Odoutesthes ledae, Malabarba & Dyer, 2002, 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 : 266-268

Odontesthes ledae , new species

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Fig.)

Holotype. MCP 26151 , 136.6 mm SL; Brazil: Rio Grande do Sul: lagoa Fortaleza , Cidreira, (30°09 ' 33" S 50° 13 ' 44"W); 7 Oct 1998; L. R. Malabarba. B. Dyer, L. Beheregaray, F. Becker G. V. Bertaco.

Paratypes. All from Brazil: Rio Grande do Sul: rio Tramandaí drainage : MCP 13849 , 7, 145.0- 1903 mm SL; lagoa da Solidão , Mostardas; 27 Nov 1989; Jr. Sadi . — MCP21396 , 22, 71. 0- 1870 nun SL; lagoa do Cipó , Quintão, Palmares; 1 Nov 1991; L.. R. Malabarba S - Hartz, F. Becker G. W. Bruschi . - MCP 21394 , 14, 613- 1523 mm SL; FMNH 103612 , ñ, 494- 1749 mm SL; lagoa Rondinha , Pinhal; 31 Oct 1991; L. R. Malabarba, S. H artz, F. Becker & W. Bruschi . — MCP 21393 , 20 43.4- 140.5 mm SL; lagoa Cerquinha , Pinhal; 31 Oct 1991; L. R. Malabarba, S. Hartz, F. Becker Jr W. Bruschi . — MCP 21397 , 9, 30- 110 mm S L; lagoa Fortaleza , Cidreira; 1 Nov 1991; L. R. Malabarba, S. Hartz, F. Becker ¿r W. Bruschi. - MCP 21395 , 13, 127-165 mm SL; lagoa das Custódias , Tramandaí; 8 Nov 1991, L. R. Malabarba, W. Bruschi 8r C. E. Guntzel.

Diagnosis. See discussion.

Description. Morphometric data are summarized in Table 1. Body fusi form and elongate; greatest body depth usually near to pelvic-fin origin. Dorsal profile slightly convex from snout tip to first or second dorsal fin, and posteroventrally slanted along second dorsal-tin base. Ventral body profile convex from snout tip to anal-fin base, posteruclorsally slanted along anal-fin base. Caudal peduncle depth progressively smaller from second dorsal and anal fins to caudal-fin base. Head relatively elongate, more notably in larger specimens. Ventral head profile slightly convex, ivithotit a conspicuous angle at retroarticular ioint. Eve relatively small, clearly smaller than snout length. Shout slightly elongated, pointed in lateral view; in dorsal view, SHOUI slightly rounded in specimens up to 150 mm ofSL, and pointed in larger specimens. Mouth terminal; mouth gape horizontal in lateral view; usually larger than eye diameter in specimens larger than 150 mm S1.. Mouth gape positioned in an horizontal line crossing slightly below center of eye and near middle of head depth. Two tooth rows in dentary and premaxilla; teeth of inner row twice longer than teeth of external series Fectoral-fiıi rays i, 11- 12 (i, 12,' mean =11.7, n = 11). Pectoral fin reaching to or near to vertical line profected through pelvic-fin origin in «specimens up to nearly 150 mm SL, becoming progressively distant from pelvic finorigin in larger specimens. Pelvic fin with 1 spine and 5 rays (n = 11); pelvic fins united medially. Distance from pelvicfin origin to anal-fin origin two to three times pelvic-fin length.

First dorsal fin III-V (V; mean = 4.6, n = 15); first dorsal tin origin anterior to vertical line proiectcci through anal-fin origin. Second dorsal fin with l spine and 8- 10 rays (I, 9; mean = 8.8, n = 15); second dorsal fin above posterior half of anal-tin base. Distance from posterior tip of depressed firstdorsal fin tn second dorsal-tin origin equal or slightly longer than first dorsal-tin length. Anal fin with 1 spine and 13-18 rays (I,18; mean = 16.4; n = 15). Anal-fin profile concave. Caudal fin forked; principal caudal-fin rays i, 14-15, i (i, 14, i).

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Scalescycloid. Scales in laterallineseriesabove lateral band 48-52 (51; mean = 49.7; n = 15). Longitudinal rows of scales between second dorsal fin and anal fin, 8. Predorsal scales 23-26 (26; mean = 24.5, n = 15). Scales between first and second dorsal-fin origins 9-10 (9; mean = 9.9, n = 15). Longitudinal scale rows around caudal peduncle 15- 16 (16; mean = 15.9, n = 15).

Lower branch gill rakers 26-28 (26; mean = 28.9, n = 15); total gill rakers 33-35 (32; mean = 33.5, n = 15). Vertebrae 47(1), 48(7), 49(6).

Color in alcohol. A black lateral band extends from pectoral-fin origin to caudal-fin base, wider above anal-fin base and very narrow in caudal peduncle. Lateral band silveryin specimens whose guanine pigment was not destroyed by formalin. Scale borders clearly pigmented with dark chromatophores above lateral band, giving dorsal part of body a dark brown reticulate pattern; borders of first and sometimes second series of scales just below lateral band very weakly pigmented with dark chromatophores or unpigmented. Abdomen and sides ventral to lateral band pale cream color or yellowish. Fins without distinctive marks, ex - cept for second dorsal fin black pigmented along proximal portion of fin. Head pigmented pale brown dorsally; except for brain region dark brown pigmented. Head pale cream color or yellowish in lateral and ventral view. Cheek scales unpigmented. Lower jaw with dark brown chromatophores between both mandibles.

Color in life. See Figure 4 of a specimen taken immediately after capture. Live colors patterns are very much like those in preservative. Lateral band is silvery white. Scale borders above lateral band are clearly pigmented with dark chromatophores, in a reticulate pattern. Ground color is light olive green above lateral band, and white below lateral band. Scale borders below lateral band unpigmented, except for a few chromatophores bordering scales immediately below lateral band. Fins without distinctive marks. Head dark brown pigmented dorsally, and black in brain region. Head silvery white in lateral and ventral views. Iris light yellow. Cheek scales unpigmented.

Distribution. Odontesthes ledae is found along all interconnected lakes southern to brackish water estuarine area of the rio Tramandaí drainage, from lagoa do Armazém, near the mouth of rio do Relógio, through the lagoa do Rincao das Éguas in the South ( Fig. 1). It is further found in two partially isolated lakes South of the rio Tramandaí drainage, namely lagoa do Cipó and lagoa da Solidão. It has been found sympatrically with O. argentinensis in the lagoa do Armazém and sympatrically with A. (X.) brasiliensis in the lagoa do Armazem and lagoa das Custodias.

Etymology. Named in honor of the ichthyologist Leda Francisca Armani Jardim, now retired. She was the former advisor of several young under - graduate southern Brazilian students at the Universidade Federal do Rio Grande do Sul, in projects related to ichthyology.

Ecological notes. This species is found almost exclusively in freshwater lakes, but has also been caught occasionally in brackish water lagoons (lagoa do Armazem and Custódias). It has never been found near the estuarine area or seawater

Figures

Fig. 4. OdontesHies ledae, holotype, MCP 26151, 136.6 mm SL; Brazil, lagoa Fortaleza, a, left view; b, head, left view, c, head, dorsal view