Arctodus pristinus Edaphosaurus También se encontraron restos microscópicos

También se encontraron restos microscópicos de tejido blando y fibras de colágeno en la superficie de algunos dientes de Tyrannosaurus rex

Although they had already moved considerably away from their terrestrial ancestors

Although complete remains of its skeleton have not been found

Snout-tail length 381mm

and can reach sizes of up to 20 meters

Arctodus pristinus Edaphosaurus También se encontraron restos microscópicosArctodus pristinus is an extinct species of short faced bear belonging to the genus Arctodus , which lived in North America during the Pleistocene, approximately between 2. 5 million and 10,000 years ago. It was a close relative of Arctodus simus , although smaller in size and with some morphological differences in its skeleton that suggest different ecological adaptations. Its fossil remains have been found mainly in the southeastern United States,