RESUMO
During an ongoing project aiming to understand the dynamics of Ephemeroptera biodiversity in the Doce River Basin after the disaster, an unusual large number of Apobaetis Day, 1955 were analyzed. The occurrence of Apobaetis is quite relevant, since the combination of factors such as its small body size and its habitat preferences makes their collection difficult and its presence often neglected. For the first time in science, adults of Apobaetis irai De Lima, Massariol, Cruz & Hamada, 2022 and Apobaetis fiuzai Salles & Lugo-Ortiz, 2002 are described and diagnosed. Apobaetis irai can be easily distinguished, among other characteristics by turbinate portion of compound eyes touching each other along midline; abdominal terga II-III and V-VII with well-marked lines on lateral and posterior margins; posterior margin of subgenital plate with projection broadly rounded to slightly truncate. Apobaetis fiuzai are diagnosed by turbinate portion of compound eyes touching each other posteriorly; mesothorax brown, except for broad cream marks on anterior margin of PSp and SLS, SSLi tinged with white, posterior corner of SMS with a red spot; abdominal terga II-VI translucent orangish-brown, terga VII-X brown, terga II-III and VI with conspicuous red medial mark; posterior margin of subgenital plate with subtriangular projection, apex narrowly truncate; forceps base wider at base, inner irregular edges. The new records of A. irai and A. fiuzai extend the distribution of Apobaetis within Minas Gerais and Espírito Santo States, Brazil. Furthermore, it is reported for the first time cases of gynandromorphs for Apobaetis.