The monostome flukes (Digenea : Families Opisthotrematidae Poche and Rhodbiopoeidae Poche) parasitic in sirenians (Mammalia : Sirenia)

Abstract

A revision of the families Opisthotrematidae Poche, 1926 and Rhabdiopoeidae Poche, 1926 (Platyhelminthes : Digenea) is presented. These monostome flukes parasitize the dugong, Dugong dugon (Miiller), and a manatee, Trichechus manatus Linnaeus (Mammalia : Sirenia). Three groups of genera are recognized within the Opisthotrematidae but a formal subdivision of the family into subfamilies is not proposed. The first group is the Opisthotrema group, comprising the genera Opisthotrema Fischer, 1883, Cochleotrema Travassos & Vogelsang, 1931 and Pulmonicola Poche, 1926. Opisthotrema dujonis (Leuckart, 1874) Price, 1932, from the Eustachian tubes and middle ear of the dugong, is redescribed and O. australe, sp, nov., is described from the same host and habitat. Paracochleotrema Sharma & Gupta, 1971 is reduced to a synonym of Cochleotrema,which is removed from synonymy with Opisthotrema. Cochleotrema cochleotrema Travassos & Vogelsang, 1931, from the nasal passages and stomach of T. manatus, and C. indicum (Sharma & Gupta, 1971), comb. nov., from the nasal passages and lungs of the dugong, are redescribed. Pulmonicola contains only P. pulmonalis (von Linstow, 1904) from the lungs of the dugong, and is here regarded as a species inquirenda. The Lankatrema group of genera includes Lankatrema Crusz & Fernand, 1954 and Lankatrematoides, gen. nov., both from the dugong. Lankatrema mannarense Crusz & Fernand: 1954 occurs in the wall of the stomach and the capacious duodenum and its diverticula. L. minutum, sp. nov., from the wall of the cardiac gland of the stomach, and L. microcotyle, sp, nov., and L. macrocoryle, sp. nov., both from the wall of the ileum, are described. Lankatrematoides gardneri, sp. nov., is described from the pancreatic ducts. The Folitrema group includes a single monospecific genus, Folitrema, gen. nov. Folitrema jecoris, sp, nov., is described from the gall bladder and bile ducts within the liver of the dugong. The family Rhabdiopoeidae consists of four monospecific genera from the dugong. Subfamilies are not recognized. Rhabdiopoeus taylori Johnston, 1913, from the lumen of the intestine, and Taprobanella bicaudata Crusz & Fernand, 1954, from the lumen of the capacious duodenum and its diverticula, are redescribed. Haerator caperatus, gen. et sp. nov., from the lumen of the small intestine, and Faredifex clavata, gen. et sp. nov., from abscesses in the wall of the small intestine, are described. With the exception of Pulmonicola pulmonalis and Lankatrema mannarense, all species are figured. Keys are given to the families, to the genera within each family, and the species within each genus. A diagnosis is given of each family and genus. The geographical distribution, including many new records, is given for each species.