Do Methodological Differences in Experiments with Stream Shredders Imply Variability in Outputs? A Microcosm Approach

Experiments are useful scientific tools for testing hypotheses by manipulating variables of interest while controlling for other factors that can bias or confuse the results and their interpretation. To ensures accuracy and reproducibility, experiments must have transparent and repeatable methodologies. Due to the importance of shredder invertebrates in organic matter processing, carbon cycling, and nutrient cycling, we tested experimentally the effect of different methodological approaches in microcosm experiments on the consumption and survival of shredders. We found that the shredder species, the presence or absence of the case, and the use or non-use of air-pumps in the microcosms did not affect shredder performance (i.e., consumption and survival). Furthermore, the type of water (stream or bottled) did not affect shredder performance. On the other hand, the amount of light had a negative effect on shredder performance, with constant light (i.e., 24 h) reducing shredder consumption and survival. Our results demonstrate that the use of different methodologies does not always result in changes in outcomes, thus ensuring comparability. However, luminosity is a critical factor that deserves attention when conducting microcosm experiments. Our findings provide valuable insights that can assist researchers in designing experiments with shredders from neotropical streams and conducting systematic reviews and meta-analyses.

New species and record of Diplosmittia Sther, 1981 (Diptera: Chironomidae, Orthocladiinae) from Brazil and Colombia

Chironomidae is a diverse Diptera family found worldwide. The genus Diplosmittia Sther, 1981, currently with 11 valid species, has been found exclusively in the New World, mainly in the Caribbean and in the northern parts of South America; only three species are recorded from Brazil and none from Colombia so far. In the present study a new species of Diplosmittia is described and illustrated based on material collected in northeastern Brazil. It appears to be most closely related to Diplosmittia beluina Andersen, 1996, but can be distinguished by morphological differences in the virga and gonostylus. Diplosmittia harrisoni Sther, 1981 is documented for the first time from Colombia, and D. carinata Sther, 1985 is formally placed as a junior synonym of D. harrisoni. In addition, an update identification key to all known species of the genus has been provide.

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.

New species and records of Caenidae Newman, 1853 (Insecta: Ephemeroptera) from Rondnia State, Northern Brazil

Caenidae is a globally widespread family, inhabiting a variety of aquatic habitats. In South America, only 35 species are recognized, maybe as a consequence of the few studies until the first decade of the 21st century. Despite recent advances, large portions of Brazil, such as Rondnia State, are still characterized by Linnean and Wallacean shortfalls. Rondnia is an area predicted to have high mayfly richness, but with no record of Caenidae. From this perspective, the objective of this study is to provide the first access to primary biodiversity data of Caenidae (Ephemeroptera) from Rondnia. As result, we report five species (Brasilocaenis elidioi, Brasilocaenis irmleri, Caenis chamie, Caenis fittkaui, Latineosus sigillatus) and describe a new species based on all life stages (Caenis urupa sp. nov.).

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.

A new species of Macropelopia Thienemann, 1916 (Diptera: Chironomidae) from Southern Brazil

We report a new species of Macropelopia discovered in southern Brazil, with detailed illustrations and descriptions of all life stages. In addition, we provide an identification key specific to males of neotropical Macropelopia species, together with an amendment to the generic diagnosis.

Tanytarsus van der Wulp (Chironomidae, Diptera): new species from the western Amazon region in Peru and Brazil, new records from the Neotropics, and remarks on the taxonomy of the genus

This research is focused on the diversity and systematics of Neotropical non-biting midges of the genus Tanytarsus van der Wulp, 1874, based on specimens collected from pristine areas of the western Amazon region in Peru and Brazil. Six new species are described: Tanytarsus aries sp. nov. (Peru), T. chicomendesi sp. nov. (Brazil, Acre), T. kaxinawa sp. nov. (Brazil, Acre; Peru), T. pinedoi sp. nov. (Peru), T. serra sp. nov. (Peru), and T. frameatus sp. nov. (Peru), the latter placed in the Tanytarsus hastatus species group, here defined. Data on several recently described Neotropical Tanytarsus, obtained by analyzing specimens recorded from different regions of Brazil (Amazonas, Bahia, Federal District, Pará, São Paulo, Tocantins) are appended, and remarks on the taxonomy and variations of their diagnostic structures are provided. Tanytarsus pollicis Reis, Lin et Ferreira-Keppler, 2022 is treated as a new synonym of Tanytarsus insolens Dantas et Giłka, 2017. Further two species, Tanytarsus marianae Reis, Lin et Ferreira-Keppler, 2022 and Tanytarsus rafaeli Reis, Lin et Ferreira-Keppler, 2022 are placed in the Tanytarsus kiche group. The Tanytarsus curvicristatus group is also supplemented with Tanytarsus giovannii Sanseverino et Trivinho-Strixino, 2010.

Do microplastics and climate change negatively affect shredder invertebrates from an amazon stream? An ecosystem functioning perspective

Pollution and climate change are among the main threats to the biodiversity of freshwater ecosystems in the 21st century. We experimentally tested the effects of microplastic and climate change (i.e., increase in temperature and CO₂) on the survival and consumption by an Amazonian-stream shredder invertebrate. We tested three hypotheses. (1) Increased microplastic concentrations and climate change reduce shredder survival. We assumed that the combined stressors would increase toxic stress. (2) Increased concentrations of microplastics have negative effects on shredder food consumption. We assumed that blockage of the digestive tract by microplastics would lead to reduced ability to digest food. In addition, increased temperature and CO₂ would lead to an increase in metabolic cost and reduced consumption. (3) The interaction between microplastics and climate change have greater negative effects on survival and consumption than either alone. We combined different concentrations of microplastic and climate change scenarios to simulate in real-time increases in temperature and CO₂ forecast for 2100 for Amazonia. We found that both stressors had lethal effects, increasing mortality risk, but there was no interaction effect. Shredder consumption was negatively affected only by climate change. The interaction of microplastics and climate change on shredder consumption was dose-dependent and more intense in the extreme climate scenario, leading to reduced consumption. Our results indicate that microplastic and climate change may have strong effects on the consumption and/or survival of insect shredders in Amazonian streams. In addition, microplastic and climate change effects may affect not only populations but also ecosystem functioning (e.g., nutrient cycling). Integrative approaches to better understand and mitigate the effects of both stressors are necessary because plastic pollution and climate change co-occur in environments.

Molecular circumscription of the blackfly Simulium oyapockense from South America

Problems related to the identity of Simuliidae species are impediments to effective disease control in Amazonia. Some of these species, such as Simulium oyapockense Floch & Abonnenc, 1946 (Diptera: Simuliidae), are vectors of the organisms that cause onchocerciasis and mansonellosis diseases. This blackfly species has a wide distribution in South America, and it is suspected of being a complex of cryptic species. The aim of this study is to characterize the nominal species S. oyapockense using partial COI gene sequences. Seven populations of S. oyapockense (morphologically identified) were analysed, including one from its type-locality. The other six populations were collected in Brazil and in Argentina. A taxon collected in Amazonas state, Brazil, with adults similar to S. oyapockense but with distinct pupae, was also included in the analysis (Simulium 'S'). The nominal species S. oyapockense is circumscribed, and its geographical distribution is restricted to areas north of the Amazon River. Populations of S. oyapockense s.l. collected south of the Amazon River comprise a species complex that needs to be evaluated using integrative taxonomy. Simulium 'S' represents a species with unique morphological and molecular characteristics. Distinguishing cryptic species is a prerequisite for reducing the taxonomic impediment, especially in medically important taxa.

New species and new distributional records of the hygropetric water scavenger beetle genus Ephydrolithus Girón & Short (Coleoptera: Hydrophilidae) from the Brazilian Shield

The water scavenger beetle Ephydrolithus Girón and Short, 2019 contains five species, all occurring in the southeastern region of Brazil. In this paper, 5 new species are described from the Brazilian Shield, bringing the number of species in the genus to 10: Ephydrolithus bentoi sp. nov., Ephydrolithus cipo sp. nov., Ephydrolithus mucugensis sp. nov., Ephydrolithus serro sp. nov., and Ephydrolithus vivas sp. nov. New geographical records in the Brazilian Shield are provided for Ephydrolithus hamadae Girón and Short, 2019, Ephydrolithus spiculatus Girón and Short, 2019, and Ephydrolithus teli Girón and Short, 2019. Corroborating the previously described habitat for the genus, all new species are associated with hygropetric zones such as wet rocks, waterfalls, and seepages. An updated key to identify adults of Ephydrolithus is provided.

Notalina (Neonotalina) ralphi sp. nov. (Trichoptera, Leptoceridae), a new long-horned caddisfly from the Cerrado biome of Brazil, with new records for N. (Neonotalina) brasiliana Holzenthal, 1986 and an identification key

The long-horned caddisfly genus Notalina Mosely, 1936 contains 27 species divided into two subgenera. The Neotropical N. (Neonotalina) Holzenthal, 1986 occurs exclusively in South America. Its species are organized into two species groups, brasiliana and roraima. Nine species have been recorded so far in Brazil, mainly distributed in the Cerrado and Atlantic Forest biomes of Southeast Region, and only one species has been recorded from the Central-West and Northeast Regions. In this paper a new species of N. (Neonotalina) is described and illustrated based on adult males from two protected and preserved areas in the Cerrado biome of Brazil. Notalina (Neonotalina) ralphisp. nov. belongs to the brasiliana species group and can be recognized mainly by the morphology of the preanal appendages and segment X. New distributional records are provided for N. (Neonotalina) brasiliana Holzenthal, 1986. Additionally, a key to identify males of the ten species in the brasiliana species group is provided.

After a decade, a new Venezuelan species of Corydalus Latreille (Megaloptera, Corydalidae, Corydalinae) is discovered

A new species of dobsonfly from Venezuela, Corydalusralphi Martins, Azevêdo, Hamada & Contreras, sp. nov., was discovered a decade after the last description of a species of this genus in the country. The new species is morphologically similar to C.wanningeri Contreras-Ramos & von der Dunk, sharing a uniform reddish coloration of body and wings and similar male genitalic structures. Likewise, it shares this particular coloration with C.neblinensis Contreras-Ramos but the genitalic structure fits within the C.crossi Contreras-Ramos species group. Two specimens, one male and one female, were collected on Tarotá River, in the Gran Sabana region, Canaima National Park, in southern Venezuela. A key to identify males of the Venezuelan species of Corydalus is provided.

"Out of the Shield": the Discovery of Platyparnus Shepard and Barr, 2018 (Coleoptera: Dryopidae) in Brazil with New Species

The Neotropical Dryopidae genus Platyparnus Shepard and Barr, 2018 was recently established based on three species originally described in Helichus Erichson, 1847: Platyparnus bollowi (Hinton, 1939), Platyparnus frater (Hinton, 1939) and Platyparnus gibbicollis (Hinton, 1939). Until now, the genus and its species have been reported solely in the Guiana Shield area (in French Guiana and Guyana). Based on the examination of material from several localities in Brazil, we report Platyparnus for the first time in the country and describe two new species based on males and females: Platyparnus beatriceae sp. nov. and Platyparnus glaucoi sp. nov. We also propose an amendment to the original diagnosis of Platyparnus, present an updated key to the species, and provide new records for P. frater. Since the new species described here and P. frater were found to occur below the Equator and far south the Amazon River, the geographic distribution of the genus is extended to outside the Guiana Shield.

New species and new distributional records of the hygropetric water scavenger beetle genus Oocyclus Sharp (Coleoptera, Hydrophilidae) from the Brazilian Shield

Nine new species of the water scavenger beetle genus Oocyclus Sharp, 1882 are described from the Brazilian Shield: O. ecolab sp. n., O. espinhacu sp. n., O. giganteus sp. n., O. humboldti sp. n., O. lacia sp. n., O. ovalis sp. n., O. sulcatus sp. n., O. thrixdiastematus sp. n., and O. thysanus sp. n. New locality records are provided for four species previously known from Brazil: O. rotundus Clarkson Short, 2012, O. pilosus Jordo, Clarkon Ferreira-Jr, 2018, O. xanthus Clarkson Short, 2012 and O. yubai Clarkson Short, 2012. All species are associated with rock-face seepages such as wet rocks, waterfalls, and seepages. An updated key to the Brazilian species of Oocyclus is provided.

A new minute riffle beetle (Coleoptera: Elmidae: Pagelmis) from the Brazilian Amazon

The monotypic genus Pagelmis Spangler, 1981 was described from six thousand specimens of Pagelmis amazonica Spangler, 1981 collected with blacklight traps in Ecuador. For many years the known distribution of this genus was restricted to its type-locality, and recently it was recorded in Venezuela, Suriname and Brazil (Roraima State). Now, 40 years after the description of the genus, we describe the second Pagelmis species, based on male and female collected in the Amazon forest (Amazonas State, Brazil). With the description of the second species in the genus we provide an emended diagnosis of Pagelmis. Since adults of this genus were previously collected only in light traps, no habitat information was known. We collected adults of the new species in the first- and second-order streams with black, acidic water and sandy streambeds. The main substrates available in these streams were leaves and roots of riparian vegetation.

Novelties in central Amazonian microcaddisflies: Three new species of Ochrotrichia Mosely (Trichoptera: Hydroptilidae)

Ochrotrichia Mosely is the most species-rich group of microcaddisflies in the Neotropical Region. However, knowledge about this genus in Brazil is still limited; only 11 species are known, distributed in the Atlantic Forest (9), Caatinga (3), and Amazon (1) biomes. In this paper, three new species of Ochrotrichia are described and illustrated based on adult males collected in the Ducke Forest Reserve, a protected area administered by the Instituto Nacional de Pesquisas da Amazonia (INPA), located in central Amazonia, Brazil. Ochrotrichia belodes sp. nov., O. buenosoria sp. nov. and O. ducke sp. nov. can be recognized mainly by the morphology of tergum X and the inferior appendages. Based on their simple, elongate tergum X, all new species are assigned to the Ochrotrichia xena Group.

Protected areas are not effective for the conservation of freshwater insects in Brazil

Biodiversity conservation has faced many challenges, especially the conversion of natural areas that compete with use for agriculture, energy production and mineral extraction. This problem is further aggravated by lack of knowledge of the biodiversity that exists and the geographical distribution of different groups. The objectives of our study were to examine the distributional pattern of Gerromorpha diversity in Brazil, create a map of conservation priority areas, estimate the degree of protection that the current network of protected areas guarantees to this insect group, and identify the size thresholds in geographical distributions that would allow species to be protected. We used species occurrences from the Water Bugs Distributional Database, and we used 19 bioclimatic variables to build models of the potential distributions of species using the MaxEnt program. Using the potential model results, we calculated diversity metrics and overlapped them with the current state and federal “conservation units” (protected areas for biodiversity) in Brazil. Total beta diversity and turnover portions were separated into two faunistic groups, one in northern and the other in southern Brazil. The Amazon has higher beta diversity than what was predicted by the null models. We detected a positive relationship between species distribution area and occurrence in conservation units. Conservation units with less than 250 km² do not protect Gerromorpha species. Our results reinforce the necessity of formulating new conservation strategies for this group, contemplating species with both restricted and ample distributions, because rare and specialist species are the most harmed by habitat reduction, given that they are more sensitive to environmental disturbance.

Discovery of Kribiodorum Kieffer (Diptera: Chironomidae) in the Neotropical region: a new species from Brazilian Amazon rainforest

Kribiodorum is a small genus of non-biting midges, currently composed of only five nominal species, one Nearctic, two African and two Oriental. The objective of this study is to provide the first report of this genus to the Neotropical region and to describe a new species, based on male and female from southern Amazonas state, Brazil. Kribiodorum amazonicum sp. n. is easily distinguished from the congeneric species by the color pattern of the wings and legs and by the morphology of the genitalia.

Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.

It is unclear whether stream detritivore diversity enhances decomposition across climates. Here the authors manipulate litter diversity and examine detritivore assemblages in a globally distributed stream litterbag experiment, finding a positive diversity-decomposition relationship stronger in tropical streams, where detritivore diversity is lower.

On the Identity of Smicridea (Smicridea) aequalis Banks, 1920 (Trichoptera: Hydropsychidae): Morphology of Adults and Immature Stages, Bionomics, Distribution, and Male Color Dimorphism

After 100 years of its description, the morphological circumscription of Smicridea aequalis Banks, 1920 is provided in this study by the integration of morphological characters of adult, pupal, and larval stages. This fact facilitates its recognition in faunal inventory studies and allows its use in biomonitoring programs, mainly in the Amazon and Cerrado biomes, two biodiversity hotspots where this species is widely distributed. Adults of S. aequalis may have diurnal activity as they are found frequently and abundantly on the riparian vegetation of fast-flowing streams and rivers during the day. The remarkable color dimorphism observed in males of this species was not reported previously for caddisflies.

Pedrowygomyia (Diptera: Simuliidae): Discovery of a New Species After 30 yr

Pedrowygomyia is a Neotropical genus of Simuliidae composed of four species; all were described in 1989 from high-elevation (above 3,000 m) areas in the Andean region. In this article, a new species for this genus, Pedrowygomyia hanaq n. sp., is described based on all stages of development. The new species was collected in the south-central Andes of Peru at an altitude above 4,000 m, and its known distribution is currently restricted to the type-locality. Based on the pupal stage, the new species appears to be more closely related to Pedrowygomyia punapi (Wygodzinsky & Coscarón) (Diptera: Simuliidae), a species known from Argentina, Bolivia, and Chile.

Morphological remarks on Adelphydraena amazonica Perkins amp; Ribera, 2020 and new records of two other Hydraenidae from Brazil (Coleoptera)

Undescribed morphological features of Adelphydraena amazonica Perkins Ribera, 2020 are provided based on material collected in the type locality (Amazonas State, northern Brazil). Aedeagus, male sternite X, last female abdominal segments and spermatheca are illustrated and described for the first time. Habitat information on the type locality is also included. New records on two Brazilian Hydraenidae species are provided.

Back from the past: Molecular and morphological support for Simulium mutucuna Nunes de Mello & Vieira da Silva, 1974 (Diptera: Simuliidae) as a valid species

Simulium mutucuna, a species described based on a single female from Roraima state, was previously synonymized with Simulium paynei and currently is considered a synonym of Simulium rubrithorax. In the present paper we present morphological and molecular evidence supporting the validity of S. mutucuna based on analysis of specimens from Brazil, Venezuela and Mexico. We redescribe the female and describe, for the first time, the male, pupa and larva of S. mutucuna and discuss the morphological differences between this species and the others that are already considered as its senior synonyms. Currently, the distribution of S. mutucuna is restricted to Roraima state. The distribution record for S. rubrithorax in Brazil's North region needs to be removed, since the previous records were based on occurrence of S. mutucuna. Finally, we present new evidence of cryptic diversity in the S. paynei complex based on molecular information.

Two new species of Smicridea (Rhyacophylax) Müller 1879 (Trichoptera: Hydropsychidae) from Atlantic Forest, Brazil

Smicridea (Rhyacophylax) Müller 1879 contains 106 species, 41 of which occur in Brazil, mainly in the Atlantic Forest biome. Despite its diversity, it is estimated that many undescribed species are believed to be housed in scientific collections, waiting to be described. Smicridea specimens housed in two Brazilian insect collections (Coleção Entomológica Professor José Alfredo Pinheiro Dutra, Rio de Janeiro and Museu de Zoologia da Universidade de São Paulo, São Paulo) were examined and two new species of S. (Rhyacophylax) were detected. The objective of this study is to describe and illustrate these species. Smicridea (Rhyacophylax) boraceia sp. nov. and Smicridea (Rhyacophylax) dumasi sp. nov. inhabit the Atlantic forest biome and can be recognized mainly by the morphology of tergum X and the phallic apparatus. Six species groups are recognized in S. (Rhyacophylax); however, the two new species described here cannot be placed in any of these groups.

Latitude dictates plant diversity effects on instream decomposition

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113° of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes.

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.

Integrated terrestrial-freshwater planning doubles conservation of tropical aquatic species

Conservation initiatives overwhelmingly focus on terrestrial biodiversity, and little is known about the freshwater cobenefits of terrestrial conservation actions. We sampled more than 1500 terrestrial and freshwater species in the Amazon and simulated conservation for species from both realms. Prioritizations based on terrestrial species yielded on average just 22% of the freshwater benefits achieved through freshwater-focused conservation. However, by using integrated cross-realm planning, freshwater benefits could be increased by up to 600% for a 1% reduction in terrestrial benefits. Where freshwater biodiversity data are unavailable but aquatic connectivity is accounted for, freshwater benefits could still be doubled for negligible losses of terrestrial coverage. Conservation actions are urgently needed to improve the status of freshwater species globally. Our results suggest that such gains can be achieved without compromising terrestrial conservation goals.

How Habitat Filtering Can Affect Taxonomic and Functional Composition of Aquatic Insect Communities in Small Amazonian Streams

Responses in taxonomic and functional composition of communities were analysed in small Amazonian streams at the small and large scale (habitat patches, river segment scale, and catchment scale). We hypothesised that similar responses in community structure to local environmental factors were a correlation between taxonomic and functional composition. To evaluate the response of taxonomic composition to environmental variables, redundancy analysis (RDA) and RLQ analysis were performed to investigate the response of community abundance (L) as a function of the environment (R) and traits (Q). The fourth-corner analysis was applied to summarize specific interactions between environmental variables and traits. Then, community taxonomic composition was associated with models at multiple scales of habitat (i.e. riparian/channel, substrates, and water variables). Likewise, the fourth-corner tests and RLQ axes showed associations between trait composition and environmental variables related to variables, such as riparian cover and channel morphology followed by variation in substrate size and composition. Unexpectedly, these results did not show specific associations between unique environmental variables and traits. At last, results showed that local conditions of stream habitat regulated community structure and functional composition of aquatic insects. Thus, these findings indicate that the local environmental filtering appears to be strongly associated with selected species traits adapted to occur in a range of habitat conditions. Despite the low number of analysed streams, these results provide important information for understanding the simultaneous variation in functional trait composition and community composition of aquatic insect assemblages.

Immature stages of three species and new records of five species of Phylloicus Müller (Trichoptera, Calamoceratidae) in the northern region of Brazil

The larvae, pupae, and cases of Phylloicus amazonas Prather 2003, P. fenestratus Flint 1974, and P. passulatus Prather 2003 are described and illustrated, and the adult females of P. amazonas and P. passulatus are illustrated. Additionally, the lateral coremata with an eversible membranous sac and the everted phallus of the male of P. passulatus are illustrated and described. Larval bionomics are presented for each species. First records of species are presented for Brazil (P. passulatus), Pará state (P. amazonas, P. dumasi Santos Nessimian 2010, P. elektoros Prather 2003), and Tocantins state (P. fenestratus).

Leaf litter quality drives the feeding by invertebrate shredders in tropical streams

Amazon and Cerrado-forested streams show natural fluctuations in leaf litter quantity along the time and space, suggesting a change on litter quality input. These natural fluctuations of leaf litter have repercussion on the organic matter cycling and consequently effects on leaf decomposition in forested streams. The effects of the quantity of leaf litter with contrasting traits on consumption by larvae of shredder insects from biomes with different organic matter dynamics have still been an understudied question. The Trichoptera Phylloicus spp. is a typical shredder in tropical headwater streams and keep an important role in leaf litter decomposition. Here, we assessed the consumption by shredder Phylloicus spp., from Amazonia and Cerrado biomes, on higher (Maprounea guianensis) and lower quality leaves (Inga laurina) in different proportions and quantities. Experiments were performed concomitantly in microcosms approaches, simulating Cerrado and Amazonian streams. Higher leaf consumption occurred in Cerrado microcosms. Litter quantity influenced negatively leaf consumption by shredders in Cerrado, in opposition to Amazonia, where consumption was not affected by leaf quantity. In both sites, we observed higher consumption by shredders in treatment with only M. guianensis and no difference between other treatments with mixture of leaves. In treatment with litter of I. laurina, we noted the use of substrate for case building (due to the higher leaf toughness), affecting the fragmentation process. Therefore, our results indicate that leaf litter quality drives the preference of consumption by Phylloicus larvae in Cerrado and Amazonia streams.

Hydaticus aequalis sp. n. and a new record of H. devexus Trémouilles, 1996 from Brazil (Coleoptera, Dytiscidae, Hydaticini)

Hydaticus aequalis sp. n. is described from Brazil, where it was recently discovered in the central lowlands region of the Amazon forest. The new species differs from all other Neotropical congeners by its uniformly brown dorsal surface and the shape of medial lobe. The dorsal habitus and male genitalia are illustrated, and a distribution map is provided. The habitat, a small stream and associated forest pool, is illustrated and described. In addition, a new record of H. devexus Trémouilles, 1996, previously known from a single specimen, is reported from the highlands of northeastern Brazil, and a modified key to Neotropical species of the genus is provided.

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.

A new species in Simulium (Trichodagmia) (Diptera: Simuliidae) from Chapada Diamantina region, Brazil: cryptic diversity revealed by morphological and molecular evidence

We describe new species of black fly that had previously been identified as S. scutistriatum Lutz due to morphological similarities at the pupal stage. The description of the new species, Simulium (Trichogamia) itajara n. sp., is based on molecular and morphological evidences. The known distribution of the new species is currently restricted to the Paraguaçu River hydrographic basin in Chapada Diamantina National Park and the surrounded area in Bahia state, Brazil. The distribution record for S. scutistriatum in the northeast region of Brazil needs to be removed, since the previous records were based on occurrence of S. itajara n. sp.

An unusual new species of Pentaneura Philippi (Diptera: Chironomidae) from northeastern Brazil, with an emended diagnosis to the genus

Pentaneura herbeti sp. nov. is described and illustrated based on male, female, pupa and larva collected in Northeastern region of Brazil. In addition, an amendment in the adult, pupal and larval diagnosis of Pentaneura is provided.

Rediscovery of the Neotropical water scavenger beetle Protistolophus spangleri Short with notes on its habitat and behavior (Coleoptera: Hydrophilidae: Hydrophilinae)

The water scavenger beetle genus Protistolophus Short contains a single species, P. spangleri Short, 2010, known from southern Venezuela. The genus was hitherto known only from a single partly-incomplete male specimen, making it one of the rarest and most poorly known aquatic hydrophilid genera in the world. Only one other New World aquatic hydrophilid genus, the Ecuadorian cave endemic Troglochares Spangler, is known from a single specimen or locality. In a phylogenetic analysis of the Hydrophilini based on adult morphology, the genus Protistolophus was resolved as the sister taxon to the remaining genera of the tribe, implying it is an ancient and possibly relict lineage-it possesses a very unusual combination of characters, including a very weakly developed mesoventral keel. It was the only genus not included in a recent molecular phylogeny of the Hydrophilini as no suitable material was available for DNA (Toussaint et al. 2017).

Two new species of Hydraena Kugelann, 1794 from Brazil (Coleoptera: Hydraenidae)

Hydraena (Hydraenopsis) josefinae sp. nov. and H. (H.) pernambucana sp. nov. are described respectively from Amapá and Pernambuco States, Brazil. Hydraena (H.) josefinae sp. nov. is a member of the scintillabella subgroup of the leechi group, while H. (H.) pernambucana sp. nov. belongs to the orcula complex in the marginicollis subgroup of the marginicollis group. Descriptions and diagnostic characters for both new species are offered; habitus photographs and line drawings of male genitalia of the two new species, as well as drawings of female genitalia of H. josefinae sp. n., are provided. Male genitalia of H. alterra Perkins, 1980 is illustrated and compared with that of the closely related H. josefinae sp. nov. Habitat and distributional data of the two new species are also included.

Hydrodessus ducke sp. n. and new records of other species of the genus (Coleoptera, Dytiscidae, Bidessini)

Hydrodessus ducke sp. n. is described and illustrated based on specimens collected in Amazonas State (northern Brazil), bringing the total number of Hydrodessus species to 33. The new species can be distinguished from other species in the genus by body size and shape, coloration, and characteristics of the elytral carina, prosternal process, metaventral carina, and male genitalia. The male of H. latotibialis Miller, 2016 is described and illustrated for the first time from specimens collected in Pará State, northern Brazil. New records for 17 species from Brazil, French Guiana and Suriname are provided, and the newest existing key to species is updated to accommodate the new taxon.

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 Rheotanytarsus Thienemann amp; Bause (Diptera: Chironomidae) from Peruvian Andes, with updated key to South American species

Rheotanytarsus is a speciose genus, currently composed by more than 100 nominal species distributed worldwide, 19 are known from the Neotropical region, four from South America and only one is registered for Peru. In the present study, a new species is described and illustrated based on males collected in the Peruvian Andes. In addition, the key to the South American species is updated and a distribution map of them is provided. Rheotanytarsus amaru sp. n. is easily distinguished from the congeneric species by the dark general coloration and the hypopygial morphology.

Checklist of dragonflies and damselflies (Insecta: Odonata) of the Amazonas state, Brazil

Abstract: Here we provide a checklist of the odonates from Amazonas state, Brazil. We registered 324 species and 101 genera, making Amazonas the Brazilian state with the most Odonata species recorded. The families with the highest number of species were Coenagrionidae with 32 genera and 101 species, followed by Libellulidae with 28 genera and 100 species and Gomphidae with 12 genera and 45 species. Some regions of Amazonas state remain poorly explored, such as the southern area, and large municipalities, such as São Gabriel da Cachoeira. This work underlines the importance of the biological diversity from Amazonas state and the Amazonian Biome for Odonata species richness in Brazil and shows that many areas in the world’s largest tropical forest have not yet been sampled.

Two new species of Enderleina Jewett (Plecoptera: Perlidae) from northern Brazil

Enderleina Jewett, 1960 is a small genus of Perlidae with seven species occurring in Venezuela and northern Brazil. Specimens deposited in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Brazil, identified formerly as E. flinti Stark, 1989 (n = 3) and E. yano Stark, 1989 (n = 6), were determined to represent three taxa, two of which are new species. Both new species were collected in Amazonas State, Brazil and are distinctive within the genus due to their unique adult color patterns. The third taxon is represented by a female similar to E. khazeni Derka Tierno Figueroa, 2013, the male of which was described from the nearby Gran Sabana, Venezuela. However, since the female of this species is not known, the specific identity of this female cannot be assigned specifically with confidence. In this paper, we describe two new species of Enderleina from Brazil, clarifying the specific status of the Enderleina specimens in the collection of INPA, and correcting the geographical distributions of E. flinti and E. yano. There are no valid records of these two species for Brazil. Currently, four species of the genus are known from Brazil.

Three new neotropical species of Ablabesmyia Johannsen, 1905 (Diptera: Chironomidae)

Three new species of Ablabesmyia are described from Brazil: A. akemiae sp. n. based on the male, female, pupa and larva; A. adamantis sp. n. based on the male, pupa and larva; and A. monticola sp. n. based on the adult male. Ablabesmyia akemiae sp. n. immatures were collected in a small river associated to aquatic vegetation, A. adamantis sp. n. larva was collected in a first order stream associated with accumulated fallen leaves, and adults of A. monticola sp. n. were collected with light-traps, in a mountainous region at about 1000 m altitude.

Belostomatidae (Heteroptera: Nepomorpha) held in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil: inventory and new distributional records

Belostomatidae is a family of giant water bugs with 52 valid species in Brazil. Here, we list 33 valid species housed in the Invertebrates Collection of the Instituto Nacional de Pesquisas da Amazônia – INPA, Manaus, Brazil. Of the total species examined, 26 had their distributional ranges increased (new records provided in parentheses): Belostoma amazonum Estévez & Polhemus (Mato Grosso and Roraima); B. aurivillianum (Montandon) (Rondônia); B. bosqi De Carlo (Maranhão); B. candidulum Montandon (Mato Grosso do Sul); B. carajaensis Ribeiro & Estévez (Amazonas); B. dallasi De Carlo (Bahia and Pará); B. dentatum (Mayr) (Roraima); B. denticolle Montandon (Roraima); B. dilatatum (Dufour) (Maranhão); B. discretum Montandon (Rio Grande do Sul); B. elongatum Montandon (Paraná); B. estevezae Ribeiro & Alecrim (Amazonas); B. fittkaui De Carlo (Roraima); B. gestroi Montandon (Pará); B. guianae Lauck (Brazil, in Roraima); B. micantulum (Stål) (Maranhão, Rio Grande do Norte, Rondônia and Roraima); B. minusculum (Uhler) (Brazil, in Amazonas, Pará and Rio Grande do Norte); B. parvum Estévez & Polhemus (Amazonas and Roraima); B. plebejum (Stål) (Roraima); B. pygmeum (Dufour) (Pará); B. ribeiroi De Carlo (Mato Grosso do Sul); B. stollii (Amyot & Serville) (Roraima); Horvathinia pelocoroides Montandon (Rondônia); Lethocerus annulipes (Herrich-Schaeffer) (Maranhão, Paraíba and Paraná); L. delpontei De Carlo (Amazonas and Pará) and L. maximus De Carlo (Acre, Amapá, Amazonas and Roraima). In addition, we provide a list of type and non-type specimens of Belostomatidae from INPA’s collection identified to the species level, photographs of these species and relevant taxonomic notes, when available.

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.

Description of the second- and third instar larvae of Platynectes (s. str.) decemnotatus (Aubé, 1838) (Coleoptera: Dytiscidae: Agabinae: Platynectini)

The second- and third instar larvae of Platynectes (s. str.) decemnotatus (Aubé, 1838) are described and illustrated in detail for the first time, with special emphasis on morphometry and chaetotaxy. Larvae of P. decemnotatus can be distinguished from most other Agabinae by having secondary setae on the urogomphus and share with the other known species described in detail the presence of a ventroapical spinula on antennomere 3 and the absence of an occipital suture, natatory dorsal setae on tibia and tarsus and natatory setae on urogomphus. Platynectes decemnotatus larvae differ from larvae of Agabus Leach, 1817, Hydrotrupes Sharp, 1882 (currently in Hydrotrupini), Ilybiosoma Crotch, 1873, Ilybius Erichson, 1832 and the previously described Platynectes species in having a one-segmented urogomphus, a character previously observed only in larvae of Agabinus Crotch, 1873. The second- and third instar larvae of P. decemnotatus differ from those of P. (Agametrus) curtulus (Régimbart, 1899) in having the apical lateroventral process of antennomere 3 protruding (not protruding in P. curtulus). The third-instar larva of P. decemnotatus can also be distinguished from that of P. (Gueorguievtes) decempunctatus (Fabricius, 1775) by the absence of secondary dorsal setae on the tibia.