Hemibrycon metae Myers, 1930

Bertaco, Vinicius A. & Malabarba, Luiz R., 2010, A review of the Cis-Andean species of Hemibrycon Günther (Teleostei: Characiformes: Characidae: Stevardiinae), with description of two new species, Neotropical Ichthyology 8 (4), pp. 737-770 : 752-754

Hemibrycon metae Myers, 1930

Figs. 14-15

Hemibrycon metae Myers, 1930: 68-69 (original description; diagnosis; type locality: Guaiacaramo , río Guavio, Colombia).

Hemibrycon dentatus metae . - Schultz, 1944: 362-363 (table 27; in key; new subspecies; non-type material examined).

Diagnosis. Hemibrycon metae is distinguished from most of its congeners by the number of branched anal-fin rays (25-31 vs. 15-24, Fig. 2 ). From the species sharing similar branched anal-fin rays counts, it differs from H. boquiae by the number of caudal peduncle scales (16 vs. 14), and by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5); from H. brevispini by the number of cusps of three anteriormost dentary teeth (5 vs. 3), and by absence of bony hooks in the caudal-fin rays (vs. presence); from H. cairoense by the number of lateral line scales (40-43 vs. 43-46), and by the number of cups of first dentary teeth (5 vs. 3); from H. dariensis by the absence of pigment in the distal tip of rays just above and below to middle caudal-fin rays; from H. dentatus , and H. huambonicus by the number of lateral line scales (40-43 vs. 44-50); from H. divisorensis and H. surinamensis by the absence of a wide black asymmetrical spot covering base of caudal-fin rays; from H. inambari by the of gill rakers (19-21 vs. 16-18) and by the number of scales along anal-fin base scale sheath (10-19 vs. 6-10); from H. jabonero by the number of caudal peduncle scales (16 vs. 14), and the number of scale rows below lateral line (5-7 vs. 4- 5); from H. jelskii by the size of humeral spot (5-6 vs. 7-9 horizontal series of scales); from H. polyodon by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5), caudal peduncle length (11.1-14.8 vs. 14.4-16.6% SL), and head length (22.1-25.0 vs. 20.9-22.9% SL); from H. quindos by the number of cusps of premaxillary inner row teeth (5-7 vs. 3- 4); from H. raqueliae by the number of predorsal scales (14- 16 vs. 10-13) and by the number of cusps of first maxillary tooth (3 vs. 5); and from H. taeniurus by the number of cusps of second tooth of premaxillary inner row teeth (7 vs. 5), and by the humeral spot size (5-6 vs. 4-5 horizontal series of scales).

Description. Morphometric data for H. metae summarized in Table 4. Largest male 79.7 mm SL, largest female 93.1 mm SL. Body compressed and moderately elongate; greatest body depth anterior to dorsal-fin origin. Dorsal profile of head slightly convex. Dorsal body profile convex from occipital bony to base of last dorsal-fin ray; straight from this point to adipose-fin origin. Ventral profile of head slightly convex. Ventral body profile convex from pectoral-fin origin to pelvicfin origin, and straight to slightly convex to anal-fin origin. Body profile along anal-fin base posterodorsally slanted. Caudal peduncle elongate, nearly straight to slightly concave along dorsal and ventral margins.

Snout rounded from margin of upper lip to vertical through anterior nostrils. Head small. Mouth terminal, mouth slit nearly at horizontal through middle of eye. Maxilla long and slightly curved, aligned at angle of approximately 45º to longitudinal body axis, and its posterior tip extending below orbit, reaching nearly to vertical through center of eye.

Premaxilla with two tooth rows; outer row with 4-5, tri- to pentacuspid teeth with central cusp slightly longer; inner row with 4 penta- to heptacuspids teeth, gradually decreasing in length from first to third teeth and last smaller; central cusp twice or three times longer and broader than other cusps. Maxilla toothed with 6-11 uni- to pentacuspid teeth, with central cusp longer. Three anteriormost dentary teeth larger, with 5 cusps, followed by medium sized tooth with 3-5 cusps, and 8-10 teeth with 1-3 cusps or conical; central cusp in all teeth two to three times longer and broader than other cusps. Cusp tips slightly curved posteriorly and lingually ( Fig. 15 ).

Dorsal-fin rays ii,8 (n = 104); first unbranched ray approximately one-half length of second ray. Dorsal-fin origin located posterior to middle of SL and posterior to vertical through pelvic-fin origin. Profile of distal margin of dorsal fin nearly straight to slightly concave. Males with bony hooks in distal one-third of first branched rays. Adipose-fin located at vertical through insertion of last anal-fin rays. Anal-fin rays ii-vi,25-30 (one with 24 and two with 31, mode = 28, n = 104, Fig. 2 ). Analfin profile slightly concave in males and females.Anal-fin origin approximately at vertical through insertion in the last dorsal fin rays. Anal-fin rays of males bearing one pair of small bony hooks along posterolateral border of each segment of lepidotrichia, along last unbranched ray and eighth to twelfth branched rays. Hooks usually located along posteriormost branch and distal 1 / 2 to 2 / 3 of each ray. Pectoral-fin rays i,10-13 (mode = 11, n = 104). Pectoral-fin tip surpassing pelvic-fin origin

V. A. Bertaco & L. R. Malabarba 753

in males and nearly reaching in females. Males with bony hooks on distal portion of unbranched and all branched rays. Pelvicfin rays i,6,i (three with i,7,i and two with i,6, n = 104). Pelvic-fin origin located 4-5 predorsal scales anterior to vertical through dorsal-fin origin. Pelvic fin of males usually bearing 1 small bony hook per segment of lepidotrichia along ventromedial border of second to eighth branched rays. Caudal fin forked with 19 principal rays without bony hooks (n = 104); lobes similar in size. Caudal-fin base have a few scales. Dorsal procurrent rays 11-12 and ventral procurrent rays 10-11 (n = 5).

Scales cycloid, moderately large. Lateral line complete with 40-43 (mode = 42, n = 89, Fig. 3). Scale rows between dorsal-fin origin and lateral line 7-8 (mode = 8, n = 103); scale rows between lateral line and pelvic-fin origin 5-6 (rarely 7, mode = 6, n = 103). Predorsal scales 14-16, arranged in regular series (mode =15,n = 94). Scales rows around caudal peduncle 16 (n = 96).Axillary scale on pelvic-fin origin extends posteriorly covering 2-4 scales. Scale sheath along anal-fin base with 10-19 scales in single series, extending to base of most anterior branched rays.

Precaudal vertebrae 17-18; caudal vertebrae 22-24; total vertebrae 39-41 (n = 6). Supraneurals 6-8 (n = 6). Gill rakers on upper limb of outer gill arch 7-8, and on lower limb 12-13 (n = 19).

Color in alcohol. Holotype discolored. General ground body color brown yellowish. Color based on the non-type specimens. General ground body color yellowish. Dorsal portion of head and body with concentration of black chromatophores. Dorsolateral portion of head and body with scattered black chromatophores. One large and vertical black humeral spot, located over third to fifth lateral line scales and extending over 5-6 horizontal series of scales, including lateral line. Midlateral dark stripe extending from humeral region to middle caudal-fin rays, broad in the caudal peduncle. Abdominal region almost devoid of black chromatophores. Dorsal and caudal fin with dark pigmentation diffuse and anal fin with small black chromatophores along its border forming narrow stripe.Pectoral, pelvic and adipose fins hyaline ( Fig. 14 ).

Sexual dimorphism. Males of Hemibrycon metae are easily recognized by the presence of bony hooks on the dorsal-, pectoral-, anal- and pelvic-fin rays. Males and females also slightly differ in pectoral- and pelvic-fin lengths, and body depth ( Table 4). Mature males with gill gland on first gill arch, covering the first branchial filaments ( Fig. 7 ).

Distribution. Hemibrycon metae is known from río Orinoco basin, Venezuela and Colombia, and Caribbean coastal basins of Venezuela ( Fig. 4 ).

Remarks. Hemibrycon metae was proposed by Myers (1930) from río Guavio, río Meta drainage, Guaiacaramo, Colombia based only in the holotype.We have compared the populations from río Meta and río Apure, two large rivers from río Orinoco basin, and did not find differences in meristic and morphometric characters.

754 A review of the Cis-Andean species of Hemibrycon

In this study some Hemibrycon populations were identified from small coastal river basins in the Golfo de Paria, Venezuela. All these specimens do not exceed 51.3 mm SL, being smaller than río Orinoco specimens, and difficult to compare regarding body measurements. In relation to scales and maxillary tooth number, this population is more similar to H. metae than H. taeniurus from Trinidad Island. Samples of large specimens from coastal basins of Venezuela are necessary to confirm whether those populations are indeed conspecific. However, we tentatively assign the examined specimens from that area to H. metae .

Material examined. Holotype. CAS 123727 (ex-SU 23727), female (x-ray), 77.2 mm SL, at junction of río Guavio and río Upía, río Meta drainage, río Orinoco basin, Guaiacaramo, Colombia, ca. 04º43’N 73º02’W, Jan 1928, H. A. Maria. Nontype specimens. Colombia. Meta, río Meta drainage: IAvH-P 2973, 7, 53.1-76.0 mm SL, quebrada Palmicha, afluente del río Unete , Casanare, ca. 05º10’N 72º30’W, 1 Aug 1984. IAvH-P 3122 , 10 , 47.6 -93.0 mm SL, quebrada Chichaca afluente del río Cachiza , Aguazul, Casanare, ca. 05º15’N 72º29’W, 1 Mar 1994. IAvH-P 3322 , 10 , 51.3 -70.0 mm SL, quebrada Guamalera, Yopal, Casanare, ca. 05º21’N 72º23’W, 1 Aug 1993. IAvH-P 3628 , 25 , 45.0- 70.6 mm SL, río Unete , Casanare, ca. 05º10’N 72º30’W, 1 Aug 1993. IAvH-P 3632 , 65 , 45.0- 86.8 mm SL, ríos Tocaria, Charte and Cravo Sur drainages, ca. 05º20’N 72º20’W, 18 Aug 1995. NRM 23991, 1 , 48.8 mm SL, caño Candelaria tributary to río Negro , ca. 20 km SW of Villavicencio, ca. 04º5’N 73º42’W, 10 Jan 1988. NRM 23993, 1 , 67.3 mm SL, caño Union tributary to río Ocoa , where crossed by road Villavicencio -Acacias, ca. 04º00’N 73º43’W, 6 Jan 1988. Venezuela. Río Orinoco basin, río Apure drainage: INHS 27766 , 30 of 51, 29.4-45.8 mm SL, caño Curito at Ruta 5, Barinas, 07º58’41”N 71º00’05”W, 7 Jan 1992. INHS 31851 , 12 , 27.0- 44.5 mm SL, río La Yuca 17 km N Barinas, Barinas, 08º46’00”N 70º15’00”W, 31 Dec 1993. INHS 61270 , 22 of 28, 30.7-61.4 mm SL, río Santa Barbara 3 km NE Santa Barbara, Barinas, 07º50’14”N 71º11’14”W, 7 Jan 1992. MCNG 98 , 10 of 27, 34.4-43.9 mm SL, 1 km al S carretera 5, via Cd Bolivia, Barinas, 08º20’8”N 70º31’04”W, 13 Jun 1979. MCNG 5646 , 17 of 54, 29.5-47.0 mm SL, río Tucupido en Las Canoas, Portuguesa, 09º03’00”N 70º05’30”W, 18 Mar 1982. MCNG 6759 , 23 of 73 (3 c&s), 25.5-49.5 mm SL, río Tinaco , carretera entre Tinaco y Tinaquillo, entre San Carlos e Valencia, Cojedes, Tinaco , 09º48’10”N 68º23’50”W, 3 Feb 1982. MCNG 7923 , 12 of 64 (2 c&s), 44.5-71.6 mm SL, caño Grande en Finca Cano Grande , Barinas, Pedraza, 08º24’10”N 70º39’25”W, 7 Dec 1982. USNM 121466 , 18 , 35.6-50.5 mm SL, río Guárico and tributaries between San Sebastian and San Casemiro, Aragua, ca. 09º57’N 67º11’W, 12 May 1942. USNM 121467 , 12 of 117, 42.7-72.8 mm SL, río Torbes , 1 km above Táriba, Tachira, ca. 07º40’N 72º15’W, 31 Mar 1942. Golfo de Paria coastal basin: USNM 228563 , 16 of 21, 38.3-52.4 mm SL, Sucre, Clavellino reservoir Sucre, 29 Sep 1979. MCNG 17030 , 20 of 58 (3 c&s), 27.3- 49.2 mm SL, Sucre, Benitez, El Pilar , río Pilar , ca. 10º32’N 63º08’W, 28 Aug 1984. MCNG 17035 , 20 of 76 (3 c&s), 30.0- 46.9 mm SL, Sucre, Libertador, caño 20 km E de El Pilar, ca. 10º35’N 63º04’W, 28 Aug 1984. MCNG 16796 , 10 of 19, 30.3-50.2 mm SL, Sucre, Benitez, caño 3 km S de El Pilar, ca. 10º30’N 63º07’W, 29 Aug 1984. CAS 70096, 58 , 35.0- 64.9 mm SL, Miranda, río Tiquirito at Concejo , a tributary of the Tuy River , 1 Aug 1918. FMNH 105860 , 52 , 21.4- 46.7 mm SL, Venezuela , Monagas, río Azuma at edge of municipio Punceres on road to Caripito , 8 Aug 1985. MNHN 1920.0002 , 1 , 67.4 mm SL.

Figures

Fig. 14. Hemibrycon metae, INHS 61270, female, 61.4 mm SL, río Apure basin, Venezuela.

Fig. 15. Hemibrycon metae, MCNG 17030, female, 39.8 mm SL. Scanning electron micrograph of right side upper and lower jaws. Scale bar = 1 mm.

Fig. 2. Tukey box plots of number of branched anal-fin rays in Hemibrycon species. Mean represented by thick vertical bar, and 25th and 75th percetiles as lateral borders of box plots. Number in parentheses = N.

Fig. 7. First gill arch showing gill gland. Lateral view of the left side of (a) Hemibrycon helleri,ANSP 180775, (b) Hemibrycon metae, USNM 228563; (c) Hemibrycon huambonicus, USNM 086794; (d) Hemibrycon jelskii, MCP 35022. Scale bars = 1 mm.

Fig. 4. Map of central and northern South America showing geographic distribution of Hemibrycon beni (1, solid hexagon), H. divisorensis (2, open triangle), H. helleri (3, ellipse), H. huambonicus (4, solid triangles), H. jelskii (5, solid dots), H. inambari (6, rectangles), H. metae (7, solid squares), H. mikrostiktos (8, open square), H. polyodon (9, inverted triangle), H. surinamensis (10, solid diamonds), H. taeniurus (11,Trinidad Island), H.tridens (12, open circle).Some symbols represent more than one lot or locality of specimens. 1-12 = type locality of each species.