A 66-million-year-old molar found in India may have huge ramifications for theories about the spread of ancient mammals. A study led by Guntupalli Prasad of the University of Jammu, in India, theorizes that the tooth may have been from a condylarth, one of a group of primitive hoofed mammals that evolved into modern goats, cows, sheep, and deer.

The kicker is that the tooth is about three million years older than the oldest condylarth specimen. This means that the condylarth who lost his tooth hung out in India when the subcontinent was a giant island, having just broken off from Gondwana, the supercontinent (which itself broke off from Pangaea, the supersupercontinent). This fact supports a controversial theory arguing that most of today's plant and animal life actually came from the Indian subcontinent: "[M]any researchers had postulated that mammalian groups... may have originated from basal Gondwanan stocks during the northward flight of India and finally dispersed to Asia when India collided with the Asian mainland around 55 million years ago," Prasad told National Geographic.

Not all scientists are sure the tooth is from a condylarth, though. "[I]f it turns out to be something else, it means nothing as far as the radiation of [hoofed mammals]," Kenneth Rose of Johns Hopkins University told National Geographic.