A histological investigation of dental crown characters used in mosasaur phylogenetic analyses

Mosasaur researchers have used varieties of tooth crown ornamentation as diagnostic and phylogenetic characters for decades. Such features include facets, flutes, striations, serrated carinae, coarse anastomosing texture. This study investigates the relative contribution dentine enamel to development these dental assesses possible homologies between structures. Histological analysis isolated mosasaur teeth revealed that flutes facets develop initially from dentine, external morphology we observe macroscopically mirrors shape underlying dentine. Striations combine contributions with additional irregular deposition results strictly amelogenesis. In both carinae texture border is smooth, ornamentations form through variations in development. Based on observations, infer are part a morphological spectrum should not be treated separate characters. Conversely, striations differently than therefore distinct character. We recommend referring “serrations” crenulations differentiate enamel-only structures true denticles possessing core. Anastomosing can also coincide significant apical thickening, which could adaptations processing hard-shelled prey. Care must taken when using or because seemingly different morphologies similar developmental origins, more closely tied diet common ancestry.