Search

Eigenmannia oradens, new species Figs. 1– 3, Table 1 Holotype. ANSP 190768, xr, 121.6 mm LEA, Venezuela, Amazonas, Río Ventuari at Raudales Chipirito, 88.5 Km east of San Fernando de Atabapo, 04°04’6”N 66°54’13”W, 0 1 April 2010, M. Sabaj-Pérez, N.K. Lujan, D.C. Werneke, T. Carvalho, S. Meza V., A. Luna & O. Santaella. Paratypes. ANSP 190912, 2 xr, 62.6–101.1 mm LEA, Venezuela, Amazonas, Río Ventuari ca. 20 airmiles NE of confluence with Río Orinoco, near ornamental fish market in river, 04°04’32”N 66°53’34”W, 0 3 April 2005, N.K. Lujan, M. Arce, E.L. Richmond, M.P. Grant & T.E. Wesley. ANSP 203212, 1xr, 76.7 mm LEA, collected with the holotype, MPEG 35287, 1xr+1CS, 94.7–111.1 mm LEA, collected with the holotype. MZUSP 122802, 1MS, 102.3 mm LEA, collected with the holotype. USNM 440377, 1xr, 91.4 mm LEA, collected with the holotype. Diagnosis. Eigenmannia oradens differs from all congeners by presence of bony dorsolateral flange of dentary which also anchors numerous teeth along its extension (versus dorsolateral flange absent and teeth are attached only in dentary rim), and first premaxillary teeth row mobile, teeth attached to anteroventral margin of premaxilla (versus first premaxillary teeth row immobile, teeth completely attached to ventral surface of premaxilla). It is further distinguished from remain congeners, except E. besouro Peixoto & Wosiacki, 2016, E. correntes Camposda-Paz & Queiroz, 2017, E. meeki Dutra, de Santana & Wosiacki, 2017, E. vicentespelaea Triques, 1996, E. virescens Valenciennes, 1836, and E. waiwai Peixoto, Dutra & Wosiacki, 2015 by the subterminal mouth (versus terminal: Fig. 2). The new species is diagnosed from E. besouro, E. correntes, E. meeki, E. vicentespelaea, and E. virescens by having 38–42 teeth on premaxilla (versus 18–29 in E. besouro, 17–20 in E. correntes, 30–35 in E. meeki, 25–26 in E. vicentespelaea, and 22 in E. virescens). It is distinguished from E. besouro, E. correntes, E. meeki, E. virescens, and E. waiwai by the coronomeckelian bone corresponding to 45% of length of Meckel’s cartilage (versus 20% of length of Meckel’s cartilage in E. correntes, E. meeki, E. virescens and E. waiwai and 30% of length of Meckel’s cartilage in E. besouro). Eigenmannia oradens also differs from E. meeki, E. vicentespelaea, and E. waiwai by having 99–107 scales along lateral line until the end of anal fin (versus 140–168 in E. meeki, 110–125 in E. vicentespelaea, and 111–128 in E. waiwai). It is further distinguished from E. besouro, E. correntes, E. vicentespelaea and E. waiwai by absence of superior midlateral stripe (versus presence). The new species is additionally diagnosed from E. meeki, E. virescens, and E. waiwai by depth of posterodorsal expansion on infraorbitals 1+2 approximately equal to total length of infraorbitals 1+2 (versus less than 50% of the length of infraorbitals 1+2). Eigenmannia oradens also differs from E. besouro, E. correntes and E. waiwai by having ii, 16–17 pectoral fin rays (versus ii, 13–14 in E. besouro, ii, 11–12 in E. correntes, and ii, 13–15 in E. waiwai). It is distinguished from E. correntes and E. meeki by having 31–38 dentary teeth (versus 16–18 and 20–23 respectively), and 164–192 anal-fin rays (versus 211–240). It also differs from E. virescens by presence of narrow stripe on lateral line (versus absence). Eigenmannia oradens is diagnosed from E. waiwai by having 14 precaudal vertebrae (versus 12 or 13). Description. Body shape and pigmentation in Figs. 1 and 2. Morphometric data for examined specimens in Table 1. Largest examined specimen 121.6 mm LEA. Body elongate, distinctly compressed laterally. Greatest body depth at vertical through distal margin of pectoral fin. Dorsal profile of body convex to straight. Ventral profile slightly convex. Caudal filament elongate. Head compressed, greatest width in opercular region and greatest depth at nape (Fig. 2). Dorsal profile of head convex. Ventral profile of head slightly straight. Snout subconical in lateral view. Mouth subterminal. Premaxillary teeth 38(1) or 42 (1) arranged in five (1) or six (1) rows. First premaxillary teeth row mobile, teeth attached only to anteroventral margin of premaxilla. Maxilla slender with short, hook-shaped anterodorsal process. Posterior margin of maxilla reaching posterior margins of first and second infraorbitals. Dentary teeth 31(1) or 38(1) arranged in three (2) rows. Dentary teeth attached in bony dorsolateral flange of dentary (Fig. 3). Coronomeckelian bone corresponds to 45% of length of Meckel’s cartilage. Endopterygoid teeth 10(1) arranged in single row. Mouth rictus extending posteriorly to vertical between nares or on posterior nostril. Anterior naris tube-like, closer to snout tip than to anterior margin of eye. Posterior naris rounded, without tube; near midpoint between anterior naris and anterior margin of eye. Eye small, circular, completely covered by thin membrane, on anterior one-half of HL and laterally oriented. Antorbital and infraorbitals 1 to 4 enlarged, partially cylindrical with slender osseous arches. Fifth and sixth infraorbitals slender and tubular. Depth of posterodorsal expansion on infraorbitals 1+2 equals total length of infraorbitals 1+2. Gill opening limited to posterior margin of opercle and extending above and below pectoral-fin base. Gill rakers tiny and fleshy. Seven (1) gill rakers on first ceratobranchial. Six (2) gill rakers on first infrapharyngobranchial. Upper pharyngeal plate with 10(1) teeth. Lower pharyngeal plate with nine (1) teeth. Branchial membranes joined at isthmus. Branchiostegal rays five (1). First and second branchiostegal rays narrow. Third to fifth branchiostegal rays spatulate. First to fourth branchiostegal rays attached to anterior ceratohyal. Fifth branchiostegal ray attached to posterior ceratohyal. Anus and urogenital papilla adjacent. Position of anus and urogenital papilla shifting through ontogeny from vertical through posterior margin of eye to vertical through middle of eye. Scales small, cycloid, extending from immediately posterior of head to tip of caudal filament. Scales present on mid-dorsal region of body. Scales above lateral line at midbody eight(4), nine(1), ten*(2), or 11(1). Lateral-line scales to vertical through anal-fin terminus 99(1), 100(3), 104(1), 105(2), or 107*(1). Pectoral-fin rays ii,16(7) or ii,17*(1). Three proximal radials. Distal pectoral-fin margin straight. Total anal-fin rays 164(1), 173(1), 177(1), 178*(2), 182(1), or 192(1). Anal-fin origin below pectoral-fin insertion. Distal margin of anal fin straight. First unbranched rays tiny; rays progressively increasing in size to first branched rays. Branched rays all of nearly equal length, except for posterior most rays that progressively decrease in size. Precaudal vertebrae 14*(7). Transitional vertebrae three (3) or four* (4). Vertebrae to end of anal fin 57(1), 59(2), 60(2) or 61(1). Pleural ribs six*(3) or seven (7). Displaced hemal spines four* (7). Coloration in alcohol. Body ground coloration cream. Body densely covered by dark chromatophores gradually more spaced ventrally. Chromatophores more concentrated on perforated scales forming lateral line stripe (Fig. 1). Second layer of pigmentation formed by multiple, small bars of dark chromatophores situated between musculature associated with anal-fin pterygiophores. Dark individual bars in combination form two stripes-like patterns. Inferior midlaterial stripe approximately as wide as orbital diameter. Anal-fin base stripe approximately as wide as orbital diameter. Head densely covered by dark chromatophores gradually more spaced ventrally. Lips distinctly darker than proximate areas. Pectoral and anal fins hyaline with scattered dark chromatophores overlying fin rays. Distribution. Eigenmannia oradens is only known from its type locality in the Río Ventuari, Río Orinoco basin, Estado Amazonas in Venezuela (Fig. 4). Etymology. The specific epithet, oradens, is from the Latin ora, meaning edge, and dens, meaning tooth, in allusion to the presence of a bony dorsolateral flange on the dentary in which teeth are attached. An adjective. Remarks. Eigenmannia oradens can be diagnosed among congeners by a remarkable arrangement of the oral dentition. In the premaxilla the anterobasal margin of the first tooth row is attached to it surface. Consequently, this arrangement, gives mobility freedom to the teeth, which can reach 90 degrees from the vertical. This type of attachment is also known in species of Archolaemus (Vari et al., 2012). Broadly, the premaxilla attachment in Archolaemus and E. oradens can be included in the Type 3 of Fink (1981) [“...a tooth attachment mode which acts as a hinge, with its axis of rotation being the anterior tooth attachment site”; pg. 176]. In contrast, the first tooth row is completely attached to the premaxilla in Sternopygidae, Type 2 of Fink (1981). The dentary of E. oradens is characterized by a bony dorsolateral flange, which anchors numerous teeth along its extension (Fig. 3). Such condition also occurs in Archolaemus, D. guchereauae, and Japigny. And according to the current hypotheses of phylogenetic relationships it is considered a convergence among the four taxa (e.g., Tagliacollo et al., 2016). As noted in the diagnosis for the new species, the number of teeth rows of premaxilla and dentary have a large variation across Eigenmannia and can be explored as source of taxonomic characters. The description of E. oradens corroborates with previous studies that used teeth arrangement and attachment as a valuable source of taxonomic information at different hierarchical levels (e.g., Vari et al., 2012; Peixoto et al., 2015; Peixoto & Wosiacki, 2016; Campos-da-Paz & Queiroz, 2017; Dutra et al., 2017; Peixoto & Waltz, 2017). Comparative material examined. Archolaemus blax: INPA 6424, 20+4CS, 118–270mm TL, Rio Tocantins above Tucuruí Dam, Brazil. MNRJ 12158, 18+4CS of 93, 90.0–382.0 mm TL, Rio Bezerra, Rio Tocantins basin, Brazil. Archolaemus ferreirai: INPA 6422, 8+4CS paratypes, 131.0–269.0 mm TL, Rio Mucajaí, Rio Branco basin, Brazil. INPA 36379, 20+1CS paratype, 119.0–342.0 mm TL, Rio Mucajaí, Rio Branco basin, Brazil. Archolaemus janeae: INPA 36380, 14+2CS paratypes, 136.0–225.0 mm TL, Rio Iriri, Rio Xingu basin, Brazil. Archolaemus luciae: INPA 20964, 8+4CS paratypes, 106.0–200.0 mm TL, Rio Trombetas, Brazil. Archolaemus orientalis: FMNH 94418, 1CS of 3 paratype, Rio São Francisco, Brazil. MPEG 21508, holotype, 156.0 mm TL, Rio Paracatu, Rio São Francisco basin, Brazil. MPEG 21509, 1MS paratype, 150.0 mm TL, Rio Paracatu, Rio São Francisco basin, Brazil. Archolaemus santosi: INPA 36382, 6+3CS paratypes, 73.0–212.0 mm TL, Rio Jamari, Rio Madeira basin, Brazil. Distocyclus conirostris: INPA 11482, 7+3CS of 32, 100.2–197.0 mm LEA, Rio Purus, Brazil. INPA 28879, 2CS of 19, 108.7–165.0 mm LEA, Rio Negro, Brazil. INPA 28915, 2CS of 11, 108.1– 130.5 mm LEA, Rio Negro, Brazil. INPA 34018, 8+1CS, 132.0– 174.5 mm LEA, Praia Grande above community of Carapanã, Rio Purus basin, Brazil. MPEG 20023, 2+1CS, 120.9–196.4 mm LEA, Rio Arari, Ilha do Marajó, Brazil. MPEG 20024, 2+1CS, 149.1–181.0 mm LEA, Rio Arari, Ilha do Marajó, Brazil. MZUSP 6982, 2+1CS, 156.2–166.0 mm LEA, Rio Madeira, Brazil. Distocyclus guchereauae: MNHN 2003-0013, 1, 222.0 mm TL, Maroni drainage, French Guiana. MNHN 2003-0014, 1, 232.0 mm TL, Maroni drainage, French Guiana. MNHN 2003-0018, 2, 322.0–321.0 mm TL, Maroni drainage, French Guiana. Eigenmannia antonioi: MPEG 10182, 6+1CS paratypes, 77.0– 118.3 mm LEA, Rio Anapu, Brazil. Eigenmannia besouro: MZUSP 57890, holotype, 91.9 mm LEA, Rio Grande, São Desidério, Brazil; MZUSP 119104, 5+1CS, paratypes, 69.6–106.1 mm LEA. MZUSP 83792, 6+1CS, paratypes, 55.8–68.8 mm LEA, Rio Preto, Brazil. Eigenmannia desantanai: NUP 3470, 10+1CS paratypes, 119.8– 142.8 mm LEA, Rio Cuiabá, Brazil. Eigenmannia guairaca: NUP 6467, 8+2CS paratypes, 81.4–135.8 mm LEA, Riacho Água do Ó, Brazil. Eigenmannia humboldtii: IAvH-P 6788, 1, 316.7 mm LEA, Río Atrato, Colombia. IAvH-P 6794, 1, 330.0 mm LEA, Río Atrato, Colombia. IAvH-P 6800, 288.3 mm LEA, Río Atrato, Colombia. IAvH-P 6806, 1CS, 205.7 mm LEA, Río Atrato, Colombia. IAvH-P 7024, 1, 199.8 mm LEA, Río Atrato, Colombia. IAvH-P 7415, 2, 240.9– 270.1 mm LEA, Río Atrato, Colombia. IAvH-P 7822, 1, 312.0 mm LEA, Río Magdalena, Colombia. IAvH-P 7823, 1, 264.0 mm LEA, Río Magdalena, Colombia. NRM 27741, 1, 294.1 mm LEA, Canõ Ponelaolla, Colombia. USNM 247229, 3, 134.9– 175.6 mm LEA, Río Salado, Colombia. Eigenmannia limbata: INPA 18288, 2CS, 98.0–151.0 mm LEA, Lago Mamirauá, Brazil. USNM 305802, 10+2CS, 122.6–250.5 mm LEA, Rio Matos, Bolivia. Eigenmannia macrops: BMNH 1897.8.6.1, holotype, 128.5mm LEA, Potaro River, Guyana. USNM 402684, 6, 80.1–116.8 mm LEA, Cuyuni River, Guyana. USNM 405265, 3, 56.3–107.8 mm LEA, Cuyuni River, Guyana. USNM 405266, 15+1CS, 63.3–162.9 mm LEA, Cuyuni River, Guyana. Eigenmannia matintapereira: MZUSP 109618, 3+1CS paratypes, 79.7–143.6 mm LEA, Rio Uneiuxi, Brazil. MZUSP 109695, 5+1CS paratypes, 65.7–167.7 mm LEA, Rio Urubaxi, Brazil. Eigenmannia meeki: USNM 293171, holotype, 235.7 mm LEA, Río Pucuro, Panamá. MPEG 33912, 1+1 CS, 194.6–222.0 mm LEA, Río Pucuro, Panamá. Eigenmannia microstoma: BMNH 1868.7.8.2–3, 2 syntypes, 101.1–139.3 mm LEA, Rio São Francisco basin, Brazil. ZMUC P2516 (formally ZMUC 21), 1 syntype (photo and radiograph), 162.8 mm LEA, Rio São Francisco basin, Brazil. ZMUC P2517 (formally ZMUC 23), 1 syntype, 153.8 mm LEA, Rio São Francisco basin, Brazil. ZMUC P2518 (formally ZMUC 24), 1 syntype, 176.6 mm LEA, Rio São Francisco basin, Brazil. ZMUC P2519 (formally ZMUC 25), 1 syntype, 105.1 mm LEA, Rio São Francisco basin, Brazil. ZMUC P2520 (formally ZMUC 26), 1 syntype, 101.1 mm LEA, Rio São Francisco basin, Brazil. MCP 45216, 5+1CS, 57.7–91.6 mm LEA, Rio Pandeiros, Brazil. Eigenmannia muirapinima: MPEG 21777, 1+3CS paratypes, 84.6–98.5 mm LEA, Lago Jará, Brazil. MPEG 29489, 11+2CS paratypes, 76.2–97.7 mm LEA, Igarapé Santo Antônio, Brazil. Eigenmannia nigra: ANSP 162130, 3 paratypes, 243.0–265.0 mm LEA, Río Casiquiare, Venezuela. BMNH 1998.3.17, 8 of 15, 133.0– 192.9 mm LEA, Paraná Apara, Brazil. CAS 54387, 3+1CS of 5, 139.2– 166.9 mm LEA, Río Orinoco bifurcation, Venezuela. CAS 54518, 1, 130.3 mm LEA, Río Orinoco bifurcation, Venezuela. INPA 9976, 3+1CS of 10, 149.7– 223.1 mm LEA, Paraná Apara, Brazil. INPA 15813, 12, 148.4– 222.4 mm LEA, Lago Tefé, Brazil. USNM 260240, 4+1CS of 22, 192.2– 225.2 mm LEA, main channel of Río Apure, Venezuela. Eigenmannia pavulagem: MPEG 9524, 3CS paratypes, 90.7–108.5 mm LEA, Igarapé Anuera-Grande, Brazil. MPEG 29490 paratypes, 25+2CS, 26.2–176.6 mm LEA, Igarapé Paraquequara, Brazil. Eigenmannia sayona: MZUSP 96497, holotype, 131.8 mm LEA, Río Parguaza, Cedeño, Venezuela; MZUSP 119711, paratypes, 6+2CS, 27.8-116.2 mm LEA. Eigenmannia trilineata: UFRGS 6635, 10, 58.5–143.8 mm LEA, Rio Tramandaí, Brazil. UFRGS 6790, 12, 92.8–159.1 mm LEA, Arroio Gueromana, Brazil. UFRGS 8788, 3, 114.2– 130.5 mm LEA, Rio Pardo, Brazil. UFRGS 13329, 1, 124.3 mm LEA, Arroio Corrientes, Brazil. Eigenmannia virescens: MCP 12474, 1, 190.1 mm LEA, Rio Uruguai, Brazil. MCP 13416, 5, 148.7–196.0, Rio do Peixe, Brazil. MCP 16797, 5+2CS, 143.7–182.0 mm LEA, Rio Ijuizinho, Brazil. MCP 19330, 1, 147.0 mm LEA, Rio Uruguai, Brazil. MCP 21139, 3, 157.3– 236.1 mm LEA, Rio das Antas, Brazil. MCP 26819, 1, 212.9 mm LEA, Rio Ibicui, Brazil. Eigenmannia vicentespelaea: MZUSP 83461, 3+1CS, 108.0– 164.5 mm LEA, Cave of São Vicente I, Brazil. Eigenmannia waiwai, INPA 37594, 31+2CS paratypes, 94.0– 138.1 mm LEA, Rio Mapuera, Brazil. INPA 37567, 3+1CS paratypes, 74.9–154.8 mm LEA, Cachoeira Porteira, Brazil. “ Eigenmannia ” goajira: USNM 121596, holotype, 377.0 mm LEA, Río Socuy, Venezuela. USNM 121596, 1, paratype, 335.6 mm LEA, Río Socuy, Venezuela. Japigny kirschbaum: MNHN 2008-1201, 110.9 mm TL, holotype, Mana River, French Guiana; MNHN 2000-5954, 2, 99–111 mm TL, paratypes, Maroni drainage, French Guiana. FMNH 50185, 3CS, New River drainage, head of Itabu Creek, Guyana. Rhabdolichops caviceps: INPA 20157, 8+2CS, 108.7–134.5 mm LEA, Paraná do Xiboquena, tributary of Rio Solimões, Brazil. Rhabdolichops eastwardi: INPA 12361, 2CS of 41, Lago do Prato, Rio Negro, Amazonas, Brazil. MPEG 1189, 2CS, 115.1–127.8 mm LEA, Rio Goiapi, Ilha do Marajó, Brazil. Rhabdolichops electrogrammus: INPA 28863, 8+2CS of 79, 96.8– 101.5 mm LEA, Rio Negro, Brazil. Rhabdolichops lundbergi: INPA 11406, 7+3CS of 111, 133.6– 155.6 mm LEA, Rio Coari, tributary of Rio Solimões, Brazil. Rhabdolichops nigrimans: INPA 28862, 11+2CS, 97.3–132.0 mm LEA, Rio Negro, Brazil. Rhabdolichops troscheli: MPEG 1174, 1, Rio Goiapi, Ilha do Marajó, Brazil. MPEG 2604, 9+2CS, 90.0– 94.7 mm LEA, Rio Goiapi, Ilha do Marajó, Brazil. MPEG 2803, 1CS, 222.0 mm LEA, Rio Goiapi, Ilha do Marajó, Brazil. MPEG 8482, 1CS, 170.1 mm LEA, Tomé-Açu, Pará, Brazil.

Dutra, Guilherme Moreira, Peixoto, Luiz Antônio Wanderley, Santana, Carlos David De, Wosiacki, Wolmar Benjamin (2018): A new species of Eigenmannia Jordan & Evermann (Teleostei: Gymnotiformes: Sternopygidae) from Río Ventuari, Venezuela. Zootaxa 4422 (1): 132-140, DOI: https://doi.org/10.11646/zootaxa.4422.1.8

EIGENMANNIA DESANTANAI SP. NOV. (FIGS 7, 8; TABLE 1) Diagnosis: Eigenmannia desantanai can be distinguished from other species in the E. trilineata species group by the inferior medial stripe, which is one scale deep (versus two or three scales deep). Eigenmannia desantanai can be further distinguished from the other members of the species group, except for E. waiwai, by the 11 or 12 precaudal vertebrae (versus 13 or 14 in E. antonioi; 15 in E. guairaca, E. muirapinima, and E. vicentespelaea; 13 in E. matintapereira; 14 or 15 in E. microstoma and E. trilineata; and 13–15 in E. pavulagem). Eigenmannia desantanai can be differentiated from E. waiwai by the terminal mouth (versus subterminal); the orbital diameter 14.5– 19.6% HL (versus 22.6–28.8%); the length of the anterodorsal process of the maxilla equal to 50% of the width of the posterior nostril (versus 1.5 times the width of the posterior nostril); the depth of the posterodorsal expansion on infraorbitals 1 + 2 approximately equal to the total length of infraorbitals 1 + 2 (versus less than 50% of the length of infraorbitals 1 + 2); and by the dentition pattern of the dentary with 21– 23 teeth distributed in two rows (outermost row with ten to 12 teeth; innermost row with nine to 13 teeth) [versus 37 or 38 teeth distributed in four rows (outermost row with seven teeth; second with 11–15 teeth; third with eight to 15; innermost row with four to eight teeth)]. Description: Morphometric data in Table 1. Body elongate and laterally compressed. Dorsal profile of body slightly convex from rear of head to vertical through middle of anal fin, and then posteroventrally aligned with tip of caudal filament. Ventral profile of body slightly concave from anterior margin of dentary to first anal-fin ray, then posteroventrally aligned with last anal-fin ray. Ventral profile of caudal filament nearly straight. Greatest body depth at vertical through distal margin of pectoral fin. Head laterally compressed with greatest width at opercular region and greatest depth at posterior margin of supraoccipital. Dorsal profile of head slightly convex from upper lip to vertical through branchial opening. Ventral profile of head slightly concave from anterior margin of lower lip to branchial opening. Snout rounded in profile. Mouth terminal. Upper lip slightly overlapping lower lip. Premaxillary teeth 24(1) or 25(1) distributed in four rows [outermost row with 5(2) teeth; second row with 6(1) or 8(1) teeth; third row with 6(1) or 7(1) teeth; innermost row with 7(1) or 8(1) teeth]. Maxilla with sickle-shaped anterodorsal process equal to 50% width of posterior nostril. Dentary teeth, 21(1) or 23(1) distributed in two rows [outermost row with 10(1) or 12(1) teeth; innermost row with 9(1) or 13(1) teeth]. Dentary teeth all similar in size. Coronomeckelian bone equal to 20% of length of Meckel’s cartilage. Endopterygoid with 14(1) or 15(1) teeth in two series. Mouth rictus at vertical through anterior nostril or in region between nares. Anterior naris tubelike, with posterior margin located at vertical through posterior margin of rictus or in median portion of rictus. Posterior naris elliptical, without tube, located closer to anterior margin of eye than snout tip. Eye approximately circular, covered by skin, laterally located on anterior one-half of head. Antorbital and infraorbitals 1–4 in form of enlarged, partial cylinders with slender osseous arches. Fifth and sixth infraorbitals slender and tubular. Depth of posterodorsal expansion on infraorbitals 1 + 2 equal to total length of infraorbitals 1 + 2. Branchial opening moderately elongate. Branchial membrane joined to isthmus, extending to inferior margin of branchial aperture. Anus and urogenital papilla shifting anteriorly ontogenetically. Anus and urogenital papilla at vertical through posterior margin of orbit in mature specimens. Cycloid scales present from immediately posterior to head to distal portion of caudal filament. Lateral line complete, with 112(6), 113(1), 118(1), 120(3), 121(1), 125(1), 128*(4), 130(1), or 132(2) perforated scales to vertical through end of anal fin. Longitudinal series of scales above lateral line, 8(7), 9(6), or 10*(7). Scales over anal-fin pterygiophores approximately one-half size of others. Pectoral-fin rays, ii,12*(18), ii,13(1), or ii,14(1). Distal margin of pectoral fin slightly rounded. Tip of pectoral fin reaching vertical through base of anal-fin rays 16– 20. Anal-fin origin immediately posterior to vertical through pectoral-fin base. Total anal-fin rays, 170– 198 (185*, N = 20; Table 2). Distal margin of anal fin approximately concave. Caudal filament cylindrical, tapering gradually distally, relatively short, and approximately 25% LEA in mature specimens. Precaudal vertebrae 11(1) or 12(1). Anterior vertebrae 9(2), transitional vertebrae 2(1) or 3(1). Displaced haemal spines 3(2). Coloration in alcohol: Background colour dark yellow. Dorsal region of head dark brown; gradually becoming lighter ventrally. Lips and suborbital region light brown. Dorsal region of body dark brown, gradually becoming lighter in region overlying anal-fin pterygiophores. Four longitudinal dark stripes along body. Lateral-line stripe thin, one scale deep, extending from first perforated lateral-line scale to distal portion of caudal filament. Superior medial stripe moderately thick, two scales deep, tapering from vertical between base of anal-fin rays 20–28 to posterior onethird of body. Superior medial stripe hardly discernible in specimens over 85.0 mm LEA. Inferior medial stripe thin, one scale deep, extending from vertical through base of anal-fin rays 13–17 to posterior onethird of body. Anal-fin base stripe thick, two scales deep, extending from vertical between base of anal-fin rays 9– 14 to last anal-fin ray. Pectoral and anal fins hyaline, with scattered tiny chromatophores on interradial membranes. Distribution: Eigenmannia desantanai sp. nov. is known only from Rio Cuiabá, Rio Paraguay basin, Mato Grosso, Brazil (Fig. 6). Etymology: The epithet ‘ desantanai ’ is in honour of Carlos David de Santana, in recognition of his contributions to our knowledge of the Gymnotiformes. Material examined Holotype: Brazil. Mato Grosso: MPEG 31306, 129.2 mm LEA, Rio Cuiabá, Baía de Chacororé, Rio Paraguai basin, Município de Barão de Melgaço, 16°14′58.9″ S, 55°52′44.4″ W, collected by Nupélia’s team, 20 October 2003. Paratypes: Brazil. Mato Grosso: NUP 12500, 9, 78.3– 106.1 mm LEA, collected with holotype. NUP 3470, 9 + 1CS, 119.8–142.8 mm LEA, Rio Cuiabá, Rio Paraguai basin, Município de Santo Antônio do Leverger, 15°58′26″ S, 55°56′26″ W, collected by Nupélia’s team, 24 October 2002; MPEG 31164, 1 + 1CS, 136.1– 136.8 mm LEA, collected with NUP 3470.

KEY TO THE SPECIES OF EIGENMANNIA TRILINEATA SPECIES GROUP 1a. Pectoral fin dusky or with conspicuous dark blotch; anal fin uniformly darkened............................................................. Eigenmannia matintapereira sp. nov. (Rio Uneiuxi and Rio Urubaxi, Rio Negro basin, Brazil) 1b. Pectoral and anal fins hyaline............................................................................................................2 2a. Mouth subterminal...........................................................................................................................3 2b. Mouth terminal............................................................................................................................... 4 3a. Body depth at vertical through the tip of the longest pectoral-fin ray, 14.9–18.7% LEA; nine or ten longitudinal series of scales above lateral line............................................................................................................................. Eigenmannia waiwai sp. nov. (Rio Mapuera and Rio Trombetas, Rio Trombetas basin, Brazil) 3b. Body depth at vertical through the tip of the longest pectoral-fin ray, 10.5–14.5% LEA; seven or eight longitudinal series of scales above lateral line..................................................................................................................................... Eigenmannia vicentespelaea (caves of São Vicente I and II, Rio Tocantins basin, Brazil) 4a. Suborbital depth, 29.9–46.6% HL........................................................................................................5 4b. Suborbital depth, 18.2–28.9% HL........................................................................................................6 5a. Total number of premaxillary teeth 31–33, arranged in four rows; total number of dentary teeth 31; length of coronomeckelian bone 20% length of Meckel’s cartilage..................................................................................... Eigenmannia trilineata (Río Yabebury and Río San Javier, Rio Paraná basin; and Río de La Plata basin, Argentina) 5b. Total number of premaxillary teeth 16 arranged in three rows; total number of dentary teeth 16; length of coronomeckelian bone 45% length of Meckel’s cartilage................................................................................................................................................... Eigenmannia microstoma (Rio São Francisco basin, Brazil) 6a. Inferior medial stripe, one scale high; precaudal vertebrae 11–12............................................................................................................ Eigenmannia desantanai sp. nov. (Rio Cuiabá, Rio Paraguai basin, Brazil) 6b. Inferior medial stripe, two or three scales high; precaudal vertebrae 13–15................................................7 7a. Pectoral-fin rays, ii,11–12.................................................................................................................. 8 7b. Pectoral-fin rays, ii,13–15..................................................................................................................9 8a. Orbital diameter 15.4–19.4% HL; 170–198 anal-fin rays; eight or nine endopterygoid teeth; 13–14 precaudal vertebrae...... Eigenmannia muirapinima sp. nov. (Igarapé Santo Antônio and Lago Jará, Rio Amazonas basin, Brazil) 8b. Orbital diameter 11.4–15.0% HL; 151–170 anal-fin rays; five or six endopterygoid teeth; 15 precaudal vertebrae.................... Eigenmannia guairaca sp. nov. (Riacho Água do Ó, upper Rio Paraná basin, Brazil) 9a. Width of mouth, 20.0–25.1% HL; 11–13 premaxillary teeth........................................................................................................................ Eigenmannia antonioi sp. nov. (Rio Anapu, Rio Amazonas basin, Brazil) 9b. Width of mouth, 10.8–19.0 HL; 15–21 premaxillary teeth.......................................................................................................................... Eigenmannia pavulagem sp. nov. (Rio Capim, Rio Guamá basin, Brazil), Published as part of Peixoto, Luiz Antônio Wanderley, Dutra, Guilherme Moreira & Wosiacki, Wolmar Benjamin, 2015, The Electric Glass Knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species, pp. 384-414 in Zoological Journal of the Linnean Society 175 (2) on page 387, DOI: 10.1111/zoj.12274, http://zenodo.org/record/6497627

EIGENMANNIA DESANTANAI SP. NOV. (FIGS 7, 8; TABLE 1) Diagnosis: Eigenmannia desantanai can be distinguished from other species in the E. trilineata species group by the inferior medial stripe, which is one scale deep (versus two or three scales deep). Eigenmannia desantanai can be further distinguished from the other members of the species group, except for E. waiwai, by the 11 or 12 precaudal vertebrae (versus 13 or 14 in E. antonioi; 15 in E. guairaca, E. muirapinima, and E. vicentespelaea; 13 in E. matintapereira; 14 or 15 in E. microstoma and E. trilineata; and 13–15 in E. pavulagem). Eigenmannia desantanai can be differentiated from E. waiwai by the terminal mouth (versus subterminal); the orbital diameter 14.5– 19.6% HL (versus 22.6–28.8%); the length of the anterodorsal process of the maxilla equal to 50% of the width of the posterior nostril (versus 1.5 times the width of the posterior nostril); the depth of the posterodorsal expansion on infraorbitals 1 + 2 approximately equal to the total length of infraorbitals 1 + 2 (versus less than 50% of the length of infraorbitals 1 + 2); and by the dentition pattern of the dentary with 21– 23 teeth distributed in two rows (outermost row with ten to 12 teeth; innermost row with nine to 13 teeth) [versus 37 or 38 teeth distributed in four rows (outermost row with seven teeth; second with 11–15 teeth; third with eight to 15; innermost row with four to eight teeth)]. Description: Morphometric data in Table 1. Body elongate and laterally compressed. Dorsal profile of body slightly convex from rear of head to vertical through middle of anal fin, and then posteroventrally aligned with tip of caudal filament. Ventral profile of body slightly concave from anterior margin of dentary to first anal-fin ray, then posteroventrally aligned with last anal-fin ray. Ventral profile of caudal filament nearly straight. Greatest body depth at vertical through distal margin of pectoral fin. Head laterally compressed with greatest width at opercular region and greatest depth at posterior margin of supraoccipital. Dorsal profile of head slightly convex from upper lip to vertical through branchial opening. Ventral profile of head slightly concave from anterior margin of lower lip to branchial opening. Snout rounded in profile. Mouth terminal. Upper lip slightly overlapping lower lip. Premaxillary teeth 24(1) or 25(1) distributed in four rows [outermost row with 5(2) teeth; second row with 6(1) or 8(1) teeth; third row with 6(1) or 7(1) teeth; innermost row with 7(1) or 8(1) teeth]. Maxilla with sickle-shaped anterodorsal process equal to 50% width of posterior nostril. Dentary teeth, 21(1) or 23(1) distributed in two rows [outermost row with 10(1) or 12(1) teeth; innermost row with 9(1) or 13(1) teeth]. Dentary teeth all similar in size. Coronomeckelian bone equal to 20% of length of Meckel’s cartilage. Endopterygoid with 14(1) or 15(1) teeth in two series. Mouth rictus at vertical through anterior nostril or in region between nares. Anterior naris tubelike, with posterior margin located at vertical through posterior margin of rictus or in median portion of rictus. Posterior naris elliptical, without tube, located closer to anterior margin of eye than snout tip. Eye approximately circular, covered by skin, laterally located on anterior one-half of head. Antorbital and infraorbitals 1–4 in form of enlarged, partial cylinders with slender osseous arches. Fifth and sixth infraorbitals slender and tubular. Depth of posterodorsal expansion on infraorbitals 1 + 2 equal to total length of infraorbitals 1 + 2. Branchial opening moderately elongate. Branchial membrane joined to isthmus, extending to inferior margin of branchial aperture. Anus and urogenital papilla shifting anteriorly ontogenetically. Anus and urogenital papilla at vertical through posterior margin of orbit in mature specimens. Cycloid scales present from immediately posterior to head to distal portion of caudal filament. Lateral line complete, with 112(6), 113(1), 118(1), 120(3), 121(1), 125(1), 128*(4), 130(1), or 132(2) perforated scales to vertical through end of anal fin. Longitudinal series of scales above lateral line, 8(7), 9(6), or 10*(7). Scales over anal-fin pterygiophores approximately one-half size of others. Pectoral-fin rays, ii,12*(18), ii,13(1), or ii,14(1). Distal margin of pectoral fin slightly rounded. Tip of pectoral fin reaching vertical through base of anal-fin rays 16– 20. Anal-fin origin immediately posterior to vertical through pectoral-fin base. Total anal-fin rays, 170– 198 (185*, N = 20; Table 2). Distal margin of anal fin approximately concave. Caudal filament cylindrical, tapering gradually distally, relatively short, and approximately 25% LEA in mature specimens. Precaudal vertebrae 11(1) or 12(1). Anterior vertebrae 9(2), transitional vertebrae 2(1) or 3(1). Displaced haemal spines 3(2). Coloration in alcohol: Background colour dark yellow. Dorsal region of head dark brown; gradually becoming lighter ventrally. Lips and suborbital region light brown. Dorsal region of body dark brown, gradually becoming lighter in region overlying anal-fin pterygiophores. Four longitudinal dark stripes along body. Lateral-line stripe thin, one scale deep, extending from first perforated lateral-line scale to distal portion of caudal filament. Superior medial stripe moderately thick, two scales deep, tapering from vertical between base of anal-fin rays 20–28 to posterior onethird of body. Superior medial stripe hardly discernible in specimens over 85.0 mm LEA. Inferior medial stripe thin, one scale deep, extending from vertical through base of anal-fin rays 13–17 to posterior onethird of body. Anal-fin base stripe thick, two scales deep, extending from vertical between base of anal-fin rays 9– 14 to last anal-fin ray. Pectoral and anal fins hyaline, with scattered tiny chromatophores on interradial membranes. Distribution: Eigenmannia desantanai sp. nov. is known only from Rio Cuiabá, Rio Paraguay basin, Mato Grosso, Brazil (Fig. 6). Etymology: The epithet ‘ desantanai ’ is in honour of Carlos David de Santana, in recognition of his contributions to our knowledge of the Gymnotiformes. Material examined Holotype: Brazil. Mato Grosso: MPEG 31306, 129.2 mm LEA, Rio Cuiabá, Baía de Chacororé, Rio Paraguai basin, Município de Barão de Melgaço, 16°14′58.9″ S, 55°52′44.4″ W, collected by Nupélia’s team, 20 October 2003. Paratypes: Brazil. Mato Grosso: NUP 12500, 9, 78.3– 106.1 mm LEA, collected with holotype. NUP 3470, 9 + 1CS, 119.8–142.8 mm LEA, Rio Cuiabá, Rio Paraguai basin, Município de Santo Antônio do Leverger, 15°58′26″ S, 55°56′26″ W, collected by Nupélia’s team, 24 October 2002; MPEG 31164, 1 + 1CS, 136.1– 136.8 mm LEA, collected with NUP 3470., Published as part of Peixoto, Luiz Antônio Wanderley, Dutra, Guilherme Moreira & Wosiacki, Wolmar Benjamin, 2015, The Electric Glass Knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species, pp. 384-414 in Zoological Journal of the Linnean Society 175 (2) on pages 392-394, DOI: 10.1111/zoj.12274, http://zenodo.org/record/6497627

Peixoto, Luiz Antônio Wanderley, Dutra, Guilherme Moreira, Wosiacki, Wolmar Benjamin (2015): The Electric Glass Knifefishes of the Eigenmannia trilineata species-group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species. Zoological Journal of the Linnean Society 175 (2): 384-414, DOI: 10.1111/zoj.12274, URL: http://dx.doi.org/10.1111/zoj.12274