The shrew-like animal with a long, pointed snout was described in this week's British journal Biology Letters. Paucidentomys vermidax is the only rodent out of more than 2,200 known species that does not have molars and instead has bicuspid upper incisors.
The rat was found in the forests of southern Sulawesi Island last year.
Co-author Anang Setiawan Achmadi from the Bogor Zoological Museum says since it lacks cheek teeth, the rat sucks in earthworms and slices them with its incisors before spitting out the pieces and then slurping bites down whole.
The researchers say the discovery is important because it shows how species evolve to survive in challenging environments.