A new priapulid assemblage from the early Cambrian Guanshan fossil Lagerstätte of SW China

Feeding behavioural patterns have the potential to shed light on evolutionary trends, especially at the critical point of the Cambrian Explosion. In this context, we present specimens of the tubiform priapulid Selkirkia sinica, preserved in situ, collected from the lower Cambrian (Stage 3) Xiaoshiba Lagerstätte, which show the diverse morphology of its intestinal contents within the dark‐coloured gut and the formation of faecal pellets. The two digestive modes displayed by S. sinica suggest that it is a putative dietary generalist rather than a typical scavenger as previously thought. Moreover, the asymmetry exhibited by the paired caudal appendages of S. sinica provides direct evidence of the development of dorsoventral (DV) differentiation in Selkirkia, which aids our understanding of the lifestyle of this tubiculous worm.

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“…Hu et al . ) and S. sinica caudal outgrowths (Fig. A–C) are rigid structures, which differ from other priapulid soft‐bodied caudal outgrowths.…”

Section: Discussionmentioning

confidence: 87%

“…) and Corynetis fortis (Hu et al . ), are preserved with their mud intestinal contents. This is similar to the extant Priapulus caudatus , which although being chiefly carnivorous, does also occasionally ingest mud (Huang et al .…”

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confidence: 99%

The feeding behaviour of the Cambrian tubiculous priapulid Selkirkia

Lan

Yang

Hou

et al. 2015

LET

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“…In most such localities infaunal ecdysozoans flourished, represented by priapulids (Conway Morris ) and palaeoscolecidans, with associated traces (Hu et al . ; Weber et al . ).…”

Section: Associated Body Fossilsmentioning

confidence: 99%

The Tommotian phase of the Early Cambrian Agronomic Revolution in the carbonate mud environment of central Siberia

Mazurek

2014

LET

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The profound ecological change of the marine benthos that eventually led to the almost complete destruction of the Precambrian matgrounds by benthic grazers and bioturbators (the agronomic revolution) was largely completed in the Tommotian. At that time, burrows produced by bottom‐dwelling animals as shelters against predators were supplemented by burrowing for food by predators and sediment feeders. The limy mud ichnofauna of that age in Siberia was very different from the roughly coeval sand bottom faunas of Baltica. Although the exact zoological identity of the animals forming the infaunal Tommotian traces remains unknown, they probably mostly represent various kinds of early nemathelminthes. No apparent locomotion traces of mollusc origin have been encountered in the Early Cambrian, despite the abundant occurrence of skeletal fossils attributed to molluscs. Possibly the standard muscular foot, typical of modern molluscs, had not yet developed. Ichnotaxa represented are Teichichnus isp., Rhizocorallium isp., Chondrites isp., possibly the Buren ichnocomplex and others.

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“…Their evolutionary significance is further enhanced by an excellent fossil record in the Cambrian Period. For example, early Cambrian deposits near Chengjiang of South China alone preserve more than 20 species of scalidophorans (Han et al 2004;Hou et al 2004;Huang et al 2004aHuang et al , 2004bHuang et al , 2006Ma et al 2010;Hu et al 2012). For example, early Cambrian deposits near Chengjiang of South China alone preserve more than 20 species of scalidophorans (Han et al 2004;Hou et al 2004;Huang et al 2004aHuang et al , 2004bHuang et al , 2006Ma et al 2010;Hu et al 2012).…”

Section: Introductionmentioning

confidence: 99%

The oldest known priapulid‐like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans

Liu

Xiao

Shao

et al. 2014

Evolution and Development

108

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Morphological phylogenetic analyses suggest that scalidophorans (priapulids, loriciferans, and kinorhynchs) and nematoids (nematodes and nematomorphs) form the ecdysozoan clade Cycloneuralia, which is a sister group to panarthropods. It has been proposed that extant priapulids and Cambrian priapulid-like scalidophorans, because of their conserved evolution, have the potential to illuminate the ancestral morphology, ecology, and developmental biology of highly derived ecdysozoans such as nematods and arthropods. As such, Cambrian fossils, particularly Markuelia and possibly olivooids, can inform the early evolution of scalidophorans, cycloneuralians, and ecdysozoans. However, the scalidophoran Markuelia is known exclusively as embryo fossils, and the olivooids have been alternatively interpreted as cnidarians or cycloneuralians. Here, we describe a post-embryonic scalidophoran fossil Eopriapulites sphinx new genus and species, which represents the oldest known scalidophoran, from the early Cambrian Period (∼535 Ma) in South China. E. sphinx is similar to modern scalidophorans in having an introvert armed with hollow scalids, a collar with coronal scalids, and a pharynx with pharyngeal teeth, but its scalids and pharyngeal teeth are arranged in a hexaradial pattern. Phylogenetically resolved as a stem-group scalidophoran, E. sphinx shares a hexaradial pattern with the hexaradial arrangement of certain anatomical structures in kinorhynchs, loriciferans, nematoids, and Cambrian fossils such as Eolympia pediculata, which could also be a scalidophoran. Thus, the bodyplan of ancestral cycloneuralians may have had a component of hexaradial symmetry (i.e., some but not necessarily all anatomical parts are hexaradially arranged). If panarthropods are nested within paraphyletic cycloneuralians, as several molecular phylogenetic analyses suggest, the ancestral ecdysozoans may have been a legless worm possibly with a component of hexaradial symmetry.

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A new priapulid assemblage from the early Cambrian Guanshan fossil Lagerstätte of SW China

Cited by 28 publications

References 11 publications

The feeding behaviour of the Cambrian tubiculous priapulid Selkirkia

The feeding behaviour of the Cambrian tubiculous priapulid Selkirkia

The Tommotian phase of the Early Cambrian Agronomic Revolution in the carbonate mud environment of central Siberia

The oldest known priapulid‐like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans

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