Late Jurassic (Tithonian)

Morrison Formation

Bone Cabin Quarry, Albany County, Wyoming, USA

Ultra-rare 1mm mammal tooth.

Mammal.

With all the great dinosaurs to look for in the Morrison Formation, few collectors look for the tiny mammal teeth also known from that unit.  These mammals would have looked like rodents to us (and some of their teeth were rodent-like) but they lived at least 85 million years before the earliest true rodents of about 55 million years ago. Many Jurassic mammals were still laying eggs (not far removed from the earliest mammals of the Late Triassic) and had names only a specialist would recognize.

This kind of tooth appeals to the completist collector who wants whatever is available from the Morrison Formation or who wants a example of as many mammal groups as possible.