Oligoneuria macabaiba sp. nov. (Insecta: Ephemeroptera) from Brazil.

The former monotypic genus Oligoneuria Pictet was known solely by a female subimago of the type-species Oligoneuria anomala Pictet. A new species of the genus Oligoneuria from the Atlantic rainforest of Macaé, Rio de Janeiro is described. The description was based in males and females imagos of Oligoneuria macabaiba sp. nov. caught with light traps. This species presents similar wing venation, abdominal posterolateral spines, as well as a membranous extension on anterior portion of the head as seen in the genus. Based on features of the new species, the genus is herein redefined. The species represents the first record of the genus from Southeastern Brazil.