Abstract
The study of pelvic and hind limb bones and muscles in basal dinosaurs is important for understanding the early evolution of bipedal locomotion in the group. The use of data from both extant and extinct taxa placed into a phylogenetic context allowed to make well-supported inferences concerning most of the hind limb musculature of the basal saurischian Staurikosaurus pricei Colbert, 1970 (Santa Maria Formation, Late Triassic of Rio Grande do Sul, Brazil). Two large concavities in the lateral surface of the ilium represent the origin of the muscles iliotrochantericus caudalis plus iliofemoralis externus (in the anterior concavity) and iliofibularis (in the posterior concavity). Muscle ambiens has only one head and originates from the pubic tubercle. The origin of puboischiofemoralis internus 1 possibly corresponds to a fossa in the ventral margin of the pré-acetabular iliac process. This could represent an intermediate stage prior to the origin of a true pré-acetabular fossa. Muscles caudofemorales longus et brevis were likely well developed, and Staurikosaurus is unique in bearing a posteriorly projected surface for the origin of caudofemoralis brevis.
Highlights
Bipedalism is a form of locomotion adopted by few groups of animals (Alexander 2004, Gatesy and Biewener 1991, Hutchinson and Gatesy 2006, McGowan 1999)
In this work we propose a detailed reconstruction of the pelvic and hind limb musculature of the basal Saurischian Staurikosaurus pricei Colbert, 1970
The condition observed in Crocodylia and Aves will be presented along with the preserved osteological evidence that supports the inferences for Staurikosaurus
Summary
Bipedalism is a form of locomotion adopted by few groups of animals (Alexander 2004, Gatesy and Biewener 1991, Hutchinson and Gatesy 2006, McGowan 1999). Dinosaurs first evolved as bipedal animals and all living representatives of this clade are bipeds. The evolution of this type of locomotion is associated with several modifications in posture, orientation of the hind limbs, as well as correlated osteological and myological modifications. According to Lockley and Gillette (1989), studies of trackways dating from the 19th century allowed the estimate of velocity (Alexander 1976, Farlow 1981, Day et al 2002) and posture (Coombs 1980, Ishigaki 1989, Thulborn 1989, Wade 1989, Jones et al 2000, Day et al 2002) of dinosaurs. Muscle reconstructions have led to new propositions about dinosaur locomotion (e.g., Hutchinson et al 2005)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
