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Updated: Sep 29, 2026

Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
New evidence on the anatomy and phylogeny of the earliest vertebrates
Hou Xian-guang1, Richard J Aldridge, David J Siveter
1Yunnan Research Centre for Chengjiang Biota, Yunnan University, Kunming 650091, Yunnan Province, People's Republic of China. hghou@ynu.edu.cn
Abstract:
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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