Melanorivulus schuncki (Costa & De Luca 2011)

Can be diagnosed from all other species of the subgenus Melanorivulus by the following characters: snout pointed in lateral view; 12 rows of scales around the caudal peduncle; bright green bars on the flank and caudal fin in males, flank dark brown with small light gray spots on ventral part in females; pelvic fin without dark gray or black anterior margin in females; and by the absence of red bars or dots arranged in chevron-like pattern on flank (Ref. 86535).

Dorsal soft rays (total): 8 - 9; Analsoft rays: 11 - 13

This species occurs generally near stream banks, in shallow places (5-50 cm) and sites where the water had high transparency. It usually inhabits lentic streams, but sometimes also near the bank of lotic streams, where the environment conditions resemble those of lentic water habitats. It was also found in the shallow parts of the Curiaú lake, a peculiar environment formed only during the rainy season (January to June) when Curiaú River overflows from its main channel. In the areas north of the Amazonas River, the streams were directly exposed to sunlight as they flow over a savanna vegetation region, characterized by the presence of the buriti palm Mauritia flexuosa, and the water was hyaline or slightly yellow; south of the Amazonas River, this species was always found close to the forest border, in lentic black water streams, with high water transparency. Both the northern and southern populations are often sympatric with the poeciliid Fluviphylax palikur, the cichlid Laetacara sp., juveniles of the erythrinid Hoplerythrinus uniteniatus and a great variety of lebiasinid species (Ref. 82137).