Three new species of Mesabolivar ( Aranea , Pholcidae ) from leaf litter in urban environments in the city of São Paulo , São Paulo , Brazil

In this study we describe three new litter inhabiting species of Mesabolivar González-Sponga, 1998 from nine urban forest remnants in the metropolitan region of the city of São Paulo, Brazil: M. forceps, M. mairyara and M. cavicelatus. In three of these remnants, we conduced a three year sampling using pitfall traps. Mesabolivar forceps sp. nov. was the most abundant pholcid (n=273 adults), always present in the samples, but with highest numbers in spring and summer. Mesabolivar mairyara sp. nov. was the second most abundant species (n=32), but the majority of individuals were collected in March 2001. Only three individuals of M. cavicelatus sp. nov. were collected.

The genus Mesabolivar González-Sponga, 1998 currently includes 36 nominal species (PLATNICK, 2005;HUBER et al., 2005).The genus is widespread in the Neotropical region and was revised by HUBER (2000).However, many species remain undescribed, and few of the known species were collected using specific methods, especially targeting soil and leaf-litter communities.The microhabitats of best known diversity suspiciously coincide with the levels most easily accessible to humans, i.e., the shady areas near the ground and between buttresses, and the low vegetation (HUBER, 2000), suggesting an influence of the sampling method, i.e., visual search.Some habitats, such as the canopy and the leaf litter, remain poorly known.Only three species of Mesabolivar are known to live in the litter layer, having been captured with pitfall traps, namely M. cuarassu and M. samatiaguassu (HUBER et al., 2005), and M. difficilis (Mello-Leitão, 1918) (ÁLVARES et al., 2004).There are probably many more undescribed litter dwelling species, and the morphology of some other known species (relatively short and strong legs), such as M. banksi (Moenkhaus, 1898) and M. simoni (Moenkhaus), suggests that they may also have been collected in this habitat.Despite the great number of Brazilian species described by Mello-Leitão, the new species herein described are not similar to any of them.Of the Brazilian species, only M. aurantius (Mello-Leitão), M. azureus (Badcock), M. fluminensis (Mello-Leitão) and M. nigridentis (Mello-Leitão), were not examined by HUBER (2000) and the original descriptions do not present the diagnostic chacteres of the species herein described.
In general, there is limited information on habitat or temporal variation in Neotropical pholcids.For Mesabolivar, the biology of most species is poorly known.Only M. eberhardi Huber, 2000 has been studied in some detail (EBERHARD & BRICEÑO, 1983;1985).All this results in a poor knowledge on pholcids of ground or low vegetation habitats.Besides, only now studies on DNA sequences of Mesabolivar species are being conduced (ASTRIN et al., 2006), including M. mairyara sp.nov.and species related to the new species here presented.
This paper is a result of a three year sampling using pitfall traps in urban forests in the city of São Paulo, Brazil, in a subproject named "Soil spiders of the city of São Paulo" (CANDIANI et al., 2005) of the project "Biodiversity of Arachnida and Myriapoda from the state of São Paulo" within the BIOTA/FAPESP program.The main objective was to evaluate the Atlantic forests remnants in urban areas of the city of São Paulo.The Atlantic forest is one of the most important hotspots, due to the high diversity and high concentration of endemic species of fauna and flora and is one of the most endangered ones (MYERS et al., 2000).In fact, the deforestation and fragmentation of this biome heavily threaten both fauna and flora (BROOKS & BALMFORD, 1996;SILVA & TABARELLI, 2000).The project has collected a lot of information in this respect, and we expect that more undescribed species will be discovered.Here we describe three new species of Mesabolivar, and give some information on the temporal variation of two of them.

MATERIAL AND METHODS
The specimens used to access ecological data were sampled in the following urban forested areas: Horto Oswaldo Cruz, Instituto Butantan; Mata da Cidade Universitária Armando Salles (C.U.A.S.O.), campus of the Universidade de São Paulo and Parque da Previdência, all described in details in CANDIANI et al. (2005).All three localities are in the municipality of São Paulo, state of São Paulo, Brazil.Sampling was done using pitfall traps (BRENNAN et al., 1999)  Etymology.The specific name is a Latin noun in apposition and refers to the peculiar shape of the tip of the procursus.
Diagnosis.Mesabolivar forceps is easily distinguished from congeners by the large and strongly curved procursus (Figs.3-6), with enlarged tip and distal concavity (Figs.4-6).The female is distinguished from most species by the absence of apophyses or humps combined with the medium-sized median pocket in the epigynum (Fig. 10).
Diagnosis.Males of Mesabolivar mairyara are distinguished from known congeners by the broad procursus with conspicuous tip, slightly bent dorsally (Figs.15,16) and chelicerae with median pair of apophyses and small pair of proximal protrusions (Figs 13,14).The female is distinguished by the epigynum with pair of prominent humps, anterior position of small pocket (Fig. 20) and two pairs of strong smooth hairs on posterior plate behind gonopore (Fig. 21).
Variation.Three males: carapace width 0.94-1.12;tibia I 3.84-4.00.Two females: carapace width 0.95; tibia I 3.16.Ecological Data.In three year sampling in the three areas (CANDIANI et al., 2005) were collected four pholcid species.Three of these species belonged to the genus Mesabolivar, represented by a total of 308 adult specimens, and one species of Tupigea Huber, 2000, represented by only one specimen.Among the three Mesabolivar species, M. forceps was collected in the largest numbers (n=273) with highest numbers in spring and summer, which are the rainy seasons.It was the most abundant among the pholcids collected (Tab.I) which enabled us to evaluate some aspects of the temporal variation.This species was always present in the samplings, showing a continuous distribution over time   (Fig. 35).The present study suggests that seasonal fluctuations do occur, but adult specimens can be collected throughout the year.This species seems to present some degree of tolerance to habitats influenced by human activity, although all localities showed a reasonable degree of preservation, even though surrounded by buildings.Among the sampled areas, M. forceps was more abundant in Horto Oswaldo Cruz, especially in the rainy months of the years 2000 and 2001, since 1999 presented a extended dry season and there was an unusually high abundance of ants.The greater abundance of this species in Horto Oswaldo Cruz maybe can be related to the human ecological impact and alteration of the original flora, more intense than other sampled areas.It's possible that M. forceps was favored by the reduction of the flora diversity and consequent availability of microhabitats.The ratio of males/females was 1.58, differing significantly from and homogeneous ratio (χ 2 = 13.63;p = 0.0002), probably due to the male bias in pitfall traps, as observed in COSTA (1998) and ÁLVARES et al. (2004).Probably this is affected by a intense activity of the males in the reproductive period.
Mesabolivar mairyara was the second most abundant species (n=32) and was mostly collected in the Parque da Previdência (Tab.I), and the majority of the individuals (37.5%) were collected in a single season (March 2001) in the Parque da Previdência (Fig. 36).The ratio of males/females was 1.46 (χ 2 = 1.125; p = 0.2888), showing that the ratio males/females of M. mairyara was 1:1.This ratio is not significant, problably due the low number of adult specimens collected.
In most Mesabolivar species, there is no information on sampling methodology, but most were probably collected manually.The species living in low vegetation and among buttresses are far more easily collected and the exploitation of the leaf litter with pitfall methodology is relatively recent.We expect, with the development of projects specifically targeting the leaf litter environment, a substantial increase in the number of known ground dwelling species in the areas of the city of São Paulo.
with 70% alcohol.Fifty pitfall traps were placed in each area and kept open for seven days, every 3 months.This resulted in a total of twelve sampling periods between April 1999 and March 2002, totalling 1800 samples.Additional material from other seven soil spider fauna sub-projects of the Instituto Butantan was examined.The material examined is deposited in the collections of Instituto Butantan, São Paulo (IBSP, A. D. Brescovit), Museu de Zoologia da Universidade de São Paulo, São Paulo (MZSP, R. Pinto da Rocha) and Zoological Research Institute and Museum Alexander Koenig, Bonn (ZFMK, B. A. Huber).Descriptions and measurements follow HUBER (2000).Measurements are given in millimeters.The ratio tibia I length/diameter (L/d) is a measure of the robustness of the legs (HUBER, 2000).The epigynum was dissected and immersed in clove oil for visualization of internal structures following LEVI (1965).All drawings were done with a camera lucida.Chi-squared tests were performed at 0.05 levels to verify the sex ratio (ZAR, 1996).Mesabolivar forceps sp.nov.(Figs.1-12) Types.Male holotype from Horto Oswaldo Cruz (46º43'W, 23º33'S), campus of the Instituto Butantan, Butantã, São Paulo, state of São Paulo, Brazil, 11-18.VIII.2000,D. Candiani et al. col., with pitfall traps, deposited in IBSP 52648.Paratypes: female, same data as holotype, 16-23.XI.1999 (IBSP 52649) and male and female, same data as holotype, 11-18.XII.2001(MZSP 25563, 25561).

Table I .
Number of specimens by area.