A Morphological and Molecular Study ofSpectatus spectatus(Kathlaniidae), Including Redescription of the Species and Amendment of Genus Diagnosis

Abstract

Spectatus spectatus Travassos, 1923 (Nematoda: Kathlaniidae) found in the intestine of Piaractus mesopotamicus (Holmberg, 1887) (Characiformes: Serrasalmidae) from the River Miranda, Mato Grosso do Sul, Brazil is redescribed based on morphological evaluation of newly collected material and examination of type and voucher specimens from the Coleção Helmintológica do Instituto Oswaldo Cruz. The following characteristics previously unreported or insufficiently described were observed: morphology of lips, presence of lamellae-like supplementary lips, presence of pharynx and cuticular ring surrounding the oral opening associated with a complex cuticular apparatus anterior to the pharynx, the number and arrangement of caudal papillae (13 pairs plus 1 unpaired), and the position of nerve ring. Since S. spectatus is the type species of Spectatus, the diagnosis of this Neotropical genus is amended. Synonymy of Chabaudinema Díaz-Ungría, 1968 with Spectatus, first proposed in 1980 by Baker, is supported by the present data. Molecular data that include the first sequence of the SSU rDNA for any species of Spectatus indicate a basal position of S. spectatus within Cosmocercoidea, forming a distant lineage from that comprising 2 species of Falcaustra Lane, 1915. This separate position of S. spectatus supports validity of the genus.

Molecular characterization of Ichtyobronema hamulatum (Moulton, 1931) (Nematoda: Quimperiidae), a common parasite of burbot Lota lota (Linnaeus) (Actinopterygii: Lotidae)

“…In both cases, quimperiids clustered with Falcaustra representatives forming a sister clade with Cucullanidae representatives with the low level of support (NJ bootstrap value for 60 % in Rajabloo et al, 2016 study) (Fig.1, B). In addition, our data support the conclusions of Pereira et al (2015) and Rajabloo et al (2016) on the polyphyly of Kathlaniidae. Separated from other qumperiids, the position of Paraseuratum sp.…”

Pathobiology and first report of larval nematodes (Ascaridomorpha sp.) infecting freshwater mussels (Villosa nebulosa, Unionidae), including an inventory of nematode infections in freshwater and marine bivalves

“…As an aside, Cosmocercoidea and Seuratoidea (and their respective families) were paraphyletic or polyphyletic in the recovered tree, and Cucullanidae was recovered as an early branching lineage (monophyletic). These results corroborate earlier findings regarding the phylogenetic interrelationships of these taxa (Pereira et al., 2015; Choudhury and Nadler, 2016; Sokolov and Malysheva, 2017). The superfamilies Seuratoidea (Cucullanidae, Quimperiidae, Seuratidae, et al.)…”

Helminth parasites of South American fishes: current status and characterization as a model for studies of biodiversity

“…The lack of molecular data is also a barrier to the elucidation of these taxonomic issues, as recently observed by Pereira et al . (2015a, b), these problems including the detection of possible cryptic or sibling species, as in the case of those host-generalist parasites.…”