Wednesday, March 24, 2010

Seitaad ruessi, New Sauropodomorph from Utah

A New Basal Sauropodomorph Dinosaur from the Lower Jurassic Navajo Sandstone of Southern Utah. 2010. J. J. W. Sertich & M. A. Loewen, PLoS ONE 5(3): e9789.

Image by Luis Rey
Utah’s red rocks have yielded a rare skeleton of a new species of sauropodomorph, Seitaad ruessi, that lived 185 million years ago and may have been buried alive by a collapsing sand dune. The discovery confirms the widespread success of sauropodomorph dinosaurs during the Early Jurassic Period.

Seitaad ruessi (SAY-eet-AWD ROO-ess-EYE), is derived from the Navajo word, “Seit’aad,” a sand-desert monster from the Navajo (DinĂ©) creation legend that swallowed its victims in sand dunes (the skeleton of Seitaad had been “swallowed” in a fossilized sand dune when it was discovered); and Ruess, after the artist, poet, naturalist and explorer Everett Ruess who mysteriously disappeared in the red rock country of southern Utah in 1934 at age 20.

In life, Seitaad would have stood about about 1 m tall at the hips and was 3 to 4.5 m long. It would have weighed approximately 70 to 90 kg, and could walk on two or four legs. Like its later gigantic sauropod relatives, Seitaad most likely ate plants.

Life on the edge of the Navajo Erg by Russell Hawley
The closest relatives of Seitaad are known from similar-aged rocks in South America and southern Africa. Other, less complete, fossils from northern Arizona hinted at the presence of sauropodomorphs like Seitaad, but none were complete enough to understand exactly what species was living in the American Southwest. The discovery of Seitaad confirms that this group of dinosaurs was extremely widespread and successful during the Early Jurassic, approximately 175 million to 200 million years ago.