Abstract
The aquatic bug family Naucoridae (Hemiptera: Heteroptera: Nepomorpha) is currently represented in Brazil by 68 species. Although the diversity of the family has been the target of several recent studies, large areas of the country are still unexplored and several species that have been deposited in entomological collections are waiting for a formal description. Aiming to fill these knowledge gaps, a series of expeditions were carried out in six states of eastern Brazil between 2018 and 2023: Alagoas, Bahia, Ceará, Espírito Santo, Pernambuco, and Sergipe. The fieldwork targeted protected areas, but surrounding regions were also explored. The material obtained, in addition to specimens previously deposited in a national entomological collection, revealed the existence of Australambrysus margaritifer Jordão, Santos and Moreira, a new species herein described, and new records for other 11 species and two subspecies belonging to the genera Carvalhoiella De Carlo, 1963, Limnocoris Stål, 1876, Maculambrysus Reynoso-Velasco and Sites 2021, and Pelocoris Stål, 1876.