evolutionary innovation.
The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in e... more The Early Cambrian Chengjiang Biota of China has preserved many species of vermiform animals in exquisite detail, which provide a unique window into the origin and early evolution of different vermiform phyla. This article reviews and discusses the forty-five Chengjiang vermiform animals discovered so far, and specifically comments on the phylogeny, modes of life, evolutionary significance as well as existing debates concerning the Chengjiang priapulid and lobopodian phyla. This article analyzes existing problems with Chengjiang vermiform morphological research and highlights various factors that affect the final preserved fossil morphology, including taphonomy and shape change caused by vermiform movement, as well as proposing that Anningvermis multispinosa and Corynetis brevis are synonymous. Chengjiang vermiform animals displayed a great diversity of morphologies and ecological roles, which is significant for understanding the origin and evolution of early metazoans; the potential for future research is enormous but needs to be broadened by interdisciplinary work involving taphonomy, geochemistry, cladistics, and genetics.
New material of the lobopodian Luolishania longicruris has been recovered from the Lower Cambrian... more New material of the lobopodian Luolishania longicruris has been recovered from the Lower Cambrian Chengjiang Lagerstä tte, southwest China. The specimens throw new light on several morphological features of the species, including the paired antenniform outgrowths, eyes, head shield, setae and other cuticular projections, as well as the differentiated sclerites, appendages, claws, and lobopod interspaces. L. longicruris shows well developed tagmosis: a distinct head and a trunk divided into two sections. The new data allow a revised comparison with other lobopodians. Miraluolishania haikouensis Liu et al., 2004 is considered to be a junior synonym of L. longicruris Hou and Chen, 1989. Evidence from gut filling and specialized morphological characters indicates that L. longicruris may have had a filter feeding lifestyle. A new cladistic analysis suggests that fossil lobopodians are paraphyletic or even polyphyletic and L. longicruris may be an important representative of the stem lineage leading to arthropods.
Cheungkongella , was interpreted as a urochordate. regarded the genus to be a junior synonym of P... more Cheungkongella , was interpreted as a urochordate. regarded the genus to be a junior synonym of Phlogites , and to represent a type of tentaculate similar to entoprocts. We agree with the latter interpretation. However, we have a different interpretation of the tentacles and add to the understanding of general morphology and anatomy. While accepting the similarities to tentaculates such as entoprocts and bryozoans, we believe that they are mainly the results of parallel achievements of ciliary feeding through paedomorphosis. Additional similarities, such as the presence of a stiff periderm, may indicate that the separate origins should be sought for among interrelated worm groups, presumably gnathiferans. Phlogites therefore seems to represent a separate phylum, for which we introduce the name Dendrobrachia.
The group Cnidaria includes ‘jellyfish’, soft-bodied anemone and anemone-like forms and calcified... more The group Cnidaria includes ‘jellyfish’, soft-bodied anemone and anemone-like forms and calcified corals. These diploblastic organisms have a fossil record extending back to the earliest metazoans of the Neoproterozoic; however certain cnidarians of the subclass Zoantharia, characterized by soft-bodied anemone-like forms, are absent or poorly represented in the fossil record. Despite the paucity of fossils, it is thought that calcification by soft anemone-like animals was responsible for producing the skeleton that allowed the preservation of the first corals. We report discovery of an abundant assemblage of in situ soft-bodied polyps with tissues. They are preserved in exquisite detail and come from the well-known Lower Cambrian Chengjiang biota of Yunnan, China. The soft-bodied polyps display a simple anatomy that is comparable to some extant anemones of the order Actinaria. The new fossils are assigned to Archisaccophyllia kunmingensis n. gen. et n. sp. Their simple and conservative form suggests that these fossils may represent some kind of ancestral rootstock. The preserved life assemblage provides a unique snapshot of Lower Cambrian anemone life and provides clues for relationships with extant actiniarians as well as calcified corals.
New specimens of Paucipodia inermis Chen, Zhou & Ramsköld, 1995, are described from the Lower Cam... more New specimens of Paucipodia inermis Chen, Zhou & Ramsköld, 1995, are described from the Lower Cambrian Chengjiang Lagerstätte in Haikou, Kunming. Details not previously seen in the Chengjiang material appear to be caused by early diagenetic processes. Some features not previously observed in Palaeozoic lobopodians include details of the dermomuscular sac, body cavities, contents of the gut, possible paired ventral nerve ganglia, and a rasping or biting apparatus with teeth. The latter implies a fundamental difference from onychophorans and rules out an ancestral position for Palaeozoic lobopodians. The supposed tail is shown to be the head, and it is shown that this animal possessed nine pairs of lobopods rather than six, as originally stated. The family Paucipodiidae n. fam. is introduced.
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sparsa improves our understanding of the deep evolutionary links between moulting animals
sparsa improves our understanding of the deep evolutionary links between moulting animals