The First Dinosaurs' Surprise Neighbors: Lagerpetids

New species Buriolestes schultzi, seen here in situ, is one of the earliest dinosaurs known — and as you can tell from its teeth, it was no plant eater. Credit: Cabreira et al. Two new Triassic species found in Brazil and dating from the very Dawn of Dinosaurs are filling in some important gaps in the fossil record, including what one of the first dinosaurs ate (hint: not what you might think) and which other animals shared its space (spoiler alert: lagerpetids, dinosaur precursors — another surprise). A study published today in Current Biology reveals a doubly delightful find in southern Brazil's Santa Maria Formation: fossils from four individuals, including two new species from the earliest part of the Late Triassic, 228 million to 237 million years ago. Bonus: two of the specimens are in great shape. What makes the discovery even more exciting is that one of the new species is a dinosaur and the other belongs to a group of dinosaur precursors called the lagerpetids. This bolsters the idea that dinos and dino-daddies were coexisting for longer than we thought: Conventional thinking had long held that once dinosaurs were on the scene, the more primitive species quickly went extinct. (Or, in a variation of that that theme, once the more primitive species went extinct, dinosaurs quickly moved in. Either way, the idea is the dinosaurs and lagerpetids didn't overlap much). The lagerpetid individual described in today's paper as Ixalerpeton polesinensis includes the first skull, shoulder and forelimb examples from the dinosaur precursors, which is important for understanding how they eventually evolved into dinosaurs proper.