Morphological aspects in the ontogeny of Salminus hilarii Valenciennes, 1850 (Ostaryophysi: Characidae)

摘要

This study compared various morphological characteristics of S. hilarii , in order to verify possible variations over the life of the fish. It was used individuals collected from the Tiet?a river basin (sub-basins of Sorocaba, Jacar?? Pepira and Corumbata?- rivers) and from the Rio Grande basin (sub-basins of Pardo and Mogi Gua?§u rivers). For the analysis we used 15 relative values of morphological attributes. Measures of S. hilarii were taken from samples with a range of size ranging between 49-430 mm standard length. The relative values were first analyzed by an array of Principal Component Analysis of correlation (PCA). Subsequently the most important attributes of PCA were correlated with standard length, using the Pearson correlation coefficient. The PCA revealed eight most important characteristics, and six showed a significant correlation with standard lengths (relative height, depth ratio, relative area of caudal fin, relative head length, eye diameter relative height and relative mouth height), indicating common variations along the fisha??s growth besides indicating an adaptation to the conditions of the environment it occupies. On the other hand some characteristics have not changed, maintaining typical morphological patterns of fish that occupy the middle water and piscivorous predators.