Archolaemus santosi

Archolaemus santosi is a species of glass knifefish endemic to Brazil where it is found in the Rio Mucajaí and Rio Uraricoera in the north-eastern portions of the Amazon basin. This species reaches a length of 21.2 cm.

Etymology
The knifefish is named in honor of Geraldo Mendes dos Santos of the Instituto Nacional de Pesquisas da Amazônia, who collected the type specimen.