Data from: Dental ontogeny in extinct synapsids reveals a complex evolutionary history of the mammalian tooth attachment system

AbstractThe mammalian dentition is uniquely characterized by a combination of precise occlusion, permanent adult teeth, and a unique tooth attachment system. Unlike the ankylosed teeth in most reptiles, mammal teeth are supported by a ligamentous tissue that suspends each tooth in its socket, providing flexible and compliant tooth attachment that prolongs the life of each tooth and maintains occlusal relationships. Here we investigate dental ontogeny through histological examination of a wide range of extinct synapsid lineages to assess whether the ligamentous tooth attachment system is unique to mammals and to determine how it evolved. This study shows for the first time that the ligamentous tooth attachment system is not unique to crown mammals within Synapsida, having arisen in several non-mammalian therapsid clades as a result of neoteny and progenesis in dental ontogeny. Mammalian tooth attachment is here re-interpreted as a paedomorphic condition relative to the ancestral synapsid form of tooth attachment., Usage notesThrinaxodon adult BP/1/7199Images from CT reconstruction of the skull of an adult Thrinaxodon (BP/1/7199) used to score ontogenetic stages of teeth.Thrinaxodon adult BP 1 7199.zipThrinaxodon young (BP/1/5372)Images from CT reconstruction of the skull of a juvenile Thrinaxodon (BP/1/5372) used to score ontogenetic stages of teeth.Thrinaxodon young 5372.zipGalesaurus adult BP/1/5064Images from CT reconstruction of the skull of an adult Galesaurus (BP/1/5064) used to score ontogenetic stages of teeth.Galesaurus adult BP-1-5064.zipGalesaurus subadult BP/1/4602Images from CT reconstruction of the skull of a subadult Galesaurus (BP/1/4602) used to score ontogenetic stages of teeth.Galesaurus subadult BP-1-4602.zip