Animated Allosaurus, an allosauroid
Allosauroidea is a clade subdivided into three families — the Sinraptoridae, Carcharodontosauridae and Allosauridae. The taxon was originally proposed by Currie and Zhao (1993; p. 2079), then noted as an undefined stem-based taxon by Sereno (1997). Later, Sereno (1998; p. 64) provided a stem-based definition for the Allosauroidea, defining the clade as "All neotetanurans closer to Allosaurus than to Neornithes." Most recently, Holtz et al. (2004; p. 100) defined the Allosauroidea as "Allosaurus fragilis, Sinraptor dongi, their most recent common ancestor, and all of its descendants."
The oldest-known allosauroid, Cryolophosaurus, appears in the Early Jurassic (Pliensbachian) of Antarctica, and the latest-known survivor of the clade is Allosaurus fragilis (Late Jurassic, Tithonian). Allosauroids have long, narrows skulls, large orbits, three-digit hands, and usually have "horns" or ornamental crests on their heads. The most famous and best understood allosauroid is the North American genus Allosaurus.
- Currie, P. J., and X. Zhao. 1993. A new carnosaur (Dinosauria, Theropoda) from the Upper Jurassic of Xinjiang, People's Republic of China. Canadian Journal of Earth Sciences 30:2037-2081.
- Holtz, T. R., Jr. and Osmólska H. 2004. Saurischia; pp. 21-24 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria (2nd ed.), University of California Press, Berkeley.
- Sereno, P. C. 1997. The origin and evolution of dinosaurs. Annual Review of Earth and Planetary Sciences 25:435-489.
- Sereno, P. C. 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 210:41-83.
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