New insights on the dental anatomy of Manidens condorensis (Ornithischia: Heterodontosauridae): maxillary dentition and replacement pattern

BECERRA, MARCOS G.,; POL, DIEGO; RAUHUT, OLIVER W.M.

San Luis (Capital)

Congreso; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2017

Asociación Paleontológica Argentina

Micro-Computed Tomography scanning of the holotype of Manidens condorensis (Pol,Rauhut and Becerra, 2011; MPEF-PV 3211) provided new data on the anatomy of this species. The micro-CT information allows the identification of the previously unknownmaxillary dentition for the species, bearing at least eight teeth. These teeth are low at theirapical half, with symmetrically distributed denticles and enlarged lingual cingular margins,contrasting with the opposing hand-shaped dentary teeth, whereas the preservation of a mesialcavity and the similar height-width proportions are the only features shared between maxillaryand dentary teeth. This new information on the maxillary dentition allows referring toManidens an isolated maxilla (MPEF-PV 3809) and isolated teeth, improving itsmorphological characterization. In MPEF-PV 3809 and the isolated maxillary teeth, themesial lingual cingulum bears two to six denticles, whereas the distal lingual cingulum bearsserrations, varying in orientation from V to Z-shaped in anteroposterior direction. Additionalcingular edges are identified labially, a distal cingulum in most of the teeth, and a smallbulging to shelf-like mesial edge in posterior teeth only, which in some cases have denticles.Wear facets indicate a complex occlusion: the function of the lingual cingula during chewing(wear at cingular edges); a alternate occlusion (bifacial arrangement of wear); possiblemislocation of opposing teeth pertaining to different tooth families (wear at the non-functionalface). The identification of replacement teeth in these specimens reminds a reptilianZahnreihe type of tooth development for Manidens, being the taxon with the best-preservedtooth replacement pattern among Heterodontosauridae.