Moenkhausia jamesi Eigenmann, 1908

Petrolli, Marina G. & Benine, Ricardo C., 2015, Description of three new species of Moenkhausia (Teleostei, Characiformes, Characidae) with the definition of the Moenkhausia jamesi species complex, Zootaxa 3986 (4), pp. 401-420 : 411-413

Moenkhausia jamesi Eigenmann, 1908

( Figs. 7 a–c, 9a, Table 2 )

Moenkhausia jamesi Eigenmann, 1908: 102 . Type Locality: “Iça; Obidos; Lago do Máximo; Tajapuru”.

Diagnosis. Moenkhausia jamesi is distinguished from M. justae , M. ischyognatha , and M. alesis , by the number of teeth on dentary (five vs. four in the last three). It is further distinguished from M. justae , M. alesis , and M. sthenosthoma by the number of scale rows between the lateral line and midventral scale series (six vs seven in M. sthenosthoma , and seven to eight in M. justae and M. alesis ). Additionally, it is distinguished from M. justae by the number of teeth in maxilla (edentulous vs one tooth with 5 cusps in M. justae ), and by the number of cusps on the fourth dentary tooth (three to five vs six in M. justae ). Moenkhausia jamesi is additionally distinguished from M. ischyognatha by its greater body depth (45.0–51.3% in SL vs 38.2–43.9% in SL in M. ischyognatha ) and by its greater head depth (34.4–39.2% in SL vs 29.3–32.6 in SL in M. ischyognatha ).

Description. Morphometric data summarized in Table 2 . Largest specimen examined 56.9 mm SL. Body compressed and deep. Greatest body depth slightly anterior to or at dorsal-fin origin. Dorsal profile of head slightly convex; straight to slightly concave along the occipital spine; slightly convex to convex from tip of supraoccipital spine to end of dorsal-fin base; straight to slightly convex from end of dorsal fin up to end of adipose fin; caudal peduncle concave in dorsal and ventral margins; ventral profile slightly convex from tip of snout to end of anal fin.

Mouth terminal. Maxilla only reaching the vertical through anterior margin, and not trespassing anterior third of second infraorbital. Premaxillary teeth in two rows. Inner row with five tetracuspidate (symphyseal) or pentacuspidate teeth with median cusp pronounced, the first two or three teeth from the symphysis with cusps arranged in a pronounced arch when examined in a ventral view; outer row with four to five pentacuspid teeth; edentulous maxilla. Dentary bearing four to five pentacuspidate teeth with central cusp longest followed by three to four distinctly small conical or tricuspidate teeth. First two or three dentary teeth from the symphysis with cusps arranged in a pronounced arch when examined from a dorsal view.

Dorsal-fin rays ii,9. Pectoral-fin rays i,11(3), 12*(37), 13(20), 14(4). Tip of pectoral fin extends slightly beyond anterior insertion of pelvic fin. Pelvic-fin rays i,7, Tip of adpressed pelvic fin not reaching anal fin. Analfin rays iv,28(11), 29(15), 30(18), 31(15), 32*(5). Caudal fin forked with i,9,8,i.

Scales cycloid. Lateral line with 34*(3), 35(11), 36(24), 37(22), 38(4) perforated scales; Scale rows between lateral line and dorsal-fin origin seven. Scale rows between lateral line and midventral scale series six. Circumpeduncular scale rows 13(8), 14(37), 15(13), 16(1). Scale sheath along anal-fin base 7–20, in one series, covering base of anteriormost rays. Small scales covering proximal two-third of caudal-fin lobes.

First gill arch with 12(18), 13(23) gill rakers on lower limb and 8(10), 9(25), 10(6) on upper limb. Total vertebrae 32. Supraneurals 4.

Color in alcohol. Overall coloration slightly silvery or yellow tan. Field of few dark chromatophores on upper lip and maxilla. Infraorbital and opercular series silvery due to the presence of guanine pigmentation. Dark chromatophores more densely concentrated along entire dorsal midline. Sparsely spread dark chromatophores dorsal of horizontal skeletogenous septum. Dark line over horizontal skeletogenous septum. Conspicuous silver midlateral stripe extending from posterior margin of opercle to base of median caudal fin-rays. In some individuals, silver stripe is not preserved. Irregularly shaped humeral mark located over fourth to eight lateral line scales and extending vertically over four-five horizontal scale rows above and over one-two horizontal scale rows below lateral line. Paired fins and anal fin hyaline. Round dark spot at the base of the caudal-fin rays formed by few chromatophores. Adipose with very few dark chromatophores ( Figs. 7 a–c).

Distribution. Moenkhausia jamesi occurs along Rio Amazonas basin and appears to be restricted to the Amazon lowlands area, as defined by Lima & Ribeiro (2011) ( Fig. 4 ).

Material examined. Types: MCZ 20734, 1, syntype, 51.3 mm SL, Amazonas, Lagoa do Máximo (lake near to Parintins), 2°40" S, 56°45". MCZ 20742, 1, syntype, 53.6 mm SL, Pará, Tajapuru ( Ilha de Marajó, Furo Tajapuru), 1° 50" S, 50° 25". MCZ 20816, 2, syntypes, 47.0– 53.1 mm SL, Amazonas, Rio Putomajo, Rio Iça (tributary of Rio Solimões), near to Brazil / Colombia border, 3°7" 0' S, 67° 58" 0' W. MCZ 20827, 1, paralectotype (by present designation), 38.5 mm SL, Pará, Obidos, (Rio Amazonas), 1°52"0' S, 55° 30" W. Non Types: USNM 307025, 2, 49.8–52,9 mm SL, Amazonas, Ressaca da Ilha de Marchantaria. USNM 307035, 2, 37.1–46,9 mm SL, Amazonas, Paraná de Janauacá, entrance of Lago do Castanho. USNM 307323, 2, 58.6–59.4 mm SL, Amazonas. USNM 307331, 3, 31.6–40.5 mm SL, Amazonas, Lago Murumuru, curral de gado, Janauacá. USNM 307362, 1, 42.5 mm SL, Amazonas, Ressaca da Ilha de Marchantaria. USNM 308062, 1, 36.9 mm SL, Amazonas, Paraná de Janaucá, entrance of Lago do Castanho. USNM 308197, 2, 23.8–24.9 mm SL, Amazonas. MZUSP 17583, 2, 47.9–52.4 mm SL, Amazonas, Jutaí; Ilha Xibeco, rio Solimões, upstream of mouth of Rio Jutaí; 02°45’00”S, 66°45’00”W. LIRP 5010, 1, 35.9 mm SL, Amazonas, Manaus; Rio Solimões, Paraná de Janauacá, entrance of Lago do Castanho; 3°33’28”S, 59°11’38”W. MZUSP 105860, 1, 33.6 mm SL, Amazonas, Manaus; Rio Solimões, Paraná de Janauacá, entrance of Lago do Castanho; 3°33’28”S, 59°11’38”W. MZUSP 17430, 4, 47.8–52.2 mm SL, Amazonas; Rio Solimões, in front of Jacaré, near to Fonte Boa; 3°36’10”S, 61°19’02”W. MZUSP 49507, 54 (5 c&s), 44.9–56,9 mm SL, Acre; Rio Acre, Bôca do Acre, Rio Purus; 8°43’48”S, 67°23’55”W. MCP 47788, 4, 49.9–55.7 mm SL, Brasil, Pará, Rio Tapajós, Alter do Chão, 02°31’00”S, 54°57’00”W, R.B. Oliveira, 0 3 Dec 1997.

Figures

FIGURE 4. Partial map of South America indicating the distribuition of Moenkhausia jamesi species complex and M. justae. Red circle = M. jamesi; Blue circle = M. ischyognatha; Orange circle = M. alesis; Light blue circle = M. sthenosthoma; Yellow circle = M. justae.

FIGURE 7. Moenkhausia jamesi. (a) MCZ 20734, syntype, 51.3 mm SL. (b) MZUSP 105860, 33.4 mm SL. (c) MCP 28197, 50.84 mm SL.