ABSTRACT A list of spider species is presented for the Belém Area of Endemism, the most threatened region in the Amazon Basin, comprising portions of eastern State of Pará and western State of Maranhão, Brazil. The data are based both on records from the taxonomic and biodiversity survey literature and on scientific collection databases. A total of 319 identified species were recorded, with 318 occurring in Pará and only 22 in Maranhão. About 80% of species are recorded at the vicinities of the city of Belém, indicating that sampling effort have been strongly biased. To identify potentially high-diversity areas, discounting the effect of variations in sampling effort, the residues of a linear regression between the number of records and number of species mapped in each 0.25°grid cells were analyzed. One grid, representing the Alto Turiaçu Indigenous land, had the highest deviation from the expected from the linear regression, indicating high expected species richness. Several other grid cells showed intermediate values of the regression residuals, indicating species richness moderately above to the expected from the model.

RESUMO Nós compilamos uma lista de espécies de aranhas registradas no Mato Grosso do Sul (Brasil) a partir da literatura taxonômica e de inventários não publicados. A lista inclui 228 espécies em 134 gêneros e 32 famílias. Apenas cerca de 35% da área do estado apresenta registros de ocorrência de espécies de aranhas, e não mais que 5% apresenta mais de um registro de ocorrência por quadrícula de 0,5° (≈2.916 km2). Existem grandes lacunas de amostragem no estado, particularmente na porção norte do Pantanal. A maioria das espécies tem menos de 10 registros de ocorrência, ou seja, sua distribuição geográfica é praticamente desconhecida. Extrapolando a curva de acumulação de espécies dessas aranhas, concluímos que seria necessário ampliar em 10 vezes a área amostrada para que sejam listadas 90% das espécies que ocorrem no estado. Número de espécies: no mundo, 44.906; no Brasil, 3.730; no Mato Grosso do Sul, 228. Portanto, novos inventários são essenciais para que a araneofauna do Mato Grosso do Sul seja minimamente conhecida.

ABSTRACT Here we compile a list of spider species recorded in Mato Grosso do Sul state (Brazil), based on information from the taxonomic literature and unpublished inventories. The list includes 228 species in 134 genera and 32 families. Only approximately 35% of the state area have records of spider species, and no more than 5% of the area presents more than one record per 0.5° grid cell (≈2,916 km2). There are large gaps in the knowledge of the state’s spider fauna, particularly in the northern Pantanal. Most of the species are known by less than 10 distribution records, indicating that their geographic distribution is virtually unknown. Extrapolating a species accumulation curve, we show that a ten-time increase in sampled area would be necessary to discover 90% of the species occurring in the state. Number of species: in the world, 44,906; in Brazil, 3,730; in Mato Grosso do Sul, 228. Therefore new inventories are essential for an adequate description of the spider fauna of the state of Mato Grosso do Sul.

Two new species of Alpaida O.P.-Cambridge, 1889 are described based on male and female specimens from seven restinga areas from northeastern to southern Brazil. Alpaida teresinha sp. nov., from Rio de Janeiro and Espírito Santo, differs from other species of the genus in the wider lobe of the conductor, the concave median apophysis and with the posterior lobe ventrally positioned, and the wrinkled distal projection of the terminal apophysis in males. Females can be recognized by having widely spaced epigynal lips and by the narrow epigynal notch in ventral view. Alpaida toninho sp. nov., from Bahia, Espírito Santo, Rio de Janeiro and Santa Catarina, can be distinguished by the round lobes of the terminal apophysis, and by the median apophysis with a distal lobe and a projection in males, and by the epigynum elliptical, with a short scape in females.

In this study, 10 nominal species of Eustala Simon, 1895 are synonymized with other species of the genus, mostly based on matching males and females erroneously described as different species. Parawixia rimosa (Keyserling, 1892) is considered a senior synonym of Eustala decemtuberculata Caporiacco, 1955. Eustala isosceles Mello-Leitão, 1939 is transferred to Kapogea Levi, 1997 and considered a senior synonym of Kapogea alayoi (Archer, 1958) based on abdomen shape and coloration. Micrathena beta Caporiacco, 1947 is redescribed, illustrated and transferred from Linyphiidae back to Araneidae. This species can be easily distinguished from other members of the genus by the male palpus with an enlarged and modified paracymbium and a narrower hook as a conductor. Micrathena sanctispiritus Brignoli, 1983 is removed from the synonymy with M. lindenbergi Mello-Leitão, 1940 and considered a senior synonym of M. guanabara Levi, 1985.

A new species, Mangora ouropreto sp.nov., is described and illustrated based on male and female specimens from Ouro Preto, state of Minas Gerais, Brazil. Males of the new species can be distinguished by an anterior projection on the terminal apophysis, which is wider apically and has a serrated edge. Females resemble those of M. chiguaza Levi, 2007 in the shape of epigynum, but differ in the smaller and posteriorly directed scape.

A new species of Nesticus is described based on specimens collected during a structured inventory of the Reserva Particular do Patrimônio Natural Mata Samuel de Paula, state of Minas Gerais, Brazil. Nesticus ivone sp. nov. can be recognized by the paracymbium of the male palpus with three not hooked processes, and by the presence of a central vulval plate in the female epigynum. Additionally, a new record is presented for Nesticus taim Ott & Lise, 2002, extending the known distribution range of this species northwards.

Pozonia Schenkel, 1953 is a genus of Neotropical orb-weaving spiders that currently includes four species, three of which are known only from females. In this paper, the male of Pozonia bacillifera (Simon, 1897) is described and illustrated for the first time, based on a specimen from Nova Lima, state of Minas Gerais, Brazil. It differs from the male of P. nigroventris (Bryant, 1936), the only other known male of the genus, in characters of the genitalia, such as the larger embolus and the smaller ventral lobe of the paracymbium, as well as in the shape of the sternum. This represents the first record of P. bacillifera for the region

Fire is a major determinant of structure and dynamics in savannas, and the rapid increase of human activities in this biome has changed the natural burning regime. The effects of fire on the fauna of the cerrado (Brazilian savanna) are still poorly understood, and studies comparing sites frequently and infrequently burned are scarce. In this study, the abundance of epigaeic arthropod orders and trophic guilds was assessed in cerrado sites located in the Brazilian Central Plateau that were subjected to three burning frequencies: frequent (HighFi), intermediary (MidFi), and infrequent (LowFi). In general, we found a positive relationship between the abundance of epigaeic arthropods and fire frequency. When arthropods were analyzed by orders, the abundance of Collembola and Orthoptera was lower in the LowFi site, while for Hemiptera, it was higher in the MidFi site. No significant differences were found for Hymenoptera, Coleoptera, and Araneae. The abundance of detritivores and herbivores decreased from HighFi to LowFi, but did not change significantly for omnivores and predators. These results indicate that some arthropod groups may not only be resilient to fire effects, but actually might benefit from fire effects in the cerrado. Characterizing arthropod responses to burning frequency at high taxonomic or functional levels is important for applied studies. Based on the results of the current study, springtails and ants seem to be particularly appropriate focal groups for further exploratory studies on the effects of fire at the species level.

The male of Hypognatha belem Levi, 1996 is described and illustrated for the first time. New records expand the distribution range of the species to northeastern and southeastern Brazil.