The teeth - which have no corresponding groove on the lower jaw - would have been used to stab prey (most likely beetles). The presence of these teeth suggest that this predation strategy may have been more common than previously thought during the Palaeocene.
There are only four mammals on the planet today that use venom - the Caribbean Solenodon the North American Short-tailed Shrew, the Eurasian Water Shrew, and Australia's Duck-billed Platypus.
Read the LETTER at Nature.com