This intimidating squirrel-like beastie with the impressive choppers lived 94 million years ago. Scientists from the University of Louisville recently discovered fossilized remains of the animal, named Cronopio dentiacutus, in Argentina. Apparently, it was about the size of a mouse. From CNN:
(Paleontologist Guillermo Rougier believes Cronopio dentiacutus) was an insectivore, which is common for small animals today. Their teeth seem to be specialized for cutting and crushing; the large canines of Cronopio dentiacutus could puncture through small insects. To give you some perspective on the size of these canines, imagine if one of your front teeth came down below your chin, Rougier said.
“Tiny ‘saber-toothed squirrel’ found” (CNN)
“Highly specialized mammalian skulls from the Late Cretaceous of South America” (Nature)