INVESTIGADORES
CANDELA Adriana Magdalena
artículos
Título:
Functional Anatomy of the Limbs of Erethizontidae
Autor/es:
CANDELA A. M. Y PICASSO M.
Revista:
JOURNAL OF MORPHOLOGY
Editorial:
Wiley Interscience
Referencias:
Año: 2008 vol. 269 p. 552 - 593
ISSN:
0362-2525
Resumen:
ABSTRACT Functional analysis of the limb bones of
the erethizontid Steiromys duplicatus, one of the most
abundant Miocene porcupines from Patagonia, provides
evidence to infer their locomotor behavior. Remains of
the giant Neosteiromys pattoni (Late Miocene of Northeast
Argentina) are also analyzed. Osteological and
myological features of extant porcupines were evaluated
and used as a model to interpret the functional significance
of Miocene species limbs. Several features in erethizontids
are compatible with the ability to climb: the
low humeral tuberosities indicate a mobile gleno-humeral
joint; the prominent and distally extended deltopectoral
crest indicates a powerful pectoral muscle, which
is particularly active when climbing; the humero-ulnar
and humero-radial joints are indicative of pronationsupination
movements; the well-developed lateral epicondylar
ridge and the medially protruding entepicondyle
are in agreement with an important development
of the brachioradialis, supinator, flexor digitorum profundus,
and pronator teres muscles, acting in climbing
and grasping functions; the mechanical advantage of
the biceps brachii would be emphasized because of its
distal attachment on the bicipital tuberosity. As with
extant porcupines, in Miocene species, the large femoral
head would have permitted a broad range of abduction
of the femur, and the medially protruding lesser trochanter
would have emphasized the abduction and outward
rotation of the femur by the action of the iliopsoas
complex. In S. duplicatus, the shape of the hip,
knee, and cruro-astragalar, calcaneo-astragalar, and
astragalo-navicular joints would have allowed lateral
and rotational movements, although probably to a lesser
degree than in extant porcupines. Foot features of S.
duplicatus (e.g., great medial sesamoid bone, medial
astragalar head, complete hallux) indicate that this
species would have had grasping ability, but would not
have achieved the high degree of specialization of
Coendou. Steiromys duplicatus would have been a
semiarboreal dweller, resembling Erethizon dorsatum.