Description of three new species of the genus Odontesthes from the rio Tramandaí drainage, Brazil (Atheriniformes: Atherinopsidae) Author Malabarba, Luiz R. Departamento de Zoologia, IB, UFRGS, Av. Bento Gonyalves, 9500 - bloco IV - Prédio 43435, CEP: 90540 - 000, Porto Alegre, RS, Brasil; and Museu de Ciencias e Tecnologia, PUCRS, Av. Ipiranga 6681, 90.619 - 900, Porto Alegre, RS, Brasil. Author Dyer, Brian S. Centro Ciencias y Ecologia Aplicada, Escueia Pesquerias y Cultivos, Universidad del Mar, Carmen 446, Placeres, Valparaiso, Chile. text Ichthyol. Explor. Freshwaters 2002 2002-01-11 13 3 257 272 journal article 10.5281/zenodo.10813684 10813684 3984F3D2-E2FF-4019-8B33-3A247D742599 Key of Atherinopsidae species from rio Tramandaf drainage (specimens larger than 140 mm SL) 1. -Rostralsensorysystem bearing 4 anterior and 2posterior fossae; 35-40 scales in lateral lineseries abovelateral band. ... Atherine ll a(Xenom elaniris)brasiliensis -Rostral sensorysystem absent;48-60 scales inlateral lineseries above lateral band. ....................................................... 2 2. - 9- 11 longitudinal rows of scales between seconddorsalandanalfins;53-60 scales in laterallineseriesabovelateral band; 29-35 predorsalscale rows; 18-20 scale rows aroundcaudalpeduncle; 9-10 longitudinal scalerowsbetween left and right lateral bandsabovepelvic fins; 30-38 lower gill rakers;40-48totalgillraker count. ...................................Odontesthes bonariensis - 8longitudinalrows ofscales between seconddorsalandanalfins; 48-52 scales in the lateral line seriesabovethelateral band (47­ 53 in O.piquava); 23-26 predorsal scale rows; 13-16scalerowsaround caudal peduncle; 6 -7longitudinalscalerowsbetween left and rightlateralbandsabove pelvic fins; 26-30 lowergill rakers;32-37total gill raker count. ....................................... 3 3. - Three longitudinal series of scales in the infraorbital area; anterior row of teeth longer and more robust than posterior row of teeth. ............................. Odontesthes argentinensis - Two longitudinal series of scales in the infraorbital area; anterior row of teeth shorter than posterior row of teeth ( Odontesthes perugiae species-group). ........................... 4 4 -Ventralheadprofileusually split into two straight sections,forming an angle at retroarticularjoint; mouthslightly upturned in lateralview,andpositioned above an horizontallinecrossing nearcenter of eye and above anhorizontallinecrossing near middle ofheaddepth( Fig.2b );premaxilla not extendedanteriorlyinits medialmost portion; snout short,aslong as wide in dorsal view( Fig.2c ). ....................................... Odontesthes piquava -Ventralheadprofilenearlystraight,or with slightconvexityatretroarticularjoint;mouth terminal,positioned in an horizontal line crossingnearcenterofeyes pupil and middle ofheaddepth( Figs. 3b , 4b);premaxilla extendedanteriorlyinits medialmost por - tion; snoutelongated, pointedin dorsal view ( Figs.3 c ,4c). ...................... 5 5. -Widthofanteriorexposed dorsal border of thepremaxilla2- 4times wider than exposedportionofposterolateral branches of premaxilla( Fig.3c );snout length clearly largerthan interorbital width (snout length 1.2 -1.7 times interorbital width,mean = 1.4, n = 35);eyessmall, diameter 1.4-2.2 times snoutlength(mean =1.7,n= 59). .......................................... Odontesthes bicudo Fig. 1. Map of the rio Tramandaf drainage, northern Rio Grande do Sul state, Brazil, with the known distribution of Odontesthes ledae (lagoons 1 -8), O. bicudo (11, 13, 17, 19), and O. piquava (20-25, 28, 30). There are no collections available in lagoons 9, 10, 12,14-16, 18, 26, 27, 29. Odontesthes ledae is further known from two isolated lagoons, namely lagoa da Solidão and lagoa do Cipó, not in the map. Lagoons: 1, Cerquinha; 2, Rondinha; 3, Cidreira; 4, Fortaleza; 5, Manuel Nunes; 6, Gentil; 7, Custódias; 8, Armazem, 9, Tramandaí; 10, Emboabinha; 11, Emboaba; 12, Bigua; 13, Horacio; 14, Inacio; 15, Rincao; 16, Veados; 17, Caconde; 18, Traíras; 19, Lessa; 20, Caieira; 21, Peixoto; 22, Pinguela; 23, Palmital; 24, Malvas; 25, Passo; 26, Negra; 27, Ramalhete; 28, Quadras; 29, Boa Vista; 30, Itapeva. - Widthofanteriorexposed dorsal border of thepremaxillanearlytwotimes wider than theexposedportion of the posterolateral branchesofthepremaxilla ( Fig. 4c ); snout lengthnearlyequalorlarger than interor - bitalwidth(snout length 0.9-1.3 times inter - orbitalwidth, mean = 1.1, n = 22);eye diameter 1.1 -1.6timessnoutlength (mean = 1.4, n = 56). .................................... ........ Odontesthes ledae