Thecodontosaurus

Taxobox
name = "Thecodontosaurus"
fossil_range = Late Triassic

---

image_width = 250px
image_caption = Life restoration of "Thecodontosaurus antiquus"
regnum = Animalia
phylum = Chordata
classis = Sauropsida
superordo = Dinosauria
ordo = Saurischia
subordo = Sauropodomorpha
familia = Thecodontosauridae
familia_authority = Lydekker, 1890
genus = "Thecodontosaurus"
genus_authority = Riley & Stuchbury, 1836
subdivision_ranks=Species
subdivision=
*"T. antiquus" Morris, 1843 (type)

"Thecodontosaurus" ("socket-tooth lizard") is a genus of herbivorous dinosaur which lived during the late Triassic period Period (Norian and/or Rhaetian age). Its remains are known mostly from Triassic "fissure fillings" in South England and Wales. On average, it was 1.20 metres (4 ft) long, 0.3 metres (1 ft) tall, and weighed 11 kilograms (25 lb).

"Thecodontosaurus" had a rather short neck supporting a fairly large skull with quite big eyes. Its jaws contained many small- to medium-sized, serrated, leaf-shaped teeth. This dinosaur's hands and feet each had five digits, and the hands were long and rather narrow with an extended claw on each. This dinosaur's front limbs were much shorter than the legs, and its tail was much longer than the head, neck and body put together.

Although not actually the earliest member of the group , "Thecodontosaurus" is the most primitive well-known representative of the sauropodomorph dinosaurs. Originally it was included under the Prosauropoda (Upchurch 1998) but more recently it has been suggested that "Thecodontosaurus" and its relatives were prior to the prosauropod-sauropod split (Yates & Kitching 2003). New reconstructions show that its neck is proportionally shorter than in more advanced early sauropodomorphs.

The original type specimen of "Thecodontosaurus" was a victim of World War II bombings by the Germans. The remains of this dinosaur and other material related to it were destroyed in 1940. However, more remains have been found at a number of localities, including Bristol. Some of this new material pertains to a juvenile specimen that may belong to a distinct species, "Thecodontosaurus caducus" Yates, 2003. The dinosaur "Agrosaurus macgillivrayi" (Seeley, 1891), once thought to be from Australia, but more likely from England and misidentified, is probably synonymous with "Thecodontosaurus antiquus" (Vickers-Rich "et al.", 1999).

In 2007, a paper by Yates, Galton, and Kermack put forth the claim that "Thecodontosaurus caducus" belongs to a different genus, which they have named "Pantydraco".

References

* Upchurch, P. (1998). The phylogenetic relationships of sauropod dinosaurs. "Zool. J. Linnean Soc." 124: 43–103.

*Vickers-Rich, P., Rich, T.H., McNamara, G.C., & Milner, A. (1999). "Agrosaurus": Australia's oldest dinosaur? Records of the Western Australian Museum Supplement 57: 191-200.

* Yates, A. M. (2003). A new species of the primitive dinosaur "Thecodontosaurus" (Saurischia: Sauropodomorpha) and its implications for the systematics of early dinosaurs. "Journal of Systematic Palaeontology" 1(1): 1-42.

* Yates, A.M. & Kitching, J. W. (2003). The earliest known sauropod dinosaur and the first steps towards sauropod locomotion. "Proc. R. Soc. Lond.: B Biol Sci." 2003 Aug 22; 270(1525): 1753–8.

* Galton, P.M., Yates, A.M., & Kermack, D. (2007). "Pantydraco" n. gen. for "Thecodontosaurus caducus" Yates, 2003, a basal sauropodomorph dinosaur from the Upper Triassic or Lower Jurassic of South Wales, UK. Neues Jahrbuch für GEologie und Paläontologie, abh., 243: 119-125.

* Moody, Richard. Dinofile. Pg. 23. Octopus Publishing Group Ltd., 2006

External links

* [http://palaeo.gly.bris.ac.uk/bristoldinosaur The Bristol Dinosaur] .
* [http://www.dinodata.org/index.php?option=com_content&task=view&id=9141&Itemid=67 "Thecodontosaurus" at DinoData]
* [http://www.users.qwest.net/~jstweet1/sauropodomorpha.htm Sauropodomorpha] at "Thescelosaurus"! (scroll down)
* [http://www.dinodata.org/index.php?option=com_content&task=view&id=9561&Itemid=103 New genus "Pantydraco" at DinoData]