Myllokunmingia

Myllokunmingia is a genus of basal chordate from the Lower Cambrian Maotianshan shales of China, thought to be a vertebrate,[1] although this is not conclusively proven.[2] It is 28 mm long and 6 mm high.

Myllokunmingia
Temporal range: Lower Cambrian, ~518 Ma
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An artist's conception of Myllokunmingia fengjiaoa.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Superclass: Agnatha
Order: †Myllokunmingiida
Family: †Myllokunmingiidae
Genus: †Myllokunmingia
Shu, Zhang & Han, 1999
Species:
†M. fengjiaoa
Binomial name
†Myllokunmingia fengjiaoa
Shu, Zhang & Han, 1999

It is among the oldest possible craniates, found in the lower Cambrian Chengjiang (518 million years ago). It appears to have a skull and skeletal structures made of cartilage. There is no sign of biomineralization of the skeletal elements.

The holotype was found in the Yuanshan member of the Qiongzhusi Formation in the Eoredlichia Zone near Haikou at Ercaicun, Kunming City, Yunnan, China. The animal has a distinct head and trunk with a forward sail-like (1.5 mm) dorsal fin and a ventral finfold (probably paired) further back. The head has five or six gill pouches with hemibranchs. In the trunk there are 25 segments (myomeres) with rearward-facing chevrons. There is a notochord, a pharynx and a digestive tract that may run all the way to the rear tip of the animal. The mouth cannot be clearly identified. There may be a pericardial cavity. There are no fin radials.

There is only one specimen, which has the tip of the tail buried in sediment.[1] Only one species is known – Myllokunmingia fengjiaoa (Shu, Zhang & Han).

Related creatures are Haikouichthys and Zhongjianichthys.

See also

References
  1. Shu, D-G.; Luo, H-L.; Conway Morris, S.; Zhang, X-L.; Hu, S-X.; Chen, L.; Han, J.; Zhu, M.; Li, Y.; Chen, L-Z. (1999). "Lower Cambrian vertebrates from south China". Nature. 402 (6757): 42. Bibcode:1999Natur.402...42S. doi:10.1038/46965.
  2. Donoghue, P.C.J.; Purnell, M.A. (2005). "Genome duplication, extinction and vertebrate evolution" (PDF). Trends in Ecology & Evolution. 20 (6): 312–319. doi:10.1016/j.tree.2005.04.008. PMID 16701387. Archived from the original (PDF) on 2008-12-17. Retrieved 2008-11-06.


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