Helmintos de la República de Costa Rica IV. Algunos Tremátodos de animales domésticos y silvestres

Abstract

In this contribution seven forms of digenetic trematodes, some parasitic on cattle and some in wild animals, are described. Excepting Fasciola hepatica Linnaeus, 1758, whose presence in cattle and horses in Costa Rica has been cited by Chavarria in 1940, all the species considered are new to the helminthologic fauna of Costa Rica. Specimens of a paramphistomid found in Costa Rica catt1e have been classified as Paramphistomum cervi (Zeder, 1790) Fischoeder, 1901, in view of the presence of a genital sucker, the configuration of the digestive apparatus, and the structure and disposition of the reproductive organs and vitelline glands. Fasciola hepatica Linnaeus, 1758 is also a frequent parasite in Costa Rica, the precise life cycle of this parasite is unknown in the Republic but studies have been undertaken to determine its intermediate mollusean host. Choledocystus intermedius Caballero, Bravo and Cerecero, 1944 has been found for the first time in Costa Rica, in toads Bufo marinus marinus Linnaeus, 1758 thus allowing its range to be defined from southern Mexico to Panama. Gorgoderina megalorchis Bravo, 1948 is another species of trematode parasite of the amphibian host cited above; our specimens differ from those studied by M. Bravo Hollis only in size, the specimens from Costa Rica being larger than those from Mexican toads; the new locality record extends its geo­graphical distribution to Central America. Urotrema scabridum Braun, 1900 has been collected in Costa Rica for the first time, from the bat Eptesicus propinquus Peters which is also considered to be a new host record. Two species of the genus Rhapalias: R. coronatus (Rudolphi 1819) Stiles and Hassall, 1898 and R. horridus (Diesing, 1850) Stiles and Hassall, 1898 are registered from the Costa Rican opossum, Didelphis marsupialis etensi Allen; both species are known to parasitize various South American and Mexican marsupials and the Costa Rican specimens do not differ from these in structural or measurable details. Finally, the trematode Heronimus chelydrae Mac Callum, 1902 has been collected from the lungs of freshwater turtles of the genus Kinosternon. According to the studies of E. Caballero y C. 1940, it is believed that this is the only species in the genus; it has also been reported from turtles of Panama, Mexico and the United States in North America. It has been noted that an early regression of the testes occurs in this species, since these were persistent in only a few of the specimens described.