INVESTIGADORES
ELISSAMBURU Andrea
congresos y reuniones científicas
Título:
Limb proportions and adaptation in caviomorph rodents (Rodentia, Caviomorpha).
Autor/es:
ELISSAMBURU ANDREA; VIZCAÍNO, S. F.
Lugar:
Mar del Plata
Reunión:
Jornada; Jornadas Argentinas de Mastozoología; 2002
Institución organizadora:
SAREM
Resumen:
Caviomorph rodents (Rodentia: Caviomorpha) are an anatomically variable group with diverse ecological types, including cursorial, digging, fossorial and swimming forms. Their appendicular skeleton is rather generalised and extreme modifications or reductions in the long bones of limbs are not present. It is of special interest to evaluate functional adaptive variations of appendicular skeleton within this group. Although much work has been devoted to study structure, function, and kinematics of legs in mammals, most of them do not consider particular functions and behaviour within different mammalian lineages. We performed morphometric and biomechanical studies to test relationship between adaptation and morphology of proximal and middle bone segments of limbs in terrestrial caviomorph rodents. Fifty-four specimens belonging to 10 species with different limb adaptations and representing a wide range of body sizes were measured. Diameters and functional lengths of long bones were taken and nine functional indices were built. Humerus (HRI) and ulna (URI) robustness, humerus deltoid (SMI) and epicondyle (EI) developement, olecranon proportion (IFA), femur (FRI) and tibia (TRI) robustness, and gluteal muscle insertion at femur (GI), were calculated. Only TRI and, to a lesser degree, SMI and EI, were significantly related to body mass. A functional sequence cursorial-generalised-ocassional digging-diggers with a principal relation to increase of force and muscular development in medial segments of fore limb is recognised. The hind limb shows a decrease of the speed efficiency of the femur and an increase of limb robustness in the transition from cursorial to digging forms. Although overlapping of speed and force functions in the limbs is evident, functional differentiation for speed in the proximal and force in the medial segments can be inferred.
