is wider than long and has a tall boxy expansion at its rear. The underside of the calcaneum has a large facet for distal tarsal IV and metatarsals III-IV, followed by a teardrop-shaped depression. The two distal tarsals (III and IV) were roughly triangular. Metatarsal III is the longest bone in the foot, while the thick and hooked metatarsal V is the shortest, followed by metatarsal I. All the metatarsals had strongly developed ginglymoidal joints. I-III and V are triangular in cross-section, while IV is hourglass shaped. The foot has a phalangeal formula of 2-3-4-3-X, indicating that the fourth toe was much smaller than the second and third, an unusual trait among early loricatans. The first toe had a large curved claw, the third toe was thick, and the second toe had both traits. Classification The cladogram below follows a simplified version of the strict reduced consensus tree by Desojo et al. (2020): Paleobiology Musculature In 2013, a study of the structure of its hind limb bones inferred that Prestosuchus chiniquensis had 13 leg muscle groups in common with both crocodilians and birds (which together make up the two living groups of archosaurs) but only two muscle groups in common with only crocodilians, indicating that the musculature of Prestosuchus better represents a basal ("primitive") condition for archosaurs than it does a derived condition for crocodile-line or pseudosuchian archosaurs. The leg musculature of Prestosuchus was also compared to that of Poposaurus, a Triassic pseudosuchian that walked on two legs. While the strongest leg muscles of Poposaurus are thought to drive the forward and backward motion of the leg necessary for bipedal movement, the strongest leg muscles of Prestosuchus were responsible for the rotation of the limb, which is an indication of quadrupedal movement. References Paracrocodylomorphs Late Triassic pseudosuchians Ladinian genera Late Triassic reptiles of South America Triassic Brazil Fossils of Brazil Santa Maria Formation Fossil taxa described in 1942 Prehistoric pseudosuchian genera