A brief history and revision of the systematics of the cladid crinoid Sinocrinus

The erisocrinid Sinocrinus differs from other erisocrinid genera (Erisocrinus and Exaetocrinus) by possessing a rounded, bowl-shaped cup, bearing tumid cup plates with impressed sutures. Sinocrinus Tien, 1926 is refined using Principal Component Analysis and neighborhood cluster analysis. The genotype of Sinocrinus, S. microgranulosus Tien, 1926, is a junior subjective synonym of S. granulatus (Wanner, 1924). Sinocrinus [Erisocrinus] stefaninii (Yakovlev, 1934) is a junior synonym of Sinocrinus lichengensis Tien, 1926 and S. asymmetricus Strimple and Watkins, 1969 is the junior synonym of S. sheareri Strimple and Watkins, 1969. Other valid species include: S. [Erisocrinus] cernuus (Trautschold, 1867); S. [Erisocrinus] obliquus (Wanner, 1916); S. houkouensis Tien, 1926; S. nodosus Tien, 1926; S. [Erisocrinus] stefaninii (Yakovlev, 1934). Because of its refined inclusiveness, the temporal span of the genus now extends from the Late Carboniferous (Moscovian) through the early Permian (Sakmarion). This study also widens the current geographic range of Sinocrinus, with specimens collected across a wider span of Eurasia.