The Collaborative International Dictionary of English v.0.48:

Patas \Pa*tas"\, n. (Zool.)
   A West African long-tailed monkey (Cercopithecus ruber);
   the red monkey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

patas
    n 1: reddish long-tailed monkey of west Africa [syn: patas,
         hussar monkey, Erythrocebus patas]