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.
| Trilophosauridae | |
|---|---|
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| Mounted skeleton of Trilophosaurus | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauromorpha |
| Clade: | †Allokotosauria |
| Order: | †Trilophosauria Romer, 1956 |
| Family: | †Trilophosauridae Gregory, 1945 |
| Genera | |
| Synonyms | |
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Teraterpetidae Sues, 2003 | |
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]
| Sauria |
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References
edit- ^ 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.
- ^ Carroll, R. L. (1988). Vertebrate Paleontology and Evolution. New York: W.H. Freeman & Co. p. 266.
- ^ 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. hdl:2246/6624. ISSN 0003-0090.
Sources
edit- Benton, M. J. (2000), Vertebrate Paleontology, 2nd ed. Blackwell Science Ltd, p. 144
External links
edit- Archosauromorpha: Rhynchosaurs and Trilophosaurus at Palaeos
- Trilophosauria. Beaked, lizard-like reptiles. UC Museum of Paleontology. Archive copy from 6 February 2019.