SAGITTAL OTOLITHS FROM SOUTHEASTERN-SOUTHERN BRAZIL: COMPARISON OF THREE EUCINOSTOMUS SPECIES (GERREIDAE)

Due to the morphological similarity among the species of the Eucinostomus genus, an approach that would help their identification is the morphological and morphometric analysis of sagittal otoliths. The Laboratory of Ichthyofauna and Growth of the Oceanographic Institute (IOUSP) has a Collection of Otoliths of Teleost Fish of the Southeastern-Southern Brazilian area (COSS Brazil) which contains 1289 sagittae of three species of the genus Eucinostomus :  Eucinostomus argenteus , Eucinostomus gula and Eucinostomus melanopterus . Morphological analysis of 155 of these structures was done based on the classification of Assis (2004) and Tuset et al. (2008). The frequency of fifteen features were compared within and between fish length class (20 mm) through multiple χ2 tests (p>. 0.05). Morphometric analysis was carried on length, height, thickness, area, perimeter, circularity and rectangularity data. The diagnosis of the three species revealed: in E. argenteus ventral edge is lobed to sinuate, antirostrum is absent in mostly individuals, cauda morphology is tubular strongly or markedly curved; in E. gula the ventral edge is sinuate to entire or only sinuate, antirostrum is developed and ever present, cauda morphology is tubular slightly curved or straight; E. melanopterus presents  ventral edge sinuate or lobed to sinuate, antirostrum developed and absent in some specimens and cauda morphology tubular markedly curved or curled. This study points out the possibilities of using otoliths morphology and morphometry in solving problems within the genus. This study is part of an otoliths atlas from the Southeastern-Southern Brazilian area which has been prepared and published.