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Temporal range: Triassic, 247.2–Rhaetian Ma
Trilophosaurus BW.jpg
restoration of Trilophosaurus
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Allokotosauria
Order: Trilophosauria
Romer, 1956
Family: Trilophosauridae
Gregory, 1945

Teraterpetidae Sues, 2003

Trilophosaurs are lizard-like Triassic allokotosaur reptiles related to the archosaurs. The best known genus is Trilophosaurus, a herbivore up to 2.5 metres (8.2 feet) 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.

Trilophosaurus buettneri

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.[2]

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).[3]




Protorosaurus speneri


Macrocnemus bassanii

Langobardisaurus pandolfii

Tanytrachelos ahynis

Amotosaurus rotfeldensis

Tanystropheus longobardicus

 Crocopoda sensu Ezcurra (2016) 

Mesosuchus browni

Rhynchosaurus articeps

Teyumbaita sulcognathus


Prolacerta broomi


Pamelaria dolichotrachela


Azendohsaurus laaroussii

Azendohsaurus madagaskarensis


Teraterpeton hrynewichorum

Trilophosaurus buettneri

 Spinosuchus caseanus 

"Trilophosaurus" jacobsi

Spinosuchus caseanus holotype


  1. ^ David I. Whiteside, FLS; Christopher J. Duffin, FLS (2017). "Late Triassic terrestrial microvertebrates from Charles Moore's "Microlestes" quarry, Holwell, Somerset, UK". Zoological Journal of the Linnean Society. 179 (3): 677–705. doi:10.1111/zoj.12458.
  2. ^ Carroll, R. L. (1988). Vertebrate Paleontology and Evolution. New York: W.H. Freeman & Co. p. 266.
  3. ^ Nesbitt, S.J.; Flynn, J.J.; Pritchard, A.C.; Parrish, M.J.; Ranivoharimanana, L.; Wyss, A.R. (2015). "Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles". Bulletin of the American Museum of Natural History (398): 1–126. doi:10.5531/sd.sp.15. ISSN 0003-0090.


  • Benton, M. J. (2000), Vertebrate Paleontology, 2nd ed. Blackwell Science Ltd, p. 144

External links[edit]