Fossils of Apateon are found in freshwaters strata of Latest Carboniferous (Gzhelian) to Early Permian (Asselian) of Germany.

On opposite sides of the head there are three pairs of long, spiral-shaped external gills.

They had a weakly ossified skeleton and a wide, short skull, with huge eye holes.

[3] Apateon were sexually mature in the larval state, with the retention by adults of traits seen in the young (neoteny).

However, in exceptionally harsh environmental conditions, the species A. gracilis engaged in cannibalism.