Silesauridae is an extinct clade of dinosauriformes, a group of Triassic reptiles that included early ancestors and relatives of the dinosaurs. The silesaurids were a sister clade to the dinosaurs. The group was named in 2010 by paleontologist Max C. Langer and colleagues from Brazil and Argentina. They defined it as a branch-based clade of all archosaurs closer to Silesaurus opolensis than to either Heterodontosaurus tucki or Marasuchus lilloensis. At the same time, a second group of scientists independently named Silesauridae as a node-based clade consisting of Lewisuchus, Silesaurus, their common ancestor and all its descendants. Currently, both definitions encompass the same group of animals. In a later paper, Nesbitt and colleagues noted that the earlier definition by Langer et al. di