Daemonosaurus

Life

Daemonosaurus Temporal range: Late Triassic, Rhaetian PreЄ Є O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	Saurischia
Node:	Eusaurischia
Suborder:	Theropoda
Genus:	†Daemonosaurus Sues et al., 2011
Species:	†D. chauliodus
Binomial name
Daemonosaurus chauliodus Sues et al., 2011

Daemonosaurus (meaning "demon reptile" in Greek) is a genus of theropod dinosaur from the Late Triassic of New Mexico. Fossils have been found from deposits in the Chinle Formation, which is latest Triassic in age. While theropods had diversified into several specialized groups by this time, Daemonosaurus is a basal theropod that lies outside the clade Neotheropoda.^[1] Daemonosaurus is unusual among early theropods in that it had a short skull and long protruding teeth.^[2] The type species of Daemonosaurus, D. chauliodus, was described in the journal Proceedings of the Royal Society B in 2011. Because the description has not yet been published, the genus is considered a nomen nudum. The generic name means "demon reptile" in Greek, while the specific name, derived from Greek χαυλιόδους, means "prominent toothed" in reference to its procumbent front teeth.

Description

Daemonosaurus is known from a single holotype, CM 76821, consisting of a skull, some vertebrae, and ribs collected from the Ghost Ranch quarry in New Mexico in the 1980s. Ghost Ranch is famous for an abundance of fossils of the similar theropod Coelophysis. Fossils of Coelophysis were present on the same block that contained the skull of Daemonosaurus, which was uncovered by a volunteer at the State Museum of Pennsylvania.^[2]

Based on the proportions of related theropods, Daemonosaurus is estimated to have been around 1.5 m (5 feet) long.^[2] The skull of Daemonosaurus differs considerably from all other Triassic theropods. The snout is short and bears large premaxillary and maxillary teeth in the upper jaw. Procumbent teeth project forward from the tips of the upper and lower jaws,^[1] which is highlighted in the species name chauliodis that roughly means "buck-toothed".^[3]

Classification

Daemonosaurus lies outside the clade Neotheropoda, a group that includes more advanced Triassic theropods like Coelophysis and their descendants. With such a basal position, it represents a lineage that extended from the earliest radiation of dinosaurs in the Middle Triassic with forms such as Eoraptor and Herrerasaurus from South America. A phylogenetic analysis conducted in its original description found D. chauliodus to be closely related to Tawa hallae, a theropod that was described from Ghost Ranch in 2009, and the Neotheropoda. Although the two theropods are closely related, Tawa was found in a quarry that is slightly older than Ghost Ranch. Below is a cladogram showing the phylogenetic relationships of Daemonosaurus:^[1]

Theropoda	Staurikosaurus Herrerasaurus Chindesaurus Eoraptor Daemonosaurus Tawa  Neotheropoda  Megapnosaurus Coelophysis Liliensternus Zupaysaurus Cryolophosaurus Dilophosaurus Jurassic theropods

References

1. ^ ^{a b c} Sues, H.-D.; Nesbitt, S.J.; Berman, D.S.; and Henrici, A.C. (2011). "A late-surviving basal theropod dinosaur from the latest Triassic of North America". Proceedings of the Royal Society B in press. doi:10.1098/rspb.2011.0410. http://rspb.royalsocietypublishing.org/content/early/2011/04/05/rspb.2011.0410. 
2. ^ ^{a b c} Choi, C.Q. (12 April 2011). "T. Rex had a toothy ancestor that couldn't cut it". Live Science. http://www.livescience.com/13678-toothy-carnivore-dinosaur-rex-fossils.html. Retrieved 12 April 2011. 
3. ^ Font size Print E-mail Share 0 Comments. "Missing link ties older to newer dinosaurs". CBS News. http://www.cbsnews.com/stories/2011/04/14/scitech/main20053986.shtml. Retrieved 2011-04-14. 

Dinosaurs portal