Abstract Living reptiles including turtles, crocodilians, birds and squamates are descended from a common ancestor among the Neodiapsida that lived in the late Permian c . 257 million years ago. Their origin was preceded by key evolutionary changes to cranial architecture that are poorly understood due to the rarity of early neodiapsids in the fossil record. Here, we describe a monospecific aggregation of a new non‐saurian neodiapsid from the late Permian of South Africa. Synchrotron microtomography of four complete skulls reveals a mosaic of classic ‘saurian’ features such as a tympanic fossa and cephalic condyle of the quadrate and an open lower temporal bar, alongside surprising plesiomorphies including a rectangular denticle field on the braincase and a comparatively robust stapes. Phylogenetic analysis finds the new taxon within the Younginidae, sister to Akkedops bremneri and Youngina capensis as the earliest‐diverging neodiapsid lineage. Our results demonstrate that the mobile (strepostylic) quadrate evolved only shortly after the origin of the tympanic fossa and the loss of the lower temporal bar, among crownward stem reptiles. This suggests a functional evolutionary linkage between these important traits related to hearing and feeding during the rise of crown reptiles.
Jenkins et al. (2026) studied this question.