Apparently this species is polymorphic with body patterning varying significantly depending on locality. Individuals collected from black water habitats tend to be noticeably darker in overall colouration, for example, with this being particularly evident among populations from the Guiana Shield.

The genus Ageneiosus was at one point classified in…

Type locality is ‘Río Yuruari, 3 kilometers east of El Callao, 7°18’N, 61°50’W, Bolivar, Venezuela’, and this species is also known from the Rupununi River drianage in Guyana and the Courantyne/Corantijn system in Suriname.

The Yuruari, an affluent of the Río Cuyuni, an…

This species is also referred to as ‘South American puffer’, ‘SAP’, ‘Amazonian puffer’, ‘Peruvian puffer’, or ‘Brazilian puffer’ in the ornamental trade.

Within the genus Colomesus, C. asellus can be immediately identified by possessing a unique transverse row of dermal flaps across the chin which is absent in its congeners C. psittacus and C. tocantinensis.

This is the type species of the genus Aequidens and has the widest distribution of any member species. It exists in various colour forms depending on locality with variants from Ecuador and Peru being particularly sought after since they develop striking red (Ecuador) or orange (Peru) colouration on the lower part of the jaw, head and anterior portion of the belly whereas those from Brazil tend to have an overall grey/blue/green colouration, for example.

Despite its type status it's long…