A new petalichthyid placoderm from the Early Devonian of Yunnan, China

Pauropetalichthys magnoculus, a new genus and species within the Petalichthyida (Gnathostomata: Placodermi), is described from the Late Emsian (Early Devonian) of Qujing, Yunnan, southwestern China. A three-dimensional reconstruction of the skull roof and neurocranium based on high-resolution computed tomography reveals the pattern of sensory canals, the visceral surface of the skull roof, and the profile of the endocranium. The perichondral lining of the nasal capsules provides the first hard evidence of nasal capsules in petalichthyids. A phylogenetic analysis resolves the new taxon as the most basal member of the Quasipetalichthyidae, an endemic group sister to the Macropetalichthyidae. In light of the newly revealed endocranial features, we discuss the morphological disparity of petalichthyid endocrania. The paleogeographic distribution of the Petalichthyida is summarized to show the group's center of origin and routes of dispersal.