Triportheus brachipomus

Malabarba, Maria Claudia S. L., 2004, Revision of the Neotropical genus Triportheus Cope, 1872 (Characiformes: Characidae), Neotropical Ichthyology 2 (4), pp. 167-204 : 176-177

Triportheus brachipomus

(Valenciennes, in Cuvier & Valenciennes, 1850) Figs. 5 and 6

Chalcinus brachipomus Valenciennes in Cuvier & Valenciennes, 1850:259-262. Garman, 1890 (synonym of Chalcinus angulatus ). Ulrey, 1895:294 (synonym of Chalcinus angulatus ). Eigenmann, 1910:440 (designated as type-species of Chalcinus ). Eigenmann, 1912:377 (synonym of Chalcinus rotundatus ). Fowler, 1950:359 (synonym of Triportheus rotundatus ).

Chalcinus brachypomus . (misspelling or unjustified emendation) Günther, 1864:341. Eigenmann, 1910:440 (synonym of Chalcinus angulatus ). Eigenmann, 1912:377 (synonym of Chalcinus rotundatus ). Eigenmann & Allen, 1942:260-261 (synonym of Chalceus angulatus ); 262 (synonym of Chalcinus rotundatus ). Géry, 1977:343, 672 (synonym of Triportheus rotundatus ). Portugal, 1990:91 (synonym of Triportheus rotundatus ).

Chalcinus brachypoma . Eigenmann & Eigenmann, 1891:56 (synonym of Chalcinus angulatus ).

Chalcinus trachypomus . (error) Regan, 1911:19.

Characinus brachyformes . (error) Travassos, 1951: 284

Diagnosis. An elongate Triportheus species reaching 219 mm SL (depth at dorsal-fin origin, 24.9-32.4 % SL; depth at pectoral-fin insertion, 27.5-34.1 % SL). The presence of 1 longitudinal scale row between the pectoral-fin insertion and the ventral keel distinguish this species from all deep bodied Triportheus species all of which have two longitudinal scale rows between the pectoral-fin insertion and the ventral keel. The combination of the possession of 32-38 lateral line scales, 22-28 branched anal-fin rays, 32-40 gill rakers on the lower limb of first arch distinguishes T. brachipomus from elongate congeners except by T. albus . T. brachipomus is distinguished from T. albus by the length of the postorbital region of the head (36.1-44.6% of HL, mean = 39.9, n = 30 versus 43.3-48.9% of HL, mean = 45.8,n = 30 in T. albus ), and the distance from the insertion of posterior Guyana, Demerara River, 8 km SSW Linden.

most dorsal-fin ray to the adipose-fin origin (14.5-21.2% of SL, mean = 17.4, n = 30 versus 20.2-23.2% of SL, mean = 21.4, n = 30 in T. albus ).

Description. Morphometric data for Triportheus brachipomus presented in Table 5. Body elongate and compressed laterally. Greatest body depth located slightly posterior to vertical through pectoral-fin insertion. Dorsal profile of head slightly convex from upper lip to nares; nearly straight from nares to rear of head. Dorsal profile of body gently convex from rear of head to dorsal-fin origin; posteroventrally slanted along dorsal-fin base; straight from posterior end of dorsal fin to caudal peduncle; slightly concave along caudal peduncle. Dorsal portion of body transversely rounded.

Ventral profile of head vertical and straight from dorsal border of lower lip to anteroventral margin of dentary; posteroventrally slanted from that point to joint with quadrate. Ventral profile of body distinctly convex from isthmus to pelvic-fin insertion; nearly straight from that point to anal-fin insertion; posterodorsally slanted along anal-fin base; slightly concave along caudal peduncle. Prepelvic region ventrally expanded with midventral keel.

Head obtusely pointed in profile; snout straight in profile. Mouth terminal; lower jaw slightly longer than upper jaw. Nostrils of each side close together; anterior opening circular; posterior kidney-shaped. Eye large, without adipose eyelid.

Premaxillary teeth in 2 rows. Outer row with 5 pentacuspidate teeth and somewhat irregular. Seven teeth on inner row in premaxilla; 2 medial teeth smaller than other teeth in series; teeth of inner row larger.Teeth on maxilla 2-3, smaller than those on premaxilla and tricuspidate. Teeth on lower jaw in two rows, 6 teeth with 5-7 cusps on outer row; inner row with conical symphyseal tooth.

Scales cycloid, thin, and large. Lateral line distinctly decurved ventrally, completely pored from supracleithrum to base of caudal-fin rays. Thirty-two to 38 (mean = 35.4, n = 39) scales in lateral line (50% of specimens with 36-37 scales); 5 scale series between lateral line and dorsal-fin origin; 2 scale rows between lateral line and pelvic-fin insertion. Large scale row between pectoral-fin insertion and midventral keel; 12-17 (mean = 14.6, n = 28) scales along mid-dorsal line between tip of supraoccipital spine and dorsal-fin origin. Four rows of scales on caudal peduncle.

Dorsal-fin rays ii,9; anal-fin rays iii,22-28 [26] (mean = 24.9, n = 45); pectoral-fin rays i,12-13 [12]; pelvic-fin rays i,6. Dorsal-fin margin straight, dorsal-fin base situated on posterior one-half of body; base of last dorsal-fin ray located anterior to vertical through anal-fin origin. Pectoral fins large and extending posteriorly past one-half length of pelvic fin. First branched anal-fin ray longest; following rays rapidly decreasing in length. Caudal emarginate, nearly forked, scaled only at base. Middle caudal-fin rays extended slightly beyond posterior margin of remainder of fin.

Total vertebrae 37-38 [38].

Coloration in alcohol. Overall ground color yellowish brown. Snout, lower lip, and dorsal portion of head dark. Dorsolateral portion of postorbital region with scattered, small, dark chromatophores. Body with mid-lateral dark stripe extending from supracleithrum posteriorly to caudal peduncle; posterior portion of stripe vertically expanded and broadened into distinctly wider diffuse dark spot on lateral surface of caudal peduncle. Body darker dorsal to stripe. Dark chromatophores forming a diffuse and posterodorsally inclined stripe situated above analfin base. Stripe distinctly separated from anal fin base anteriorly, and approaching base posteriorly. Dorsal and pectoral-fin rays outlined by dark chromatophores. Distal tips of anal-fin rays dark. Caudal-fin rays outlined by series of dark chromatophores.

Distribution. Río Orinoco, Essequibo River, Demerara River, Courantijne River, Maroni River and rio Araguari drainages ( Fig. 2 ).

Remarks about type specimens. There are three lots identified as syntypes of Chalcinus brachipomus at MNHN. Two specimens (MNHN 5402) brought from Mana by M. Dourmec Leschenault, and two lots, MNHN A 9916, 5 specimens, and MNHN A 9836, 1 specimen, both from the Essequibo River by Schomburgk. An examination of the material revealed the presence of two species among the syntypes, with the specimens in MNHN 5402 and MNHN 9836 belonging to a different species than MNHN A 9916. The original description of Chalcinus brachipomus includes few features that are useful to determine that the specimens in MNHN 5402 and MNHN 9836 served as the basis of the original description of the species. Proportions of body depth in total length, head length in total length, eye diameter in head length and dorsal fin position cited in the original description are coincident with those presented by the specimens in the lots MNHN A 9836 and MNHN 5402. One of the specimens registered as MNHN 5402 is designated herein as the lectotype of Chalcinus brachipomus , and numbered as MNHN 2004-3095 ( Fig. 6 ). Remaining specimens of the lot MNHN 5402 and MNHN A 9836 become paralectotypes. The original syntypes numbered MNHN A 9916 are also paralectotypes, but are herein identified as Triportheus angulatus .

Type-material examined. Chalcinus brachipomus : Lectotype by present designation, MNHN 2004-3095, 219 mm SL, French Guyana, Mana, Dourmec Leschenault, 1824. Paralectotypes, MNHN 5402 (1), 175 mm SL, French Guyana, Mana, Dourmec Leschenault, 1824 [5°44’N, 53°54’W]. MNHN A 9836, 180 mm SL, Essequibo river drainage, Guyana, R. H. Schomburgk, 1847. MNHN A 9916 (5), 125-185 mm SL, [specimens originally designated as syntypes of Chalcinus brachipomus but belonging to Triportheus angulatus ].

Non-type material: Brazil: Amapá: MZUSP 58855 (7 of 13), channel of rio Araguari , município Ferreira Gomes (0°08’N, 51°13’W) . French Guyana: NRM 28397 (1), Maroni,St-Laurent-du-Maroni, Maroni River: small tributaries on French Guiana side and left bank island on Suriname side, ca. 2 h up Maripasoula (3º30’N, 54ºW); USNM 304943 (1), shore of Maroni River by ban Shore of Grand Santi (4°15’N, 54°22’W) . Guyana: AUM 27844 (6), Mazaruni-Potaro River drainage (5º59’N, 58º33’W) ; INHS 49320 (3) Mazaruni-Potarodrainage (5º59’N, 58º33’W) ; AUM 27940 (2), Demerara River 5.05 mi SSW Linden (5º56’N, 58º18’W) ; INHS 49094 (3), 5 mi SSW Linden, Demerara River (05°56’0”N, 58°18’22” W) ; AUM 27791 (1 of 2), Mazaruni-Potaro, Essequibo River ,beach 0.72 mi SW Rockstone (5º58’N, 58º33’W) ; INHS 49232 (3), Essequibo River , beach 0.72 mi SW Rockstone (5º58’N, 58º33’W) ; AUM 28012 (2), Mazaruni-Potaro , large sandbar and small cataract, 31.9 mi S Rockstone (5º31’N, 58º37’W) ; AUM 28061 (3), Potaro River at beach on N bank, downstream of Tumatumari cataract (5º21’N, 59º 0’W) ; INHS 49441 (3), Potaro River at beach on N bank, downstream of Tumatumari cataract (5º21’N, 59º0’W) ; AUM 28091 (2), Mazaruni-Potaro, Creek on N side of Potaro River (5º21’N, 59º0’W) ; FMNH 53592 (5), Crab Falls , (6°15’N, 58°47’W) ; FMNH 7554 (1) Crab Falls, Essequibo River (6°15’N, 58°47’W) ; FMNH 53591 (2), Bartica (6°24’N, 58°37’W) ; FMNH 53590 (1), Wismar (6°0’N, 58°18’W) . Suriname: USNM 225628 (1), Matappi Creek (5º1’N, 57º17’W) ; USNM 225280 (1), Nickerie District; Creek About 2 km N of Matapi (5º3’N, 57º17’W) ; AMNH 54948 (6), Nickerie, Courintijn river, Camp Hydro, 30 km north of Tiger Falls (3°58’N, 58°1’W) ; AMNH 220999 (2), Marowijne Albina (5°30’N, 54°2’W) ; AMNH 221001 (1), Marowijne, Litani river, Third compound (3°17’N, 54°5’W) . Venezuela: Amazonas: FMNH 103913 (11), pool behind beach of río Ventuari on S side of river, about 12 km above mouth in Río Orinoco laguna Pavon (4 o 4’N, 66º56’W) ; FMNH 103911 (1), pool behind beach of rio Ventuari on south side of river, 5 hr (12 km) above mouth in Río Orinoco laguna Pavon (4º5’N, 66º56’W) ; FMNH 103903 (7), caño Tuparero, above San Francisco de Atabapo, in Río Orinoco (4°2’N, 67°42’W) . Apure: INHS 98928 (1), caño San Miguel, Río Cinaruco (6º34’N, 67º17’W) .

Figures

Fig. 5. Triportheus brachipomus, INHS 49094, 133.57 mm SL,

Fig. 6. Chalcinus brachipomus, lectotype, MNHN 2004-3095, 219 mm SL, French Guiana.

Fig. 2. Map of central and northern South America showing geographic distribution of Triportheus angulatus (circles; diamond = neotype locality) and T. brachipomus (squares; asterisk = lectotype locality) (some symbols represent more than one locality or lot of specimens).