A new species of Masteria ( Araneae : Dipluridae : Masteriinae ) from southeastern Brazil

A new species of Masteria L. Koch, 1873 from iron ore caves at Caeté and Santa Bárbara, state of Minas Gerais, Brazil, Masteria emboaba sp. nov., is described. It was collected inside caves and in the litter of nearby dry forests. It is the first masteriine species described from southeastern Brazil and the second masteriine species for the country. The new species is the only known Masteria with only two eyes. Additionally, the male of M. emboaba sp. nov. has only two regular, thin spines at the apex of tibia I, lacking the tibial apophysis found in most other Masteria species. The only other described Masteria species that has spines in the place of tibial apophysis is M. aimeae (Alayón, 1995) from Cuba; however, the last species has a longer and sinuous embolus, contrasting the embolus of M. emboaba sp. nov., which is much smaller, less sinuous and transversally placed. The only other described Brazilian species, M. manauara Bertani, Cruz & Oliveira, 2013, has a double tibial apophysis, with both ends tipped by a strong, short spine, and a very long embolus, parallel to the bulb.

Besides M. manaura, there are records of an unidentified Masteria species from the state of Piauí (L.S. Carvalho unpubl.data) and several areas of the state of Minas Gerais: Nova Lima (ANGLOGOLD ASHANTI 2009), Conceição de Mato Dentro (LEÃO & AULER 2012), Caeté and Santa Bárbara (COELHO et al. 2010).The records from Minas Gerais are based on material collected in and around caves in iron ore deposits.
There are more than 3,000 caves in iron ore deposits in Brazil (AULER et al. 2014).Most of these caves are located at the two major iron ore provinces: Carajás ridge, in the Amazon, and Iron Quadrangle, in Minas Gerais, southeastern Brazil.The Iron Quadrangle caves are found on iron-rich deposits topped by "canga", an iron-rich breccia surface cemented by ferruginous matrix (AULER et al. 2014).The vegetation of the "canga" areas is open grassland with scattered trees and is dominated by herbs and bushes.The alfa and beta diversity of plant species is high, including dozens of rare and endemic species (CARMO & JACOBI 2013).The plant species are a mix of elements from the Atlantic Forest, Cerrado and Serra do Espinhaço (CARMO & JACOBI 2013).
Despite the small average size of iron ore caves, they have "a high potential as habitat of troglobitic invertebrates in Brazil" (TRAJANO & BICHUETTE 2010).Several troglobitic species have been found in Brazilian iron ore caves, both in the Carajás area (PELLEGRINI & FERREIRA 2011, PEDROSO & BAPTISTA 2014) and the Iron Quadrangle (SOUZA & FERREIRA 2005, COELHO et al. 2010).Caves from iron ore areas are usually near the surface and have an extensive array of microchannels that house a highly diverse associated fauna (FERREIRA 2005).The fauna of the "canga" ABSTRACT.A new species of Masteria L. Koch, 1873 from iron ore caves at Caeté and Santa Bárbara, state of Minas Gerais, Brazil, Masteria emboaba sp.nov., is described.It was collected inside caves and in the litter of nearby dry forests.It is the first masteriine species described from southeastern Brazil and the second masteriine species for the country.The new species is the only known Masteria with only two eyes.Additionally, the male of M. emboaba sp.nov.has only two regular, thin spines at the apex of tibia I, lacking the tibial apophysis found in most other Masteria species.
The only other described Masteria species that has spines in the place of tibial apophysis is M. aimeae (Alayón, 1995) from Cuba; however, the last species has a longer and sinuous embolus, contrasting the embolus of M. emboaba sp.nov., which is much smaller, less sinuous and transversally placed.The only other described Brazilian species, M. manauara Bertani, Cruz & Oliveira, 2013, has a double tibial apophysis, with both ends tipped by a strong, short spine, and a very long embolus, parallel to the bulb.KEYWORDS.Iron ore; lateritic cave; Minas Gerais; Mygalomorphae; Serra da Gandarela.
Herein we describe the second masteriine species from Brazil and the first from Southeast Brazil.In addition, it is the first Masteriinae from iron ore caves collected at Caeté and Santa Barbára, Minas Gerais.

MATERIAL AND METHODS
Specimens were collected inside and near iron ore caves located at the hilltops of "Serra da Gandarela" (Gandarela range), at Caeté and Santa Bárbara, in the Iron Quadrangle area, state of Minas Gerais, southeastern Brazil.The caves are located on "canga" plates; however, the collecting area also included dry patches of Atlantic forest, especially on the small river valleys near the tips of the hill range.Most specimens were collected during a trip of the "Projeto Mina Apolo", a project to study the environmental impact from the installation of a large iron ore mine.The first author participated in the project as a member of the environmental consulting "Amplo Consultoria" team.Additional specimens from the caves in the collecting area had been mentioned by COELHO et al. (2010).
The general description format follows RAVEN (1981) with some modifications; e.g., eye diameters are given in their real measurements, not in ratios.All measurements are in millimeters and were obtained with a Leica LAS Interactive Measurements module.Leg and palp measurements were taken from the dorsal aspect of the left side (unless appendages were lost or obviously regenerated).A Leica LAS Montage and LAS 3D module, mounted on a Leica M205C dissecting microscope, were used to capture images of the structures of spiders.Illustrations of spermathecae were drawn over images obtained with a Leica DM 2500 compound microscope.The spermathecae soft tissues were digested with trypsin for several days and subsequently cleared with clove oil before they were photographed.
Specimens are deposited in the arachnological collection of the Museu Nacional, Universidade Federal do Rio de Janeiro (MNRJ).

Figs. 1-16
Diagnosis.Males and females of Masteria emboaba sp.nov.have only two eyes (Figs. 5 and 14).Most other species have six to eight eyes and two, M. pecki and M. caeca (Simon, 1892), have no eyes at all.This new species is much smaller than the other known South American species, except for M. manauara, a tiny species from the state of Amazonas and the only other species described from Brazil.The male of M. emboaba sp.nov.has only two regular, thin spines at the apex of tibia I, lacking the tibial apophysis found in most other Masteria species.The only other described Masteria species with spines in the place of tibial apophysis is M. aimeae, from Cuba; however, the last species has a longer and sinuous embolus (ALAYÓN 1995: figs. 1c-d), contrasting with the embolus of M. emboaba sp.nov., which is much smaller, less sinuous and transversally placed (Figs.6-8).The only other described Brazilian species, M. manauara, has a double tibial apophysis, with both ends tipped by a strong, short spine, and a very long embolus, parallel to the bulb (BERTANI et al. 2013: figs. 6-9).Table I summarizes the available information on the geographical range and characters of all species of Masteria.
Palp with elongated cymbium, bearing seven spines on apical edge; bulb pear-shaped, tegulum 0.22 long, 0.12 wide, tapering and giving origin to a short (0.13) and relatively thin (0.012) embolus, almost transversally placed, due to a strong basal curve to retrolateral side, keeping its diameter and with a gentle curvature on apical half, not tapering to apex .Leg lengths and midwidths in Table II.
Natural history.Masteria emboaba sp.nov.was collected both inside "canga" caves and in the dry forested tracts near the "canga" area.However, they were not found in open grassland areas covering the "canga" around the caves (Fig. 17).In the dry forest (Fig. 18), they were found sieving through the litter, or were spotted under rotten wood and stones.Therefore, we may assume that this species is associated with forest litter, eventually invading nearby caves.Cave colonization would be an easy step for an animal that is already adapted to small cavities in litter.The small patches of dry forests covering the slopes of drainage valleys do not present a continuous and deep litter layer, but there are litter pockets amassed in suitable areas.The "canga" caves are placed just below the surface and are penetrated by many plant roots.They seem to offer a suitable environment for the species, with high humidity and plenty of spider food.In addition, there are many access points to the cave through the microchannels in the porous iron matrix (FERREIRA 2005).These access points may serve as a refuge for animals during dry periods, allowing the species to survive the long, dry winter of the area.
The Masteria species for which habitat information is available live in underground habitats, for instance in the depths of litter or in caves.Their pale color and some degree of eye reduction seem to be correlated with life in dark habitats.Most species of Masteria have only six eyes (e.g., SIMON 1889, 1892, RAVEN 1991), and those that have eight eyes have a pronounced reduction of the anterior median pair, e.g.M. petrunkevitchi and M. simla (CHICKERING 1964(CHICKERING , 1966)).The complete loss of eyes is found in two troglobite species: M. caeca, from Phillipines (SIMON 1892), and M. pecki, from Jamaica (GERTSCH 1982).The reduction to only two eyes in Masteria emboaba sp.nov.may point to a high degree of specialization to underground habitats.