Untangling convoluted taxonomy of Chambriella Rego, Chubb & Pavanelli, 1999 (Cestoda: Proteocephalidae), with erection of Riggenbachiella n. g. and the description of a new species from pimelodid catfishes in the Neotropical Region Author Philippe Vieira Alves Author Alain de Chambrier Author José Luis Luque Author Tomáš Scholz text Syst Parasitol 2017 2017-02-20 94 367 389 journal article 10.1007/s11230-017-9700-1 7c324801-2c22-439d-87c8-1bdb83e11827 925123 Chambriella megacephala ( Woodland, 1934 ) n. comb. Syns Monticellia megacephala Woodland, 1934 ; Goezeella agostinhoi Pavanelli & Santos, 1992 ; Chambriella agostinhoi ( Pavanelli & Santos, 1992 ) ; Lenhataenia megacephala de Chambrier & Scholz, 2008 Type-host : Sorubimichthys planiceps (Spix & Agassiz) ( Siluriformes : Pimelodidae ), originally reported erroneously by Woodland (1934) as Platystomatichthys sturio (Kner) (see de Chambrier & Scholz, 2008 ). Other hosts : Zungaro jahu (Ihering) , Zungaro zungaro (Humboldt) and Pseudoplatystoma fasciatum (Linnaeus) (all Siluriformes : Pimelodidae ). Type-locality : River Amazon (lower reaches), 50 miles downstream of Santarém, State of Pará , Brazil . Other localities : River Paraná (upper reaches), Porto Rico ( State of Paraná , Brazil ; 22 43 0S , 53 10 0W ); River Amazon , Itacoatiara (State of Amazonas , Brazil ; 3 0 9 0S , 5 8 26 0W) and Iquitos (Region of Loreto , Peru ; 3 47 0S , 7 3 20 0W). Prevalence : 38% (6/16) and 50% (11/22) in Z . jahu (syn. Paulicea luetkeni ) from River Paraná ( Brazil ) and in S . planiceps from River Amazon ( Peru ), respectively ( Pavanelli & Santos, 1991 ; de Chambrier et al., 2015b ). Site in host : Anterior intestine. Material studied : (i) Goezeella agostinhoi ex Paulicea luetkeni (= Zungaro jahu ): holotype (entire specimen, CHIOC 3 2.8 2 0a); 3 paratypes (entire specimens, CHIOC 3 2.8 2 0b-d); (ii) Chambriella agostinhoi ex Z . jahu : vouchers (2 entire specimens, 1 fragment and 1 slide with serial crosssections), River Cuiabá, Cuiabá, State of Mato Grosso (River Paraná basin, Brazil), collected by A. A. Rego on 3 1.vii. 1 9 9 3 (MHNG-PLAT 1 9 5 4 6, 2 2 4 9 7, host field nos. BR 4 0 7, BR 4 0 8); ex Z . zungaro : vouchers (4 entire specimens and 3 fragments mixed with Riggenbachiella amazonense ), River Amazon, Itacoatiara, State of Amazonas (Brazil), collected by A. A. Rego and A. de Chambrier on 8.x. 1 9 9 5, and 1 entire specimen from River Amazon, Iquitos (Peru) collected by T. Scholz and R. Kuchta on 1 6.ix. 2 0 0 6 (MHNG- PLAT 2 7 9 9 0, CHIOC 3 8 4 8 4, host field Nos. BR 6 3 4, PI 4 4 5a); (iii) Lenhataenia megacephala ex Sorubimichthys planiceps : vouchers (2 entire specimens, 1 mixed with R . amazonense ), River Amazon, Itacoatiara, State of Amazonas (Brazil), collected by A. A. Rego and A. de Chambrier on 2.x. 1 9 9 5 (MHNG-PLAT 2 0 7 6 8, host field No. BR 4 6 7); (iv) Chambriella sp. ex Pseudoplatystoma fasciatum : vouchers (2 entire specimens and fragments), River Amazon, Iquitos, Region of Loreto (Peru) collected by T. Scholz and R. Kuchta on 5.ix. 2 0 0 6 (MHNG-PLAT 6 0 0 2 6, host field no. PI 3 0 4a). Representative DNA sequences : Seven isolates of ‘ L . megacephala ’ from S. planiceps in the River Amazon had identical sequences of 1,4 9 1 bp long of the lsr DNA (D1-D3 domains) (GenBank KY2 0 7 4 4 9). Two isolates of ‘ C . agostinhoi ’, one from Z . jahu (type-host) in the River Paraná and one from Z. zungaro in the River Amazon, also had identical sequences with those of the seven isolates of ‘ L . megacephala ’ (GenBank KY2 0 7 4 4 7, KY2 0 7 4 4 8). Remarks Comparison of voucher specimens of Lenhataenia megacephala ex S. planiceps with those of Goezeella agostinhoi ex Z. jahu ( type and newly collected material; Figs. 2A–D, G , 3 ) revealed that these two taxa are indistinguishable from each other in their morphology, except for the position of the vagina in relation to the cirrus-sac (either anterior or posterior; see Table 2 ). This feature has been broadly used to distinguish congeneric species (Gil de Pertierra, 2003 ; Arredondo & Gil de Pertierra, 2010 ; Gil de Pertierra & de Chambrier, 2013 ), but its taxonomic value seems to be questionable for the above-mentioned species because their conspecificity has also been confirmed by molecular data (sequences of both taxa are identical, Fig. 1 ). Since no but one morphological differences were found among the studied specimens, the description of de Chambrier & Scholz (2008) is not repeated herein. These results thus show that C. megacephala , which possesses both an anterior and a posterior vagina in relation to the cirrus-sac, is widely distributed in South America, with records from the Amazon and Paraná River basins. It occurs in species of as many as three genera of big pimelodid catfishes ( Pseudoplatystoma Bleeker , Sorubimichthys Bleeker and Zungaro Bleeker ), which is unusual among Neotropical proteocephalids ( Rego et al., 1999 ; de Chambrier et al., 2015b ).