Differentiation of the number of vertebrae in some species of Characiformes (Osteichthyes) from the Paraná River Basin, Brazil

Abstract

The purpose of this paper was to investigate differentiation and insertion position of fins in relation to the vertebral column in adult and juvenile fish, as a way to facilitate larvae identification. To visualize the bone structure, a total of 423 individuals of 20 fish species were analysed. Every individual was submitted to dissection, clearing and staining techniques. The number vertebrae varied from 28 to 67. The insertion of fins in relation to the vertebrae varied: for pectoral fins, between the 1^st and the 8^th vertebrae, for pelvic fins, between the 6^th and the 22^nd, for dorsal fin, between the 12^th and the 46^th and anal fin, between the 12^th and the 45^th. Considering that the number of vertebrae in adults was related to the number of myomeres in larvae, we suggest that the number of vertebrae and the insertion of the fin in the vertebral column, along with other characters, may help in the identification of early life stages of fishes.