We described the postcranial skeleton of two species of sigmodontine rodents, Rhipidomys austrinus Thomas, 1921 and Graomys griseoflavus (Waterhouse, 1837). Each structure of the postcranial skeleton is here described in details of shape, size, surface, and orientation. The skeletal anatomy of these two species shows morphological characters associated with different patterns related to their type of locomotion. Rhipidomys austrinus exhibits characteristics consistent with its arboreal locomotion in several elements of the postcranium, while G. griseoflavus shows attributes related to terrestrial locomotion.
Sigmodontine rodents; Thomasomyini; Phyllotini; comparative anatomy
