Tooth-On-Tooth Interlocking Occlusion Suggests Macrophagy in the Mesozoic Marine Crocodylomorph Dakosaurus

• Autores: Young, Mark T.; Brusatte, Stephen L.; Beatty, Brian L.; Brandalise de Andrade, Marco; Desojo, Julia Brenda
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Feeding; Functional Ecology; Metriorhynchidae; Occlusion; Thalattosuchia
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Metriorhynchidae was a peculiar but long-lived group of marine Mesozoic crocodylomorphs adapted to a pelagic lifestyle. Recent discoveries show that metriorhynchids evolved a wide range of craniodental morphotypes and inferred feeding strategies. One genus, Dakosaurus, is arguably the most aberrant marine crocodylomorph due to its large, robust, ziphodont teeth; very low tooth count; and brevirostrine/oreinirostral snout. We here report an additional unusual feature of Dakosaurus that is unique among marine crocodylomorphs: tightly fitting tooth-to-tooth occlusion, whose inference is supported by reception pits along the upper and lower tooth rows, indicative of vertically orientated crowns that were in close contact during occlusion, and three distinct types of dental wear. These include irregular spalled surfaces near the apex (probably caused by tooth-food contact), semi-circular wear near the base, and elongate surfaces extending along the mesial and distal margins of the teeth, obliterating the carinae (including the denticles). Scanning electron micrographs show that these latter surfaces are marked by parallel apicobasal striations, which in extant mammals reflect tooth-tooth contact. As such, we interpret the carinal wear facets in Dakosaurus as being formed by repeated tooth-tooth contact between the mesial and distal margins of the teeth of the upper and lower jaw. We posit that this increased the available shearing surface on their high crowns. Together, these wear patterns suggest that occlusion in Dakosaurus was specialized for cutting large and abrasive prey items into portions small enough to swallow, making it a prime example of an aquatic reptile with macrophagous feeding habits. © 2012 Wiley-Periodicals, Inc.
Fil: Young, Mark T.. University of Glasgow; Reino Unido. University of Edinburgh; Reino Unido
Fil: Brusatte, Stephen L.. Columbia University In The City Of New York; . American Museum of Natural History; Estados Unidos
Fil: Beatty, Brian L.. New York College Of Osteopathic Medicine, Old Westbury;
Fil: Brandalise de Andrade, Marco. Universidade Federal do Rio Grande do Sul; Brasil
Fil: Desojo, Julia Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina