Further notes on South American species of Baetidae (Ephemeroptera) assigned to Moribaetis Waltz & McCafferty, 1985.

The types of the remaining two South American species classified in Moribaetis Waltz & McCafferty, 1985 were studied. Moribaetis comes (Navás, 1912) is designated as a nomen dubium based on the lack of information in the original description, the damaged type and the resultant improbability of assigning specimens to this species. The type-material of M. aneto (Traver, 1971), on the other hand, is well-preserved. Based on the morphology of males and females, we propose a new combination, Camelobaetidius aneto. In conclusion, we consider the genus Moribaetis to be absent from South America.

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.

Two new species and new records of Campsurus Eaton (Ephemeroptera: Polymitarcyidae) in Amazon.

Campsurus Eaton is the second most speciose genus of mayflies in South America and, until recently, one of the most problematic. The scenario was so disorganized that the description of new species was strongly discouraged. In 2010 the genus started to be revised and, after more than ten years of advances, the taxonomic impediment was drastically reduced, facilitating new researches. The new evidence allowed us to investigate specimens of this genus collected from Amap and Mato Grosso States, Brazil, which were impossible to assign to any species in the past. As results, two new species are described, Campsurus fortuitus sp. nov. and Campsurus froehlichi sp. nov.; and new records are provided for Campsurus cuyuniensis Traver, Campsurus indivisus Ulmer, Campsurus inusitatus Molineri Salles, Campsurus jorgenseni Esben-Petersen, Campsurus litaninensis Spieth, Campsurus nessimiani Molineri Salles, Campsurus pereirae Molineri Salles and, Campsurus segnis Needham Murphy.

Two new species of small minnow mayfly (Ephemeroptera: Baetidae) from a mine-tailing dam disaster area in Minas Gerais, Brazil.

After the worst mine-tailing dam disaster which occurred in Minas Gerais state, Brazil, it was necessary to understand the extent of the biodiversity loss. Thus, based on legal obligations, a monitoring of the fauna and flora along the Rio Doce basin was developed. From this large study, surprisingly, two undescribed psammophilous mayfly species were collected. Given the environmental disaster, and the particular concern with species that inhabiting sandy bottom, the two new species may be already threatened. Considering the reported circumstances, our objective is to described the new species and carry out their extinction risk assessment following the IUCN protocol. Apobaetis irai sp. nov. can be distinguished by the size and shape of the setae in the distal middle area of the dorsal surface of the labrum, with 3 minutes, blunt spatulate setae and the shape of the labial palp; is likely to be threated, plausibly eligible, at least, as Vulnerable (VU) B2ab(iii)+D2. Rivudiva watu sp. nov., can be distinguished by the distal shape of glossae, absence of row of setae on ventral margin on the hind tibiae and hypopharynx without distomedial projection; given its distribution, it was not directly impacted by the disaster, however, there is not enough data to accurately estimate the extent of its occurrence (EOO) and area of occupancy (AOO), therefore, it may be eligible for Data Deficient (DD).

Redescription of three species of Apobaetis Day, 1955 (Ephemeroptera: Baetidae).

The genus Apobaetis Day is one of the few lineages of the family Baetidae distributed throughout the continental Americas. Three very similar species of this genus-Apobaetis etowah (Traver), Apobaetis signifer Lugo-Ortiz McCaffety, and Apobaetis fiuzai Salles Lugo-Ortiz-have important morphological details, pertinent to species identification, that remain to be described. This lack of detailed taxonomic information has resulted in ample misdiagnoses of the species, particularly regarding A. fiuzai in South America. In fact, almost all the recently collected specimens have been assigned to this species. The present study aimed to establish a new morphological diagnosis of these three Apobaetis species through a redescription of their larvae, based on type material, and the proposition of a new identification key for larvae of this genus. The review of the type specimens supports two conclusions: (i) that A. etowah, A. signifer, and A. fiuzai are highly similar, yet can be considered as distinct species, and (ii) the previous diagnoses and keys do not effectively separate A. fiuzai from A. signifer.

Redescription of Apobaetis lakota McCafferty, 2000 (Ephemeroptera: Baetidae) and description of two new species from Brazil.

The genus Apobaetis Day is known by its small size and larval shifting-sand habitat preference (psammophilous). Three species of this genus are recorded in North America, from these, only Apobaetis lakota McCafferty needs to be redescribed because its original description is incomplete, turning difficult to distinguish it from species with similar morphology. Therefore, one of the objectives of this study is to redescribe A. lakota. Based on this redescription, two new species from Brazil, with similar morphology could be identified and are described (Apobaetis biancae sp. nov. and Apobaetis jacobusi sp. nov.). Apobaetis lakota can be differentiated by the labrum rectangular, distal margin without medial emargination, medial area of distal margin with three sockets of setae on dorsal surface; maxillary palp long, more than 2.0× the length of galea-lacinia, segment I with the same length as galea-lacinia; lingua subcircular with one medial lobe; glossa distally rounded; inner projection of labial palp segment II rounded and distally directed, segment III triangular; tarsal claws 1.3× the length of tarsus, without row of denticles. Apobaetis jacobusi sp. nov. can be differentiated from other species by fore tarsal claw I with the same length of tarsus, labrum medially with two protuberances and glossa with pointed apex. Apobaetis biancae sp. nov. can be differentiated by the absence of a ventral row of long thin setae near distolateral margin of labrum, four marginal spines on the paraproct, a subrectangular hypopharynx, and by the absence of robust setae on inner margin of the glossa.

One less monotypic genus in Leptophlebiidae (Ephemeroptera): A new species of Bessierus Thomas amp; Orth and new record from Brazil.

A new species of Bessierus Thomas Orth, formerly a monotypic genus, is described from Amapá State, Brazil. The type species of the genus, B. doloris Thomas Orth, had only its nymphs described until recently, when its male imago was associated to nymphs mainly based on pigmentation pattern. Bessierus riobranco sp. n. here described has no significant difference on pigmentation pattern from B. doloris, thus the new species could be the male imago of B. doloris, and the putative imago of B. doloris a new species, or even both described imagoes could be new species. Still, a new male imago existence cannot be neglected and we opted to provide a properly description, diagnosis and illustration, hence contributing to the knowledge of mayfly neotropical diversity and future research on the genus. The generic concept of Bessierus and its type species diagnoses are altered to accommodate the new species, and a new record of B. doloris is provided.

New genus and species of Baetidae (Insecta: Ephemeroptera) from Brazil.

One new taxon was brought to light during an Ephemeroptera survey in Roraima state, but it was not described. This new taxon was included in a cladistics analysis (as Gen A) in order to delimitate some Baetidae genera, and it was recovered as a new genus. Taking in account that the new genus and species status were already defined in a previously published paper, the objective of this study was to describe it based on imagoes and nymphs, and formally name it as Macuxi tunamore gen. nov. sp. nov. The new genus is sister group of Rhopyscelis Cruz, Salles Hamada + Varipes Lugo-Ortiz McCafferty clade, and can be differentiated from both mainly by the absence of long and stout setae on femora of all legs. Several characteristics were obtained in the morphological analyses to distinguish the new genus from other genera, but the paraglossa and glossa with pectinate setae, and claw with two rows of denticles, one reduced and other with apical ones larger than the others, are highlighted.

A new species of Harpagobaetis Mol, with amended diagnosis of the genus, and new considerations on predatory species of Baetidae (Ephemeroptera) from South America.

A remarkable new predatory species of Baetidae was collected in a relict patch of Amazonian savanna in Brazil. The feeding habit of the nymph of this new species is very rare in mayflies. Baetidae is composed of more than 900 species, but only 12 are considered to be predators; in South America, the only species recognized as a predator is Harpagobaetis gulosus Mol 1986. The objectives of this study are to describe Harpagobaetis brigada sp. nov., based on nymphs and to amend the diagnosis of the genus. The predatory habit of the nymphs of the new species was confirmed by gut-content analysis and by direct observations of behavior. Based on similar morphological adaptations, we hypothesized that Adebrotus lugoi Salles, 2010 possesses predatory habit. Harpagobaetis brigada sp. nov. can be classified as psammophilous, inhabiting a threatened stream in a relict patch of savanna in southern Amazonia. Based on these characteristics, we recommend evaluation of this new species to identify its conservation status and to contribute to the assessment of the state of conservation of the Brazilian fauna.

Contribution to the taxonomy of Paracloeodes Day 1955 (Ephemeroptera: Baetidae) from South America.

In recent decades, major advances in the systematics of the Western Hemisphere genus Paracloeodes Day have been made in South America. Despite the taxonomic progress, uncertainties in identification remain due to the morphological similarities among some nymphs and due to the general lack of knowledge of the imago stages (only 4 of 20 are described from throughout the range of the genus). This study addresses these impediments in part through description of the male imagoes of six species (P. atroari Nieto Salles, P. binodulus Lugo-Ortiz McCafferty, P. ibicui Lugo-Ortiz McCafferty, P. pacawara Nieto Salles, P. peri Nieto Salles, P. waimiri Nieto Salles), description of two new species based on morphologically distinct nymphs (P. aristotelesi sp. n. and P. carolinae sp. n.), description of one new species based on morphologically distinct nymph and male imago (P. prismatobranchus sp. n.); redescription of three species based on type material (P. ibicui Lugo-Ortiz McCafferty, P. leptobranchus Lugo-Ortiz McCafferty and P. eurybranchus Lugo-Ortiz McCafferty); proposal of one new synonym based on morphological analyses of specimens from Bolivia, Brazil and Uruguay, including type specimens (P. pacawara = P. morellii Emmerich Nieto); and the presentation of a new key to identify nymphs from South America to the species level.

Review of continental North and Central American Paracloeodes Day 1955 (Ephemeroptera: Baetidae), including description of a new species from Minnesota, U.S.A.

Paracloeodes Day is a western hemisphere genus with 20 species, but only three of these valid species are known from continental North and Central America. Based on available literature comparisons, species-level identifications of these three species can be difficult. Considering the apparent similarity between them, the main objective of this study was to examine type and other material housed in the Purdue Entomological Research Collection and the University of Minnesota in order to evaluate species status and to elucidate additional diagnostic characters. The evaluation resulted in validation of P. fleeki McCafferty & Lenat, P. lugoi Randolph & McCafferty and P. minutus (Daggy) and the confirmation of P. abditus Day as a junior synonym of P. minutus. Furthermore, we discovered a new species from the type locality of P. minutus. Paracloedes lotor n. sp. is described based on the nymph stage and a putative male imago from the Mississippi River in Minnesota. Paracloeodes lotor n. sp. differs from the other continental North and Central American species of the genus by the apical half of the paraglossa having an abrupt decrease in width (the "subtriangular" condition) in nymphs, and by having the posterior margin of the styliger plate with a small and pointed spine in the male imago. We provide a new identification key for nymphs of the four continental North and Central American species.

Four new species of Callibaetis Eaton (Ephemeroptera: Baetidae), nymphal description of Callibaetis (Abaetetuba) fasciatus (Pictet) and keys for South American species of Callibaetis.

The first phylogenetic study of Callibaetis Eaton indicated an unrevealed diversity in this genus, including four new species named as Callibaetis sp. A, B, C and D, and the undescribed nymph of Callibaetis (Abaetetuba) fasciatus (Pictet). Given that neither the nymph of C. (Ab.) fasciatus nor the four new species received a proper description, the objective of this study is to describe them. The nymph of C. (Ab.) fasciatus differs from the others species in the subgenus by the presence of one row of setae on basal part of inner-dorsal row of maxilla and metanotum without spines; Callibaetis sp. A is described as Callibaetis (Abaetetuba) cochlea sp. nov. and differs from the others species in the subgenus by having trapezoid segment III of labial palp in nymphs; Callibaetis sp. B is described as Callibaetis (Aiso) calophenigyn sp. nov. and differs from the others species in the subgenus by the absence of stout setae on dorsal surface of glossa in nymphs, and from the others species in the genus by the forewing with red C and Sc areas in female imago; Callibaetis sp. D is described as Callibaetis (Callibaetis) molinerii sp. nov. and differs from the others species in the subgenus, from South America, by the maxilla with tuft of stout setae on outer margin proximad of palp insertion and paraglossa without row of stout setae on ventral surface; Callibaetis sp. C is described as Callibaetis (Cunhaporanga) imperator sp. nov. and differs from the others species in the subgenus by the presence of a complete row of setae on outer margin of maxilla. Additionally, new keys for species of Callibaetis from South America are proposed.

Additions and corrections to the systematics of mayfly species assigned to the genus Callibaetis Eaton 1881 (Ephemeroptera: Baetidae) from South America.

Due to historical taxonomic impediments, species of Callibaetis Eaton are difficult to identify. Recent studies have attempted to resolve this problem, although many species still lack complete descriptions; nymphs of several species remain undetermined; and type specimens are lost or poorly known. Given these hindrances, the aim of this study is to review some of the type specimens of Callibaetis from South America. This review provides a series of taxonomic additions and corrections supported by improved morphological evaluations, illustrations and photographs of Callibaetis camposi Navás, C. (Abaetetuba) capixaba Cruz, Salles & Hamada, C. gregarius Navás, C. (C.) guttatus Navás, C. jaffueli Navás, C. (C.) jocosus Navás, C. nigrivenosus Banks, C. (A.) pollens Needham & Murphy, C. (C.) radiatus Navás, C. (A.) sellacki (Weyenbergh), C. stictogaster Navás, C. (C.) viviparus Needham & Murphy, C. (C.) willineri Navás, and C. (C.) zonalis Navás. From among these species, C. stictogaster and C. jaffueli are revalidated; C. nigrivenosus and C. gregarius are designated as nomina dubia; C. (C.) fluminensis Cruz, Salles & Hamada is proposed as a junior subjective synonym of C. (C.) zonalis; and C. gloriosus Navás is proposed as a junior subjective synonym of C. (A.) sellacki (Weyenbergh). Lectotypes are designated for C. camposi, C. jaffueli, C. (C.) radiatus and C. stictogaster.

Oligoneuria (Yawari) anatina sp. nov. (Ephemeroptera: Oligoneuriidae) from the extreme north of Brazil.

Oligoneuria (Yawari) anatina sp. nov. is described and illustrated based on nymphs and imagoes collected in the municipality of Serra do Navio, state of Amapá, Brazil. The main characteristics that can be used to distinguish the new species from other species of the genus are, in imagoes: 1) forewing with spectral cross veins between IRS and MP2 (male) or between IRS and IMP (female), 2) posterior margin of styliger plate distally rounded and with paired rounded projections; in nymphs: 1) vertex of head with two pairs of tubercles, 2) lateral margin of anterior projection of head straight. Cytochrome Oxidase subunit I (COI) sequences were used to associate male imago and immature stages of the new species.

A new species of Tricorythopsis Traver, 1958 (Leptohyphidae) and occurrence of Pannota (Insecta: Ephemeroptera) species in Amapá state, Brazil.

The objectives of this study were to describe a new species of Tricorythopsis based on adults, and to report for the first time the following species and genera in Amapá state, Brazil: Amanahyphes saguassu Salles & Molineri, Macunahyphes australis (Banks), Macunahyphes pemonensis Molineri, Grillet, Nieto, Dominguez & Guerrero, Tricorythodes yapekuna Belmont, Salles & Hamada, Tricorythopsis faeculopsis Belmont, Salles & Hamada, Tricorythopsis pseudogibbus Dias & Salles, Tricorythopsis rondoniensis (Dias, Cruz & Ferreira), Tricorythopsis yucupe Dias, Salles & Ferreira (Leptohyphidae), Coryphorus aquilus Peters (Coryphoridae) and Brasilocaenis (Caenidae). Macunahyphes pemonensis is recorded for the first time in Brazil. Tricorythopsis yusuaia sp. nov., can be distinguished from congeners by the following combination of characteristics: abdomen with black and reddish marks, a strongly sclerotized spine present on the base of the median filament, and the base and lateral margins of penes being sclerotized.

Two new species of Apobaetis Day, 1955 (Ephemeroptera: Baetidae) from Brazil.

Apobaetis Day, 1955 species are known for their small size and preference for sandy stream substrate. Species which possess such habitat preference commonly possess long and slender legs and claws, but, in Apobaetis, the length of the tarsal claw rarely is so long that it exceeds the length of tarsus, occurring only in two species: A. lakota McCafferty, 2000 from USA and A. hamadae Cruz, Boldrini & Salles, 2011 from Brazil. In the present study, two new species with tarsal claws that exceed the length of the tarsi are described: Apobaetis pucupi sp. nov. from southeast Brazil and Apobaetis kethepiali sp. nov. from northernmost Brazil. Additionally, a new key for nymphs of Apobaetis is proposed.