Abstract

OTERO, Alejandro  and  VIZCAINO, Sergio F.. Hindlimb musculature and function of Neuquensaurus australis (Sauropoda: Titanosauria). Ameghiniana [online]. 2008, vol.45, n.2, pp.333-348. ISSN 1851-8044.

We present the reconstruction of the hindlimb musculature of the titanosaur sauropod Neuquensaurus australis (Lydekker), integrating data from crocodilians and birds as a phylogenetic bracket. First, we evaluate sites of origin and insertions in N. australis by comparison with extant archosaurs as well as with previous works on dinosaur soft anatomy, and reconstruct principal muscles of the leg, such as Triceps femoris group, M. iliofibularis, Mm. adductores femores, Mm. gastrocnemii, M. ischiotrochantericus and Mm. caudofemorales. Second, we infer the probable function of each muscle comparing with our bracket taxa and with living analogs, principally mammals, because they are thought to be the best model to understand non-avian dinosaur locomotion. This analysis suggests that N. australis has developed larger moment arms in Mm. iliotibiales and M. iliofibularis than in other non-Saltasaurinae sauropods, in relation to the well developed preacetabular and postacetabular ilium; a large Mm. femorotibiales, due to the mediolateral development of the femur; and a large M. iliofibularis due to the large fibular lateral trochanter. We also interpret functional attributes of sauropod wide-gauged trackmakers, in which the extension-flexion and adduction actions are improved with respect to narrow-gauged sauropods.

Keywords : Archosauria; Extant Phylogenetic Bracket; Soft tissue; Functional morphology.