Article: Early Silurian sinacanths (Chondrichthyes) from China

Histological study of new specimens of sinacanth fin spines from the Lower Silurian of the northwestern margin of the Tarim Basin (Xinjiang, China) shows that they have the same histology as the fin spines of chondrichthyans. On this basis it is argued that sinacanths are one of the oldest known chondrichthyans, rather than acanthodians, and their spines are the oldest known shark fin spines. Previous studies on sinacanths are critically reviewed. The family Sinacanthidae is erected to include Sinacanthus and its relatives with more than 15 fin spine ridges per side. It is suggested that Sinacanthus fancunensis is synonymous with S. wuchangensis. A new sinacanth genus and species, Tarimacanthus bachuensis, from the Lower Silurian of Tarim and South China, is erected.