Cucolepis gen. n. is erected as monotypic for Cucolepis cincta sp. n., a new species of cyclophyllidean cestode of the family Paruterinidae. The new species is described from the squirrel cuckoo, Piaya cayana Lesson (Aves: Cuculiformes), taken from two localities in Paraguay in 1984 and 1985. This new genus is most similar to the genus Triaenorhina Spasskii et Shumilo, 1965 in terms of the hook morphology and large epiphyseal structures extending from both the handle and guard, but differs in several aspects of the strobilar morphology, such as the shape of the cirrus sac, genital atrium, uterus and paruterine organ. The strobilar morphology of the new genus strongly resembles that of the genus Francobona Georgiev et Kornyushin, 1994, especially the shape of the cirrus sac and genital atrium, yet Francobona spp. lack the developed epiphyseal structures observed in species of Cucolepis and Triaenorhina. Previous records and the nature of parasite-host associations between cuculiform birds and their cestode parasites are discussed.
Dictyterina cholodkowskii (Skrjabin, 1914) is recorded from iMnius collurio L. in Bulgaria (new geographical record). The species is redescribed and figured. A full list of synonyms is presented; it includes, among the other synonyms, Deltokeras delachauxi Hsii, 1935 (new synonym), Biulerina passerina of Oshmarin (1963) and Paruterina parallelipipeda of Paspalev and Paspaleva (1972). A survey of published records characterizes D. cholodkowskii as limited to the Palaearctic in six species of the genus Lanius (Aves, Passeriformes, Laniidae).
The syntypes of Deltokeras omitheios Meggitt, 1927 (the type-species of Deltokeras Meggitt, 1927), a parasite of Urocissa erythrorhyncha (Passeriformes, Corvidae) in South Asia, are redescribed. Deltokeras is considered a monotypie genus. An amended generic diagnosis is presented.
Ultrastructural characters of spermiogenesis and mature spermatozoon of Triaenorhina rectangula (Fuhrmann, 1908) are examined by transmission electron microscopy. Spermiogenesis follows the Bâ and Marchand's Type III spermiogenesis of cestodes. The process begins with the formation of a differentiation zone containing two centrioles and a cytoplasmic protrusion. The centrioles are associated with vestigial striated roots. One of the centrioles develops a free flagellum externally to the cytoplasmic protrusion. After a slight rotation, the free flagellum fuses with the cytoplasmic protrusion. In the final stage of spermiogenesis, a single crested body appears in the anterior part of the differentiating spermatozoon. The anterior extremity of the mature spermatozoon is characterised by an apical cone and a single crested body. The axoneme is of the 9+''1'' trepaxonematan type. A periaxonemal sheath and electron-dense rods are described in some parts of the mature spermatozoon. The nucleus is electron-dense and spirally coiled around the axoneme. The cortical microtubules are spirally arranged at an angle of about 40° to the spermatozoon axis. The present results show that the ultrastructural characters of spermiogenesis and mature spermatozoon of T. rectangula resemble most closely those in taeniids and metadilepidids. The comparison of these results with the only previous spermiological description of a paruterinid species reveals differences relative to the occurrence of filamentous rods of electron-dense material versus intracytoplasmic walls in the mature spermatozoon that may reflect the polyphyletic character of the Paruterinidae.