Studies on Five New Species of Xiphidiocercariae of the Virgula Type
1945; American Society of Parasitologists; Volume: 31; Issue: 4 Linguagem: Inglês
10.2307/3273004
ISSN1937-2345
Autores Tópico(s)Helminth infection and control
ResumoAlthough larval trematodes have been investigated to a considerable extent in the United States, knowledge of certain types has been limited almost entirely to species reported from other countries. One such type is a particular kind of xiphidiocercariae, the oral sucker of which possesses not only a stylet but also a peculiar structure, the so-called organ. In his scheme of classifying cercariae, Liihe (1909) placed larvae of this type in a separate group, the Cercariae Virgulae, named for Cercaria virgula Filippi, one of the first of its kind to be described. Cercaria geddesi Ameel, 1939, appears to be the only larva of the Virgula type described in the United States, although a number of species have been reported from other regions. Cable (1939) reported the occurrence of an unidentified Virgula cercaria in the prosobranch snail, Goniobasis depygis (Say), collected from McCormicks Creek, Indiana. Over a period of several years, these snails have been collected in large numbers to provide various types of larval trematodes for instructional purposes. It has been found that the Virgula species occurs in snails collected at all times of the year and causes a higher incidence of infection than does any other of the several species that may be present. Because of the apparent rarity of Virgula cercariae in the United States and the scarcity of information concerning their life cycles, the abundance and availability of the species from McCormicks Creek prompted an investigation of its morphology and life history. Later, collections of prosobranch snails from other sources within a limited radius of Lafayette, Indiana, revealed the presence of four other distinctly different species of the Virgula type, thus providing material for a comparative study of five new species.
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