Pelvic musculature and function of Caiman latirostris

The musculoskeletal hindlimb anatomy of the alligatorid Caiman latirostris Daudin is presented. The description includes origin and insertion sites as well as anatomical function of the pelvic and proximal hindlimb musculature. The hindlimb anatomy of C. latirostris described here is rather conservative when compared to that of other extant crocodilians studied. Nonetheless there is some inter-specific variation between C. latirostris and other Crocodylia, such as the well known Alligator mississippiensis. Caiman latirostris and other alligatorids have many differences between each other concerning the origin and insertion sites as well as the extent and relative development of the muscular masses involved, such as the absence of M. flexor tibialis internus 4, the addition of one dorsal vertebra to the origin of PIFI 2, totalling seven vertebrae, the exclusion of sacral vertebrae in the origin site of CFB, and the inclusion of transverse processes, as well as haemal arches in the origin site of CFL, among others. Regarding muscle function, hindlimb agonist–antagonist movements in Caiman latirostris are not performed by a sole muscle, but instead by a principal muscle and others that complete the action. These anatomical variations could be correlated with a particular locomotor behaviour and phylogenetic landscape.Facultad de Ciencias Naturales y Muse