Late ontogeny of the trilobite Tsinania shanxiensis (Zhang and Wang, 1985) from the Cambrian (Furongian) of Anhui, China and its systematic implications

A new occurrence of Tsinania shanxiensis (Zhang and Wang, 1985) n. comb., is reported herein from northern Anhui, China. This species is here transferred from Guluheia to Tsinania as the differences between the two genera are not enough to support the generic difference. The late ontogeny of T. shanxiensis is documented herein, which provides important evidence for the evolutionary origin of the Family Tsinaniidae. The late ontogeny of the pygidia of T. shanxiensis is divided into four stages: PSS+2 stage, PSS+1 stage, early holaspid stage, and late holaspid stage. The immature morphology of T. shanxiensis retains long pygidial spines, reminicent of Mansuyia. Therefore, the morphology of T. shanxiensis can be regarded as the transitional type between kaolishaniids (e.g., Mansuyia orientalis, M. tani) and tsinaniids (e.g., T. canens, Shergoldia laevigata) during the middle Furongian.