Triportheus signatus ( Garman, 1890 )

Malabarba, Maria Claudia S. L., 2004, Revision of the Neotropical genus Triportheus Cope, 1872 (Characiformes: Characidae), Neotropical Ichthyology 2 (4), pp. 167-204 : 193-194

Triportheus signatus ( Garman, 1890)

Figs. 18 and 19

Chalcinus angulatus signatus Garman, 1890:4 (diagnosis; described as a variety of C. angulatus ; type-locality: Brazil, “Rio Puty”).

Triportheus angulatus signatus . Fowler, 1950:357 (synonymy; Brazil rio Itapicuru).

Triportheus signatus . Portugal, 1990:159-165 (redescription; synonymy list; illustration; map).

Diagnosis. A deep-bodied Triportheus species reaching 158.0 mm of SL (depth at dorsal-fin origin, 27.6-35.0 % SL; depth at pectoral-fin insertion, 29.5-37.2 % SL). The presence of 2 longitudinal scale rows between pectoral-fin insertion and the ventral keel distinguishes this species from elongate-bodied Triportheus species that have 1 longitudinal scale row between pectoral-fin insertion and the ventral keel. Among deep bodied Triportheus species T. signatus can be distinguished by the combination of the number of gill rakers on the lower limb of the first gill arch (35-44, mean = 39.2, n = 32); the number of lateral-line scales (34-37, mean = 35.8, n = 29); and the presence of 6 scale series dorsal to the lateral-line series.

Description. Morphometric data for Triportheus signatus presented in Table 14. Body deep and compressed laterally. Greatest body depth located slightly posterior to vertical through pectoral-fin insertion. Dorsal profile of head straight from snout 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; gently curved along caudal peduncle.

Ventral profile of head straight from tip of lower lip to anteroventral margin of dentary; straight from that point to isthmus. Ventral body profile strongly arched from isthmus to pelvic-fin insertion; slightly convex from pelvic-fin insertion to analfin origin; posterodorsally slanted along the anal-fin base; nearly straight along the caudal peduncle. Prepelvic region very expanded ventrally and compressed, with well-developed keel.

Mouth slightly upturned, with lower jaw equals to upper jaw. Posterior margin of opercle almost reaching vertical through pectoral-fin insertion. Nostrils of each side close together; anterior opening circular; posterior elongate.

Gill rakers thin and close together, length equivalent to one-half of branchial filament length; gill rakers on lower limb of first arch 35-44 [37-43] (mean = 39; n = 33).

Teeth on premaxilla in 3 rows; teeth of inner row largest. Five to 6 tricuspidate teeth on outer row; outer row teeth arranged along external margin of mouth and can be seen externally in closed mouth. Middle tooth row with 2-3 tricuspidate teeth. Inner row with 6 or 7 multicuspidate teeth. Maxilla with 1-3 teeth tricuspidate and much smaller than those on premaxilla. Teeth on lower jaw in two rows, outer row with 4-6 larger teeth, with 5-7 cusps, teeth decreasing in size posteriorly. Inner dentary row consisting of conical, symphyseal tooth.

Scales cycloid, thin, and large. Lateral line distinctly decurved ventrally, completely pored from supracleithrum to base of caudal-fin rays. Scales along lateral line 34-37 [35-37] (mean = 35.8; n = 33); 6 scale series above lateral line; 2 scale rows below lateral line. Two scale rows between pectoral-fin insertion and midventral keel; 5 scale series on caudal peduncle. Scales along mid-dorsal line irregular, 9-14 scales from tip of supraoccipital spine to dorsal-fin origin.

Dorsal-fin rays ii, 9; anal-fin rays iii, 25-31 (mean = 28.6; n = 33) [29-31]; pectoral-fin rays i, 10-13 [10-12]; pelvic-fin rays i, 6. Dorsal-fin margin straight, situated on posterior one-half of body; base of last dorsal-fin ray located along vertical through base of first anal-fin ray; second unbranched and first branched dorsal-fin ray longest with following rays progressively decreasing in length. Pectoral-fin pointed, reaching up to vertical through middle of pelvic fin. Anal-fin margin straight, first branched anal-fin ray longest; following rays gradually decreasing in length. Margin of caudal fin truncate; median rays extended for one-third of their length beyond margin of remainder of fin. Basal one-third of caudal fin covered with scales.

Total vertebrae 37-38 [37-38]

194 Revision of the Neotropical genus Triportheus

Coloration in alcohol. Overall ground color yellowish. Snout and dorsal portion of head dark. Some scattered dark chromatophores on opercle and postorbital region. Body darker dorsally and over anal-fin base and peduncle. Three or four weak, dark longitudinal stripes present on dorsolateral portion of body. Dark chromatophores distributed over all fins. Scattered, dark chromatophores present on pectoral, dorsal, and anal fins. Middle caudalfin rays very dark.

Distribution. Rio Parnaíba basin and some Brazilian northeastern coastal drainages (Fig. 4).

Type-material remarks. Garman (1890:1) cites the material that served as the basis of the description of Chalcinus angulatus signatus as having been collected by the Thayer

expedition and deposited in MCZ, but did not provide catalog numbers for the type-material. MCZ 21267 consists of 17 specimens labeled as syntypes of Chalcinus angulatus signatus .

Type-material examined. Chalcinus angulatus signatus : syntypes, MCZ 21267 (17), 92.6-147.1 mm SL, Brazil, Piauí, rio Puty, Therezina [rio Poti, tributary rio Parnaíba, in Teresina] Dec 1865, O. St. John [Appr. 5º5’S, 42º49’W] .

Non-type material. Brazil: Paraíba: UMMZ 147372 (5), açude Piranhas, Cajazeiras (7°10’S, 38°28’W) ; USNM 181973 (4), açude Piranhas (7°10’S, 38°28’W) . Maranhão: MZUSP 19359 (2) rio Mearim (3°4’S, 44°34’W) . MZUSP 19571 (4), rio Mearim, Santa Vitória (3°4’S, 44°34’W) . Ceará: MCP 22063 (3), rio Turiaçu, Araguana (6°35’S, 48°40’W) . MZUSP 37581 (10), Aiuaba, riacho do Umbuzeiro (6°33’S, 40°0’W) ; UMMZ 147364 (5), Icó, rio Salgado (6°19’S, 38°41’) . Piauí: MCP 22682 (1), Brazil, rio Parnaíba, Teresina on the road Teresina- Palmerais (5°28’38”S, 42°58’15”W) ; MZUSP 5105 (6), Teresina, rio Paraíba (5°4’S, 42°48’W) .

Figures

Fig. 18. Chalcinus angulatus signatus, syntype, MCZ 21267, 136.49 mm SL, Brazil, rio Poti.

Fig. 19. Triportheus signatus, MCP 22682, 126.28 mm SL, Brazil, rio Parnaíba, Teresina on the road between Teresina and Palmerais.