mylodon

from WordNet (r) 3.0 (2006)

mylodon
    n 1: large (bear-sized) extinct edentate mammal of the
         Pleistocene in South America

from The Collaborative International Dictionary of English v.0.48

Mylodon \Myl"o*don\, n. [Gr. ? a mill + 'odoy`s, 'odo`ntos, a
   tooth.] (Paleon.)
   An extinct genus of large slothlike American edentates,
   allied to Megatherium.
   [1913 Webster]