Palaeobranchiostoma hamatotergum is an extinct chordate from the Early Permian-aged Whitehill Formation in South Africa.[1] It is known from a single, 11 mm long specimen found in black shale.[1][2] The body shows the presence of a notochord-like structrure running along the length of the body, along with gill slits, along with several unpaired fins, including a tail (caudal) fin with rays that is round and small, a pronounced pelvic fin and a humped dorsal fin covered in spikes.[3] In its original description it was considered to be a cephalochordate (also known as a lancelet), though some other authors have considered its placement in the group as not definitive, due to a number of aspects of its anatomy like the fins being strongly divergent from living lancelets.[4]
| Palaeobranchiostoma Temporal range:
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| Artist's restoration | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Genus: | †Palaeobranchiostoma Oelofsen & Loock 1981 |
| Species: | †P. hamatoterga
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| Binomial name | |
| †Palaeobranchiostoma hamatoterga Oelofsen & Loock 1981
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References
edit- ^ a b Oelofsen, B. W., and J. C. Loock. "A Fossil Cephalochordate From the Early Permian Whitehill Formation of South-Africa." South African Journal of Science 77.4 (1981): 178-180. [1]
- ^ Blieck, Alain. "At the origin of chordates." Geobios 25.1 (1992): 101-113.
- ^ Bayramov, Andrey V.; Yastrebov, Sergey A.; Mednikov, Dmitry N.; Araslanova, Karina R.; Ermakova, Galina V.; Zaraisky, Andrey G. (May 2024). "Paired fins in vertebrate evolution and ontogeny". Evolution & Development. 26 (3). doi:10.1111/ede.12478. ISSN 1520-541X.
- ^ Chen, Jun‐Yuan (November 2008). "Early crest animals and the insight they provide into the evolutionary origin of craniates". genesis. 46 (11): 623–639. doi:10.1002/dvg.20445. ISSN 1526-954X.