Trilophosaurs are lizard-like Triassic allokotosaur reptiles related to the archosaurs. The best known genus is Trilophosaurus, a herbivore up to long. It had a short, unusually heavily built skull, equipped with massive, broad flattened cheek teeth with sharp shearing surfaces for cutting up tough plant material. Teeth are absent from the premaxilla and front of the lower jaw, which in life were probably equipped with a horny beak. The skull is also unusual in that the lower temporal opening is missing, giving the appearance of a euryapsid skull, and originally the Trilophosaurs were classified with placodonts and sauropterygia. Carroll (1988) suggests that the lower opening may have been lost to strengthen the skull. Trilophosaurs are so far known only from the Late Triassic of North America and Europe. Below is a cladogram showing the phylogenetic relationships of Trilophosauridae within Archosauromorpha as recovered by Nesbitt et al. (2015). References Sources Benton, M. J. (2000), Vertebrate Paleontology, 2nd ed. Blackwell Science Ltd, p. 144 External links Archosauromorpha: Rhynchosaurs and Trilophosaurus at Palaeos Trilophosauria. Beaked, lizard-like reptiles. UC Museum of Paleontology. Archive copy from 6 February 2019. Allokotosaurs Prehistoric reptile families Triassic reptiles Anisian first appearances Rhaetian extinctions