Heros severus, previously known as Cichlasoma severum, is a tropical freshwater cichlid species native to the upper Orinoco and upper Rio Negro basins in South America. Over the years, it has often been mistaken for other species within the Heros genus, including H. liberifer.
While Heros severus is not commonly found in the aquarium trade, the more frequently encountered species is Heros efasciatus. The misidentification of Heros severus persisted for a long time until 2015 when the true Heros severus was properly identified. Initially described in 1840, this species was recognized as having a partially formed 7th band. However, the identification was disregarded as an anomaly. In 2015, the true Heros severus, displaying the distinctive partial 7th band described in 1840, was rediscovered. It was temporarily referred to as Heros sp. 'Curare' or Tiger severum before being officially recognized as the true severus species.
Interestingly, the cichlid previously believed to be Heros severus, which turned out to be a separate species, was subsequently classified as Heros liberifer by Staeck, Wolfgang & I. Schindler.
In summary, Heros severus is a species of freshwater cichlid found in the upper Orinoco and upper Rio Negro basins in South America. Its true identification and distinction from other species took time and involved previous misidentifications. While less commonly available in the aquarium trade, it has an intriguing history of taxonomic clarification.