Five new species of Apobaetis Day (Ephemeroptera: Baetidae) and updated key to nymphs.

This study focuses on the Baetidae family of Ephemeroptera, particularly the Pan-American genus Apobaetis Day, 1955, in Brazil. Baetidae is the second richest family in this order, with over 1100 species globally. Although extensively studied in Brazil, there is still a considerable Linnean deficit, emphasizing the need for further exploration and identification. This research reveals that in-depth studies of specific groups often lead to the discovery of new species and corrections to existing records, enhancing the accuracy of identification. We conducted a detailed study of Apobaetis resulting in the identification of five new species: A. dalcolmoae sp. nov., A. danielae sp. nov., A. nisiae sp. nov., A. sabinoae sp. nov., and A. trivellae sp. nov., each described here from nymphs and distinguished by specific morphological features. The study provides detailed comparisons with existing species, emphasizing characteristics such as maxillary palp, paraproct, glossa shape, and setae presence. We also propose an updated identification key to aid in the recognition of all Apobaetis species known in the nymphal stage. We also address the distribution of certain species in Brazil, pointing out potential misidentifications and the need for further revision. In conclusion, the research expands the known species within Apobaetis to 22. The findings underscore the importance of continuous taxonomic studies for accurate species identification and pave the way for future evolutionary research within this genus.

Two new species of Baetodes Needham & Murphy, 1924 with an updated checklist of Baetidae (Ephemeroptera) of Rondônia state, Brazil.

Baetidae is one of the most taxon-rich families in the order Ephemeroptera, and the most studied mayfly in Brazil. Despite recent advances, the vast majority of the Brazilian territory has not yet had its diversity well documented. Some of these critical gaps are in the South-Western Amazon, with emphasis on the state of Rondônia due to the high level of environmental threat (especially deforestation). In the state, only one small survey was carried out 11 years ago. Given this scenario, the objective of this study is to describe two new species and provide access to primary biodiversity data of the family Baetidae in Rondônia. As a result, two new species, Baetodes vermelho sp. nov. and Baetodes cerejeiras sp. nov., are described. Baetodes vermelho sp. nov. can be differentiated from other species by the presence of robust and pointed setae on the dorsal margin of the femora and coxal gills with medial constriction; Baetodes cerejeiras sp. nov. can be differentiated from B. liviae Polegatto & Salles, 2008 (in Salles & Polegatto, 2008) and B. capixaba Souza, Salles & Nessimian, 2011 by the absence of a tubercle on the metanotum, the presence of small blunt setae on the dorsal arc of the labrum, and less prominent tubercles on the abdomen. We have documented 50 species across 54 sites in the Rondônia. Among these, 18 species are being reported for the first time in the state, three species are recorded for the first time in the north of Brazil, and two species are new records for Brazil. Rondônia is the most speciose state in Brazil regarding the family Baetidae.