Evolution of venom across extant and extinct eulipotyphlans

Orally delivered venom in animals is found in distantly related invertebrate and vertebrate taxa, but is relatively rare in overall abundance. The trait would appear to be highly adaptive for prey capture and defence, and has been suggested to be a key innovation that led to the diversification of the venomous snakes. In extant mammals, oral venom is only found in the Eulipotyphla (which includes solenodons, shrews, moles and hedgehogs), and is only known to be present in four species. The phylogenetic distribution of venom across extant mammals suggests that venom evolved independently three times in the Eulipotyphla. In extant shrews, grooved teeth are not associated with venomousness; only the solenodon has both grooved lower incisors and salivary venom. Given these data, recent inferences of widespread venomous abilities in extinct eulipotyphlans on the basis of grooved teeth are not justified.