Gephyrocharax venezuelae Schultz 1944
Creators: name: Vanegas-Ríos, James A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Characiformes
Characidae
Gephyrocharax
Gephyrocharax venezuelae

description: Gephyrocharax venezuelae Schultz, 1944
(Figs. 33–34)
Gephyrocharax venezuelae Schultz, 1944: 323 –326, table 20, fig. 44 [key, original description, holotype USNM 121369, type locality: “Río San Juan at the bridge south of Mene Grande, Motatán system” (= Venezuela: Trujillo, Lake Maracaibo system, Motatán basin, San Juan River at bridge south of Mene Grande)]. Taphorn & Lilyestrom, 1984: 13 [key]. Weitzman & Fink, 1985: 29, 104 [comments on morphology of males, examined material]. Burns, Weitzman, Grier & Menezes, 1995: 133 –135 [spermatozoid morphology, evidence of insemination]. Bonilla-Rivero & López-Rojas, 1997: 45 –49 [description of sexual dimorphism]. Bonilla-Rivero & López-Rojas, 2001: 1 –10 [morphological and genetic study]. Bushmann, Burns & Weitzman, 2002: 189 [gill gland morphology]. Weitzman, 2003: 225 [catalogue]. Lasso, Lew, Taphorn, DoNascimiento, Lasso-Alcalá, Provenzano & Machado-Allison, 2004: 152 [listed from Venezuela]. Rodríguez- Olarte, Coronel, Taphorn & Amaro, 2007: 2 [Venezuela: Caribbean versant, Tocuyo River]. Ortega-Lara, Lasso-Alcalá, Lasso, Pasquier, Bogotá-Gregory, 2012: [Colombia and Venezuela: Lake Maracaibo basin, Catatumbo River]. Bonilla- Rivero & López-Rojas, 2013: 487 –495, tables 1–4, figs. 1–3 [phylogeographically compared with remaining Venezuelan congeners]. Vanegas-Ríos, Azpelicueta, Mirande & Gonzales, 2013: 283 [examined material]. Thomaz, Arcila, Ortí & Malabarba, 2015: Add. File 5 [tentative classification].
Diagnosis. Gephyrocharax venezuelae differs from its congeners by the caudal peduncle blotch posteriorly extending beyond the midlength of the middle caudal-fin rays (vs. caudal peduncle blotch diffuse or, when well defined, only reaching the midlength of the middle caudal-fin rays), the absence of denticles on gill rakers (vs. presence of denticles), and the dorsal margin of the pouch scale in adult males located on the caudal-fin ray 12 or ventral to it (vs. dorsal margin of the pouch scale located dorsal to caudal-fin ray 12, except in G. atracaudatus and G. chocoensis). The species is also distinguished from G. atracaudatus, G. caucanus, G. chocoensis, G. intermedius, and G. valencia by having two tendinous fibers posteriorly inserted from flexor dorsalis superior to caudal-fin rays (vs. one tendinous fiber). The possession of an osseous lamella between the first and second basibranchials (vs. absence of this lamella) differentiates G. venezuelae from G. atracaudatus, G. melanocheir, and G. va l en c i a. From G. caucanus, G. melanocheir, G. t o r re s i, and G. valencia it is also distinguished by the pouch scale of adult males posterodorsally attaching via soft tissue (apparently connective) to a point on the caudal-fin ray 14 (vs. pouch scale attaching to a point on caudal-fin ray 13 or between caudal-fin rays 15 and 17).
Description. Morphometric data in Table 9. Largest male 39.7 mm SL, largest female 41.4 mm SL. Body laterally compressed, with maximum depth at vertical through point between anal- and pelvic-fin origins. Dorsal profile of head slightly convex from margin of upper lip to posterior tip of ascendant process of premaxilla, and straight from this point to tip of supraoccipital spine. Dorsal profile of body straight or slightly convex from posterior end of supraoccipital spine to dorsal-fin origin, slanting posteroventrally along dorsal-fin base, and straight from posteriormost dorsal-fin ray to caudal peduncle (Fig. 33). Ventral profile of body convex from tip of dentary to vertical crossing pelvic-fin origin, straight from this point to anal-fin origin, slanting posterodorsally and straight from this point to caudal peduncle origin. Anterior fontanel usually well developed, rarely reduced to narrow or medium-sized opening by anterior contact between frontals. Anterior nostril rounded and separated by skin fold from larger posterior nostril. Groove with at least three rows of neuromasts extending from half-length between posterior pore of nasal bone and nostrils to posterior portion of frontals. Small groove with few neuromasts located between nostrils and nasal bones.
Mouth superior, lower jaw projecting somewhat anterior to tip of upper jaw. Premaxilla with two rows of teeth. Outer row with 2 (18), 3* (35), or 4 (4) teeth, usually tricuspid, rarely bicuspid. Inner row with 4 (11), 5* (46), or 6 (1) teeth; symphyseal tooth tri- or tetracuspid, remaining teeth tetra- to hexacuspid. Maxilla with 1* (53) or 2 (4) teeth, tri- to pentacuspid (sometimes bicuspid) (Fig. 34 A). Maxilla posteriorly reaching vertical through anterior one-third of eye. Dentary with 9 (1), 10 (3), 11 (8), 12 (13), 13 (14), 14 (10), 15* (4), or 16 (1) teeth; three anteriormost teeth larger, pentacuspid, followed by one median-sized tooth tri- to pentacuspid, and 5 (1), 6 (3), 7 (8), 8 (13), 9 (14), 10 (10), 11* (4), or 12 (1) smaller conical to tricuspid teeth (Fig. 34 B).
Dorsal-fin rays ii,7 (4), 8* (58), or 9 (1). Nine* proximal pterygiophores on dorsal fin (6 rad, 5 c&s). Dorsalfin origin located at vertical between anal-fin rays 6–12. Adipose-fin origin located at vertical through base of posteriormost anal-fin rays or slightly anterior to this point. Anal fin-rays iv (35), v* (27), or vi (1), 25 (3), 26 (6), 27* (17), 28 (24), 29 (8), 30 (4), or 31 (1). Twenty-six to 32 proximal pterygiophores on anal fin (6 rad, 5 c&s). Anal-fin origin closer to origin of hypural joint than to snout tip. Pectoral-fin rays i,8 (17), 9* (38), or 10 (8). Pectoral-fin distal tip posteriorly reaching one-quarter to one-half of pelvic-fin length. Pelvic-fin rays i,6* (57), i,5 rarely in single specimen. Pelvic-fin origin located at vertical between pored lateral-line scales 9–10 and anterior to body midlength. Caudal fin forked with 10/9 principal rays in all specimens.
Scales cycloid, with numerous radii along posterior margin. Lateral line complete, pored scales 36 (5), 37 (17), 38 (11), 39 (13), 40* (9) or 41 (2). Terminal lateral-line tube present. Predorsal scales 16 (1), 17 (23), 18 (19), 19 (6), 20 (3), or 21 (2). Scale rows between dorsal fin and lateral line 5 (28) or 6* (28). Scale rows between lateral line and anal fin 4 (23) or 5* (33). Scale rows between lateral line and pelvic fin 3 (1), 4* (47), or 5 (4). Circumpeduncular scales 13 (4), 14 (34), or 15* (14). One row of 9 (1), 10 (1), 11 (2), 12 (2), 13 (1), 14 (4), 15 (9), 16 (6), 17 (3), 18 (1), or 19 (2) scales forming sheath along anal-fin base. Total number of vertebrae 38* (9), 39 (1), or 41 (1); 15* (9) or 16 (2) precaudal and 22 (1), 23* (9), or 25 (1) caudal (6 rad, 5 c&s). Gill-rakers on dorsal limb of first branchial arch 6* (24), 7 (12), or 8 (1); ventral limb with 11* (15), 12 (20), or 13 (2).
Color in alcohol. Ground color pale yellowish or light brown, darker along mid-dorsal line and slightly lighter ventrally. Minute dark chromatophores scattered over body, less so or absent on lateral and ventral regions of abdomen and ventral region of caudal peduncle. Dark midlateral stripe diffuse (silvery in specimens retaining guanine), extending from posterior region of humeral blotch to posterior region of caudal peduncle. Dark chromatophores present along myosepta between lateral line and upper portion of anal fin. Dark humeral blotch vertically elongate and narrow. Dark blotch on caudal peduncle, horizontally elongate, and extending from middle or posterior region of peduncle across interradialis muscles to tips of middle caudal-fin rays. Dorsal fin light gray, with dark chromatophores on membranes and rays. Anal fin light gray, with dark chromatophores more concentrated on interradial membranes than on rays. Caudal fin light gray, with dark chromatophores on membranes and rays. Pectoral and pelvic fins light gray, with few dark chromatophores mainly on rays. Head darker dorsally than ventrally. Dark chromatophores more concentrated on opercle and on margins of infraorbitals bordering eye. Premaxilla, anterior portion of maxilla, dentary, and lips with scattered dark chromatophores. Variations in color pattern between males and females not observed.
Color in life. Based on Schultz (1944) and Bonilla-Rivero & López-Rojas (1997). Dorsal portion of eye with bright orange spot. Black humeral blotch vertically elongate. Black blotch on caudal peduncle reaching distal portion of middle caudal-fin rays. Caudal-fin base with bright orange or crimson spot at each side of black midlateral stripe.
Sexual dimorphism. Males with bony hooks on anal-, caudal-, and pelvic-fin rays. Caudal fin with short, slender, and anterodorsally oriented hooks, especially on branched portions of rays 13–18 (Fig. 34 C). Pelvic-fin rays, except unbranched ray, with short, slender, anteroventrally oriented hooks on nearly entire length of rays, unpaired, absent or in minor proportion on bases of rays; hooks usually paired or one per segment. Anal fin with slender, anterolaterally placed hooks with broad bases; from 1 to 15 pairs per ray located on posteriormost unbranched ray and up to 12 anterior branched rays (larger hooks on middle rays of this range). In adult males, usually posteriormost unbranched anal-fin ray and up to middle branched rays slightly longer than remaining rays, resulting in convex-shaped margin. In females, anal-fin rays gradually decreasing in length from anteriormost branched ray to posteriormost branched ray; anal-fin margin somewhat concave or straight. Anal-fin base of adult males slightly concave or curved along its midlength, this base straight in females. Adult females without externally developed urogenital papillae.
Based on Bonilla-Rivero & López-Rojas (1997) following color features varying in life specimens: males with all fins brightly reddish but pectoral, pelvic, and adipose more faintly pigmented; females having all fins lightly yellowish but distal portion of six or seven anterior anal-fin rays with lightly reddish hue. Mature males with hypertrophied scale forming pouch on lower caudal-fin lobe and with ventral procurrent rays 2 and 3 forming spurshaped structure. Scarce small aggregations of apparent glandular tissue located on caudal-fin rays and medially to pouch scale. First ventral procurrent ray with concavity on its ventral margin (Fig. 34 C). Second ventral procurrent ray somewhat longer than third ray, reaching posteriorly midlength of first ventral procurrent ray, and flattened in sagittal plane, especially on its posterior portion. Posterior portion of third ventral procurrent ray weakly developed laterally. Pouch scale with 20–31 radii, usually located between caudal-fin ray 15 and third ventral procurrent ray. Posteroventral pouch-scale lobe well developed, extending posteriorly along third ventral procurrent ray (Figs. 34 C–D). Dorsal surface of pouch scale attached via soft tissue (apparently connective) to caudal-fin rays 10 or 12 to 14. Posterior margin of pouch scale between caudal-fin ray 14 and third ventral procurrent ray. Four scales in vertical series situated ventral to terminal lateral-line scale, overlapping posterior portion of pouch scale. Dorsal margin of pouch scale without notches. Females with large scale with 16 (1), 17 (1), 15 (1), 21 (1), or 22 (1) radii on lower caudal-fin lobe.
Mature males with gill gland (holotype with damaged filaments), formed by fusion of 6 (2), 7 (5), 8* (3), 9 (11), 10 (1), 11 (2), 12 (1), or 14 (1) anterior gill filaments of ventral limb of first gill arch. Total number of ventral limb gill filaments 20 (1), 21 (1), 22 (6), 23 (6), 24 (2), 25* (3), 26 (4), 27 (1), or 29 (1). Gill-gland length 2.7–4.8 % SL (mean = 3.5 % SL), 3.6* % SL. Regression comparisons of morphometric data by sex with major differences in pectoral fin to pelvic fin length (higher values in females than in males), but larger specimens not completely separating on SL axis.
Distribution. Gephyrocharax venezuelae is distributed in different drainages across the Gulf of Venezuela, Lake Maracaibo basin, and Caribbean versant in Colombia and Venezuela (Fig. 3). An additional record was mentioned by Bonilla-Rivero & López-Rojas (1997) from the Alpargatón River in Venezuela.
Remarks. Gephyrocharax valencia and G. venezuelae have been morphologically and genetically compared in different studies (Bonilla-Rivero & López-Rojas 2001, 2013; Bonilla-Rivero et al. 2002), which have confirmed that these species are distinct and phylogenetically related (although not as sister species). Bonilla-Rivero & López-Rojas (2001, 2013) and Bonilla-Rivero et al. (2002) have confirmed that G. valencia and G. venezuelae are sympatric species in the Tocuyo and Urama rivers basins, Caribbean versant in Venezuela.
The holotype and examined paratypes of G. venezuelae are in good conditions with the scales, rays, and teeth well preserved; some of the paratypes are slightly faded. During the examination of the lot USNM 121363, 10 of 11 paratype specimens reported by Schultz (1944), were identified as G. venezuelae (the other specimen corresponds to an unidentified species).
Material examined. Colombia: IAvH-P 9788, 9, 32.1–41.4 mm SL, Norte de Santander, middle Catatumbo basin, river before El Aserrío-Divisó, approximately 8°31'28.92"N 73°15'29.16"W 410 m a. s. l. ICNMHN 2401, 4, 22.6–30.7 mm SL, Norte de Santander, Corregimiento La Garraba, Brandy River, tributary of Catatumbo River, approximately 8°58'12.13"N 72°58'22.95"W 181 m a. s. l. ICNMHN 17668, 2, 28.1–28.7 mm SL, Norte de Santander, Cúcuta, Corregimiento Carmen de Tonchalá, place of Corponor, Lake Maracaibo system, Zulia River basin, approximately 7°51'1.17"N 72°34'11.64"W 246 m a. s. l. Venezuela: MBUCV 23840, 3, 18.0– 39.5 mm SL (1 c&s 39.5 mm SL), Zulia, Hacienda el Totumo, Sierra de Perijá, Lake Maracaibo system, Lajas River, approximately 10°33'27.93"N 72°27'21.17"W 305 m a. s. l. MBUCV 24079, 4, 21.4–27.3 mm SL, Venezuela, Falcón, Caribe versant, on route to El Tocuyo de La Costa, Tabaná River, approximately 11°0'7.56"N 68°21'15.81"W 5 m a. s. l. MBUCV 24258, 5, 28.2–31.0 mm SL (1 c&s 31.0 mm SL), Yaracuy, Caribe versant, Urama River at the bridge on Morón-San Felipe route, approximately 10°27'24.04"N 68°19'18.22"W 27 m a. s. l. UF 23804, 5, 19.3–30.2 mm SL, Mérida, Lake Maracaibo system, Onia River at the bridge of Onia, approximately 8°35'34.13"N 71°41'34.72"W 85 m a. s. l. USNM 121359, 1 paratype, 23.8 mm SL, [Zulia], Maracaibo basin, Apón River about 35 km S of Rosario, approximately 10°5'43.67"N 72°23'37.95"W 58 m a. s. l. USNM 121360, 1 paratype, 21.6 mm SL, [Caribe, Gulf of Venezuela, Zulia], mouth of Caño de Sagua, 35 km N of Sinamaica, approximately 11°18'2.24"N 71°57'6.77"W 3 m a. s. l. USNM 121361, 24 paratypes (25 in original description), 22.2–36.3 mm SL, collected with the holotype. USNM 121362, 11 paratypes, 22.2–34.9 mm SL, [Zulia], Palmar River near Totuma about 100 km SW of Maracaibo, approximately 10°27'37.67"N 72°16'52.19"W 65 m a. s. l. USNM 121363, 10 paratypes, 20.2–32.2 mm SL, [Trujillo], Motatán River, 4 km above Motatán, L. P. Schultz, 9°26'7.16"N 70°34'47.70"W 294 m a. s. l. USNM 121364, 43 paratypes (41 in original description), 20.4–34.4 mm SL, [Trujillo], Motatán River at the bridge 22 km N of Motatán, 9°25'4.70"N 70°34'58.68"W 334 m a. s. l. USNM 121365, 22 paratypes, 22.9–32.0 mm SL, [Trujillo], Motatán River 8 km below Motatán, approximately 9°21'42.61"N 70°35'47.61"W 366 m a. s. l. USNM 121366, 129 paratypes, 20.6–31.7 mm SL, [Zulia], Maracaibo basin, Negro River below mouth of Yasa River, approximately 9°41'20.59"N 72°25'26.26"W 26 m a. s. l. USNM 121367, 6 paratypes, 21.7–27.1 mm SL, [Zulia], San Juan River 12 km S of Rosario, approximately 10°12'23.63"N 72°19'8.45"W 63 m a. s. l. USNM 121368, 94 paratypes, 19.1–31.6 mm SL, [Zulia], Machango River at the bridge S of Lagunillas, approximately 9°56'48.23"N 71°5'36.14"W 8 m a. s. l. USNM 121369, holotype of Gephyrocharax venezuelae, 32.0 mm SL (rad), male, [Trujillo, Lake Maracaibo system], Motatán basin, San Juan River at the bridge S of Mene Grande, approximately 9°44'46.82"N 70°48'7.92"W 41 m a. s. l. USNM 121533, 3 paratypes, 26.6–28.1 mm SL, [Zulia], San Pedro River at the bridge S of Mene Grande, approximately 9°46'4.55"N 70°54'49.20"W 9 m a. s. l. USNM 236087 (previously USNM 121366), 3 c&s paratypes, 28.7–32.7 mm SL, [Zulia], Maracaibo basin, Negro River below mouth of Yasa River, approximately 9°41'20.59"N 72°25'26.26"W 26 m a. s. l. MCZ 37269 (previously USNM 121366), 5 paratypes, 29.0– 33.8 mm SL (5 rad), [Zulia], Maracaibo basin, Negro River below mouth of Yasa River (75 km on route S of Rosario), approximately 9°41'20.59"N 72°25'26.26"W 26 m a. s. l.
description: Published as part of Vanegas-Ríos, James A., 2016, Taxonomic review of the Neotropical genus Gephyrocharax Eigenmann, 1912 (Characiformes, Characidae, Stevardiinae) in Zootaxa 4100 (1) on pages 76-81, DOI: 10.11646/zootaxa.4100.1.1, http://zenodo.org/record/261565