A new genus and species of Baetidae (Insecta: Ephemeroptera) from Brazil

A new genus (Callibaetoides) and species (Callibaetoides caaigua) of Baetidae (Ephemeroptera) is described based on nymphs and adults of both genders collected in forested areas of Amazonia and Mata Atlântica biomes. The nymphs were collected from leaf packs accumulated in the backwaters of small streams. The genus and species can be easily distinguished from other members of the family in South America by the following combination of characteristics: male and female imagos with costal process of hind wing centrally located and strongly projected; marginal intercalary veins long and paired in male imago; nymphs with deep medial emargination of labrum, maxillary palp three segmented and third segment of labial palp quadrangular.