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

Abstract

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 Tietê river basin (sub-basins of Sorocaba, Jacaré Pepira and Corumbataí rivers) and from the Rio Grande basin (sub-basins of Pardo and Mogi Guaçu 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 fish'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.Keywords: tabarana, development, adaptation, traits. Aspectos Morfológicos na ontogenia de

Characterizing functional morphology and trophic niches in a neotropical Characiforms (Actinopterygii: Teleostei) assemblage in middle Munim River basin, Maranhão, Brazil

“…Morphological traits serve as invaluable tools for understanding how fish species delineate their trophic and habitat niches across various scales, from macrohabitats to microenvironments (Bower and Winemiller, 2019). This approach has played a crucial role in unraveling niche partitioning within assemblages (Sibbing and Nagelkerke, 2000), assessing responses to environmental changes and predation pressure (Santi et al, 2020), comprehending susceptibility to parasitism (Pegg et al, 2015) and evaluating aspects of ontogeny (Villares Junior and Goitein, 2016). However, it is essential to recognize that morphological specialization alone does not rigidly dictate trophic niches, especially in resource-rich systems.…”