INVESTIGADORES
ELISSAMBURU Andrea
artículos
Título:
Limb proportions and adaptations in caviomorph rodents (Rodentia: Caviomorpha)
Autor/es:
ELISSAMBURU, A; VIZCAÍNO, S. F.
Revista:
JOURNAL OF ZOOLOGY
Editorial:
The Zoological Society of London
Referencias:
Lugar: London; Año: 2004 p. 145 - 159
ISSN:
0022-5460
Resumen:
J. Zool.,
Lond. (2004) 262, 145159 C_ 2004 The Zoological Society of London Printed in the United Kingdom
DOI:10.1017/S0952836903004485
Limb proportions and adaptations in
caviomorph rodents
(Rodentia:
Caviomorpha)
A. Elissamburu and S. F. Vizcaíno
Departamento
Científico Paleontología de Vertebrados; Museo de La Plata,
Paseo del Bosque s/n, 1900 La
Plata, CONICET, Argentina
(Accepted
1 July 2003)
Abstract
Caviomorph rodents (Rodentia:
Caviomorpha) are an anatomically variable group with diverse ecological andmorphological types, including
cursorial, digging, fossorial and swimming forms. Their appendicular skeleton
is rather generalized 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 the appendicular skeleton within this group.
Although much work has been devoted to study
structure, function, and kinematics of legs in mammals, most studies do not consider particular functions and
behaviour within differentmammalian lineages.Morphometric and biomechanical studies were performed to test the
relationship between adaptation and morphology of the bones of the proximal and middle limb segments 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) development, 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 (cursorialgeneralizedoccasional digging diggers) which seems to reflect an
increase in force and muscular development in middle segments of the fore limb is recognized. The hind limb
shows a decrease in the speed efficiency of the femur and an increase in 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 middle segments can
be inferred.