A New Antiarch, Bothriolepis zhujiangyuanensis sp. nov., from the Eifelian (Middle Devonian) of Qujing, Yunnan, SW China

Abstract

A new species of Bothriolepis (Placodermi, Antiarcha), B. zhujiangyuanensis sp. nov., is described from the Eifelian (Middle Devonian) Shangshuanghe Formation at the Pearl River Source Scenic Area, Qujing, Yunnan Province, southwestern China and is characterized by a broad postpineal plate bearing a straight anterior margin, a premedian plate wider than long, and a weakly developed dorsal median ridge of the trunk shield. As the eighth Bothriolepis taxon in China, B. zhujiangyuanensis sp. nov. provides a wealth of morphological data to clarify the intrageneric interrelationships. Maximum parsimony analysis, using a revised data set of the genus with 76 ingroup taxa and 72 characters, yields a well-resolved consensus tree for Bothriolepis. The phylogenetic result shows a sister-group relationship between B. zhujiangyuanensis and B. babichevi from Kazakhstan, corroborating the biogeographic proximity between the South China and Kazakhstania blocks during the Middle Devonian.