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 findings on Nilothauma Kieffer (Diptera: Chironomidae) from Brazil and Peru.

Two new species of Nilothauma from Brazil and Peru are described and illustrated based on adult males collected respectively in the central and western Amazon. In addition, new records of Nilothauma complicatum Mendes & Andersen, 2009 in Brazil are provided.

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.

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.

The first microcaddisflies Metrichia Ross, 1938 recorded in Tocantins State, northern Brazil (Trichoptera: Hydroptilidae): Metrichia elongata sp. nov. and Metrichia vulgaris Santos, Takiya & Nessimian 2016.

The microcaddisfly Neotropical genus Metrichia Ross, is recorded for the first time from the state of Tocantins, northern Brazil, through the discovery of two species: Metrichia elongata sp. nov. and Metrichia vulgaris Santos, Takiya & Nessimian 2016. Herein, the new species is described and illustrated based on males collected in a protected and preserved area in Cerrado biome of Tocantins. Metrichia elongata sp. nov. can be recognized mainly by the type and position of setae on the inferior appendages and morphology of the dorsolateral hook. The discovery of these species increases the number of Metrichia species in the Brazilian Cerrado from seven to eight and are only the eleventh and twelfth caddisfly species reported for Tocantins State.

Updates on the taxonomy of Ilyobius nubilus (Navs, 1933) (Megaloptera: Sialidae: Sialinae) and Ilyobius brasiliensis (Navs, 1936) from southeastern Brazil.

Species of the Neotropical genus Ilyobius Enderlein, 1910 (Megaloptera: Sialidae) are rare and poorly known because adults are infrequently collected in the field and the larvae have restricted habitat in the stream, facts that make obtaining specimens difficult to access for study. Herein we redescribe the female, describe the male and the larva of Ilyobius nubilus (Navs, 1933) based on specimens collected on the coast of So Paulo State. Adults were obtained mainly by rearing larvae in laboratory condition until adult emergence. The holotype for Ilyobius brasiliensis (Navs, 1936) was examined, and we contand that it is a valid species. Therefore, we do not corroborate its synonymy with I. nubilus. Ilyobius nubilus is a member of the I. chilensis group, and the male genitalia structure, described in this work, also supports its inclusion in this species group.

Systematics of Pilielmis Hinton, 1971 (Coleoptera: Dryopoidea: Elmidae).

Pilielmis is a small genus of Neotropical Elmidae found in the Amazon basin and French Guiana, with distribution in five countries: Brazil, Colombia, French Guiana, Peru, and Venezuela. Currently, seven species of Pilielmis are known, six of which were described in the original description of the genus by Hinton (1971), and the most recent one was described by Polizei & Barclay (2019). In this paper, we review the genus Pilielmis based on the analysis of type-specimens and material collected in different regions of northern South America. A phylogenetic study was performed to hypothesize the relationship between all species of Pilielmis and to test the monophyly of this genus. For this purpose, 42 morphological characters of adults were investigated, among them some structures that were not illustrated and described in the original descriptions. As result, all seven previously known species were redescribed with standardized morphological information. Three new species were discovered in the examined material: Pilielmis baniwa sp. nov., Pilielmis muricula sp. nov., Pilielmis nheengatu sp. nov. A key for identification of the adults of Pilielmis is proposed and new records for Suriname, Peru, and some Brazilian states are presented. The phylogenetic analysis corroborated the monophyly of Pilielmis and presented phylogenetic information from characteristics not used before in the taxonomy of the genus, such as mouth parts and female ovipositor.

Poxyaibamberus Andersen & Dantas, gen. nov. (Diptera, Chironomidae, Orthocladiinae) from Brazil.

Poxyaibamberus Andersen & Dantas, gen. nov. is erected based on the males of two species, P.jamanximensis Andersen & Dantas, sp. nov. from Jamanxim National Park, Pará State, Brazil, and P.ubajarensis Andersen & Dantas, sp. nov. from Ubajara National Park, Ceará State, Brazil. Both species have a comparatively short and wide head, with large eyes and short, five-segmented palps; a strong subapical seta on the ultimate flagellomere; scalpellate acrostichals; no setae on the wing veins except for one seta on the brachiolum; a long costal extension; and a large triangular anal point and a very long heel on the gonostylus. The systematic position of the new genus is briefly discussed.

Two new species of Fittkauimyia Karunakaran (Diptera: Chironomidae) from Brazil.

Two new species of the genus Fittkauimyia from Brazil are described and illustrated. Fittkauimyia mayumiae sp. n. from Amazonian forest is described based on adult male, female and pupae and F. carranquensis sp. n. from mountainous region of southeast is described based on adult male and pupae.

Review of Xenochironomus Kieffer, 1921 (Diptera: Chironomidae) with description of six new species.

The genus Xenochironomus Kieffer is reviewed. Five new species are described from Brazil, X. alaidae, X. amazonensis and X. martini as male; X. grini and X. mendesi as male, pupa and larva, and X. ethiopensis from Ethiopia is described as adult male. X. canterburyensis (Freeman) is redescribed as male, pupa and larva; X. trochanteratus (Thompson), X. trisetosus (Kieffer), X. ugandae (Goetghebuer) and X. tuberosus Wang as males; notes on X. xenolabis (Kieffer), X. flaviventris (Kieffer), X. longicrus (Kieffer), X. lacertus Dutta et Chaudhuri and X. ceciliae Roque et Trivinho-Strixino are also given. The species X. nigricaudus Hashimoto is recognized as nomen dubium. Keys to males, pupae and larvae are presented.

Two new species of Xiphocentronidae (Trichoptera) and their bionomics in Central Amazonia, Brazil.

Two new Xiphocentronidae species are described, Machairocentron falciforme sp. nov. and Xiphocentron (Antillotrichia) sclerothrix sp. nov. Illustrations of the males, females and pupae are presented. Adults were obtained through the emergence of pupae in the laboratory and from collections in traps suspended 1 m above the water in four streams in Presidente Figueiredo, Manaus and Barcelos municipalities in Amazonas state, and Oiapoque municipality in Amapd state, Brazil. Larvae inhabiting submerged substrates and on stream banks were collected in order to determine the feeding habits by examining gut contents. Larvae of both species are practically indistinguishable; the list of material observed in the gut content therefore refers to both species. Larvae of analyzed species have scraper feeding habits.

Description of the adult male of Aeschnosoma auripennis Geijskes, 1970 (Odonata: Corduliidae s.s.).

The male of A eschnosoma auripennis is described for the first time, based on a specimen reared from a larva collected in the Reserva Biologica do Uatumã, Amazonas State, Brazil. The species is newly reported from the Roraima State, Brazil.

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 Gilka, 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.

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.

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

The species of the water scavenger beetle genus Oocyclus Sharp are reviewed for the Guiana Shield region of South America. Seven species are recorded, including one here described as new: Oocyclus paraiso sp. n. from the Brazilian state of Pará. New records of previously described species are also reported for Brazil, French Guiana, Guyana, and Suriname. The aedeagus of O. coromoto Short & García is illustrated for the first time. As with all other known members of the genus, all Guiana Shield species are hygropetric habitat specialists. A key to the Oocyclus of the Guiana Shield is provided.

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.

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.

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.).

Simulium (Psilopelmia) virescens, a new black-fly species (Diptera: Simuliidae) from the southwestern region of the state of Bahia, Brazil.

The last-instar larva, pupa, male and female of Simulium virescens sp. nov. are described and illustrated. This species has a peculiar larva, which has an elongated head capsule and light-green colour. The first thoracic segment has tubercle on its dorsal region and the third thoracic segment has one pair of tubercles; the first to the fourth abdominal segments have one pair of tubercles on each segment. Until now this new species had only been collected at the type locality, which is on the middle stretch of the Correntina River in the southwestern portion of the state of Bahia, Brazil. Females were voraciously biting humans during the field work. This new species represents the second species of Simulium (Psilopelmia) in Brazil and the first registered outside of the Brazilian Amazon Region.