Triportheus guentheri ( 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 : 188-190

Triportheus guentheri ( Garman, 1890)

Fig.15

Chalcinus güntheri Garman, 1890:4 . (description, typelocality: rio São Francisco). Eigenmann, 1912:377 (as synonym of Chalcinus rotundatus ).

Triportheus güntheri . Fowler, 1945:153-154 (listed).

Triportheus guentheri . Fowler, 1950:359 (synonym of T. rotundatus ).

Chalcinus guentheri . Fowler, 1975:296 (synonym of Triportheus rotundatus ).

Diagnosis. A deep-bodied Triportheus species reaching 133.7 mm of SL (depth at dorsal-fin origin, 28.2-37.0, mean = 33.4% SL, n = 26); depth at pectoral-fin insertion, 29.3-34.9, mean = 32.2% SL, n = 25). The presence of 2 longitudinal scale rows between the pectoral-fin insertion and the ventral keel distinguish this species from Triportheus species with elongate bodies that have 1 longitudinal scale row between the pectoral-fin insertion and the ventral keel. Triportheus guentheri differs from all other deep-bodied congeners in the higher number of gill rakers on the lower limb of the first gill arch (52- 57, mean = 54.8, n = 26).

Description. Morphometric data for Triportheus guentheri presented in Table 11. Body deep and compressed laterally. Greatest body depth located slightly posterior to vertical through pectoral-fin insertion. Dorsal profile of head very slightly convex from snout to rear of head. Dorsal profile of body gently curved from rear of head to dorsal-fin origin; posteroventrally slanted and slightly convex from dorsalfin origin to caudal peduncle; slightly curved along caudal peduncle.

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

Head bluntly rounded in profile; posterior margin of opercle falling short of vertical through pectoral-fin insertion. Snout margin vertically straight. Mouth terminal; lower jaw as long as upper jaw. Nostrils of each side close together; anterior opening circular; posterior elongate. Gill rakers thin and close together, length equivalent to that of branchial filaments; gill rakers on lower limb of first arch 52- 57 [50] (mean = 54.8, n = 26).

Teeth on premaxilla in 3 rows; teeth of inner row largest. Four or 5 tricuspidate teeth in outer row; outer row teeth arranged along external margin of mouth and visible externally in closed mouth. Medial tooth row with 3 tricuspidate teeth. Six, rarely 7, multicuspidate teeth on inner row of premaxilla. Maxilla with 0-2 flattened teeth, smaller than those on premaxilla. Teeth on lower jaw in 2 rows. Outer row with 4-5 larger anterior teeth, followed by 4-6 smaller teeth. 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 to 33 (mean = 32.1, n = 20) scales in lateral line; 5 scale series above lateral line; 2 scale rows between lateral line and pelvic-fin insertion. Two scale rows between pectoral-fin insertion and midventral keel; 4-5 scale series on caudal peduncle. Scale series along middorsal line irregular, 6-13 scales from supraoccipital process to dorsalfin origin.

Dorsal-fin rays ii,9; anal-fin rays iii,27-32 [29] (mean = 30.5, n = 20); pectoral-fin rays i,11-12 [10]; pelvic-fin rays i,6. Dorsal-fin base situated on posterior one-half of body; base of last dorsal-fin ray located anterior to vertical through anal-fin origin; first branched ray longest with following rays slightly decreasing in length. Pectoral fin pointed, tip reaching vertical through distal one-third of pelvic fin. Anal fin margin straight; first branched anal-fin ray longest; following rays gradually decreasing in length. Margin of caudal fin emarginate; median caudal-fin rays not extended beyond the posterior margin of fin. Scales cover basal onethird of fin.

Total vertebrae [37].

the description of C. brachypomus by Günther (1864). In

the description that follows this diagnosis, Garman, how-

ever, described a specimen (“Taking one from the San Fran-

cisco river as a typical specimen,...”) with counts different

that those reported for C. brachypomus by Günther (1864)

most notably the counts of anal-fin rays and lateral-line

scales. The specimen discussed by Garman is then the ho-

lotype of Triportheus guentheri which differs from

Chalcinus brachipomus Valenciennes, 1850 . In the same

paper, Garman (1890:3) considered, “ C. brachipomus Val. ”

to be synonym of C. angulatus and different from “ C.

brachypomus Günther ”. Later authors erroneously refer

Chalcinus brachypomus as a junior synonym of Triportheus

PROOFS [1850

guentheri brachypomus Günther , described, following (] 1864 from for Chalcinus Garman : Mana 341), Essequibo presented (1890 brachipomus ). River a new. Valenciennes spelling, Coloration in alcohol. Overall ground color yellowish with silver. Snout and dorsal portion of head darker. Scattered Type material. Chalcinus guentheri , holotype, MCZ 21173, dark chromatophores located posterodorsal and posterior 105.9 mm SL, Brazil, Minas Gerais, São Francisco river, ‘below to orbit on infraorbitals 5 and 6 and opercle. Longitudinal the falls” [probably near Pirapora, Brazil], F.C. Hartt, 1867 dark stripe extends from supracleithrum to caudal peduncle. (Pirapora coordinates 17°21’S, 44°56’W]. Stripe broadened into diffuse dark spot on lateral surface of caudal peduncle. Body darker above stripe. Dark chromato- Type-material remarks. Garman (1890:1) cited his studied matephores scattered over all fins. Caudal fin outlined by dark rial as having been collected by the Thayer Expedition and depigmentation. posited in the Museum of Comparative Zoology. Eschmeyer

(1998:686) considered three uncatalogued BMNH specimens as Distribution. Rio São Francisco basin ( Fig. 8 ). syntypes of C. guentheri , which the type-locality as Essequibo

and São Francisco based on the argument that Garman did not Remarks. Garman (1890:4-5) stated that C. brachypomus clearly designate a type. However, T. guentheri was based on Günther, 1864 “is so different in essential aspects from that of one specimen (MCZ 21173) from rio São Francisco (“Taking one Valenciennes [ C. brachipomus ] that the two cannot be con- from San Francisco river as a typical specimen”) and as such the sidered identical” and consequently that the material reported BMNH specimens are not syntypes.

Non-type material. Brazil: Bahia: MZUSP 20436 (2), Represa de Sobradinho (12°60’S, 38°59’W) ; MCP 16710 (3 of 30), Bom Jesus da Lapa, riacho Santana, 31 km from Bom Jesus da Lapa (13º31’S, 43º21’W) . Minas Gerais: MZUSP 19663 (13 of 24), Represa de Três Marias (18°40’S, 45°15’W) ; MCP 14037 (3 of 16), rio São Francisco, Represa de Três Marias (18°40’S, 45°15’W) . Alagoas: FMNH 56494 (5), Penedo (10°16’S, 36°35’W) .

Figures

Fig. 15. Triportheus guentheri, MCP 14037, 133.7 mm SL, Brazil, Minas Gerais, rio São Francisco, Represa de Três Marias.

Fig. 8. Map of central and northern South America showing geographic distribution of Triportheus auritus (circles; asterisk = neotype locality), T. guentheri (black squares; white square = type-locality) and T. curtus (triangle; diamond = syntype-localities) (some symbols represent more than one locality or lot of specimens).