Revueltosaurus

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Revueltosaurus Fossil range: Late Triassic
Scientific classification
Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Superclass: Tetrapoda Class: Sauropsida Subclass: Diapsida (unranked) Archosauria (unranked) Crurotarsi Genus: Revueltosaurus Hunt, 1989 Species: R. callenderi
Binomial name
Revueltosaurus callenderi Hunt, 1989

Revueltosaurus ("Revuelto lizard") was a prehistoric pseudosuchian reptile from Late Triassic New Mexico and Arizona. It was originally described as an ornithischian dinosaur based on several discoveries of teeth, but was reclassified when a partial skeleton was discovered in 2004. Since all but one Triassic ornithischians are known only from teeth and jaw fragments, the discovery has challenged their validity. The reclassification of Revueltosaurus from herbivorous dinosaur to crocodile-like reptile has raised the very real possibility that the two major dinosaur orders, Ornithischia and Saurischia, did not evolve at the same time.

According to William Parker, who discovered the partial skeleton, "we have pretty much erased the record of Triassic ornithischian dinosaurs from North America, Europe and worldwide, except for South America."^[1] His co-author Randall Irmis said, "because the teeth look like those we know from herbivorous ornithischians, people assigned them to the dinosaurs. We think we've shown that you can't rely on the dentition to determine what is an early dinosaur, which casts doubt on all the ornithischians from the Triassic of North America".^[2]

[edit] Notes

1. ^ Quoted in Sanders 2005, para. 6.
2. ^ Quoted in Sanders 2005, para. 4.

[edit] References

• Hunt, A. P. 1989. A new ornithischian dinosaur from the Bull Canyon Formation (Upper Triassic) of east-central New Mexico. In Luca, S. G. and A. P. Hunt (Eds.), Dawn of the age of dinosaurs in the American Southwest 355–358.

• Parker, W. G., R. B. Irmis, S.N. Nesbitt, J. W. Martz, and L. S. Browne. 2005. The Pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. In Proceedings of the Royal Society London B 272(1566):963–969.

• Sanders, Robert. June 24, 2005. Revueltosaurus skeleton unearthed at Petrified Forest upsets dinosaur tale. University of California Berkeley News. Retrieved March 15, 2006.