Progenesis in Proctoeces lintoni (Fellodistomidae), a parasite of Fissurella crassa (Archaeogastropoda) in a latitudinal gradient in the Pacific coast of South America

The fellodistomid Proctoeces lintoni is a common parasite of the gonads of key-hole limpets Fissurella spp. (Archaeogastropoda). It has also been foun d in the mantle of Octopus vulgaris and as an intestinal parasite of haemul id and gobiesocid fishes. Fissurella crassa, a host for progenetic P. linto ni, can be found from Huarmey, Peru (10 degrees S) to Chiloe, Chile (42 deg rees S). Proctoeces lintoni has been found parasitizing fishes and molluscs from Callao, Peru (12 degrees S) to Valdivia, Chile (39 degrees S). Progen esis is thought to be a latitude-dependent phenomenon, and high progenesis is expected at higher latitude. In the present article, the association bet ween latitude and progenesis was examined over a latitudinal gradient of ab out 3,000 km. Data suggest that progenesis of P. lintoni infecting F. crass a was not associated with latitude. Low levels of progenesis found in the P eruvian population could be a consequence of parasite-induced mortality rat her than of low latitude, as would be predicted by the latitude dependence hypothesis.