Portal de Periódicos da CAPES

Studies on the Life History of Posthodiplostomum minimum (MacCallum 1921)

1954; American Society of Parasitologists; Volume: 40; Issue: 3 Linguagem: Inglês

10.2307/3273737

1937-2345

Joseph H. Miller,

Parasite Biology and Host Interactions

Complete life histories in the STRIGEIDA are few and the result of comparatively recent investigations. Previous to 1920, the developmental stages of these trematodes were neglected by helminthologists, who were diverted by Leuckart's (1889) theory that the holostomes were metastatic trematodes having an alternation of hosts but not of generations. The basis for the theory was the superficial resemblance of developing holostome miracidia to tetracotyles found in nature. This similarity led Leuckart to the belief that tetracotyles develop directly from ova without the interpolation of a cercarial stage. Lutz (1921) showed that the tetracotyle of Cotylurus cornutus in Planorbis sp. developed from a furcocercous cercaria. This experimental demonstration and its confirmation by Mathias (1922) and Ruszkowski (1922) invalidated the metastatic theory and investigators turned with renewed interest to a study of the STRIGEIDA. The most intensive investigations in North America were carried out at the University of Michigan by La Rue and his students in the period since 1926. The first record of Posthodiplostomum minimum was made by Leidy (1856), who found the metacercaria encysted in the liver of a sunfish Lepomis sp. He erroneously identified this larval stage as Diplostomum cuticola von Nordmann, 1832, a European form encysted in the integument of fresh-water fish. Mac Callum (1921) inadequately described the adult from Ardea herodias (great blue heron) which died at the New York Zoological Park. He named this adult Diplostomum minimum. Agersborg (1926) described a metacercaria from Hyborhynchus notatus (blunt nosed minnow) which he named Diplostomum van cleavei. Hughes (1928) considered Agerborg's metacercaria identical with the metacercaria reported by Leidy (1856). Various strigeid larval types have been categorized as an aid to the recognition and description of morphologically similar larvae. Hughes (1927) erected the larval group Neascus to contain the metacercaria Neascus ambloplitis nov. sp. from a sunfish (= Uvulifer ambloplitis according to Hunter and Hunter, 1935) and Neascus cuticola (= Diplostomum cuticola von Nordmann, 1832). Recognized larval types were: TETRACOTYLE Filippi, 1854, in which the body is pyriform, with or without a small hind-body, with well developed lateral suckers, and with the reserve bladder in the form of large spaces; CODONOCEPHALUS Diesing, 1850, fore-body reduced to a flattened disc, lateral suckers absent, excretory system a complicated