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Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian through the Lower Carboniferous (Mississippian). A possible early graptolite, Chaunograptus, is known from the Middle Cambrian. Recent analyses have favored the idea that the living pterobranch Rhabdopleura represents an extant graptolite which diverged from the rest of the group in the Cambrian.
Yohoia is an extinct genus of megacheiran arthropod from the Cambrian period that has been found as fossils in the Burgess Shale formation of British Columbia, Canada. The type species, Yohoia tenuis, was described in 1912 by Walcott, who considered it an anostracan crustacean. 711 specimens of Yohoia are known from the Greater Phyllopod bed, where they comprise 1.35% of the community. In 2015, Conway Morris et al. reported another species, Y. utahana, from the Marjum Formation, Utah.
Pterobranchia, members of which are often called pterobranchs, is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 25 known living pterobranch species in three genera, which are Rhabdopleura, Cephalodiscus, and Atubaria. On the other hand, there are several hundred extinct genera, some of which date from the Cambrian Period.
Odaraia is a genus of bivalved arthropod from the Middle Cambrian. Its fossils, which reach 15 centimetres (5.9 in) in length, have been found in the Burgess Shale in British Columbia, Canada.
Marpolia has been interpreted as a cyanobacterium, but also resembles the modern cladophoran green algae. It is known from the Middle Cambrian Burgess shale and Early Cambrian deposits from the Czech Republic. It comprises a dense mass of entangled, twisted filaments. It may have been free-floating or grown on other objects, although there is no evidence of attachment structures. 40 specimens of Marpolia are known from the Greater Phyllopod bed, where they comprise 0.08% of the community.
Dalyia is a genus of worm-like fossilized organisms found in the Walcott Quarry and Trilobite beds of the Burgess shale from the middle Cambrian. Due to its branching structure, it was previously interpreted as a red alga. However further examinations in 2015 suggest they may instead be pterobranchs, a class of small tube-dwelling worms. It has smooth or faintly lineated stems, which branch into up to four equal branches at branching points. 37 specimens of Dalyia are known from the Greater Phyllopod bed, where they comprise 0.07% of the community.
Plenocaris plena is a genus of extinct bivalved hymenocarine arthropod that lived in the Cambrian aged Burgess Shale and Chengjiang. Originally described as a species of Yohoia by Walcott in 1912, it was placed into its own genus in 1974.
Liangshanella is a genus of Cambrian bradoriid known from the Chengjiang biota and Burgess Shale. 6263 specimens of Liangshanella are known from the Greater Phyllopod bed, where they comprise 11.9% of the community.
Morania is a genus of cyanobacterium preserved as carbonaceous films in the Middle Cambrian Burgess Shale. it is present throughout the shale; 2580 specimens of Morania are known from the Greater Phyllopod bed, where they comprise 4.90% of the community. It is filamentous, forms sheets, and resembles the modern cyanobacterium Nostoc. It would have had a role in binding the sediment, and would have been a food source for such organisms as Odontogriphus and Wiwaxia.
The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil Lagerstätte. It was quarried by Charles Walcott from 1911–1917, and was the source of 95% of the fossils he collected during this time; tens of thousands of soft-bodied fossils representing over 150 genera have been recovered from the Phyllopod bed alone.
Chaunograptus is a genus of putative graptolite known from the Middle Cambrian Burgess Shale. 11 specimens of Chaunograptus are known from the Greater Phyllopod bed, where they comprise 0.02% of the community.
Cambrorhytium is an enigmatic fossil genus known from the Latham Shale (California), and the Chengjiang (China) and Burgess Shale lagerstätte. 350 specimens of Cambrorhytium are known from the Greater Phyllopod bed, where they comprise 0.7% of the community.
Acrothyra gregaria is a species of gregarious brachiopod known from the Middle Cambrian Burgess Shale. 253 specimens of Acrothyra are known from the Greater Phyllopod bed, where they comprise 0.5% of the community.
Eiffelia is an extinct genus of sponges known from the Middle Cambrian Burgess Shale as well as several Early Cambrian small shelly fossil deposits. It is named after Eiffel Peak, which was itself named after the Eiffel Tower. It was first described in 1920 by Charles Doolittle Walcott. It belongs in the Hexactinellid stem group. 60 specimens of Eiffelia are known from the Greater Phyllopod bed, where they comprise 0.11% of the community.
Emeraldella is a genus of arthropod known from the Middle Cambrian of North America. The type species E. brocki was described in 1912 from the Burgess Shale. 21 specimens of Emeraldella are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. A re-study on the species was done in 2012. A second species E. brutoni is known from the Wheeler Shale, which was described in 2011. An additional specimen of E. brutoni was described in 2019, which revealed more of the anatomy. It has been placed as a basal member of the clade Vicissicaudata within Artiopoda, a group of arthropods containing trilobites and their relatives.
Louisella is a genus of worm known from the Middle Cambrian Burgess Shale. It was originally described by Charles Walcott in 1911 as a holothurian echinoderm, and represents a senior synonym of Miskoia, which was originally described as an annelid. 48 specimens of Louisella are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. It has been stated to have palaeoscolecid-like sclerites, though this is not in fact the case.
Leptomitus is a genus of demosponge known from the Middle Cambrian Burgess Shale. Its name is derived from the Greek lept ("slender") and mitos ("thread"), referring to the overall shape of the sponge. 138 specimens of Leptomitus are known from the Greater Phyllopod bed, where they comprise 0.26% of the community.
Protospongia is a genus of Porifera known from the Middle Cambrian Burgess Shale. 102 specimens of Protospongia are known from the Greater Phyllopod bed, where they comprise 0.19% of the community.
Rhabdopleura is a genus of colonial sessile hemichordates belonging to the Pterobranchia class. As one of the oldest living genera with a fossil record dating back to the Middle Cambrian, it is also considered to be the only living genus of graptolites.
This is a list of the biota of the Burgess Shale, a Cambrian lagerstätte located in Yoho National Park in Canada.
References
- 1 2 Briggs, D. E. G.; Erwin, D. H.; Collier, F. J. (1995), Fossils of the Burgess Shale , Washington: Smithsonian Inst Press, ISBN 1-56098-659-X, OCLC 231793738
- 1 2 3 Steven T. LoDuca; Jean-Bernard Caron; James D. Schiffbauer; Shuhai Xiao & Anthony Kramer (2015). "A reexamination of Yuknessia from the Cambrian of British Columbia and Utah". Journal of Paleontology. 89 (1): 82–95. Bibcode:2015JPal...89...82L. doi: 10.1017/jpa.2014.7 . S2CID 129248278.
- ↑ Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. Bibcode:2006Palai..21..451C. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022. S2CID 53646959.
- ↑ Michael Steiner & Jörg Maletz (2012). "Cambrian graptolites (Pterobranchia) and the origin of colonial organization in metazoans" (PDF). TERRA NOSTRA – Schriften der GeoUnion Alfred-Wegener-Stiftung. Centenary Meeting of the Paläontologische Gesellschaft. Programme, Abstracts, and Field Guides. 2012/3: 173–174.
- ↑ Maletz, Jörg; Steiner, Michael (2015). "Graptolite (Hemichordata, Pterobranchia) preservation and identification in the Cambrian Series 3". Palaeontology. 58 (6): 1073–1107. Bibcode:2015Palgy..58.1073M. doi: 10.1111/pala.12200 . S2CID 129341868.
