IDENTIFICATION OF SNOOKS AND SNAPPERS FROM SOUTHEASTERN-SOUTHERN BRAZIL BASED ON SAGITTAL OTOLITHS MORPHOLOGY AND MORPHOMETRY

The otoliths morphology is defined by genetic and environmental factors. Morphological variations between species are more pronounced according to their phylogenetic distance. The shapes of these structures are species-specific and thus they are important tools for studies of taxonomy, phylogeny, ecology, food webs, and others. The Collection of Otoliths Fish Teleosts of the Southeastern-Southern of Brazil (COSS Brazil) contains otoliths of three species of Lutjanidae ( Lutjanus synagris, Lutjanus anali s and Pristipomoides freemani ) and two species of Centropomidae ( Centropomus parallelus and Centropomus undecimalis ). Morphological analysis of 30 left sagittae of Centropomidae and 28 of Lutjanidae were done being them grouped in fish total length classes of 20 mm. The classification of the otoliths features followed the morphological methodology presented by Assis (2004) and Tuset et al. (2008). For the fifteen features analyzed the frequency of morphological types was calculated within each length classes and among length classes (along fish development). A multiple χ2 test (p>.0.05) was applied to the data, verifying the statistical significances of the variations. Morphometric analysis included: length, height, thickness, perimeter, area, circularity and rectangularity. Centropomus species differed by the opening sulcus acusticus which is pseudo-ostial or para-ostial in C. parallelus but ostial in C. undecimalis . The otoliths of the Lutjanus species differed in posterior region, ostium morphology and cauda morphology. L. synagris presented posterior region angle-round, ostium funnel-like and cauda tubular slightly curved, whereas L. analis presented posterior region round, ostium rectangular and cauda tubular strongly curved. Pristipomoides freemani differed from the Lutjanus species by its anterior region peaked, cauda morphology tubular slightly curved or tubular straight, and the values of the otolith thickness/height ratio and circularity. This study is part of an otoliths atlas from the Southeastern-Southern Brazilian area which has been prepared and published.