Odontesthes piquava, Malabarba & Dyer, 2002

Malabarba, Luiz R. & Dyer, Brian S., 2002, Description of three new species of the genus Odontesthes from the rio Tramandaí drainage, Brazil (Atheriniformes: Atherinopsidae), Ichthyol. Explor. Freshwaters 13, No. 3, pp. 257-272 : 261-262

Odontesthes piquava , new species

(Fig- 2)

Holotype. MCP 26152 , 134 mm SL; Brazil: Rio Grande do Sul: lagoa da Pinguela , Tramandaí (29°49'0"S 50 ”10' 14"W); 7 Oct 1998; L. R. Malabarba, B. Dyer, L. Beheregaray F. Becker & V. Bertaco .

Paratypes. All from Brazil: Rio Grande do Sul: rio Tramandai drainage: MCP 21403 , 8, 82.0­ 178.1 mm SL; FMNH 103614 , 2, 151.0- 176.0 mm SL; lagoa do Peixoto , Osório; 7 Nov 1991; L. R. Malabarba, W. Braschi & C. E. GiintzeL - MCP 21406 , 25, 62.0- 169.2 mm SL; lagoa do Palmital , Osorio; 7 Nov 1991; L. R. Malabarba, W. Braschi & C. E. Güntzel - MCP 21405 , 24, 96.0-152.0 mm SL; lagoa dos Quadros , near state fish station , Osório; 13-14 Nov 1991; L. R. Malabarba, W. Bruschi, S. Hartz & A. Kindel.

Additional material (non types). MCP 16364 , 9; lagoa Caconde , Osório, Aug 1992.

Diagnosis. See discussion.

Description. Morphometric data are summarized in Table 1 . Body fusiform and elongate; greatest body depth usually near to pelvic-fin origin. Dor - sal profile nearly straight to slightly convex from snout tip to first or second dorsal fin, and poster - oventrally slanted from second dorsal fin to caudal-fin base. Ventral body profile convex from snout tip to anal-fin base, posterodorsally slanted along anal-fin base. Caudal peduncle ventral profile nearly straight.

Head relatively short. Ventral head profile usually split into two straight sections, forming an angle at the retroarticular joint. Eyes very large, usually equal to snout. length in specimens up to 150 mm SL; slightly smaller than snout length in specimens larger than 150 mm SL. Snout short, anterodorsally directed in lateral view; as long as wide in dorsal view. Mouth terminal; mouth gape slightly oblique in lateral view; usually smaller than eye diameter; mouth gape positioned above an horizontal line crossing near the center of eye and positioned clearly above an horizontal line crossing near the middle of head depth. Two tooth rows in dentary and premaxilla; teeth of inner row slightly longer than teeth of external series.

Pectoral-fin rays i, 11-13 (i, 12; mean = 12.2, n = 11). Pectoral fin reaching to or near to vertical line projected through pelvic-fin origin in specimens up to nearly 150 mm SL, becoming progressively distant from pelvic-fin origin in larger spec ­ imens. Pelvic fin with 1 spine and 5 rays (n = 11); pelvic fins united medially. Distance from pelvic-fin origin to anal-fin origin two to three times pelvic-fin length.

First dorsal fin III-V (V; mean = 4.3, n = 11); first dorsal-fin origin anterior to vertical line projected through anal-fin origin. Second dorsal fin with 1 spine and 7-9 rays (I, 9; mean = 8.5, n = 11); second dorsal fin above posterior half of anal-fin base. Distance from posterior tip of depressed first dorsal fin to second dorsal-fin origin equal or slightly longer than first dorsal-fin length. Anal fin with 1 spine and 16-20 rays (I, 16; mean = 18.4; n = 11). Anal-fin profileconcave. Caudal finforked; principal caudal-fin rays i, 14- 15, i (i, 14, i).

Scalescycloid. Scales in lateral lineseries above lateral band 47-53 (51; mean = 49.3; n = 11). Longitudinal rows of scales between second dorsal fin and anal fin, 8. Predorsal scales 24-26 (26; mean = 25.1, n = 11). Scales between first and second dorsal-fin origins 9- 10 (9; mean = 9.5, n = 11). Longitudinal scale rows around caudal peduncle 13- 16 (16; mean = 15.6, n = 11).

Lower branch gill rakers 26-30 (26; mean = 28.1, n = ll); total gill rakers 33-37 (32; mean = 35.2, n = ll). Vertebrae 47(4), 48(5), 49(1).

Color in alcohol. A black lateral body band ex - tends from pectoral-fin origin to caudal-fin base, wider below first and second dorsal fins. Lateral body band silvery in specimens whose guanine pigment was not destroyed by formalin. Scale borders weakly pigmented with dark chromatophores above lateral band; scales below lateral band usually unpigmented. Abdomen and sides ventral to lateral band pale cream color or yellowish. Fins without distinctive marks. Head pigmented dark brown dorsally in brain region; pigmented light brown in dorsal border of maxilla and snout. Head pale cream color or yellowish in lateral and ventral view. Cheek scales, unpigmented.

Color in life. See Figure 2 of a specimen taken immediately after capture. Live color patterns are very much like those in preservative. Lateral band is silvery white. Scale borders above lateral band are weakly pigmented with dark chromatophores, giving ahardlyperceptive reticulate pattern. Background color is light olive green above lateral band, and white below lateral band. Scale bordels below lateral band unpigmented. Fins without distinctive marks. Head black pigmented dorsally in brain region; light olive green in dorsal border of maxilla and snout. Head silvery white in lateral and ventral views, except for snout which is light brown in lateral view and anterior region between both mandibles weakly pigmented with dark chromatophores. Iris light yellow. Cheek scales unpigmented.

Distribution. Odontesthes piquava is foundin largest interconnected freshwater lakes of the rio Tramandaí drainage, north of the brackish water estuarine area of the laguna Tramandaf ( Fig. 1). It has been recorded in lagoa Itapeva entering the mouth of rio Tres Forquilhas, in lagoa dos Quadras entering the mouth of rio Maquiné, in lagoa Pinguela, lagoa do Peixoto and lagoa Caconde. It has been found sympatrically with O. bonariensis in lagoa Itapeva and lagoa dos Quadras, and sympatrically with O. bicudo in lagoa Caconde.

Etymology. The specific name piquava joins part of the names of the lagoas Pinguela, Quadros, and Itapeva, along the area of distribution of this species.

Ecological notes. This species is found exclusively in freshwater, being absent in the estuarine area of the rio Tramandaí drainage.