Typ species: Mesonauta insignis (1862 Günther)
Mesonauta sp. Xingu
In the whole Amazon region, from Peru to the mouth and his big inflows. Also in the Rio Orinoko region and southwards to the Pantanal and northern Paraguay.
The most species grow up to a size from 12 to 20 cm.
The most species are peaceful and are living in little groups.