Discovering the diversity of tadpoles in the mid-north Brazil: morphological and molecular identification, and characterization of the habitat.

Brazil stands out for presenting the highest amphibian anuran diversity in the world. However, taxonomic studies that address characteristic of larval stage of anurans are incipient, representing only 62% of known species. We assess the species diversity of tadpoles from eastern Maranhão state, mid-northern region of Brazil based on morphological and molecular identification (i.e., 16S rRNA gene fragment), and we also provide characteristics of the habitats occupied by each species. We carried out 30 field samplings during 13 months in 16 environments along an ecotonal area, over five cities inside the limits of state of Maranhão, between the Maranhão Babaçu Forest and Cerrado ecoregions. We searched for tadpoles in a variety of water bodies, and the tadpoles that reached the developmental stage between 34 to 40 Gosner were morphologically identified. The tadpoles collected herein represent 26 species belonging to five families. The external morphology enabled the identification of 24 species, while the molecular data recognized 22 unique evolutionary units. The most represented family was Hylidae (Hylinae 11 spp., Phyllomedusinae one spp.) followed by Leptodactylidae (Leptodactylinae seven spp., Leiuperinae three spp.), Microhylidae (Gastrophryninae two spp.), and Bufonidae (two spp.). Our results show that oral morphology was the most important character for identifying tadpoles based on morphology, and the specific 16S rRNA primer was suitable for molecular identification. This study pioneers the use of both morphological and molecular data to identify tadpoles in the state of Maranhão. It also provides, for the first-time, habitat characteristic for the species. Our study reveals a high number of anuran species sampled at the larval stage in the region, identifies species that require further taxonomic and systematic attention, and extends the geographic distribution of six species, three of which represent new occurrences for the state. Our results strengthen the hypothesis that the diversity of amphibians from Maranhão is underestimated and highlight the importance of herpetological inventories in poorly sampled areas, decentralizing the knowledge of biodiversity.

Environmental thresholds of dragonflies and damselflies from a Cerrado-Caatinga ecotone.

Aquatic ecosystems are affected by different land uses that modify gradients of environmental conditions. These impacts act directly on the community structure, especially the most sensitive ones, such as aquatic insects. Thus, dragonflies have been used as good models to assess these changes, since their suborders Anisoptera and Zygoptera have different ecophysiological and behavioral requirements. This study aimed to evaluate the following hypotheses: (1) dragonfly species composition differs along the environmental gradients of streams; therefore, we expect a higher proportion of species of the suborder Anisoptera in environments with a higher degree of disturbance, since these environmental conditions select heliothermic species with exophytic oviposition; (2) the reduction of habitat integrity and canopy cover will lead to a lower richness of the Zygoptera suborder, due to the restrictions of its thermoregulation and oviposition behavior in relation to Anisoptera, since the higher light input would favor heliothermic and exophytic species; (3) alterations in habitat integrity create ecological thresholds and points of change in the abundance and frequency of Odonata species, generating gradients in the environmental integrity conditions. Specimens were collected from 24 streams (first to third order), in a gradient of land uses. Canopy cover and stream width were predictors of taxonomic richness and abundance of the suborders Anisoptera and Zygoptera, with greater coverage and smaller width, positively affecting Zygoptera and negatively Anisoptera. The turning points were determined by a habitat integrity index, where below 0.38 there is an increase in generalist taxa and a decline in sensitive taxa. On the other hand, above 0.79, there was a sensitive taxa increase in detriment of generalists. Four individual taxa indicators were selected, two of which associated with a negative response (Perithemis tenera and Acanthagrion aepiolum) and two with positive responses (Epipleoneura metallica and Zenithoptera lanei) for habitat integrity. Our results are important to guide management strategies, recovery, and protection policies for areas of permanent protection, aiming to conserving biodiversity and natural resources essential to life quality maintenance.

The genus Anacroneuria Klapálek, 1909 (Plecoptera: Perlidae) from Maranhão State, northeastern Brazil.

Based on collections made from streams of the Itapecuru, Parnaíba and Tocantins River basins, three species of Anacroneuria Klapálek are recorded for the first time from Maranhão State, northeastern Brazil: A. atrifrons Klapálek, A. minuta Klapálek and A. singularis Righi-Cavallaro Lecci. Additionally, A. leccii sp. nov. is described from this material and remarks concerning A. marlieri are also presented.

The role of spatial and environmental variables in shaping aquatic insect assemblages in two protected areas in the transition area between Cerrado and Amazônia / O papel das variáveis espaciais e ambientais na formação de assembleias insetos aquáticos em duas áreas protegidas na área de transição entre Cerrado e Amazônia

Abstract: The distribution of aquatic insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) can be influenced by factors such as water quality, habitat integrity and biogeography. The present study evaluated the structure of EPT assemblages in streams in the Cerrado, a global biodiversity hotspot. Samples were collected from 20 streams in two protected areas: Parque Estadual do Mirador (10 streams) and Parque Nacional da Chapada das Mesas (10 streams). A total of 1987 specimens were collected, representing 46 taxa of EPT. The two study areas did not differ significantly in taxonomic richness of EPT genera (t = -1.119, p = 0.279) and abundance of individuals (t = 0.268, p = 0.791) but did differ in genus composition (Pseudo-F = 2.088, R2 = 0.103, p = 0.015) and environmental variables (Pseudo-F = 2,282, R2 = 0.112, p = 0.014). None of the tested environmental variables were correlated with the community but a spatial filter captured an effect of the spatial distribution of streams. The region of the study is located in MATOPIBA, which is the last agricultural frontier of the Cerrado. Therefore, it is important that there is police and monitoring so that the "Parque Estadual do Mirador" and the "Parque Nacional da Chapada das Mesas" continue to play their role in conserving biodiversity in the future.

Resumo: A distribuição de insetos aquáticos das ordens Ephemeroptera, Plecoptera e Trichoptera (EPT) pode ser influenciada por fatores como qualidade da água, integridade do habitat e biogeografia. O presente estudo avaliou a estrutura das assembleias do EPT em riachos do Cerrado, um hotspot de biodiversidade global. Foram coletadas amostras em 20 riachos em duas áreas protegidas: Parque Estadual do Mirador (10 riachos) e Parque Nacional da Chapada das Mesas (10 riachos). Um total de 1987 espécimes foram coletados, representando 46 táxons de EPT. As duas áreas de estudo não diferiram significativamente na riqueza taxonômica dos gêneros EPT (t= -1,119; p= 0,279) e abundância de indivíduos (t= 0,268; p= 0,791), mas diferiram na composição do gênero (Pseudo-F= 2,088, R2= 0,103; p= 0,015) e variáveis ambientais (Pseudo-F= 2,282; R2= 0,112; p= 0,014). Nenhuma das variáveis ambientais testadas foi correlacionada com a comunidade, mas um filtro espacial capturou um efeito da distribuição espacial dos riachos. A região do estudo está localizada em MATOPIBA, que é a última fronteira agrícola do Cerrado. Portanto, é importante que exista fiscalização e monitoramento para que o "Parque Estadual do Mirador" e o "Parque Nacional da Chapada das Mesas" continuem desempenhando seu papel na conservação da biodiversidade no futuro.

Evaluating the habitat integrity index as a potential surrogate for monitoring the water quality of streams in the cerrado-caatinga ecotone in northern Brazil.

Human activities have long been altering the natural conditions of streams, including the quality of their water, throughout most of Brazil. This problem is even worse in regions with low rainfall levels, such as the Brazilian Northeast, where water quality needs to be monitored more carefully. In this context, the present study investigated the effects of environmental integrity on the physicochemical characteristics of the streams of the basin of the Itapecuru River in northeastern Brazil. We tested the hypothesis that streams with lower habitat integrity would have higher conductivity, pH, and temperature, due to the reduced input of allochthonous organic matter and the greater washout of sediments to the stream bed. A total of 15 streams, of a sedimentary basin, were evaluated in the municipality of Caxias, in the Brazilian state of Maranhão, between June 2015, and July 2016; each stream was sampled once a month during the drought period in the region, where physicochemical measurements were taken to determine the environmental integrity of the stream through the application of a habitat integrity index. Streams with greater habitat integrity had lower conductivity, pH, and temperature and had higher discharge rates. The index proved to be not an effective tool for the evaluation of water quality, but was found to be important for the management of hydrographic basins by indicating important changes in environmental variables. In this case, the index can be used primarily for the management of hydrographic basins, given that it can be applied straightforwardly, it can be interpreted easily by decision-makers, and it can quantify alterations to the structure of the system with precision.

New genus and new species of Chauliodinae (Insecta: Megaloptera: Corydalidae) from Brazil.

A new genus and new species of Chauliodinae are described and illustrated, Puri gen. nov. and P. aleca sp. nov. The material was collected in the Mantiqueira Mountain Range, Itamonte Municipality, State of Minas Gerais, Brazil. This is the first report of adults of this subfamily from Brazil. In the male, the new genus is diagnosed by the short subserrate antennae, length less than ½ of forewing; wings alternating dark and pale venation; forewings with crossvein between 1A and 2A placed between footstalks of 1A and 2A; hindwings with basal r-m crossvein connected to M by an additional short branch; dorsally, ninth tergum anteriorly truncate; laterally, ventral margin acutely produced; ninth sternum with membranous apical process; laterally tenth tergum with proximal margin vertical; tenth gonocoxite with bifurcation indistinct; lateral lobes connected by a broad and feebly sclerotized plate. The female is unknown.