Descrizione originale come Crenicichla cyclostoma:
ZooBank:BEA4E03D-9BDA-4D55-814E-D3DBBD62DFA8.
- Ploeg, Alex. 1986. "The cichlid genus Crenicichla from the Tocantins River, state of Para, Brazil, with descriptions of four new species (Pisces, Perciformes, Cichlidae)". Beaufortia. 36:5:57-80 (crc00072) (riassunto)
Conservazione: Crenicichla cyclostoma è valutata dalle organizzazioni internazionali di salvaguardia delle specie a rischio come (CR) Situazione critica di pericolo (2018). Crenicichla cyclostoma is only known to two of the Tocantins River Region. After the construction of the Tucuruí hydroelectric dam, the species was no longer registered in the reservoir area. The remainder of the distribution currently known for C. cyclostoma is part of the flood area of two planned dams, Santa Isabel and Marabá. When the period of about 8 years (in 2013) until the complete filling of these reservoirs is completed, the species will lose its entire occupation area to dams, causing a 100% population loss since the species is restricted to rapids (ICMBio, 2022).