A new species of Dimeragrion Calvert, 1913 (Odonata: Zygoptera: Heteragrionidae) from Northwestern Brazil.

Dimeragrion Calvert, 1913 is a genus with five species, restricted to the Pantepui region. Here, we describe Dimeragrion baniwa sp. nov. (Holotype. ♂ (LABECO, N° 12276), BRAZIL, Amazonas, São Gabriel da Cachoeira, (0.017, -66.891, 81 m a.s.l.), first-order stream inside Terra Firme Forest, in lateral swamps: 29.xi.2021, C. C. Mendoza-Penagos & M. Gonçalves, leg.), the sixth species of the genus from 13 males and 3 females collected in the municipality of São Gabriel da Cachoeira in the Brazilian Amazon, located at the southern extreme of the Pantepui region. Additionally, we provide photographs of the diagnostic characters of the male and female, photographs of live specimens as well as information on their biology. Finally, identification keys are provided, as well as a distribution map of the species of the genus.