Subgenus Andiorrhinus (Amazonidrilus) Righi, 1993

Type species. Andiorrhinus (Amaz.) rondoniensis Righi, 1986

Diagnosis. The subgenus Andiorrhinus (Amazonidrilus) is defined by the presence of four pairs of intestinal hearts in segments 10, 11, 12, and 13 (Righi 1993). Number of species: 20. Distribution: Brazil (13), Venezuela (6), Bolivia (2), Colombia (1), Paraguay (1). In some cases, the same species has been found in two countries (Brown & Fragoso 2007).