What is "arapaimidae"

Arapaimidae is a family of freshwater osteoglossiform fishes known as the bonytongues. This family includes the arapaimas of the Amazon and Essequibo basins in South America, and the African arowana from Africa. This family is sometimes considered to be a part of the arowana family, Osteoglossidae.

A genetic study shows that the Arapaimidae (arapaimas and African arowana) diverged from Osteoglossidae about 220 million years ago, during the Late Triassic. Within Osteoglossidae, the lineage leading to the South American Osteoglossum arowanas diverged about 170 million years ago, during the Middle Jurassic. The Asian and Australian arowanas in the genus Scleropages separated about 140 million years ago, during the Early Cretaceous.