Triportheus angulatus (Spix & Agassiz, 1829)

Malabarba, Maria Claudia S. L., 2004, Revision of the Neotropical genus Triportheus Cope, 1872 (Characiformes: Characidae), Neotropical Ichthyology 2 (4), pp. 167-204 : 171-173

Triportheus angulatus (Spix & Agassiz, 1829) Fig. 1

Chalceus angulatus Spix & Agassiz, 1829:67-68 , fig. 34 (description; inexact type-locality: “in Brasiliae aequinoctialis fluviis”).

Chalcinus angulatus . Valenciennes, in Cuvier & Valenciennes, 1850:263-4 (discussion).

Chalcinus angulatus vittatus Garman, 1890:4 (description, type-locality: “José Fernandez, Villa Bella, Porto do Moz, and Santarem ”).

Chalcinus angulatus fuscus Garman, 1890:4 (description, type-locality: “Villa Bella and Lake Hyanuary”).

Chalcinus müllerii De Filippi, 1853:165-166 (type-locality: Hab. rio Napo).

Triportheus flavus Cope, 1872:264 (description, río Ampyacu, Peru).

Chalcinus angulatus angulatus . Bertoni, 1939:56

Triportheus angulatus . Fowler, 1941:194

Triportheus angulatus angulatus . Fowler, 1950:355-356

Diagnosis. A deep bodied Triportheus species reaching 163 mm of SL (depth at dorsal-fin origin, 29.0-36.7 % SL; depth at pectoral-fin insertion, 32.9-39.8 % SL). The presence of 2 longitudinal scale rows between the pectoral-fin insertion and ventral keel distinguish this species from the Triportheus species with elongate bodies that have 1 scale row between the pectoral-fin insertion and the ventral keel. Triportheus angulatus differs from the other deep bodied congeners in the combination of lateral line scale counts (34-37, mean = 35.7, n = 62); the count of gill rakers on the lower limb of first arch (29-37, mean = 32.3, n = 68); the number of branched anal-fin rays (26-31, mean = 28.8, n = 67); and the presence of longitudinal dark stripes on the lateral surface of the body.

Description. Morphometric data of Triportheus angulatus presented in Table 3. Body deep and compressed laterally.

Greatest body depth located slightly posterior to vertical through insertion of pectoral fin. Dorsal profile of head straight or slightly convex 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; straight along caudal peduncle. Dorsal portion of body slightly keeled.

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

Mouth slightly upturned, with lower jaw longer than upper jaw. Posterior margin of opercle 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 half of branchial filament length; gill rakers 29-37 [33] (mean = 32.3; n = 68).

Teeth on premaxilla in 3 rows; teeth of inner row largest. Five or 6 tricuspidate teeth on outer row; outer row teeth arranged along external margin of premaxilla and visible externally. Medial premaxillary tooth row with 2 or 3 tricuspidate teeth. Six or 7 multicuspidate teeth on inner row of premaxilla. Teeth on maxilla 1-3, much smaller than those on premaxilla and tricuspidate. Teeth on lower jaw in 2 rows. Outer row with 4-6 larger teeth, with 5-7 cusps, and decreasing in size posteriorly. Inner row formed by a small conical tooth, slightly curved posteriorly.

Scales cycloid, thin, and large. Lateral line distinctly decurved ventrally, completely pored from supracleithrum to base of caudal fin rays. Thirty-four to 37 [36] scales along lateral line (mean = 35.7; n = 62); 5-6 (usually 6) [6] scale series above lateral line. Two scale rows below lateral line. Two scale rows between pectoral-fin insertion and midventral keel. Five scale series on caudal peduncle. Scales along mid-dorsal line very irregularly arranged, with 6-13 [13] scales from supraoccipital process to dorsal-fin origin.

Dorsal-fin rays ii,9; anal-fin rays iii,26-31 [28] (mean = 28; n = 67); pectoral-fin rays i,11-13 [11]; pelvic fin rays i,6. Dorsal-fin margin straight, situated on posterior half of body; base of last dorsal-fin ray situated slightly anterior to, or at, vertical through anal-fin origin; second unbranched and first branched ray longest; following rays slightly decreasing in length. Pectoral fin pointed, tip falling within region from middle to tip 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 extend slightly beyond margin of remainder of fin. Scales present over anterior one third of fin.

Total vertebrae 38.

Coloration in alcohol. Overall ground color yellowish and overlain with guanine. Snout and dorsal region of head

172 Revision of the Neotropical genus Triportheus

dark. Some scattered dark chromatophores present on opercle and infraorbitals 5 and 6. Body darker dorsally and on analfin base and peduncle. Five or 6 longitudinal brown stripes present on dorsolateral portion of body. Dark chromatophores distributed all over fins. Dorsal fin rays outlined by dark chromatophores. Scattered chromatophores distributed over all of pectoral fin; with more intense pigmentation on first unbranched ray and along fin margin. Some dark chromatophores outlining anal-fin rays. Middle caudal-fin rays very dark.

Distribution. Amazon and Essequibo river basins ( Fig. 2 ).

Remarks about type-locality and type-specimens. Triportheus angulatus is the first described species of the genus and its description was based on specimens collected by the Spix and Martius expedition in Brazil between 1817 and 1820. During this period they first traveled north from Rio de Janeiro, crossing tributaries of the upper rio Paraná, rio São Francisco, and several smaller Atlantic drainages prior to their arrival in Belém. From Belém they traveled by boat along a portion of the rio Tocantins and through the rio Amazonas, to the rio Negro and rio Solimões as far west as Benjamin Constant ( Papavero, 1971:65-69 and map). Thus, the collecting locality of Chalceus angulatus could be in the São Francisco, Tocantins, or Amazonas basins. Spix & Agassiz (1829:67) cite the collecting locality of the material only as “in Brasiliae aequinoctialis fluviis”.

The specimens collected by Spix (except those subsequently donated to Agassiz) were housed in Zoologische Staatssammlung München (ZSM) until its destruction during a British bombing raid on the night of 24-25 April 1944 ( Kottelat, 1988: 69). Kottelat (1988:84) presents a list of Spix & Agassiz’s types still extant in the ZSM, MHNN (Musée d’Histoire Naturelle de Neuchâtel) and MHNG (Musée d’Histoire Naturelle de Geneve). No Chalceus angulatus specimens are included in this list and the types of the species were apparently lost or destroyed. A neotype (MCP 29943) is herein designated for Triportheus angulatus , as a specimen collected in the rio Amazonas basin (Solimões drainage, Amazonas state, Brazil). This is the species that best fits the original description and drawing provided by Agassiz, in terms of general body shape, dorsal-fin position, pectoral-fin length, and anal-fin ray count.

The type locality of Chalcinus muellerii is listed as “Hab. in Rio Napo” in the original description ( Di Filippi, 1853), but the type’s label cites the locality as “Rio Negro Brasile ” .

Type-material examined. Triportheus angulatus : Neotype by present designation, MCP 29943, 130.59 mm SL, Brazil, Amazonas, rio Solimões , ilha do Prego, opposite to Alvarães, W. Crampton, 15 Jan 2001 (3°10’37”S, 64°48’1”W).

Chalcinus angulatus vittatus : syntypes, Brazil, Amazonas : MCZ 21183 (10), Villa Bella [rio Amazonas at Parintins and environs], L. Agassiz, 2 Sep 1865 [02°38’S, 56°45’W] ; MCZ 21224 (33,) José Fernandes lake [presumably near Manaus], J. M. S. Coutinho, Dec 1865. Pará : MCZ 21216 (3), Porto do Moz [rio Xingu at Porto de Mos], Sep 1865, Vinhas [1°45’S, 41°04’W] ; MCZ 21175 (22, MCZ 21201 + MCZ 21202 + MCZ 21239 + MCZ 21240), near Santarém, 1873, C. Bourget [02°43’S, 54°07’W] .

Chalcinus angulatus fuscus : syntypes, Brazil, Amazonas: MCZ 21270 (8 of 18), lago Hyanuary , 29 Sep 1865 , L. Agassiz [paraná do Janauari, 03°12’S, 60°05’W]; MCZ 21186 (10, MCZ 21190 + MCZ 21191), Villa Bella [rio Amazonas at Parintins and environs, 2°38’S, 56°45’W] 2 Sep 1865 .

Chalcinus muellerii : holotype, MZUT 92641 , Rio Napo [ Peru], M. Osculati .

Triportheus flavus : lectotype, ANSP 8077 , Peru, Ampyacu River , J. Hauxwell . Paralectotypes, ANSP 8074 (2), ANSP 8078-8080 , same data as lectotype .

Non-type material. Bolivia: Beni: UMMZ 205100 (4), arroyo Grande at mouth, 1 km N of Guayaramerin (10°48’S, 65°24’W) ; UMMZ 205124 (14), río Mamoré near head of Isla Nicolas Suarez , between Guayaramerin and Guajara Mirim (10°49’S, 65°21’W) ;

AUM 23484 (57), lago Tumi Chucua , 26 km SSW Riberalta (11°7’S, 66°11’W) ; AUM 23566 (9), Lago Tumi Chucua , 26 km SSW Riberalta (11°7’S, 66°11’W) ; FMNH 56503 (2), San Joaquin ; AUM 23520 (3), río Beni 25 km SW Riberalta (11°12’S, 66 o 9’W) ; USNM 303109 (2 of 4), Ballivia Prov., río Curiraba at 10 km NE El Porvenir Biological Station, 40 air km E San Borja (14°55’S, 66°17’W) ; UMMZ 204881 (11), río Baures 2 km above mouth (at second sand riffle) (12°32’S, 64°19’W) . Brazil: Amazonas : INHS 72382 (8), lago Terra Preta , about 8 km SW Manaus (3°12’S, 60°1’W) ; USNM 179513 (3), rio Urubu 25 miles from Itacoatiara (3º0’S, 58º25’W) ; FMNH 56505 (1), Manaus (3°12’S, 60°1’W) . Pará : FMNH 56502 (3 of 4), Santarém (0°57’S, 46°59’W) ; USNM 307111 (1), lago Murumuru , plantação de juta, Janauacá, (3°25’S, 60°16’W) ; USNM 30776 (3 of 4), paraná of Ilha de Marchantaria (4°4’S, 59°7’W) . Rondônia: UMMZ 56780 (12), Porto Velho, rio Madeira , Amazonas drainage (8°46’S, 63°54’W) . Ecuador: Napo: FMNH 103035 (3), río Yasuni, 1-2 km downstream from confluence with río Jatuncocha (0º59’S, 75º25’W) ; FMNH 103036 (2), río Yasuni, laguna Jatuncocha , all parts (1°0’S, 75°26’W) . FMNH 103042 (2), río Aguarico about 1 km upstream from Destacamento Lagartococha (0º38’S, 75º18’W) . Guyana: ANSP 178468 (1), Essequibo River , extensive sandbar 2 km upstream from Paddle Rock campsite (04°42’N, 58°42’W) . Peru: Loreto: INHS 43221 (1), Puerto Iquitos ; NRM 28635 10, río Putumayo drainage: downstream of El Estrecho, Cedros Cano (2°28’S, 72°41’W) ; NRM 30502 (1 of 4), río Putumayo right bank, El Estrecho (2°28’S, 72°41’W) ; USNM 280510 (2), District Coronel Portillo, Yarinacocha , side Cano (8º16’S, 74º36’W) ; NRM 30504 (1), río Samiria drainage: Atún Cano , gramalote (4°41’S, 74°18’W) ; NRM 30488 (1), río Itaya ; NRM 30505 (3), río Samiria drainage (4°41’S, 74°18’W) . Madre de Dios: USNM 295166 (9), Parque Nacional Manu , Pakitza and vicinity (12°15’S, 70°54’W) ; NRM 13449 (2), caño between Yarinacocha and Cashibococha , 8 km NW of Puerto Callao (8°18’S, 74°36’W) .

Figures

Fig. 1. Triportheus angulatus, neotype, MCP 29943, 130.5 mm SL, Brazil, Amazonas, rio Solimões, ilha do Prego.

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).