coelophysoids

Coelophysoids are a group of early theropod dinosaurs placed within the clade Coelophysoidea. They lived during the Late Triassic to Early Jurassic, roughly 228 to 190 million years ago. Members of this group include genera such as Coelophysis and Dilophosaurus, among others. Coelophysoids are among the earliest known predatory dinosaurs and help illustrate the early diversification of theropods.

Anatomy and lifestyle attributes common to coelophysoids include a lightweight, bipedal build, long hind limbs, and elongated skulls with sharp, serrated teeth. Their skeletons indicate agility and speed, with features adapted for active pursuit of small to medium-sized prey. The exact size range varied among genera, but many were small to medium-bodied compared with later theropods. The fossil record suggests a carnivorous or omnivorous diet with emphasis on opportunistic feeding in diverse environments.

Taxonomically, coelophysoids occupy an early-branching position within theropods and are often treated as one of the earliest theropod lineages outside the more derived clades that followed. The group encompasses several genera from multiple continents, reflecting a broad geographic distribution during their time.

Paleobiogeography and ecology indicate that coelophysoids inhabited a variety of environments, from floodplains to upland settings, with fossils found in North America, Europe, and Africa. They appeared widely across Triassic ecosystems and persisted into the Early Jurassic before gradually declining as other theropod groups diversified and became more dominant. Coelophysoids thus provide important insight into the early evolution and ecological roles of predatory dinosaurs.