Triportheus venezuelensis, Malabarba, 2004

Malabarba, Maria Claudia S. L., 2004, Revision of the Neotropical genus Triportheus Cope, 1872 (Characiformes: Characidae), Neotropical Ichthyology 2 (4), pp. 167-204 : 200-202

Triportheus venezuelensis , new species

Fig. 26

Holotype. INHS 34768 , 118.64 mm SL, Venezuela, Barinas, río Masparro , Apure drainage , 5 km NW Libertad on road to Barinas , 25 Jan 1995, L. M. Page, J. W. Armbruster, P. A. Ceas, K. S. Cummings & C. A. Mayer (08°20”N, 69°39”W).

Paratypes. Venezuela: Bolivar: USNM 270343 (17,65.7-83.4 mm SL), UNELLEZ 52000 (3 ,73-83.4 mm SL), small caño connecting with rio Orinoco immediately South of El Burro, 9 Dec 1984, R. Vari, O.Castillo & C.Ferraris (06°11’N, 67’25’W); INHS 35077 (4, 80.6-83.1 mm SL), laguna Castillero , 10 Jan 1988, M. Rodriguez (07°38’N, 66°09’W) . Apure: USNM 258079 (6,76-85 mmSL), río Apure , W of town center, 25 Jan 1983, O. Costillo et al. (7º53’N; 67º29’W) ; FMNH 85488 (10, 36.3-73.6 mm SL), river 24 km S of Biruaca on road to San Juan de Apayara , 7 Jan 1975, J. Thomerson & D.Taphorn (07°56’S, 67°5’W) . Monagas: USNM 233784 (12, 75.6-94.6mmSL); USNM 358223 (5,73.5-87.7mmSL) ; MCP 35842 (1, 82.4 mm SL), río Orinoco, laguna Tapatapa on Isla Tapatapa near downstream end of caño Limon , 16 Feb 1978, J. Lundberg & Lopez (8º32’N, 62º26’W) . Guarico: INHS 34573 (3, 68.1-69.8 mm SL), laguna Caricare , 14 Jan 1995, J. Armbruster, P. Ceas, M. Campos, R.Suarez & J. Llerandi (7º50’N, 66º32’W) ; INHS 34484 (2, 82.4-83.1 mm SL), río San Bortolo at Águas Muertas , 8 Jan 1995, L. M.Page et al. (08º04’ N, 40º50’ W) ; INHS 35294 (3 ,74.3- 77.9 mm SL), río Orinoco , laguna Larga Ii , 12 Jan 1987, M. A. Rodríguez & S. Richardson (07º38’N, 66º13”W); INHS 35114 (8, 63.1-77.3 mm SL), río Aguaro , P. N. Aguaro-Guariquito en El Paso, L. M. Page et al., 11 Jan 1995 (07º50’N, 66º30’W) .

Diagnosis. A deep-bodied Triportheus species reaching 94.9 mm SL (depth at dorsal-fin origin,26.7-37.6, mean = 32.9% SL, n = 54; depth at pectoral-fin insertion, 29.2-38.4,mean = 36.1% SL, n = 55). The presence of 2 longitudinal scale rows between the pectoral-fin insertion and the ventral keel distinguish this species from elongate-bodied Triportheus species that have 1 longitudinal scale row between the pectoral-fin insertion and the ventral keel. Triportheus venezuelensis is distinguished among deep bodied congeners by the combination of the number of gill rakers on the lower limb of the first gill arch (27-33, mean = 30.1, n = 55); the number of branched anal-fin rays (24-27, mean = 25.6, n = 54); and thenumberoflateral-linescales(33.0-36.0, mean = 34.0 n = 51).

Description. Morphometric data for Triportheus venezuelensis presented in Table 18. Body deep and compressed laterally. Greatest body depth located slightly posterior to vertical through pectoral-fin insertion. Dorsal profile of head straight from upper lip to rear of head. Dorsal profile of body gently curved from rear of head to dorsal-fin origin; posteroventrally slanted from dorsal-fin origin to caudal peduncle; curved along caudal peduncle. Dorsal portion of body slightly keeled.

Ventral profile of head straight from tip of lower lip to anteroventral margin of dentary. Ventral profile of head and body arched from base of dentary to pelvic-fin insertion; slightly curved or almost straight from pelvic-fin insertion to anal-fin origin; posterodorsally slanted along anal-fin base; straight along caudal peduncle. Prepelvic region expanded ventrally and strongly keeled.

Head blunt in profile; posterior margin of opercle almost reaching vertical through pectoral-fin insertion. Snout vertically straight. Mouth terminal; upward. Lower jaw as long as upper jaw. Nostrils of each side close together; anterior opening circular; posterior elongate.

Gill rakers thick and separated; length equivalent to one-half of length of branchial filament; gill rakers on lower limb of first arch 27-33 [32] (mean = 30.1, n = 55).

Teeth on premaxilla in 3 rows; with teeth of inner row largest. Five tricuspidate teeth of outer row arranged along external margin of mouth and externally visible in closed mouth. Medial row with 3 tricuspidate teeth. Seven multicuspidate teeth on inner row on premaxilla. Maxilla with 2-3 tricuspidate teeth smaller than those on premaxilla. Teeth on lower jaw in 2 rows, outer row with 5 medial teeth, followed by 3-4 much smaller, tricuspidate teeth. Inner row consisting of conical posteriorly curved symphyseal tooth.

Scales cycloid, thin, and large. Lateral line distinctly decurved ventrally, completely pored from supracleithrum to base of caudal-fin rays. Thirty-three to 36 [33] (mean = 34.1, n = 50) scales in lateral line; 5-6 scale series between lateral line and dorsal-fin origin; two scale rows between lateral line and pelvic-fin insertion. Two scale rows between pectoral-fin insertion and midventral keel; 4-5 scale series on caudal peduncle. Scales along mid-dorsal line very irregularly arranged with PROOFS 6-12 scales from tip of supraoccipital spine to dorsal-fin origin.

Dorsal-fin rays ii,9; anal-fin rays iii,24-27 [25] (mean = 25.6, n = 54); pectoral-fin rays i,10-12 [10] (mean = 11.6, n = 50); pelvic-fin rays i,6. Base of dorsal-fin situated on posterior onehalf of body; base of last dorsal-fin ray located anterior to vertical through anal-fin origin; second unbranched and first branched ray longest with following rays gradually decreasing in length. Pectoral fin pointed with tip extending posteriorly as far as vertical through middle of pelvic fin. Anal-fin margin slightly curved, first branched anal-fin ray longest with following rays gradually decreasing in length. One or 2 series of scale overlaying basal portions of anal-fin rays. Margin of caudal fin truncate with median rays extending for one-half of their length beyond margin of remainder of fin.

Total vertebrae 38.

Coloration in alcohol. Overall ground color yellowish brown. Snout and dorsal portion of head dark. Some scattered dark chromatophores present on opercle and postorbital region. Concentration of chromatophores forming diffuse stripe extending from supracleithrum to caudal peduncle; stripe broadened into wider dark spot on lateral surface of caudal peduncle. Body darker dorsal to midlateral stripe. Dorsal-fin rays outlined by dark chromatophores. Scattered dark chromatophores distributed all over pectoral fin; with more intense dark pigmentation on first unbranched ray and along fin margin. Some dark chromatophores outlining anal-fin rays. Median caudal-fin rays dark.

Distribution. Río Orinoco basin ( Fig. 12 ).

Etymology. Species name, venezuelensis , refers to the country drained by Río Orinoco and must be considered in apposition to the genus name

Figures

Fig. 26. Triportheus venezuelensis, holotype, INHS 34768, 118.64 mm SL, Venezuela, Barinas, río Masparro, ríoApure drainage, 5 km NW of Libertad on road to Barinas.

Fig. 12. Map of central and northern South America showing geographic distribution of T. culter (circles; asterisk = type-locality), T. albus (squares; asterisk = type-locality), T. nematurus (triangles; diamond = type-locality) and T. venezuelensis (lozenges; white square = type-locality) (some symbols represent more than one locality or lot of specimens).