Large and small rDNA sequences of 41 species of the family Opecoelidae are utilised to produce phylogenetic inference trees, using brachycladioids and lepocreadioids as outgroups. Sequences were newly generated for 13 species. The resulting Bayesian trees show a monophyletic Opecoelidae. The earliest divergent group is the Stenakrinae, based on two species which are not of the type-genus. The next well-supported clade to diverge is constituted of three species of Helicometra Odhner, 1902. Based on this tree and the characters of the egg and uterus, a new subfamily, the Helicometrinae, is erected and defined to include the genera Helicometra, Helicometrina Linton, 1910 and Neohelicometra Siddiqi et Cable, 1960. The subfamily Opecoelinae is found to be monophyletic, but the Plagioporinae is paraphyletic. The single representative of the Opecoelininae (not of the type genus) is nested within a group of deep-sea 'plagioporines'. The two representatives of the Opistholebetidae are embedded within a group of shallow-water 'plagioporine' species. The Opistholebetidae is reduced to subfamily status pro tem as its morphological and biological characteristics are distinctive. This implies that as opecoelid systematics develops with more molecular evidence, several further subfamilies will be recognised. Many of the morphological characters were found to be homoplasious, but the characters defining the Helicometrinae and Opecoelinae, such as filamented eggs, reduced cirrus-sac and uterine seminal receptacle, are closely correlated with the inferred phylogeny., Rodney A. Bray, Thomas H. Cribb, D. Timothy J. Littlewood, Andrea Waeschenbach., and Obsahuje bibliografii
Morphological examination of novel specimens of paruterinid cestodes from passerine birds from Brazil and Chile and of museum specimens from Paraguay revealed two new species: Anonchotaenia prolixa sp. n. from Elaenia albiceps chilensis Hellmayr from Chile, and Anonchotaenia vaslata sp. n. from Tyrannus melancholicus (Vieillot) (type host) and Myiodynastes maculatus (Statius Muller) from Paraguay. The generic diagnosis of Anonchotaenia Conn, 1900 is amended, prompted by the presence of the armed cirrus and the elongated cirrus sac of A. prolixa. Two species were redescribed: Anonchotaenia brasiliensis Fuhrmann, 1908 from Tachyphonus coronatus (Vieillot) and Thraupis cyanoptera (Vieillot) (new host records) from Brazil, and Thraupis sayaca (Linnaeus) and Volatinia jacarina (Linnaeus) from Paraguay (new host and geographic records); and Anonchotaenia macrocephala Fuhrmann, 1908 from Tachycineta leucorrhoa (Vieillot) (new host record) from Brazil, Tachycineta meyeni (Cabanis) from Chile (new host and geographic record) and Stelgidopteryx ruficollis (Vieillot) from Paraguay (new host and geographic record). Scanning electron microscopy of A. brasiliensis and A. macrocephala revealed less microthrix variation than has been reported for other cyclophyllidean taxa. Sequence data were generated for nuclear ssr- and lsr-DNA and mitochondrial rrnL and cox1 for A. prolixa, A. brasiliensis, and A. macrocephala. Maximum likelihood and Bayesian inference analyses supported each species as distinct, but revealed cryptic diversity among A. brasiliensis specimens from different host families. New host records of A. brasiliensis and A. macrocephala prompted a formal assessment of host specificity. Anonchotaenia prolixa was found to be oioxenous (HSS = 0), A. vaslata and A. macrocephala were found to be metastenoxenous (HSS = 3.000 and 3.302, respectively), whereas A. brasiliensis was found to be euryxenous (HSS = 5.876). Anonchotaenia brasiliensis has been found parasitising several species of different passerine families that participate in mixed-species foraging flocks in the Atlantic Forest. A diversity of species of other families join these flocks and are among the substantial number of South American passerine species yet to be examined for cestodes.