Dinosaurs / Triassic / Staurikosaurus
Staurikosaurus
Triassic STORE-ih-ko-SAWR-us, “Southern Cross lizard”
Staurikosaurus was one of the earliest known dinosaurs, living during the Late Triassic in what is now southern Brazil. Measuring just over two metres in length and weighing about thirty kilograms, it was a slender, agile bipedal hunter. Its jaw featured sharp, serrated teeth curved backwards to grasp small reptiles, rhynchosaurs, and mammal predecessors. Staurikosaurus exhibited a primitive pelvic structure with only two sacral vertebrae supporting the hips, a basal trait seen before later dinosaurs expanded this junction to carry greater weight. Discovered in the mid-twentieth century, Staurikosaurus was named after the Southern Cross constellation visible in the southern sky. It belongs to the Herrerasauridae, a lineage of early predatory dinosaurs positioned near the very root of the dinosaur family tree.
It is one of the oldest known dinosaurs, having only two sacral vertebrae fused to its pelvis.
Where and when
Staurikosaurus lived in the Late Triassic, from 233.2 to 225 million years ago (Carnian age). Its remains come from Brazil, in the Santa Maria Formation.
The numbers
Length 2.1 m (estimates run from 2 to 2.3 m). Mass about 30 kg. Hip height about 0.8 m. That is 1.2 human-lengths, or 0.19 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.