Cusk-eels

The cusk-eel family, Ophidiidae, is a group of marine bony fishes in the Ophidiiformes order. The scientific name is from the Greek ophis meaning "snake", and refers to their eel-like appearance. True eels diverged from other ray-finned fish during the Jurassic, while cusk-eels are part of the Percomorpha clade, along with tuna, perch, seahorses, and others.

The oldest fossil cusk-eel is Ampheristus, a highly successful genus with numerous species that existed from the Late Cretaceous (Maastrichtian) to the early Oligocene.