During a study on parasites of fish from cenotes (= sinkholes) in the Yucatan Peninsula, the following cestodes and acanthocephalans were found in 581 freshwater fish of 15 species: the cestodes Bothriocephalus acheilognathi Yamaguti, 1934, Bothriocephalus sp. (Bothriocephalidae), Nomimascolex sp. (Monticellidae), Proteocephalidea gen. sp. larv., Dendrouterina pa-pillifera (Fuhrmann, 1908) larv. and D. pilherodiae Mahon, 1956 larv. (Dilepididae), and the acanthocephalans Octospinifer-oides chandleri Bullock, 1957, Neoechinorhynchus golvani Salgado-Maldonado, 1978 (Neoechinorhynchidae), Polymorphus (syn. Arhythmorhynchus) brevis (Van Cleave, 1916) larv. (Polymorphidae), and an echinorhynchid larva. With the exception of B. acheilognathi, all tapeworms are found in Mexico for the first time; second-stage larvae of D. papillifera and D. pilherodiae from fish are reported for the first time.
During a survey of the parasites of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula the following species of monogeneans were found on cichlid, pimelodid, characid and poeciliid fishes: Sciadicleithrum mexicanum Kritsky, Vidal-Martinez et Rodriguez-Canul, 1994 from C.ichlasoma urophthalmus (Giinther) (type host), Cichlasoma friedrichsthali (Heckel), Cichlasoma octofasciatum (Regan), and Cichlasoma synspilum Hubbs, all new host records; Sciadicleithrum meekii Mcndoza-Franco, Scholz et Vidal-Martinez, 1997 from Cichlasoma meeki (Brind); Urocleidoides chavarriai (Price, 1938) and Urocleidoides travassosi (Price, 1938) from Rhamdia guatemalensis (Günther); Urocleidoides costaricensis (Price et Bussing, 1967), Urocleidoides heteroancistrium (Price et Bussing, 1968), Urocleidoides anops Kritsky et Thatcher, 1974, Anacanthocotyle anacanthocolyle Kritsky et Fritts, 1970, and Gyrodaclylus neotropicalis Kritsky et Fritts, 1970 from Aslyanax fasciatus; and Gyrodactylus sp. from Gambusia yucatana Regan. Urocleidoides chavarriai, U. travassosi, U. costaricensis, U. heteroancistrium, U. anops, Anacanthocotyle anacanthocotyle and Gyrodactylus neotropicalis are reported from North America (Mexico) for the first time. These findings support the idea about the dispersion of freshwater fishes and their monogenean parasites from South America through Central America to southeastern Mexico, following the emergence of the Panamanian isthmus between 2 and 5 million years ago.
Sciadicleithrum meekii sp. n. is described from the gills of the cichlid fish Cichlasoma meeki (Brind) from cenotes (= sinkholes) of the Yucatan Peninsula, Mcxico.The new species differs from congeners by having a dorsal hamuli with a prominent superficial root articulated with a straight shaft and curved point, and a vagina with a coiled tube comprised of one ring.