Triportheus albus Cope, 1872

Malabarba, Maria Claudia S. L., 2004, Revision of the Neotropical genus Triportheus Cope, 1872 (Characiformes: Characidae), Neotropical Ichthyology 2 (4), pp. 167-204 : 184-186

Triportheus albus Cope, 1872

Fig. 13

Triportheus albus Cope, 1872: 264 (type-locality: “from the Ambyiacu”).

Chalcinus albus . Garman, 1890:6 (description, Chalcinus knerii Steindachner, 1876 as synonym). Fowler, 1906:447 (description; type-material listed). Jordan, 1919:363 (designation of “logotype”). Triportheus albus . Fowler, 1945:154 (listed; synonyms).

Chalcinus knerii Steindachner, 1876:50 (type not seen) type-locality: Tefé [rio Solimões].

Chalcinus rotundatus iquitensis Nakashima, 1941:65 (type locality: Porto de Iquitos).

Diagnosis. An elongate Triportheus species reaching 151 mm SL (depth at dorsal-fin origin, 23.2-30.4, mean = 27.6% SL, n = 81; depth at pectoral-fin insertion, 24.2-33.2, mean = 28.8% SL, n = 79). The presence of 1 longitudinal scale row between the pectoral-fin insertion and the ventral keel distinguishes this species from all deep-bodied Triportheus species all of which have 2 longitudinal scale rows between the pectoral-fin insertion and the ventral keel. The combination of the possession of 32-35 lateral line scales, 24-28 branched anal-fin rays, and 30-39 gill rakers on the lower limb of the first gill arch distinguish T. albus from elongate-bodied congeners except T. brachipomus . T. albus is distinguished from T. brachipomus by the length of the postorbital region of the head (43.3-48.9% of HL, mean = 45.8,n = 30 versus 36.1-44.6% of HL, mean = 39.9, n = 30 in T. brachipomus ), and the distance from the insertion of posterior most dorsal-fin ray to the adipose-fin origin (20.2-23.2% of SL, mean = 21.4, n = 30 versus 14.5-21.2% of SL, mean = 17.4, n = 30 in T. brachipomus )

Description. Morphometric data for Triportheus albus presented in Table 9. Body elongate and compressed laterally. Greatest body depth located slightly posterior to vertical through pectoral-fin insertion. Dorsal profile of head 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 terminus of dorsal-fin base to caudal peduncle; slightly concave along caudal peduncle. Dorsal portion of body transversely rounded.

PROOFS

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

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

Gill rakers thin and close together; gill-rakers length about one-half of branchial filament length; gill rakers on lower limb of first gill arch 30-39 [32] (mean = 35.2, n = 74).

Premaxilla with 2 irregular tooth rows. Outer row formed by 5 pentacuspidate teeth. Seven teeth on inner row; 2 medial teeth smaller than other teeth in series. Maxilla with 2-3 tricuspidate teeth all smaller than teeth on pre-maxilla. Teeth on lower jaw in 2 rows, with 6 teeth of 5-7 cusps on outer row; inner row consisting of conical symphyseal tooth.

Scales cycloid, thin, large. Lateral line distinctly decurved ventrally, completely pored from supracleithrum to base of caudal-fin rays. Thirty-two to 35 (mean = 33.6, n = 75) scales in lateral line (50% of specimens with 34 scales); 5 scale series between lateral line and dorsal-fin origin; 1-2 scale rows from lateral line to pelvic-fin insertion. A series of large scales between pectoral-fin insertion and midventral keel; 9-14 (mean = 11.5, n = 68) scales along mid-dorsal line between tip of supraoccipital process and dorsal-fin origin. Four or 5 rows of scales on caudal peduncle.

Dorsal-fin rays ii,9; anal-fin rays iii,24-28 [26] (mean = 25.4, n = 78); pectoral-fin rays i,10-13 [10] (mean = 11.1, n = 78); pelvic-fin rays i,6. Dorsal-fin margin straight, situated on posterior one-half of body; base of last dorsal-fin ray located anterior to vertical through anal-fin origin. Pectoral fin extending over proximal one-third of pelvic fin. Five most anterior branched anal-fin rays much longer than following rays. Caudal fin emarginate or forked; scaled only basally. Middle caudal-fin rays terminate at or slightly beyond posterior margin of remainder of fin.

Total vertebrae 38 [37].

Coloration in alcohol. Overall ground color yellowish brown. Body with diffuse, mid-lateral, silver stripe extending posteriorly from supracleithrum to caudal peduncle; stripe expanding vertically posteriorly. Body brownish dorsal to midlateral stripe; light yellow ventral to stripe. Pectoral fin dark pigmented along first rays. Dorsal and anal fin sparsely pigmented with dark chromatophores. Distal tips of anal-fin rays dark. Caudal-fin darkly outlined; series of chromatophores distributed on anterior one-third of caudal-fin rays.

Distribution. Rios Amazonas, Tocantins and Araguaia basins ( Fig. 12 ).

Type-material remarks. Cope (1872: 264) did not provide a catalog number for the type material of Triportheus albus , but only described it as “total length m..061; length to basis of dorsal fin.0292; from D.I to basis caudal.02” and refers to the type locality as “the Ambyiacu”. Subsequently, Fowler (1906:447) listed the type as ANSP 21234. The holotype is a very damaged young specimen lacking the ventral margin of the body.

No type was designated for Chalcinus rotundatus iquitensis by Nakashima (1941) and the synonymy of that species into T. albus in this paper is based on information in the original description, in particular the 31 lateral line scales and 17+35 gill rakers (“branquiespinas”). Chalcinus rotundatus iquitensis is an homonym of Chalcinus elongatus iquitensis Nakashima (1941:63) described in the same paper.

The types of Chalcinus knerii could not be located at NMW (H. Wellendorf pers. comm., Feb.1999). The single lot identified as Chalcinus knerii in that collection (NMW 12562- 63), is not labeled as type, and contains two specimens, instead of the one described by Steindachner. Although one of these specimens fits the length provided in the original description of C. knerii , it was collected in rio Negro, rather than “ Amazonas (bei Teffe?)” as cited in the original description. Nonetheless, some data in the original description (lateral line scales 34, anal-fin rays 29, scale series above lateral line 5) suggests that C. knerii is a junior synonym of Triportheus albus .

Type- material. Triportheus albus , holotype, ANSP 21234 , 54.4 mm SL, Peru, río Ambyiacu , J. Hauxwell .

Non-type material. Bolivia: Beni: UMMZ 204248 (10), río Itenez (= rio Guaporé ), opposite Costa Marques (12º29’S, 64º16’W) . Brazil: Amazonas : INHS 66933 (11), lago Marchantaria (4°4’S, 59°7’W) ; INHS 65906 (7) lake Terra Preta , about 8 km SW Manaus (4°12’S, 59°57’W) ; INHS 73035 (1 of 4), lago Marchantaria , Camaleão Inlet, about 12 km S Manaus (4°4’S, 59°7’W) ; MZUSP 58853 (8), rio Negro, São Gabriel da Cachoeira (0°7’S, 67°5’W) ; MZUSP 5852 (10 of 14), rio Negro, Manaus (3°10’S, 60°0’W) . Roraima: MZUSP 30509 (5), rio Branco , Marara (1°2’N, 62°10’W) . Goiás: MCP 17210 (4 of 5), lakes of rio Araguaia , near Luis Alves (13º14’S, 50º35’W) . Mato Grosso: MZUSP 53590 (4), rio Araguaia , furo near Aldeia Fontoura. Pará: MCP 15160 (1), rio Tapajós , in the Centro Educacional Boas Novas , Itaituba (4°16’S, 55°59’W) ; FMNH 56496 (8), Santarém (0°57’S, 46°59’W) . Ecuador: Napo: FMNH 103053 (8), río Napo at Destacamento Tiputini (0º47’S, 75º33’W) ; FMNH 94414 (3), río Napo, at Coca , beach in middle of river just upstream from bridge (0º27’S, 76º54’W) ; FMNH 103052 (6 of 11), río Yasuni , laguna Jatuncocha (1º0’S, 75º29’W) ; FMNH 103054 (1), río Tiputini , near mouth in río Napo and Quebradas (0º49’S, 75º31’W) . Peru: Loreto: INHS 38943 (8 of 9), Iquitos at Requena (03°44’S, 73°14’W) ; INHS 43617 (1), río Napo and Quebradas . Madre de Dios: USNM 295169 (2), Parque Nacional Manu, Pakitza and vicinity (7°16’S, 76°46’W) ; USNM 264028 (1), shore of island about 15 km downriver of junction of río Tambopata and río Madre de Dios (12°30’S, 69°8’W) ; MUSM 9676 (4), río Madre de Dios, Tambopata (12°30’49”S, 68°47’44”W) . Ucayali: USNM 280577 (1), Província Coronel Portillo, main channel and side pools of río Ucayali, 10 km upstream of Pucallpa (8°31’S, 74º22’W) .

Figures

Fig. 13. Triportheus albus, MUSM 9676, 114.64 mm SL, Peru, Madre de Dios, río Madre de Dios, Tambopata.

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).