No abstract

Mega hydroelectric dams have become one of the main drivers of habitat loss in tropical forests, converting large tracts of pristine forests into isolated forest islands. Understanding how biodiversity cope with landscape modification in these archipelagic landscapes is of paramount importance to assess the environmental consequences of dam infrastructure and propose mitigation actions for biodiversity conservation. In this context, harvestmen (Opiliones, Arachnida) comprise an excellent indicator taxon of habitat quality, given their high sensitivity to desiccation and microclimatic change. We investigate the effects of landscape change induced by a mega hydropower dam on forest harvestmen species richness, abundance and composition within the Balbina Hydroelectric Dam, Central Brazilian Amazon. We sampled 20 islands and 5 mainland continuous forests, relating our biological response variables to local, patch and landscape scale metrics. Although unexpectedly species richness was unaffected by any local, patch and landscape variables, species composition and abundance were differentially affected by a set of predictor variables at different scales. Forest cover and fallen woody stems were significant predictors of species composition, whereas vegetation density, forest cover, island area, abundance of palm trees, and fallen woody stems best explained harvestmen abundance. Our results indicate that both islands embedded within greater and lower amount of forest cover are important to ensure high diversity of harvestmen. We recommend retaining large forest habitat patches surrounded by a large amount of forest cover to minimise forest disturbance effects and enhance long‐term persistence of harvestmen sensitive species in large hydroelectric dams.

Procaeculus coineaui sp. nov. from Cretaceous Burmese amber is described and its phylogenetic position discussed. This fossil taxon is the first caeculid mite known from Burmese amber and constitutes the earliest record of the family. The genus Procaeculus is redefined to include the new fossil species and internal relationships between genera of the family are discussed based on a phylogenetic hypothesis.

1. Mega hydroelectric dams have become one of the main drivers of habitat loss in tropical forests, converting large tracts of pristine forests into isolated forest islands.Understanding how biodiversity cope with landscape modification in these archipelagic landscapes is of paramount importance to assess the environmental consequences of dam infrastructure and propose mitigation actions for biodiversity conservation. In this context, harvestmen (Opiliones, Arachnida) comprise an excellent indicator taxon of habitat quality, given their high sensitivity to desiccation and microclimatic change.2. We investigate the effects of landscape change induced by a mega hydropower dam on forest harvestmen species richness, abundance and composition within the Balbina Hydroelectric Dam, Central Brazilian Amazon. We sampled 20 islands and five mainland continuous forests, relating our biological response variables to local, patch and landscape scale metrics.3. Although unexpectedly species richness was unaffected by any local, patch and landscape variables, species composition and abundance were differentially affected by a set of predictor variables at different scales. Forest cover and fallen woody stems were significant predictors of patterns of species composition, whereas vegetation density, forest cover, island area, abundance of palm trees, and fallen woody stems best explained harvestmen abundance. 4.Our results indicate that both islands embedded within greater and lower amount of forest cover are important to ensure high diversity of harvestmen. We recommend retaining large forest habitat patches surrounded by a large amount of forest cover to minimize forest disturbance effects and enhance long-term persistence of harvestmen sensitive species in large hydroelectric dams. Neto 41.59 237861 9796638 4 5

No abstract

Promecostethus unifalculatus Enderlein, 1909, is the only representative of the order Opiliones from the Crozet Islands. The species belongs to the family Triaenonychidae and is biogeographically interesting because it is a candidate for transoceanic dispersal, a very rare event in this ancient family. Despite this significance, P. unifalculatus is taxonomically still poorly known, and a redescription of this species using modern taxonomic standards is urgently needed. Here we redescribe the species, offer the first description and illustrations of the male genitalia and provide a full exomorphological survey of the species using scanning electron microscopy. Furthermore, we provide an emended diagnosis for the genus Promecostethus and discuss its relationship with some morphologically similar genera.

No abstract

Among the Amazonian families of harvestmen the members of Stygnidae are better known due to the recent revision of the family and efforts of specialists describing new taxa in the last few years. Species of Amazonian genus Auranus Mello-Leitão, 1941, have been collected in several inventories that were carried out in different locations of the Amazon basin. In this paper we provide a new diagnosis for Auranus, and the description of two new species: Auranus leonidas sp. nov. and Auranus xerxes sp. nov. from the Brazilian states of Roraima and Amazonas, respectively. We also offer complementary genital descriptions of Auranus hehu Pinto-da-Rocha & Tourinho 2012, Auranus parvus Mello-Leitão, 1941, and Auranus tepui Pinto-da-Rocha & Tourinho 2012. Five species are recognized in Auranus, including the two new species described in this paper. The lamina parva modified into a calyx is proposed as putative synapomorphy for the genus Auranus. Therefore, A. hoeferscovitorum, which does not possess this character, is removed from Auranus. Instead we propose for it the new combination Verrucastygnus hoeferscovitorum comb. nov. We also provide a key to the males of Auranus, and a map with the distribution for all species examined in this work.