Publication Date
12-31-1968
Series Number
127
Abstract
Ectosteorhachis nitidus from the Lower Permian of North America has holospondylous vertebrae, but a new North American genus of osteolepid rhipidistian of the same age has compound vertebrae each comprising a large principal and a small anterior median dorsal accessory centrum. Attempted embryological analysis of vertebral structure in Rhipidistia reveals no evidence of sclerotome resegmentation and no direct homology with tetrapod vertebrae.
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