Proteocephalids are a cosmopolitan and diverse group of tapeworms (Cestoda) that have colonized vertebrate hosts in freshwater and terrestrial environments. Despite the ubiquity of the group, key macroevolutionary processes that have driven the group's evolution have yet to be identified. Here, we review the phylogenetic relationships of proteocephalid tapeworms using publicly available (671) and newly generated (91) nucleotide sequences of the nuclear RNA28S and the mitochondrial MT-CO1 for 537 terminals. The main tree search was carried out under the parsimony optimality criterion, analysing different gene alignments simultaneously. Interestingly, we were not able to recover monophyly of the Proteocephalidae. Additionally, it was difficult to reconcile the tree with host and biogeographical data using traditional character optimization strategies in two dimensions. Therefore, we investigated if host and biogeographical data can be correlated with the parasite clades in a multidimensional space-thus considering multiple layers of information simultaneously. To that end, we used random forests (a class of machine learning models) to test the predictive potential of combined (not individual) host and biogeographical data in the context of the proteocephalid tree. Our resulting models can correctly place 88.85% (on average) of the terminals into eight representative clades. Moreover, we interactively increased the levels of clade perturbation probability and confirmed the expectation that model accuracy negatively correlates with the degree of clade perturbation. Our results show that host and biogeographical data can accurately predict proteocephalid clades in multidimensional space, even though they are difficult to optimize in the parasite tree. These results agree with the assumption that the evolution of proteocephalids is not independent of host and biogeography, and both may provide external support for our tree.

• MeSH
• Cestoda * genetika   klasifikace   MeSH
• fylogeneze * MeSH
• fylogeografie MeSH
• strojové učení * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

As part of a complex revision of proteocephalid cestodes parasitic in freshwater bony fishes of the Neotropical Region, the genus Chambriella Rego, Chubb & Pavanelli, 1999 is redefined based on detailed examination of type-specimens and newly collected material of both nominal species of the genus. This examination revealed that the type-species C. agostinhoi (Pavanelli & Santos, 1992) from Zungaro jahu (Ihering) (type-host) and Z. zungaro (Humboldt) is indistinguishable from Lenhataenia megacephala (Woodland, 1934) from Sorubimichthys planiceps (Spix & Agassiz) (all hosts Siluriformes: Pimelodidae), the type- and only species of the genus. New molecular data (partial sequences of the large subunit nuclear ribosomal RNA gene) support the conspecificity of these taxa. As a result, Lenhataenia de Chambrier & Scholz, 2008 becomes a junior synonym of Chambriella and its type-species, C. agostinhoi, a junior synonym of C. megacephala (Woodland, 1934) n. comb. The second species of Chambriella, C. paranaensis (Pavanelli & Rego, 1989) from Hemisorubim platyrhynchos (Valenciennes), is transferred to a new genus, Riggenbachiella n. g., as R. paranaense (Pavanelli & Rego, 1989) n. comb. Riggenbachiella amazonense n. sp. (syn. Chambriella sp. of de Chambrier & Scholz, 2008) from S. planiceps (type-host), Phractocephalus hemioliopterus (Bloch & Schneider) and Z. zungaro is described and designated as the type-species of the new genus. Riggenbachiella n. g. is placed in the subfamily Monticelliinae Mola, 1929, because of the cortical position of the testes, ovary, vitelline follicles and uterus, and is mainly characterised by the possession of a sigmoid cirrus-sac with voluminous, chambered internal seminal vesicle, and bi-loculate suckers.

• MeSH
• Cestoda anatomie a histologie   klasifikace   genetika   MeSH
• DNA helmintů genetika   MeSH
• druhová specificita MeSH
• řeky MeSH
• střeva parazitologie   MeSH
• sumci parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Brazílie MeSH
• Názvy látek
• DNA helmintů MeSH

An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79%) that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes) exhibit the highest proportion of records (39%) among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31%) for marine hosts and the Amazon River basin (45%) for freshwater ones. The following problems were detected during the compilation of literary data: (i) unreliability of many records; (ii) poor taxonomic resolution, i.e. identification made only to the genus or even family level; (iii) doubtful host identification; and (iv) the absence of voucher specimens that would enable us to verify identification. It is thus strongly recommended to always deposit representative specimens in any type of studies, including faunal surveys and ecological studies. An analysis of the proportion of three basic types of studies, i.e. surveys, taxonomic and ecological papers, has shown a considerable increase of ecological studies over the last decade.

• Klíčová slova
• Biodiversity, marine ecoregions, river basins, species richness, tapeworms,
• Publikační typ
• časopisecké články MeSH