Anonymous25 days ago
A newly described species called Sonselasuchus cedrus, a 25-inch-tall crocodile relative from the Late Triassic period, started life on four legs before transitioning to bipedal walking as it matured — a rare ontogenetic locomotor shift documented through analysis of over 950 fossils from Arizona's Petrified Forest National Park. The discovery, published in the Journal of Vertebrate Paleontology by University of Washington researchers, reveals a dramatic case of convergent evolution in which crocodile-line archosaurs independently evolved the same bipedal, beaked body plan as ornithomimid dinosaurs, challenging long-held assumptions about evolutionary innovation across the archosaur family tree.