Crustacea, Isopoda, Oniscidea Latreille, 1802: new continent record and distribution extension in Brazil

Terrestrial Isopods were sampled in four protected Atlantic Forest areas located in Serra do Mar, state of Sao Paulo, southeastern Brazil. A total of 2,217 individuals of six species ( Atlantoscia sp., Benthana werneri , Pseudodiploexochus tabularis , Pudeoniscus obscurus , Styloniscus spinosus and Trichorhina sp.) were captured in pitfall traps. The exotic species S. spinosus is recorded for the first time for the Americas. Another introduced species, P. tabularis , previously recorded only from the state of Rio Grande do Sul, had its geographic distribution extended to the state of Sao Paulo. The most abundant isopods in this study belong to an undescribed species of Atlantoscia.

The suborder Oniscidea (terrestrial isopods) includes more than 3,600 worldwide species (Schmalfuss 2003) that occur in almost all terrestrial habitats, from deserts to forests, rangelands, agroecosystems, mountains, bromeliads, ant nests, and caves. A survey of American Oniscidea listed 254 species (van Name 1936;1940;1942) and subsequent publications led to an increase to up to 521 described nominal species in 1997 (Leistikow and Wägele 1999). Moreover, every expedition to the tropical rain forests reveals new species and even genera (Ferrara and Taiti 1989). Since a detailed taxonomy requires careful dissections, there is a lack of reliable guides for identifying tropical woodlice and many of the tropical Oniscidea fauna remains to be described. Leistikow and Wägele (1999) present a species checklist for the Americas and their quotation in the literature. The authors provide a historical approach through prior records in the province/ state, habitat data for each species and indicate which species were probably introduced by human activities. Although these records are available for woodlice species in the American continent, data on their native distribution remains scarce.
Terrestrial isopods were sampled in four protected Atlantic Forest areas located in Serra do Mar, state of São Paulo, southeastern Brazil: Núcleo Santa Virgínia (Parque Estadual da Serra do Mar), Estação Biológica de Boracéia, Parque das Neblinas (a Natural Patrimony Private Reserve) and Reserva Biológica de Paranapiacaba. The vegetation comprises montane ombrophilous forest interspersed to some degree with secondary forest in all sites. The soil composition is predominantly red-yellow Argisol and Inceptisol. The altitude varies from 700 m to 1,100 m, and the distance from coast is about 10 to 20 km. Climate in the region is humid, with absence of a dry season (DNMet 1992).
Samplings were undertaken in each protected area with 60 pitfall traps distributed in 12 sampling units within forest areas. Each sampling unit was comprised of five Abstract: Terrestrial Isopods were sampled in four protected Atlantic Forest areas located in Serra do Mar, state of São Paulo, southeastern Brazil. A total of 2,217 individuals of six species (Atlantoscia sp., Benthana werneri, Pseudodiploexochus tabularis, Pudeoniscus obscurus, Styloniscus spinosus and Trichorhina sp.) were captured in pitfall traps. The exotic species S. spinosus is recorded for the first time for the Americas. Another introduced species, P. tabularis, previously recorded only from the state of Rio Grande do Sul, had its geographic distribution extended to the state of São Paulo. The most abundant isopods in this study belong to an undescribed species of Atlantoscia.
Crustacea, Isopoda, Oniscidea Latreille, 1802: New continent record and distribution extension in Brazil pitfall traps, arranged in a line and placed approximately two meters apart. The pitfall traps were made up with 500-mL plastic containers with 8.5 cm diameter, buried so the opening would be flush with the ground, and protected from rain and falling leaves by a styrofoam cover. A mixture of 69.9 % water, 30.0 % propylene glycol, 0.1 % formaldehyde and some drops of detergent (to break the surface tension and facilitate arthropod collection) was used as preserving liquid.  Leistikow and Wägele 1999;Schmalfuss 2003).
The most abundant species in this study was Atlantoscia sp. showing a similar pattern of abundance of A. floridana, a species that is cited as dominant in different phytogeographic regions of Brazil (Lopes et al. 2005;Almerão et al. 2006). No quantitative data is available for A. rubromarginata.
Benthana werneri is known only from the state of São Paulo (Lemos de Castro 1958;Schmalfuss 2003) and occur jointly with Atlantoscia in Atlantic Forest sites (Lemos de Castro 1958;1985).
Most species of Pseudodiploexochus have been recorded from the African continent (Taiti and Ferrara 1979;Schmalfuss 2003). Pseudodiploexochus tabularis is recorded from Cape Province (South Africa) and Brazil, where it was recently recorded in the coastline of the state of Rio Grande do Sul (Lopes et al. 2001;Lopes et al. 2005;Almerão et al. 2006). The only previous record of a species of Pseudodiploexochus from the state of São Paulo is P. gibbus (Lemos de Castro 1972;Schmalfuss 2003).
Pudeoniscus Vandel, 1963 is an american genus with only two species described (Schmalfuss 2003). Pudeoniscus obscurus is known only from the state of São Paulo (Lemos de Castro 1973).
The genus Styloniscus has a widespread distribution in the Southern Hemisphere, occurring in Argentina, Chile, Tasmania (Australia), New Zealand, Africa (including Madagascar), and several islands from the subtropics to the sub-Antarctic (Schmalfuss 2003). Twelve out of 42 species on this genus occur in the American continent (Schmalfuss 2003). This is the first record of S. spinosus in Brazil. The species is considered adventive from Hawaii and has records from Mauritius, Réunion, Madagascar and greenhouses in Great Britain (Taiti and Howarth 1996;Schmalfuss 2003).
This genus has a worldwide distribution comprising 55 currently recognized species (Araujo and Almerão 2007). Many of the species described are from the Americas (Leistikow and Wägele 1999; Schmalfuss 2003).
Although no specific studies concerning the colonization of exotic woodlice in South America have been made, we believe that the introduction of species begun around year 1500, together with the arrival of ships from European explorers, whose holds were habitually ballasted with soil from the Europe, similarly to the process occurred in North America (Palmén 1951 apud Jass andKlaumeier 2000). The trade of agricultural supplies like plant vases might also have transported such edaphic fauna (Jass and Klaumeier 2000). In Brazil, species may also have been introduced from other major shipping routes, like commercial routes between Africa and Brazil.
Pseudodiploexochus tabularis, a species introduced in Brazil, has its native distribution in South Africa. The present record of the species enlarges its geographic distribution in Brazil, since it was recorded only from the state of Rio Grande do Sul, where it was also collected in the litter layer of Atlantic forests. Therefore, we expect that new records for P. tabularis would occur within remnants of this biome.
Styloniscus spinosus was not previously recorded in the Americas (Schmalfuss 2003). In our studies comparing disturbed and undisturbed sections of Atlantic Forest reserves, this species had greater abundance in areas with higher anthropogenic disturbance (Uehara-Prado et al. 2009;Magrini et al. unpublished data).
We also report here a new species of Atlantoscia, which remains to be described.