Snakes from the Atlantic Rainforest area of Serra do Mendanha , in Rio de Janeiro state , southeastern Brazil : a first approximation to the taxocenosis composition

We studied the species composition of the snake community of Serra do Mendanha, in Rio de Janeiro state, Southeastern Brazil, with an effort of 800 hours/man in different habitats, including undisturbed forest, secondary forest, areas under regeneration, and banana plantation. We sampled snakes monthly in the area using a combination of methods including intensive visual searching and pitfall traps with drift-fences. We found a total of 191 individuals of 27 snake species, belonging to four families: Boidae, Colubridae, Elapidae and Viperidae. In terms of species richness, the most speciose snake family in the area was Colubridae (85.2%; n = 23), followed by Viperidae (7.4%; n = 2), Boidae (3.7%; n = 1) and Elapidae (3.7%; n = 1) (Table 1). Quantitatively, the family Colubridae represented 81.7% (n = 156) of the total of individuals captured throughout the study, followed by Elapidae (13.1% of the individuals; n = 25), Viperidae (4.7%; n = 9) and Boidae (0.5%; n = 1). The data obtained in the study allowed a first approximation of the richness and composition of the snake fauna from Serra do Mendanha, including the records obtained during fieldwork in the present study and those of specimens deposited in Institutional Collections and detailed field data for each voucher specimen. All records are novel data for the area.


Introduction
The Atlantic Forest of Serra do Mendanha, which is included in the municipalities of Rio de Janeiro, Mesquita and Nova Iguaçu, in Rio de Janeiro state, Brazil (Figure 1), is approximately 8,500 ha in area, and is one of the world's largest forest remnants located within the limits of a large city (Pontes, 2005; Prefeitura da Cidade do Rio de Janeiro, 2000;Rocha et al. 2003;SEMADS, 2001).This remnant is of considerable con-We sampled snakes monthly in the Serra do Mendanha from April 2002 to March 2006, totaling around 800 hours/man of study.For the snake species inventory we used a combination of methods including intensive visual searching and pitfall traps with driftfences (Heyer et al. 1994;Cechin and Martins, 2000).Sampling was made at three major habitats in the Serra do Mendanha: undisturbed forest, secondary forest and a disturbed area of the forest (mostly dominated by banana plantations).In each of these three habitats we carried out a similar sampling effort.Intensive visual searching were performed monthly during different times of day and night along four linear transects of 500 m extension in each of the three habitats, totaling 6 km of extension for the whole area of Serra do Mendanha each month.In addition, at each habitat we established three systems of pitfall traps.Each pitfall system was composed of a set of four 100 liter gallons disposed along a line in which one gallon was set 10 meters from the next.At each habitat 12 gallons were set, totaling 36 gallons for the whole area.The gallons of each pitfall system were interconnected with drift fences, totaling 50 m extension of drift fences for each system and a total 450 m of extension for the whole area.The systems remained open during 24 hours from December 2002 to May 2004.Each pitfall trap was checked every two days throughout the month.For each captured snake, its body length (total length = TTL, and snout-vent length = SVL using measuring tapes to the nearest 1mm and Vernier ® calipers to the nearest 0.2 mm) and mass (to the nearest g using a Pesola ® dinamometer) were taken.The sex of each individual was recorded whenever possible.The altitude (in m a.s.l.) and the microhabitat used by each snake at the time they were first servation value not only due to the richness of the flora and fauna this forest contains but also because it is one of the main forest remnants protecting the Guanabara Bay hydrographic basin, which is the main source of water for most municipalities surrounding the Guanabara Bay, including the metropolis of Rio de Janeiro (Pontes, 2005;Rocha et al. 2003;SEMADS, 2001).Despite the relevance of this forest remnant, the knowledge on most of its fauna and flora is still lacking.There is no previous information regarding the snake fauna inhabiting the area.During a project on the snake fauna in the Serra do Mendanha, carried out during 48 months, we monthly sampled snakes in the area which allowed a first approximation of the richness and composition of the snake fauna of the region.Here we present the snake species found, including a first checklist of the species for the Serra do Mendanha Atlantic and provide detailed field data for voucher specimens sampled.All records are novel data for the area.

Material and Methods
The study was carried out in the Atlantic Rainforest area of Serra do Mendanha, (22° 48'; 22° 51' S and 43°31'; 43° 28' W) (Figure 1), located in Rio de Janeiro state, Southeastern Brazil.The region is included in the Atlantic Rainforest Biome and presently is covered with forests with relatively low level of anthropic disturbances and secondary forests with different levels of regeneration.The climate of the area is wet and hot with a relatively dry winter and rainy summer (Aw).The mean annual temperature in the area varies from 18 to 24° C and mean annual rainfall averages 1200-2000 mm, with most rain falling from November to March (CLINO, 1996).de Janeiro we found seven specimens belonging to five species (Liophis miliaris, L. poecilogyrus, Oxyrhopus petola, Spilotes pullatus and Bothrops jararaca) but all of them were recorded during this study.We did not find snake specimens from the Serra do Mendanha deposited in the herpetological collection of the Instituto Butantan.
Voucher specimen of the species recorded in the area are listed in Appendix 1, including information on precise location (coordinates), altitude in the forest, habitat, microhabitat, height above ground, sex, size (in cm) and weight (in g).
The dominance of the family Colubridae found in the present study is compatible to findings in other studies on Brazilian snake assemblages in different Biomes such as the Pantanal (Strüssmann, 1992), the Amazonian forest (Martins and Oliveira, 1998), the Atlantic Forest (Di-Bernardo, 1998;Freire, 2001;Marques, 1998;Rocha, 1998;Rocha et al., 2000;Rocha and Van Sluys, 2006) and in the Cerrado (Sawaya, 2003).This suggests a conservative pattern in the dominance of Colubridae among snake assemblages, independent of the Biome.This trend may result from the fact that Colubridae is the largest and most structurally diverse snake group (Zug et al., 2001).
Considering only the snakes recorded by us in the field, the most abundant species in the snake assemblage of the Serra do Mendanha was Liophis miliaris (n = 32), followed by Micrurus corallinus (n = 25) and Chironius fuscus (n = 24) which together represent around 40% of the total number of recorded snakes.The least abundant snakes were Elapomorphus quinquelineatus, Pseustes sulphureus and Tropidodryas serra (one individual each species).Chironius fuscus, Liophis miliaris and Micrurus corallinus are, in general, species relatively common in Atlantic Forest areas and have usually been found with considerable frequency in studies realized in other Atlantic forest areas in the states of Rio de Janeiro (Rocha et al. 2000;Rocha and Van Sluys, 2006), São Paulo (Marques, 1998;Marques and Sazima, 2004;Sazima and Haddad, 1992), and Espírito Santo (Rocha, 1998), although the abundance of them differed somewhat from other areas.The variation in the species abundance among snake assemblages probably reflects differences in the local environment and historical features of each region (Di-Bernardo, 1998;Freire, 2001;Marques, 1998).The reduced frequencies of records of some species such as E. quinquelineatus, T. serra and U. ricardinii in the present study suggests that probably they are comparatively low in abundance in the Serra do Mendanha forest, or it may be due to their secretive or cryptic behavior, or both.The capture of the snake Uromacerina ricardinii represents the first record of this species for the Metropolitan Region of Rio de Janeiro state.
The markedly low abundance of B. constrictor (only one individual was found and associated to the anthropic area) could be due to the preference of the species to relatively open areas, which results in usually being found also in low abundance in some forested areas of Atlantic sighted were also registered.Photographs were taken of all captured specimens.Voucher specimens were deposited at the Museu Nacional, Rio de Janeiro (MNRJ).In addition, we supplemented our data with existing specimens from the Serra do Mendanha deposited in the snake collections of the Instituto Vital Brazil (IVB) in Niterói, Rio de Janeiro, the Museu Nacional, Rio de Janeiro (MNRJ) and the Instituto Butantan (IB) in São Paulo.Snakes were identified with the aid of published keys (Campbell and Lamar 2004;Dixon et al. 1993;Hoge and Romano-Hoge, 1978/79;Peters and Orejas-Miranda, 1970;Vanzolini et al. 1980) and a guide for identification of snakes (Marques et al. 2001), and their identities were posteriorly verified by Ronaldo Fernandes (Curator, Herpetology Section, Vertebrate Department Museu Nacional, Rio de Janeiro) and by Daniel S. Fernandes (Herpetology Section, Vertebrate Department Museu Nacional, Rio de Janeiro).
Acknowledgements -We thank the Secretaria Municipal de Meio Ambiente do Rio de Janeiro for the permits to work at the Parque Natural Municipal da Serra do Mendanha and the Programa de Pós-graduação em Biologia of the Universidade do Estado do Rio de Janeiro -UERJ and the Instituto Biomas for their support.We are also grateful to the park's technicians who assisted us in the field work on several occasions and helped with the installation of the pitfall traps.Davor Vrcibradic kindly reviewed the manuscript.Ronaldo Fernandes and D. S. Fernandes, both of the Departamento de Vertebrados, Museu Nacional, Rio de Janeiro, verified the identity of the specimens.Otavio Marques kindly facilitated access (provided information) to information on snakes deposited in the collection of the Instituto Butantan.The Conselho Nacional do Desenvolvimento Científico e Tecnológico -CNPq, provided grants (Nos. 307653/2003-0 and477981/2003-8)  References CAMPBELL, JA. and LAMAR, WW., 2004.The venomous reptiles of the western hemisphere.New York: Cornell University Press.vol.I., 476 p. CECHIN, SZ. and MARTINS, M., 2000.Eficiência de armadilhas de queda (pitfall traps) em amostragens de anfíbios e répteis no Brasil.Rev. Bras. Zool., vol. 17, no. 3, p. 729-740. CLINO, 1996. Climatological Normals (CLINO) for the period 1961-1990. Geneva, Switzerland: World

Figure 1 .
Figure 1.Location of the study area of Serra do Mendanha in Rio de Janeiro state, southeastern Brazil.

Figure 2 .
Figure 2. Rarefaction curve (black line) and collector curve (gray line) with CI = 95% (traced lines) (EstimateS Program and Mao Tao Indices).Serra do Mendanha in Rio de Janeiro State, Southeastern Brazil.