A histological analysis of the dentition of the small procolophonid parareptile Soturnia caliodon reveals detailed information concerning tooth implantation and replacement for this taxon. The presence of acrodont tooth implantation is verified, which contradicts current models for procolophonid dentition. A heterogeneous enamel layer, that reaches large thickness on the cusps, and a broad secondary dentine are also recorded. These structures provide a very stable occlusal morphology that extends the useful life of the teeth. During the process of replacement, old teeth were not pushed out but reabsorbed. The evidence indicates that Soturnia caliodon had a very low rate of tooth replacement which constitutes a valuable adaptation for its high−fibre herbivorous niche.

Sergio Furtado Cabreira [sergio.cabreira@terra.com.br], Universidade Luterana do Brasil, Cachoeira do Sul; and Departamento de Paleontologia e Estratigrafia, Universidade Federal do Rio Grande do Sul, Porto Alegre, CP 15001, 91540-000, Brazil; Juan Carlos Cisneros [cisneros.jc@gmail.com], Departamento de Paleontologia e Estratigrafia, Universidade Federal do Rio Grande do Sul, Porto Alegre, CP 15001, 91540-000, Brazil.