Artist rendering of Kataigidodon venetus eating a small insect. [Hannah Kligman, courtesy of Petrified Forest National Park]

Fossils discovered in the Petrified Forest National Park in Arizona have revealed a new species of early mammal, according to a research article published in the journal Biology Letters. The creature, Kataigidodon venetus, was about the size of a hamster and lived in the Upper Triassic (~220 million years ago).

“[T]his discovery sheds light on the geography and environment during the early evolution of mammals,” a press release from the national park stated, adding that at the time the creature lived Arizona was an equatorial tropical forest.