Description of a New Species and New Records of Naucoridae (Hemiptera: Heteroptera: Nepomorpha) from Eastern Brazil.

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.

A new species and new records of Oocyclus Sharp, 1882 (Coleoptera: Hydrophilidae) from Brazil.

A new species of Oocyclus Sharp, 1882, O. pilosus sp. nov. is described and illustrated from Mato Grosso State in Central-Western Brazil. Oocyclus itapecum Clarkson Short 2012 and O. yubai Clarkson Short 2012 are newly recorded from São Paulo and from Mato Grosso, Goiás and Paraná States respectively. The doubtful record of Oocyclus aeneus Clarkson Short 2012 in Mato Grosso State is herein confirmed. An updated key to the Brazilian species of Oocyclus is provided.