Despite the fact that the state is one of the smallest in Brazil, representing only 0.53% of the country area, a surprising diversity was found. Seventy-six species, 41 genera and nine families were identified, which represents about 25% of the species reported from Brazil, 65% of the genera, and almost all families. Of these, 17 species (most of Baetidae and Leptophlebiidae) are new to science. Five species, collected only at the nymphal stage, could not be identified to the species level. The present work demonstrates that, as for other organisms, the diversity of mayflies is high in the state, and more works aiming to investigate the aquatic insect composition of the Espírito Santo State should be encouraged.

Despite its wide, almost worldwide distribution, the mayfly genus Cloeon Leach, 1815 (Ephemeroptera: Baetidae) is restricted in the Western hemisphere to North America, where a single species is reported. In the Neotropics, except for some species wrongly attributed to the genus in the past, there are no records of Cloeon. Recently, however, specimens of true Cloeon were collected along the coast of Espírito Santo, Southeastern Brazil. In order to verify the hypothesis that this species was recently introduced to Brazil, our aim was to identify the species based on morphological and molecular characters and to confirm the presence of true representatives of the genus in the Neotropics. Our results revealed that the specimens found in Brazil belong to the Afrotropical species C. smaeleni Lestage, 1924. The identity of the species, its distribution, along with its previous absence in regularly sampled sites, is a clear sign that the specimens of C. smaeleni found in Espírito Santo are introduced, well established, and that the colonization took place very recently.

By using an integrative approach, we describe a new species of mayfly, Bungona (Chopralla) ponticasp. n., from Turkey. The discovery of a representative of the tropical mayfly genusBungonain the Middle East is rather unexpected. The new species shows all the main morphological characters of the subgenus Chopralla, which has its closest related species occurring in southeastern Asia. Barcoding clearly indicated that the new species represents an independent lineage isolated for a very long time from other members of the complex. The claw is equipped with two rows of three or four flattened denticles. This condition is a unique feature of Bungona (Chopralla) ponticasp. n.among West Palaearctic mayfly species. Within the subgenus Chopralla, the species can be identified by the presence of a simple, not bifid right prostheca (also present only in Bungona (Chopralla) liebenauae (Soldán, Braasch & Muu, 1987)), the shape of the labial palp, and the absence of protuberances on pronotum.

We present taxonomic contributions and new records for Neotropical Brachycercinae based on material from Brazil. We performed a phylogenetic analysis in order to test the relationship between Alloretochus Sun & McCafferty, 2008 and Latineosus Sun & Mc- Cafferty, 2008, and Alloretochus sigillatus was recovered in the Latineosus clade. Therefore, we propose a new combination, Latineosus sigillatus comb. n. The nymph of Latineosus sigillatus is described and is associated with imago through molecular tools. Moreover, Alloretochus peruanicus (Soldán, 1986) is reported for the first time from Brazil.

The genera Waltzoyphius McCafferty & Lugo-Ortiz and Zelusia Lugo-Ortiz & McCafferty are revised in the present paper based on fresh and historical material, including types. New diagnostic features are presented in order to differentiate nymphs of the two species of Waltzoyphius. The adults of both species, and therefore, the adults of the genus are described for the first time. A new species of Zelusia is described, and based on the recognition of this new species, the distribution of Z. principalis Lugo-Ortiz & McCafferty appears to be restricted to a small area near the type locality. Adults of Zelusia are also described for the first time, based on the new species.