ABSTRACT
The brain of anamnia presents the basal organizational type of all vertebrates. Comparing the systematic diversity of fishes reveals that brain structure regroups fishes of high ranked taxa. However, in the absence of complicated associative centers and superstructures in comparison with higher vertebrates the external brain morphology reflects the anamnia’s species biology: primary sensory and motor centers are modified in response to environmental needs. The spectacular diversity concerning the ecology of fishes provides a unique richness in gross brain morphology. In this chapter the morphological and histological features of the fish brain with special reference to the brainstem in relation to ecomorphology are provided.
The brainstem is a very conservative structure, thus it is suitable for comparing the taxa of high rank. The brainstem structures also present a great diversity regarding the ecology of species. The rhombencephalon’s primary somatic and visceral centers are the most variable brain structures of the anamnia.
