The evolution of the synapsid tusk: insights from dicynodont therapsid tusk histology.

ABSTRACT: The mammalian tusk is a unique and extreme morphotype among modern vertebrate dentitions. Tusks-defined here as ever-growing incisors or canines composed of dentine-evolved independently multiple times within mammals yet have not evolved in other extant vertebrates. This suggests that there is a feature specific to mammals that facilitates the evolution of this specialized dentition. To investigate what may underpin the evolution of tusks, we histologically sampled the tusks of dicynodont therapsids: the earliest iteration of tusk evolution and the only non-mammalian synapsid clade to have acquired such a dentition. We studied the tissue composition, attachment tissues, development and replacement in 10 dicynodont taxa and show multiple developmental pathways for the adult dentitions of di

SUBMITTER: Whitney MR 

PROVIDER: S-EPMC8548784 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature