Pelvic and hind limb musculature of Staurikosaurus pricei (Dinosauria: Saurischia)

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 preacetabular iliac process. This could represent an intermediate stage prior to the origin of a true preacetabular 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.

New dinosaur remains from the Late Triassic of southern Brazil (Candelária Sequence, Hyperodapedon Assemblage Zone)

“…The shaft is lacriform in cross-section being very robust laterally, but becoming thinner medially where it would have converged with its counterpart. The proximal portion of the bone bears ALCHERINGA LATE TRIASSIC DINOSAURIANS FROM BRAZIL 3 a rugose pubic tubercle, which probably associated with the ambiens musculature (Hutchinson 2001a, Langer 2003, Grillo & Azevedo 2011a. The preserved portion of the shaft is straight in lateral view.…”

Early evolution of sauropodomorphs: anatomy and phylogenetic relationships of a remarkably well-preserved dinosaur from the Upper Triassic of southern Brazil

“…34D), which extends onto the femoral shaft. A faint ridge bounds the distal margin of this concavity, and the entire region has been suggested as an insertion point for the m. caudofemoralis longus (Langer, 2003;Grillo & Azevedo, 2011;Müller et al, 2016). Distal to the fourth trochanter, the femoral shaft is ovoid in crosssection.…”

Myological reconstruction of the pelvic girdle of Anhanguera piscator (Pterosauria: Pterodactyloidea) using three-dimensional virtual animation

“…The construction of an osteological model (i.e. an overall model comprising articulated pelvis, femur and tibia) was performed and each step followed the methodology used by Grillo & Azevedo (2011). This construction required an extensive review on the osteology of pelvis, femur and tibia of Anhanguera piscator.…”