André A. Nogueira

List of species of spiders (Arachnida, Araneae) from the Pico da Neblina, state of Amazonas, Brazil

We present a list of species of spiders collected at the Pico da Neblina, the highest mountain in Brazil (Amazonas, Brazil). We sampled at six altitudes (100, 400, 860, 1,550, 2,000 and 2,400 m a.s.l.), through manual active search, during the night and with a beating tray, during the day. We obtained a total of 3,143 adult individuals, which were assigned to 529 species, from 39 families. The most species rich families were Theridiidae (108 species), Araneidae (98 species) and Salticidae (60 species). Most species were rarely collected, as 389 (73% of total richness) species were represented by up to five individuals, and 197 (37% of total richness) of them by just one individual. We briefly compare our results with those from other spider surveys in the Amazon basin.

Finding hot singles: matching males to females in dimorphic spiders (Araneidae : Micrathena) using phylogenetic placement and DNA barcoding

Abstract. Many orb-weaving spiders exhibit remarkable sexual dimorphism, hampering the matching of males and females in taxonomic studies. This is the case for the spiny Micrathena spiders, a species-rich Neotropical genus with 27% of its species known from a single sex. In this paper we document several undescribed Micrathena specimens, and test whether they belong to some of those incompletely known species. In order to do so, we: (1) tested the phylogenetic position of males and their putative females using a previous morphological dataset; (2) calculated genetic distances among individuals based on a fragment of the mitochondrial gene cytochrome c oxidase subunit I; and (3) examined their geographical distributions. These approaches, isolated or in combination, allowed us to identify and describe the previously unknown males of M. embira Levi, M. reimoseri Mello-Leitão, M. exlinae Levi, M. miles Simon, M. spinulata F.O. Pickard-Cambridge, M. yanomami Magalhães & Santos and M. cornuta (Taczanowski), and the female of M. beta di Caporiacco. We found that the males previously associated with M. bicolor (Keyserling), M. cornuta and M. lata Chickering had been incorrectly matched with females. The latter actually belongs to a hitherto unnamed species, herein described as Micrathena perfida, sp. nov. New geographical data are given for these and other Micrathena species. Our study highlights the importance of using different sources of data for matching the sexes in diverse groups with strong sexual dimorphism.

The effects of habitat size and quality on the orb-weaving spider guild (Arachnida: Araneae) in an Atlantic Forest fragmented landscape

Abstract Fragmentation of natural habitats is considered one of the greatest threats to the maintenance of global biodiversity. In this study, we tested the importance of forest patch size and vegetation structure on the richness, diversity, abundance, and composition of the orb-weaving spider guild in an area of the Atlantic Forest (State of São Paulo, Brazil). We sampled 16 sites, grouped into the following categories composed of four sites each: continuous mature forest, continuous secondary forest, large (52–175 ha) secondary forest fragments, and small secondary forest fragments (14–28 ha). The richness ranged from 29 to 55 species per site, but was unrelated to forest size or vegetation structure. The communities from the continuous mature forests were more abundant and less diverse than those from the other categories, but this was due to a few dominant species. The changes in composition were related to the vegetation structure, suggesting that this variable is more important to the composition of orb-weaving communities than the size of the forest patch. Overall, the results indicate that the orb-weaving spider community in this region, even in the fragments, is still rich and diverse, which may be attributable to some characteristics of spiders, such as generalist behaviour and a good dispersal capacity. Nonetheless, our results also highlight the importance of continuous areas, especially those with mature vegetation that harbor a characteristic orb-weaving community that can serve as a source for the fragments.

New species of Alpaida (Araneae, Araneidae) from Rondônia, Brazil

We described a new species of spider, Alpaida clarindoi sp. nov. (Araneidae), from the southwestern Amazon forest. The new species is distinguished from most Alpaida by the presence of a pair of shoulders spines. Females can be separated from similar species by the subquadrangular shape of the epigynum, and males by the shape of the terminal apophysis and the tegulum, which possess an apical pointed tip. Alpaida clarindoi sp. nov. is described based on both sexes.

Figures 5 A – E. Chrysometa Petrasierwaldae N In The Spider Genus Chrysometa (Araneae, Tetragnathidae) From The Pico Da Neblina And Serra Do Tapirapecó Mountains (Amazonas, Brazil): New Species, New Records, Diversity And Distribution Along Two Altitudinal Gradients

FIGURES 5 A – E. Chrysometa petrasierwaldae n. sp. A. Male palp, ventral view. B. Same, retrolateral view. C. Epigynum, ventral view. D. Same, posterior view. E. Same, dorsal view. Scale bars: AB, 0. 3 mm; CDE, 0. 1 mm.