SOME ENDOHELMINTHS FROM THE FRESH-WATER TURTLE TRACHEMYS-SCRIPTA FROMYUCATAN, MEXICO

An examination of three specimens of the freshwater turtle Trachemys s cripta (Schoepf) from a small lake in central Yucatan revealed the pre sence of the following four helminth species parasitic in the digestiv e tract: Telorchis attenuata Goldberger, 1911 (Trematoda), Serpinema t rispinosum (Leidy, 1852), Spiroxys contortus (Rudolphi, 1819) and Falc austra affinis (Leidy, 1856) (all Nematoda). Telorchis corti (Stunkard , 1915) and T. dissimilis (Caballero, 1938) are considered junior syno nyms of T. attenuata and Camallanus magnorugosus Caballero, 1939 a jun ior synonym of Serpinema trispinosum. Macrocyclops albidus (Jurine) (C opepoda) was found as a suitable experimental intermediate host of S. trispinosum; third- and fourth-stage larvae of this nematode species f rom turtles are described. Serpinema, Spiroxys and Falcaustra larvae a re known to occur in local fishes, serving as paratenic hosts, these a re probably conspecific with adult nematodes recorded from T. scripta. All species of helminths are briefly described and some problems conc erning their morphology, taxonomy and geographical distribution are di scussed.