Redescription of Pseudotelorchis compactus (Cable and Sanborn, 1970) Yamaguti, 1971 (Cercomeria: Trematoda: Digenea: Plagiorchiformes) with discussion of its phylogenetic affinities

Abstract

Pseudotelorchis compactus from the oviducts of Emydoidea blandingi is redescribed and its phylogenetic affinities examined. The Ochetosomatidae is considered the sister group of the Telorchiidae based on the shared presence of a well-developed glandular and muscular metraterm, and on the use of tadpoles as second intermediate hosts in the life cycle. The monophyly of the Ochetosomatidae is supported by the presence of relatively short caeca and testes located near the posterior ends of the caeca. The monophyly of the Telorchiidae is supported by the presence of postuterine testes located near the posterior end of the body. Orchidasma is excluded from the Telorchiidae because it possesses a spinose cirrus, spinose metraterm and distal portion of the uterus, and testes separated widely in the hind body by the uterus. Pseudotelorchis is considered monophyletic by virtue of having ovaries with irregular rather than smooth margins, testes that vary from side by side to tandem rather than being consistently tandem, and by inhabiting the oviducts rather than the intestine of the definitive hosts. Pseudotelorchis is the sister group of Loefgrenia plus Telorchis, the latter group diagnosed by having ovaries that are at least half an ovarian diameter posterior to the posterior margin of the ventral sucker rather than proximal to it. Loefgrenia is diagnosed by the absence of an esophagus, while Telorchis is diagnosed by strictly tandem testes with smooth margins and well-ordered ascending and descending uterine loops.