Royal Society Publishing

New evidence on the anatomy and phylogeny of the earliest vertebrates

Hou Xian-guang, Richard J. Aldridge, David J. Siveter, Derek J. Siveter, Feng Xiang-hong


We report the discovery of a new agnathan specimen from the Lower Cambrian Chengjiang Lagerstätte of China and thereby provide new evidence on the myomeres (V–shaped), the branchial apparatus (gill filaments and arches), the dorsal fin and the gonads (24–26) of the earliest vertebrates. The new specimen and the co–occurring Myllokunmingia fengjiaoa and Haikouichthys ercaicunensis represent a single species, which is a primitive member of the crown group craniates (vertebrates) and post–dates the origin of the myxinoids (hagfish). The origin of the vertebrate clade is at least as old as Early Cambrian.

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