Late Jurassic (Tithonian)

Morrison Formation

Bone Cabin Quarry,  Albany County, WY, USA

Ultra-rare 1mm mammal tooth

Mammal,

While the reign of the dinosaurs was in full swing by the Late Jurassic, mammals were relegated to less-prominent niches in terrestrial ecosystems.  They would have looked like rodents to us but they lived over 85 million years before the earliest rodents.  These small and likely nocturnal animals were surprisingly diverse as is seen in the multiple tooth forms and much rarer partial skeletons that have been found.

This tooth is unidentified.  A tooth like this might be unfamiliar even to a researcher who studies Late Cretaceous mammals.