A new rhynchosaur maxillary tooth plate morphotype expands the disparity of the group in the Ischigualasto Formation (Late Triassic) of Northwestern Argentina

A new rhynchosaur maxillary tooth plate morphotype, discovered in the Ischigualasto Formation (Late Triassic) of Northwestern Argentina, significantly expands the known morphological disparity of hyperodapedontine rhynchosaurs. This specimen, PVL 2728, features a unique combination of traits: a single longitudinal groove dividing symmetric lateral and medial tooth-bearing areas with relatively large tooth crowns, which deviates from previously documented South American rhynchosaurs. Quantitative analyses confirm its distinctiveness, suggesting a greater diversity in the group during the Late Triassic period. This finding challenges existing understanding of rhynchosaur evolution and distribution within southwestern Pangaea.

Gentil, A. R., & Ezcurra, M. D. (2018). A new rhynchosaur maxillary tooth plate morphotype expands the disparity of the group in the Ischigualasto Formation (Late Triassic) of Northwestern Argentina. Historical Biology, 1–8. https://doi.org/10.1080/08912963.2018.1438425