toxodon

From the genus name.

toxodon (plural toxodons)

1. (paleontology) A gigantic extinct herbivorous mammal from South America, having teeth bent like a bow. It is the type of the order Toxodonta.
   • 1912, Arthur Conan Doyle, “‘Our Eyes have seen Great Wonders’”, in The Lost World […], London; New York, N.Y.: Hodder and Stoughton, →OCLC, page 277:

     "Finally, I will assuredly give some account of the toxodon, the giant ten-foot guinea pig, with projecting chisel teeth, which we killed as it drank in the grey of the morning by the side of the lake."