Virtual reconstruction of the neurocranial anatomy of Kansajsuchus extensus (Neosuchia: Paralligatoridae) from the Upper Cretaceous of Tadzhikistan with a review of braincase osteology in Neosuchia

Abstract

The braincase features appear phylogenetically informative and key in assessing the still contentious relationships within Crocodylomorpha. Yet, the neurocrania of many non-crocodylian taxa are imperfectly studied. In the present paper, we describe the braincase osteology and neuroanatomy of a paralligatorid crocodylomorph Kansajsuchus extensus from the Upper Cretaceous Kansai locality in Tadzhikistan based on CT-scanning, segmentation, and 3D modeling. The detailed comparison of K. extensus with other taxa expands our understanding of the neurocranial anatomy and evolution in Neosuchia. The braincase anatomy appears to be relatively consistent across most non-crocodylian neosuchians, but important changes in its structure are traced through the neosuchian–eusuchian transition and especially at the base of Crocodylia. We question the close affinities of Dyrosauridae and Pholidosauridae based on significant differences in their braincases.