Silesaur

Silesaur

Diet : Herbivorous

Habitat : Muds and aqueous flood water

Length : 7 feet (2.1-2.3 meters)

Weight : About 88 lbs (40 kgs)

Atreipus was named by P. Olsen and D. Baird in honor of Atreus Wanner, nineteen century discoverer of many dinosaur tracks in Pennsylvania. Trackmaker of Atreipus left three-toed hind foot impressions, similar to those of Grallator – tracks of early small theropod dinosaur. Its left a tiny front foot three to five-toed prints similar to manus (hand) impressions of Chirotherium (tracks of basal archosaur). It indicates that Atreipus trackmaker walked on four legs with its rear legs larger than its front legs. This kind of small tracks – pedal prints length is approximately 4 inches (10 cm). The footprints of Atreipus are found in the Middle Triassic and Late Triassic of eastern and western United States, Germany, Poland, Italy and Morocco. In Utah, Atreipus was recognized by M. Lockley in the Chinle Group of Glen Canyon and by G. Gierliński in the Chinle Group outcrops near Moab.

Since the discovery of a Silesaurus, ornithishian-like dinosauromorph in Poland, researchers suggest the Silesaurus‘s origin for Atreipus. This seems to be also supported by the discovery of G. Gierliński, G. Niedżwiedzki and D. Mazurek. In 2009, they found Atreipus track in the same strata where the Silesaurus bones are found in Krasiejów.

The systematic position of Silesaurus opolensis, a Late Triassic herbivorous archosaur from Poland is not clear. They are more primitive than dinosaurs that are already known, therefore they are often placed among the so-called dinosauromorphs. At the present day, the family called Silesauridae comprises six different genera from Europe, Africa, South and North America, including Eucoelophysis from the Chinle Group of New Mexico. The basal Dinosauriformes were worldwide distributed.