Gymnotiformes - Taxonomy

Taxonomy

Currently, about 150 known species in 32 genera are contained in five families, and at least 50 or so additional species are known but are yet to be formally described. The actual number of species in the wild is unknown. This group is thought to be the sister group to the Siluriformes from which they diverged in the Cretaceous period (about 120 million years ago).

The families are classified over suborders and superfamilies as below.

Order Gymnotiformes

Suborder Gymnotoidei

Family Gymnotidae (banded knifefishes and electric eel)

Suborder Sternopygoidei

Superfamily Rhamphichthyoidea

Family Rhamphichthyidae (sand knifefishes)

Family Hypopomidae (bluntnose knifefishes)

Superfamily Apteronotoidea

Family Sternopygidae (glass and rat-tail knifefishes)

Family Apteronotidae (ghost knifefishes)