Anatomia encefálica comparada de serrasalmidae (Ostariophysi: Characiformes)

Abstract

Serrasalmidae is a family of neotropical fish belonging to the order Characiformes composed of 16 genera, 100 living species and one fossil, and are popularly known as piranhas and pacus. Most studies related to morphological description and classification of these species involve ostheology and/or ecology. The main objective of this study was to describe the group's external brain anatomy, in addition to interorating the results found of structures with behavior and other aspects arranged in the existing literature, contributing to expand the range of family information, as well as to data related to the Central Nervous System. The material examined in this study comes from the Coleção de Ictiologia do Campus de Porto Nacional of the Universidade Federal do Tocantins, and the Museu de Zoologia da Universidade de São Paulo and the Laboratório de Ictiologia de Ribeirão Preto. The methodology followed the dissection procedure for Characiformes proposed by Pereira and Castro (2016), respecting the specificities of the group in question. The measurements of length, width, height, volume, weight and encephalic coefficient of the animals, brain and each complex that composes it were also measured, calculated and discussed together, aiming at a better understanding and utilization of the material used. Overall, the brain varied in forms and sizes from gender to gender, tending to be more similar in close individuals phylogenetically or sharing trophic levels. A generalized classification was proposed, taking into account the most similar characteristics and forms.