Trilophosauridae

Trilophosauridae; Temporal range: Triassic, ; Anisian–Rhaetian PreꞒ Ꞓ O S D C P T J K Pg N
	Mounted skeleton of Trilophosaurus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	†Allokotosauria
Order:	†Trilophosauria; Romer, 1956
Family:	†Trilophosauridae; Gregory, 1945
Genera
	†Anisodontosaurus?; †Coelodontognathus?; †Doniceps?; †Rutiotomodon; †Spinosuchus; †Teraterpeton; †Tricuspisaurus; †Trilophosaurus; †Variodens; †Vitalia?;
Synonyms
	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.

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

Lepidosauromorpha

Archosauromorpha

Protorosaurus speneri

Tanystropheidae

Macrocnemus bassanii

	Langobardisaurus pandolfii

	Tanytrachelos ahynis

	Amotosaurus rotfeldensis

	Tanystropheus longobardicus

Crocopoda sensu Ezcurra (2016)

Rhynchosauria

Mesosuchus browni

	Rhynchosaurus articeps

	Teyumbaita sulcognathus

	Archosauriformes

	Prolacerta broomi

Allokotosauria

Pamelaria dolichotrachela

Azendohsauridae

	Azendohsaurus laaroussii

	Azendohsaurus madagaskarensis

Trilophosauridae

Teraterpeton hrynewichorum

Trilophosaurus buettneri

Spinosuchus caseanus

	"Trilophosaurus" jacobsi

	Spinosuchus caseanus holotype

References

^ 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

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.

[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.

[nesbitt2015-3] 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. hdl:2246/6624. ISSN 0003-0090.

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