IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
capítulos de libros
Título:
Diversity of craniomandibular morphology in caviomorph rodents: an overview of macroevolutionary and functional patterns.
Autor/es:
ALVAREZ, ALICIA; VIEYTES EC; BECERRA, FEDERICO; OLIVARES, AI,; ECHEVERRÍA, ALEJANDRA; VERZI DH; VASSALLO, ALDO IVÁN
Libro:
Biology of Caviomorph rodents: Diversity and Evolution
Editorial:
Sociedad Argentina para el Estudio de los Mamíferos
Referencias:
Año: 2015; p. 34 - 54
Resumen:
Abstract. Caviomorphs are a broadly diversified rodent clade. Accordingly, a great morphological disparity has been detected. This variation bears a clear phylogenetic signal, and a strong allometric component was also detected. Morphological variation is associated with the habitat occupied by each species, with the most divergent condition seen in species with burrowing habits. These species present a massive skull associated with strong masticatory musculature and a stabilized temporomandibular joint that allows the generation of high bite forces. These features are present in species that use incisors in digging or in aggressive encounters during courtship or territorial defense, as in the case of Ctenomys. Exertion of higher bite forces also influences dental morphology and enamel microstructure. Procumbent incisors, deeply implanted, with high resistance to flexion-torsion forces, are observed in species that display the aforementioned features. Features with opposite trait values are present in species that exhibit lower bite forces. With respect to the molar enamel microstructure, a generalized pattern linked to brachydont teeth can be observed; by contrast, a secondary gradual acquisition of radial enamel, strengthening the enamel band and favoring the formation of sharp edges, is related to the acquisition of hypsodonty. The strong phylogenetic signal of morphological variation observed among extant caviomorphs may be explained by an early establishment of the major pathways of craniomandibular specialization in the evolutionary history of these rodents. However, phylogenetic structure alone does not explain morphological changes. Several variables such as size, habitat, diet, habits, and diverse aspects of the life history of species, such as burrow construction and social interaction are also linked to the observed morphological variation. The integration of macroevolutionary and morpho-functional studies in future comprehensive studies that involve both approaches, together with paleoenvironmental inferences, would improve the understanding of the evolution of this exceptional group of rodents.