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Abstract: Aim: Traditionally, South American aquatic insects have been divided into cold and warm adapted forms. Cold‐adapted forms inhabit freshwater systems from higher latitudes, or higher altitudes even around the Equator. Warm‐adapted groups are defined as those found in lower latitudes and altitudes. This work aims to answer the questions: Are mayfly assemblages geographically segregated according to geographical (latitude) and topographical (altitude) surrogates of temperature? If so, where is this transition located? Location: South America. Methods: We compiled a data set about the relative incidence of 52 mayfly genera in 326 sampled communities. They span from 0 to 4,320 m and from 47.77° S to 5.74° N latitude. By virtue of the compositional nature of the data set, we applied the statistical procedures behind the Aitchison compositional data analysis. We delimited groups of assemblages based on their Aitchison distances and projected the data points onto a biplot obtained through Principal Component Analysis adjusted to compositions (Aitchison PCA). Results: A strong correspondence among biological and geographical information was detected, with mayfly assemblages clearly segregated in space. Andesiops and Meridialaris are typical cold‐adapted forms; Baetodes, Leptohyphes and Thraulodes represent the warm group. Thermal groups can be separated by a curved line of altitude in function of latitude expressed in terms of a superellipse arc. Main conclusions: The classical ecological bipartition of mayflies into warm and cold freshwater groups is formalized quantitatively. The dividing line between warm and cold assemblages levels off at high altitudes (c. 3,300 m) around the Equator and falls to sea level at southern latitudes. The community bipartition line is useful for tracking global change through records of altitudinal displacement below and above of the warm/cold line of involved ecological groups. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Many species of Ephemeroptera have been described based on either nymphs or adults. Only 10% of Ephemeroptera species in South America are known in both life stages. The current research was carried out in order to molecularly associate nymphs and adults of Ephemeroptera, using the amplified fragment length polymorphism (AFLP) technique. We obtained molecular fingerprints by the AFLP of five species: Leptohyphes albipennis, Leptohyphes coconuco, Leptohyphes ecuador, Baetodes levis and Prebaetodes sitesi. The association between nymphs and adults of L. albipennis and L. coconuco by this analysis confirmed the effectiveness of the technique. The molecular fingerprints of B. levis and P. sitesi were generated with the hope that future collections of unknown adults would match the fingerprint and solve an identification problem. We describe here for the first time the adult of L. ecuador by matching an adult trapped in the field with the DNA fingerprint of nymphs obtained by means of AFLP. [ABSTRACT FROM PUBLISHER]

The larvae of three known species of Callibaetis are described here for the first time: C. gonzalezi (Navas), C. pollens Needham & Murphy and C. sellacki (Weyenbergh). The larva of C. willineri Navas is resdescribed and the larva of C. guttatus Navas is revised and discussed. The diagnoses of the adults are also provided. [ABSTRACT FROM AUTHOR]

Nine new species of Baetodes are described, five from Argentina: B. cochunaensis sp. n., B. copiosus sp. n., B. pehuenche sp. n., B. huaico sp. n., B. uruguai sp. n., based on nymphs, and the last two species also on male imagines. Three species from Bolivia: B. gibbus sp. n., B. rutilus sp. n., B. yuracare sp. n., are also described based on nymphs and in B. yuracare from nymphs and a male subimago; and one from Peru: B. pseudogibbus sp. n., based on nymphs. The first keys for the adults and nymphs of the South American species are included. [ABSTRACT FROM AUTHOR]