The cranial morphology of Anosteira maomingensis (Testudines, Pan-Carettochelys) and the evolution of pan-carettochelyid turtles

This paper describes the cranial morphology of Anosteira maomingensis, a turtle of the clade Pan-Carettochelys, based on a skull that is part of a more complete specimen from the middle-upper Eocene Youganwo Formation of Maoming, Guangdong Province, China. The cranial data of An. maomingensis were included in a phylogenetic analysis of pan-carettochelyids, one that was complemented with new codings and characters and also including cranial and non-shell postcranial characters of Kizylkumemys schultzi (Late Cretaceous of Uzbekistan). It also included characters of vertebral scutes of pan-carettochelyids based on a newly proposed nomenclature of vertebral scutes for this group. The result of our phylogenetic analyses supports a recently proposed hypothesis of probable paraphyly of Anosteirinae, Kizylkumemys, Anosteira, and Allaeochelys. In addition, our study summarizes data on cranial morphology of pan-carettochelyid turtles and discusses some aspects of their evolution.