Rotadiscus

For the genus of snails, see Rotadiscus (gastropod).

Rotadiscus Temporal range: Early Cambrian – Middle Cambrian [1] PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of Rotadiscus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Stem group:	Ambulacraria
Clade:	† Cambroernida
Class:	† Eldonioidea
Family:	† Rotadiscidae
Genus:	† Rotadiscus Sun & Hou, 1987
Type species
R. grandis Sun & Hou, 1987
Synonyms [2]
BrzechowiaDzik, 1991

Rotadiscus is a genus of discoidal animal known from the Cambrian Chengjiang biota ^[3] and classified with the eldonioids. ^[2]

As with other eldonioids, it was originally thought to have been pelagic, but is now thought to be benthic. ^[4]

In addition to the type species R. grandis, two other Rotadiscus species have been proposed. The first is known only from one complete juvenile specimen and a few fragments, and was originally described as "Brzechowia sp." It remains without a formal species name, but has been transferred to Rotadiscus. ^[5] The species initially described as R. guizhouensis has since been reassigned to the genus Pararotadiscus . ^[2]

A 2023 cladistic analysis based on new fossils places Rotadiscus, along with other eldonioids, as stem-group ambulacrarians in the clade Cambroernida. ^[6]

References

1. Chen, Jun-yuan; Zhu, Mao-yan; Zhou, Gui-qing (1995). "The early Cambrian medusiform metazoan Eldonia from the Chengjiang Lagerstätte" (PDF). Acta Palaeontologica Polonica. 40 (3): 213–244.
2. Schroeder, Natalie I.; Paterson, John R.; Brock, Glenn A. (2018). "Eldonioids with associated trace fossils from the lower Cambrian Emu Bay Shale Konservat-Lagerstätte of South Australia" . Journal of Paleontology. 92 (1): 80–86. Bibcode:2018JPal...92...80S. doi:10.1017/jpa.2018.6. ISSN   0022-3360. S2CID   197586878.
3. Zhu, Mao-Yan; Zhao, Yuan-Long; Chen, Jun-Yuan (2002-03-01). "Revision of the Cambrian discoidal animals Stellostomites eumorphus and Pararotadiscus guizhouensis from South China" . Geobios. 35 (2): 165–185. Bibcode:2002Geobi..35..165Z. doi:10.1016/S0016-6995(02)00025-6. ISSN   0016-6995.
4. Dzik, Jerzy; Zhao, Yuanlong; Zhu, Maoyan (1997). "Mode of life of the middle Cambrian eldonioid lophophorate Rotadiscus". Palaeontology. 40 (2): 385–396. Retrieved 28 December 2024.
5. Masiak, M.; Żylińska, A. (1994). "Burgess Shale-type fossils in Cambrian sandstones of the Holy Cross Mountains" (PDF). Acta Palaeontologica Polonica. 39 (4): 329–340. Retrieved 28 December 2024.
6. Li, Yujing; Dunn, Frances S.; Murdock, Duncan J.E.; Guo, Jin; Rahman, Imran A.; Cong, Peiyun (May 10, 2023). "Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome". Current Biology. 33 (12): 2359–2366.e2. Bibcode:2023CBio...33E2359L. doi: 10.1016/j.cub.2023.04.048 . PMID   37167976.