describe this creature's physical characteristics.
Its size has been estimated in the 2.5–4.0 m range for length, a weight of 200–300 kilograms and it may have been sexually dimorphic, with one sex larger than the other
Thescelosaurus
The animal's size has been estimated in the 2.5–4.0 m range for length (8.2–13.1 ft) for various specimens, and a weight of 200–300 kilograms (450–660 pounds), with the large type specimen of "T. garbanii" estimated at 4–4.5 meters (13.1–14.8 feet) long. As discussed more fully under "Discovery, history, and species", it may have been sexually dimorphic, with one sex larger than the other.
how many years ago was the thescelosaurus in existence? More than 66 million years ago which period was that? Late Cretaceous period
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Thescelosaurus [SEP] Description
Charles M. Sternberg reconstructed it with the upper arm oriented almost perpendicular to the body, another idea that has gone by the wayside. As noted by Peter Galton, the upper arm bone of most ornithischians articulated with the shoulder by an articular surface that consisted of the entire end of the bone, instead of a distinct ball and socket as in mammals. The orientation of the shoulder's articular surface also indicates a vertical and not horizontal upper arm in dinosaurs.