NEMATODES PARASITIC IN FISHES OF CENOTES (EQUALS SINKHOLES) OF THE PENINSULA OF YUCATAN, MEXICO .1. ADULTS

The present paper comprises a systematic survey of adult nematodes col lected from fishes from cenotes (= sinkholes) of the Peninsula of Yuca tan, southeastern Mexico, in 1993-1994. Examinations of a total of 533 fishes (17 species) originating from 39 cenotes from the Mexican stat es of Yucatan and Quintana Roo revealed the presence of the following nine nematode species: Rhabdochona (Rhahdochona) kidderi, Procumallanu s (Spirocumallanus) rebecae, P. (S.) neocaballeroi, Philometroides cau data, Hysterothylacium cenotae, Pseudocapillaria yucatanensis, Paracap illaria rhamdiae, P. teixerafreitasi and Capillostrongyloides sp. (onl y females). Four species (R. kidderi, P. rebecae, P. neocaballeroi and Capillostrongyloides sq.) are briefly described and illustrated and s ome problems concerning their morphology, taxonomy, hosts and geograph ical distribution are discussed. Taxonomic changes include Procamallan us (Spirocamallanus) neocaballeroi (Caballero-Deloya, 1977) comb. n. a nd Procamallanus (Spirocamallanus ) rebecae (Andrade-Salas, Pineda-Lop ez et Garcia-Magana, 1994) comb. n. The nematode fauna of fishes in ce notes of the Yucatan Peninsula shows its appurtenance to the Neotropic al fauna with close affinities with that of fish nematodes from South America, but with a considerable degree of endemism.