New troglobitic species of Xangoniscus (Isopoda: Styloniscidae) from Brazil, with notes on their habitats and threats.

In the present work, five new species of Xangoniscus are described, increasing to eight the number of the known troglobitic species for the genus. Xangoniscus species can be distinguished from each other by the shape of pleonites epimera, the number and size of aesthetascs in the distal article of antennula, the modifications on pereopods, the shape of male pleopods and the proportion between uropod rami. Species from this genus are known for the states of Minas Gerais and Bahia with Xangoniscus aganju representing the northernmost occurrence, and X. lundi n. sp. and X. dagua n. sp. the southernmost occurrences. Of the six caves where specimens were collected, four are not registered in the national speleological database, what points to all the potential to yet be discovered regarding number of cavities and the associated biodiversity in Brazil. Some of the here mentioned type localities are not located inside protected areas, therefore exposing the species to risks related to the adjacent land use and consequent influence on water table level and input of food resources. The contribution of this work with descriptions of new troglobitic species provides support to consider them as plausible candidates to be assessed in the next list of threatened species as well as to elaborate conservation actions for the species, the caves where they inhabit and the surrounding landscape.

Choosing sampling methods for Chilopoda, Diplopoda and Isopoda (Oniscidea): a case study for ferruginous landscapes in Brazilian Amazonia

The edaphic fauna plays an important role in the organic matter dynamics of the soil. Millipeds (Diplopoda),centipeds (Chilopoda) and isopods (Isopoda) are among the main components of the soil fauna. Vegetationstructure represents one of the main factors influencing composition and diversity of these species that inhabitleaf litter and soil, what is particularly important in the Amazon Forest, where there are several singular ve-getation types. Savannah and forest areas stand out in ferruginous hills, which represents one of the most poorlyknown and highly threatened ecosystems in the Amazon. However, sampling the edaphic fauna in high diversitysites represents a challenging task. Studies have shown that sampling method may influence observed patterns ofdiversity. From this perspective, the present study aimed to (i) investigate whether assemblages of Chilopoda,Diplopoda and Isopoda differ between vegetation types in the Amazon, (ii) indicate how biological parametersbehave in such communities, (iii) identify which method or combination of methods is better suited to samplespecies richness and (iv) quantify the efficiency of each method regarding time of work and cost. Sampling wasconducted by means of hand collection, leaf litter collection, hay-bait traps and soil sampling in four patches,two in the savannah (also called canga) and two in the forest. Richness was higher in forest habitats forChilopoda and Diplopoda, while for Isopoda there was no significant difference. Species composition also dif-fered between vegetation types for Chilopoda and Isopoda, but not for Diplopoda. Beta diversity between ve-getation types was mainly determined by nestedness and balancing, while turnover was the main beta diversitycomponent responsible for differences among methods. Soil sampling and hand collection added more species tothe samples, therefore, this combination was the most efficient to access diversity. Our results support thehypothesis that differences in the soil cover promoted by distinct vegetation types influence the species diversityand composition of edaphic fauna. The differences were mainly determined by nestedness and balancing, in-dicating that the fauna sampled in the canga represents a subset of those present in the surrounding forest. In thissense, even in ecosystems with distinct vegetation types, the combination of soil and surface sampling methods isrecommended. Lastly, the present study proposes a set of decision rules and a key to select the most appropriatemethod to sample the studied taxonomic groups

Choosing sampling methods for Chilopoda, Diplopoda and Isopoda (Oniscidea): a case study for ferruginous landscapes in Brazilian Amazonia

The edaphic fauna plays an important role in the organic matter dynamics of the soil. Millipeds (Diplopoda),centipeds (Chilopoda) and isopods (Isopoda) are among the main components of the soil fauna. Vegetationstructure represents one of the main factors influencing composition and diversity of these species that inhabitleaf litter and soil, what is particularly important in the Amazon Forest, where there are several singular ve-getation types. Savannah and forest areas stand out in ferruginous hills, which represents one of the most poorlyknown and highly threatened ecosystems in the Amazon. However, sampling the edaphic fauna in high diversitysites represents a challenging task. Studies have shown that sampling method may influence observed patterns ofdiversity. From this perspective, the present study aimed to (i) investigate whether assemblages of Chilopoda,Diplopoda and Isopoda differ between vegetation types in the Amazon, (ii) indicate how biological parametersbehave in such communities, (iii) identify which method or combination of methods is better suited to samplespecies richness and (iv) quantify the efficiency of each method regarding time of work and cost. Sampling wasconducted by means of hand collection, leaf litter collection, hay-bait traps and soil sampling in four patches,two in the savannah (also called canga) and two in the forest. Richness was higher in forest habitats forChilopoda and Diplopoda, while for Isopoda there was no significant difference. Species composition also dif-fered between vegetation types for Chilopoda and Isopoda, but not for Diplopoda. Beta diversity between ve-getation types was mainly determined by nestedness and balancing, while turnover was the main beta diversitycomponent responsible for differences among methods. Soil sampling and hand collection added more species tothe samples, therefore, this combination was the most efficient to access diversity. Our results support thehypothesis that differences in the soil cover promoted by distinct vegetation types influence the species diversityand composition of edaphic fauna. The differences were mainly determined by nestedness and balancing, in-dicating that the fauna sampled in the canga represents a subset of those present in the surrounding forest. In thissense, even in ecosystems with distinct vegetation types, the combination of soil and surface sampling methods isrecommended. Lastly, the present study proposes a set of decision rules and a key to select the most appropriatemethod to sample the studied taxonomic groups

Are laboratory studies on behavior of troglobitic species always trustful? A case study with an isopod from Brazil.

There is a huge lack of information regarding the natural history of subterranean species, particularly focusing on aspects of the behavioral ecology of Brazilian cave fauna. In the present work, we aimed to describe and evaluate the behavioral repertoire of Xangoniscus itacarambiensis (Isopoda, Styloniscidae) through observations in the field and laboratory and also by means of complementary experiments. Overall, we recorded 25 spontaneous behaviors. Besides describing the physical habitat, we recorded some intraspecific interactions, agonistic and territorial behaviors, as well as the amphibian habit. There was a direct relationship between the size of travertine dams where they live (measurements of length and width) and the mean number of individuals, although there was no significant correlation with the pool depth. Behaviors observed in the laboratory differed qualitatively and quantitatively from those observed in the field, with individuals more active in the latter. This scenario alerts about the significant behavioral alteration of such isopods when removed from their natural habitat, what must be considered in future behavioral studies including troglobites given their natural sensitivity to environmental changes.

Anophtalmic and epigean? Description of an intriguing new species of Hyalella (Amphipoda, Hyalellidae) from Brazil.

The absence of eyes in Hyalella (Hyalellidae, Amphipoda) is typical of obligate groundwater-dwelling species. However, a new intriguing blind amphipod of this genus was found in epigean streams from the Iron Quadrangle (state of Minas Gerais, Brazil). Hyalella troglofugia sp nov. presents antenna 1 shorter than antenna 2, gnathopod 1 propodus inner face with four setae, gnathopod 2 propodus posterior margin longer than palm, dactylus slightly longer than palm, pereopod 5 shorter than others and uropod 3 shorter than telson. The absence of eyes and presence of reduced U3 and pereopods of H. troglofugia sp nov. may suggest that such species also inhabits interstitial subterranean spaces. Moreover, the presence of the new species on streams associated to distinct hydrological zones indicates that this species may be present in different types of subterranean habitats of the region. We hypothesize that at least part of the population of this species may have left the subterranean environment looking for food and when out of this habitat it preferentially inhabits high water flow stretches of the stream in function of predation avoidance.

Spelaeogammarus uai (Bogidielloidea: Artesiidae): a new troglobitic amphipod from Brazil.

A new species was recently found in a cave from Southeastern Brazil, in the state of Minas Gerais, which is here described. Considering all the species of the genus, Spelaeogammarus uai sp. nov. is very similar to S. santanensis and S. sanctus, although the new species differs mainly in relation to the number of plumose setae in the apical margin of maxilliped inner plate, number of setae in the anterior margin of gnathopod 1 basis and number of setae in the posterior margin of gnathopod 2 basis. Furthermore, the ratio "length/width" of several articles of the new species is higher than in other species. An identification key of the Spelaeogammarus genus is provided, as well as a complemented multivariate statistical approach of the morphometry of the genus based on a previous work of the genus.

A new species of Spelaeogammarus (Amphipoda: Bogidielloidea: Artesiidae) with an identification key for the genus.

There are five described species of the cave-dwelling amphipods of the genus Spelaeogammarus, all of them inhabiting caves on the Brazilian state of Bahia. A new species of this genus is here described, which is closely related to the already known species S. santanensis and S. titan. Spelaeogammarus sanctus sp. nov. differs from its congeneric species basically by the presence of more than 18 bifid setae on the dorsal margin of uropod 3 outer ramus and telson with one apical and two subapical stout setae, while the other species generally present less setae on the third uropod and more setae on telson. An identification key and an updated table of the Spelaeogammarus species diagnosis are provided, as well as a multivariate statistical approach of morphological variations among the species.