Scaling and adaptations of incisors and cheek teeth in caviomorph rodents (Rodentia, Hystricognathi)

BECERRA FEDERICO; VASSALLO ALDO IVÁN; ECHEVERRÍA ALEJANDRA ISABEL; CASINOS PARDOS ADRIÀ

JOURNAL OF MORPHOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2012 vol. 273 p. 1150 - 1162

0362-2525

Within mammals, the group of South American hystricognath rodents became one of the most diverse clades considering their occupied habitats, locomotor modes and body sizes, this might have been partly achieved by diversifying their masticatory apparatus? structure and its ecological commitment, e.g., chisel-tooth digging. In this contribution, based on their phylogeny, we assessed the relationship among ecological behavior and mechanical features of their incisors and molariforms. Based on 33 species of 9 families of caviomorph rodents, we analyzed incisors attributes related to structural stress resistance and molar features related with grinding capacity, e.g., second moment of inertia and enamel index (enamel band length/occlusal surface area), respectively. Most of these variables scaled isometrically to body mass, with a strong phylogenetic effect. A PCA discrimination on the enamel index clustered the species according to their geographic distribution. We presume that selective pressures in Andean-Patagonian regions, on particular feeding habits and chisel-tooth digging behaviors, have modeled the morphological characteristics of the teeth. Subterranean/burrower ctenomyids, coruros and plains viscachas showed the highest bending/torsion strength and anchorage values for incisors; a simplified enamel pattern in molariforms would be associated with a better grinding of the more abrasive vegetation present in more open and drier biomes.