PHILOMETROIDES-CAUDATA SP-N (NEMATODA, PHILOMETRIDAE) FROM RHAMDIA-GUATEMALENSIS (PISCES) IN YUCATAN, MEXICO

A new nematode species, Philometroides caudata sp.n., is described fro m the swimbladder (under the serosa cover) of the freshwater pimelodid catfish, Rhamdia guatemalensis, from cenotes (= sinkholes) in Yucatan , southeastern Mexico. It differs from all hitherto known members of t he genus, except P. maplestoni (Travassos, Artigas et Pereira, 1928), in having the functional anus, the conical tail with a terminal knob-l ike structure and the oesophagus without an anterior inflation in fema le, and in the structure of the caudal end in male. It can be distingu ished from P. maplestoni (described only from females) by the extent o f embossed cuticle, the size of body and the host type. P. caudata, re presenting a Neotropical element, is the first Philometroides species reported from freshwater fishes in Mexico.