Dinomischus
Dinomischus Temporal range:
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The holotype of Dinomischus isolatus collected by Walcott | |
Scientific classification | |
Kingdom: | |
Phylum: | stem-group Ctenophora?
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Genus: | †Dinomischus
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Type species | |
†Dinomischus isolatus Conway Morris, 1977
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Other species | |
†D. venustus Peng et al., 2006 |
Dinomischus is an extinct genus of stalked filter-feeding animals with the
History of study
In his pioneering excavations of the Burgess Shale, Charles Doolittle Walcott excavated the first, and at the time only, specimen. It had evidently caught his eye, for he had taken the trouble to carefully photograph it—but he never found the time to describe the organism, and it was not until 1977 that Simon Conway Morris described the animal. He tracked down two further specimens, collected by further expeditions by teams from Harvard and the Royal Ontario Museum, allowing him to produce a reconstruction.[1]
Description
Dinomischus isolatus reached 20 mm in height,
Distribution
Further specimens have since been produced by similarly spectacular fossil sites in China. 13 have been found in the Chengjiang, then in 2006 one specimen was identified within the Kaili Formation.[4] These organisms merited the erection of a new species, D. venustus, as their corrugated "petals" possessed radial rays.[5] 13 specimens of Dinomischus are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community.[6]
Affinity
Dinomischus is not the only sessile, stalked organism from the Cambrian, but it has no obvious relatives in other genera.
A number of affinities were considered, but on the basis of available evidence it didn't quite seem to fit into any extant phylum.[1] The most similar organisms were the much smaller
In 2019, Dinomischus and other Cambrian forms were hypothesized to be stem-gruop ctenophores. This leads to the assertion that ctenophores evolved from immotile, suspensivorous forms, a lifestyle similar to that of polyps.[13] Cladogram after Zhao et al., 2019:
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A later study suggested that Dinomischus, Diahua and Xianguangia formed a clade, Dinomischidae, with Siphusauctum more closely related to modern ctenophores.[14]
See also
References
- ^ a b c d Conway Morris, S. (1977). "A new entoproct-like organism from the Burgess Shale of British Columbia" (PDF). Palaeontology. 20 (4): 833–845.
- ^ a b
Hou, X.-G. (2004). The Cambrian Fossils of Chengjiang, China : The Flowering of Early Animal Life. ISBN 978-1-4051-0673-3.
- ^ "Dinomischus isolatus". Hooper Virtual Paleontological Museum.
- ^ Peng, J.; Zhao, Y.; Lin, J.-P. (2006). "Dinomischus from the Middle Cambrian Kaili Biota, Guizhou, China". Acta Geologica Sinica. 80 (4): 498–501.
- ^
Hagadorn, J.W. (2002). "Chengjiang: Early Record of the Cambrian Explosion". In Bottjer, D.J.; Etter, W.; Hagadorn, J.W.; Tang, C.M. (eds.). Exceptional Fossil Preservation: a unique view on the evolution of marine life. ISBN 978-0-231-10255-1.
- S2CID 53646959.
- PMID 22279532.
- ^
Dzik, J. (1991). "Is fossil evidence consistent with traditional views of the early metazoan phylogeny?" (PDF): 47–56.
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(help) - ^ Lieberman, B.S. (2008). "The Cambrian radiation of bilaterians: Evolutionary origins and palaeontological emergence; earth history change and biotic factors". .
- ^ Chen, J.Y.; Zhou, G.Q. (1997). "Biology of the Chengjiang fauna". Bull. Natl. Mus. Nat. Sci. 10: 11–105.
- ^ .
- ^
Bassett, M.G.; Popov, L.E.; Holmer, L.E. (2004). "The Oldest-Known Metazoan Parasite?" (PDF). S2CID 86756106.
- S2CID 84844387.
- ISSN 1477-2019.
External links
- "Dinomischus isolatus". Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011.
Further reading
- Briggs, Erwin & Coller (1995). Fossils of the Burgess Shale. OCLC 231793738.
- Hou, X.-G. (2004). The Cambrian Fossils of Chengjiang, China : The Flowering of Early Animal Life. ISBN 978-1-4051-0673-3.
- Knoll, A.H. (1996). "Daughter of time". S2CID 41528857.