Riggenbachiella paranaense Philippe Vieira Alves &amp; Alain de Chambrier &amp; José Luis Luque &amp; Tomáš Scholz 2017, n. comb.
Creators: name: Alves, Philippe Vieira
name: De Chambrier, Alain
name: Luque, José Luis
name: Tomáš Scholz
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Metazoa
Platyhelminthes
Cestoda
Proteocephalidea
Monticelliidae
Riggenbachiella
Riggenbachiella paranaense

description: <i>Riggenbachiella paranaense</i> (Pavanelli &amp; Rego, 1989) n. comb. Syns <i>Goezeella paranaensis</i> Pavanelli &amp; Rego, 1989; <i>Chambriella paranaensis</i> (Pavanelli &amp; Rego, 1989) Rego, Pavanelli &amp; Chubb, 1999 <i>Type- and only known host</i>: <i>Hemisorubim platyrhynchos</i> (Valenciennes) (Siluriformes: Pimelodidae). <i>Type-locality</i>: River Paraná (upper reaches) near Porto Rico (State of Paraná, Brazil; 22 43 0S, 53 10 0W). <i>Other localities</i>: River Paraguay, San Antonio near Asunción (Departamento Central, Paraguay; 25 25 0S, 57 34 0W); River Amazon, Iquitos (Region of Loreto, Peru; 3 47 0S, 73 20 0W). <i>Prevalence</i>: 37% (29/79) and 8% (1/12) in <i>H</i>. <i>platyrhynchos</i> from the Paraná and Amazon basins, respectively (Pavanelli &amp; Santos, 1991; de Chambrier et al., 2015b). <i>Site in host</i>: Anterior intestine. <i>Material studied</i>: (i) <i>Goezeella paranaensis</i> from <i>Hemisorubim platyrhynchos</i>: holotype (incomplete specimen without pregravid proglottides; CHIOC 32490), 4 paratypes (2 entire specimens and 2 slides with serial cross-sections, CHIOC 32491a, b, 32492a, b); (ii) <i>Goezeella paranaensis</i> from <i>H</i>. <i>platyrhynchos</i>: vouchers (6 entire specimens and 2 slides with serial cross-sections), River Paraguay, San Antonio, Central Paraguay, collected by C. Vaucher, S. Fisch-Muller and A. de Chambrier on 28.x.1989 and 27.xi.1993 (MHNG-PLAT 1951 4, 19519, host field nos. PY 6922/1, PY 8467); (iii) <i>Chambriella paranaensis</i> from <i>H</i>. <i>platyrhynchos</i>: vouchers (3 immature and pregravid fragments), River Amazon, Iquitos, Loreto. Peru) collected by T. Scholz on 22.iv.2004 (MHNG- PLAT 3643 0, 36431, host field nos. PI 95a, PI 95c). Redescription (Figs. 2I, J, M–O, 5) [Based on 6 specimens (6 entire specimens and 2 slides with serial cross-sections).] Proteocephalidae, Monticelliinae. Testes, ovary, vitelline follicles and uterus cortical. Total body length 19–32 mm (n = 3), maximum width up to 1.2 mm (n = 4). Strobila acraspedote, anapolytic, consisting of 59–7 6 proglottids: 40–46 immature, 5–6 mature, 6–14 pregravid and 8–10 gravid. Immature proglottides wider than long (length: width ratio 0.13–0.43); mature proglottides wider than long (length: width ratio 0.35–0.86); pregravid proglottides wider than long to longer than wide (length: width ratio 0.50–1.32); gravid proglottids longer than wide (length: width ratio 1.12–2.01). Scolex 495–630 9 485–720 (n = 4), wider than proliferative zone (neck), 325–685 9 175–380, with conical apex, without apical organ. Suckers large, biloculate, 8-shaped, with both loculi similar in length; length of suckers represents up to 78% of scolex length. Anterior loculus 130–220 wide (n = 5), posterior loculus 130–205 wide (n = 5); sucker rims well developed; septum between loculi well developed (Figs. 2I, J, 5A). Apex of scolex covered with acicular filitriches, upper part of sucker rim and medium part between suckers with acicular filitriches interspersed with gladiate spinitriches of similar appearance and density (Fig. 2M–O). Inner longitudinal musculature inconspicuous (Fig. 5F). Osmoregulatory canals situated at different levels (Fig. 5E, F). Ventral canals thin-walled, wide, mediodorsal to ventral row of vitelline follicles and medioventral to lateralmost testes (Fig. 5E, F); dorsal canals thickwalled, dorsal to ventral row of vitelline follicles and almost lateral to lateralmost testes (Fig. 5E, F). Testes cortical, spherical, small, 40–70 in diameter, in 1 irregular layer, 100–174 in number (Fig. 5B, C), reaching to ventral row of vitelline follicles (Fig. 5E). Testes in 1 field, less numerous alongside median line of proglottides (uterine stem) and at level of cirrus-sac level (Fig. 5B, C). Vas deferens strongly coiled, with loops forming elongate field reaching and crossing median line of proglottis (Fig. 5B, C). Cirrus-sac sigmoid, 180–305 9 45–110 wide (n = 28), with voluminous, chambered internal seminal vesicle (Fig. 5 B–D); length of cirrus-sac represents 18–31% (n = 28) of proglottis width; middle part of cirrus-sac muscular, with sinuous ejaculatory duct. Cirrus short, containing inverted T-shaped ejaculatory duct in its proximal part (Fig. 5D); cirrus occupies up to 38% (n = 28) of cirrus-sac length. Genital pores alternating irregularly, markedly pre-equatorial, situated at 14–26% (n = 28) of proglottis length from anterior margin (Fig. 5B, C). Ovary cortical, bi-lobed, follicular (Fig. 5B, C); length representing 19–29% of proglottis length (n = 28), width representing 69–84% proglottis width (n = 28). Mehlis’ gland 6 0–96 in diameter, representing 6–7% of proglottis width (n = 15). Relative ovarian size (see de Chambrier et al., 2012) <i>c</i>.9–14% size of mature and pregravid proglottides. Vaginal canal almost straight, with terminal part (<i>pars copulatrix vaginae</i>) surrounded by chromophilic cells and welldeveloped vaginal sphincter (Fig. 5C, D). Vagina mainly anterior (89%) or posterior (11%, n = 28) to cirrus-sac. Vitelline follicles cortical, ventrally more numerous at ovary level, arranged in 2 wide lateral rows (usually 7 to 10 follicles at same level), reaching anterior margin of proglottis, dorsally uninterrupted (Fig. 5B–D). Length of bands represents 93–98% and 92–99% of proglottis length on poral and aporal side, respectively (n = 28) (Fig. 5B, C). Uterus cortical, with development of type 2 (see de Chambrier et al., 2004, 2015a). Uterus opens by elongate, slit-like pore; uterine stem appearing in mature proglottides, occupying 85–88% (n = 7) of length of pregravid proglottides. Eggs subspherical; embryophore bi-layered, 17–19 9 16 –18; oncosphere subspherical, 10–1 3 9 7–13, embryonic hooks 6–7 long. Remarks This species was described by Pavanelli &amp; Rego (1989) as <i>Goezeella paranaensis</i> from decomposed material as evidenced by the poor quality of the illustrations (see figures 6–11 in Pavanelli &amp; Rego, 1989; the poor quality of the type-material was confirmed by observations of the present authors). Nevertheless, the most important genus-specific characteristics, i.e. the presence of a sigmoid cirrus-sac with three markedly different parts including a chambered internal seminal vesicle, and bi-loculate suckers could be observed in the holotype as well as in two paratypes studied (Fig. 5D). A new material of <i>R. paranaense</i> from Paraguay enabled us to redescribe this poorly known species. <i>Riggenbachiella paranaense</i> n. comb. differs from <i>R. amazonense</i> n. sp. in the following morphological characteristics: (i) the composition and anterior extent of the bands of vitelline follicles, which are narrower and composed from a fewer follicles in <i>R. amazonense</i> (compare Fig. 4B and Fig. 5B), almost always absent preporally (only exceptionally, 2–4 follicles anterior to the cirrus-sac can be present in some specimens of <i>R. amazonense vs</i> extensive follicles always present pre-porally in <i>R. paranaense</i>; compare Fig. 4B, C and Fig. 5B, C), and usually not reaching up to the anterior margin of proglottides in <i>R. amazonense</i> (<i>vs</i> reaching the anterior margin in <i>R. paranaense</i>; compare Fig. 4B and Fig. 5B, C); (ii) the mutual position of osmoregulatory canals, with both pairs of canals at the same level in <i>R. amazonense</i> (<i>vs</i> dorsal canal more lateral than ventral ones in <i>R. paranaense</i>; compare Fig. 4G–I and Fig. 5 E, F); (iii) the extent of the testicular fields which may reach almost to the lateral margin of proglottides in their anterior part, both on the poral and aporal sides in <i>R. amazonense</i> (<i>vs</i> testes reaching laterally only to the level of dorsal osmoregulatory canals, never to the lateral margin of proglottides in <i>R</i>. <i>paranaense</i>; compare Fig. 4 B, C and Fig. 5 B, C); and (iv) the less developed musculature of the suckers in <i>R. amazonense</i>, with the posterior loculus always wider than the anterior one (<i>vs</i> suckers with more prominent rims and a conspicuous interlocular septum in <i>R. paranaense</i>; the anterior loculus can be as wide as, or even wider than, the posterior one in <i>R. paranaense</i>; compare Figs. 2E, 4A and Figs. 2I, 5A). <i>Abbreviations</i>: out, outgroup; h, hologenophore <i>sensu</i> Pleijel et al. (2008) Ethanol-fixed material of <i>R. paranaense</i> from Paraguay has been lost and repeated attempts of the present authors to find new specimens in the typehost near the type-locality (River Paraná near Porto Rico) failed. Therefore, no molecular data on this species are available. Brooks (1 9 9 5) transferred <i>G</i>. <i>paranaensis</i> to <i>Spatulifer</i> Woodland, 1 9 3 4 as <i>S</i>. <i>paranensis</i> [sic!] based on a cladistics analysis inferred from morphological characters, but this new combination was not accepted by subsequent authors.
description: Published as part of <i>Philippe Vieira Alves, Alain de Chambrier, José Luis Luque &amp; Tomáš Scholz, 2017, Untangling convoluted taxonomy of Chambriella Rego, Chubb &amp; Pavanelli, 1999 (Cestoda: Proteocephalidae), with erection of Riggenbachiella n. g. and the description of a new species from pimelodid catfishes in the Neotropical Region, pp. 367-389 in Syst Parasitol 94</i> on pages 376-380, DOI: 10.1007/s11230-017-9700-1, http://zenodo.org/record/925123
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