The Herpetofauna from Ilha Grande ( Angra dos Reis , Rio de Janeiro , Brazil ) : updating species composition , richness , distribution and endemisms

Ilha Grande is a large continental island (total area of 19,300 ha) situated at the southern coast of the state of Rio de Janeiro, in southeast Brazil, within the Atlantic Forest Biome. Here we provide an update to the previous knowledge of the fauna of amphibians and reptiles occurring in Ilha Grande, based on primary data from our own fieldwork and on secondary data (from institutional collections and from the literature). We report the occurrence at Ilha Grande of a total of 74 species, being 34 amphibians (all of them anurans) and 40 reptiles (27 snakes, 11 lizards, one amphisbaenian and one crocodylian). Our survey added 14 species to the herpetofaunal list of Ilha Grande (three of amphibians and eleven of reptiles) and removed one species (the amphibian Cycloramphus fuliginosus) from the previous list. The data indicated that Ilha Grande houses a considerable portion of the Atlantic Forest amphibian and reptile diversity (ca. 6% and 19%, respectively, of the species occurring in this biome) together with high occurrence of species endemic to this biome plus a few amphibian species endemic to this island. Ilha Grande is thus an important reservoir of both biodiversity and endemism of amphibians and reptiles of the Atlantic Forest of Brazil, which highlights the importance of the conservation of the island and of its different habitats along the insular landscape. Key-Words. Anura; Reptile; Atlantic Rain Forest; Diversity.


INTRODUCTION
Knowing the species composition occurring in an environment is a prerequisite for the approach of the knowledge of local biodiversity and biogeographical and ecological processes, as well as for mapping conservation and management plans in protected areas.For island communities this knowledge is particularly relevant so that one can select study models for species or populations that provide potential for evaluating the effects of geographical isolation on gene flow (Bittencourt-Silva & Silva, 2013).Insular herpetofaunas constitute good research subjects in this sense because the local species richness and the individual abundance of organisms usually result from historical processes and from their species-specific capacity to transpose geographical barriers.
Ilha Grande is a continental island situated at the southern coast of the state of Rio de Janeiro, in southeast Brazil.With a total area of 19,300 ha, it is the third largest island on the Brazilian coast.Like the other continental islands on the eastern Brazilian coast, Ilha Grande is inserted within the Atlantic Forest Biome, which is one of the world's biodiversity "hotspots" (Mittermeier et al., 2011).Ilha Grande represents one of the areas of the Atlantic Forest for which the knowledge on the vertebrate fauna has continually improved with time, especially since the establishment, in 1996, of a research station there: the Centro de Estudos Ambientais e Desenvolvimento Sustentável -CEADS of the Universidade do Estado do Rio de Janeiro.There are published introductory species lists for non-volant mammals (Pereira et al., 2001), bats (Esbérard et al., 2006), birds (Alves & Vecchi, 2009), squamatan reptiles (Rocha & van Sluys, 2006) and amphibians (Bittencourt-Silva & Silva, 2013) occurring in that island.
Regarding the herpetofauna, Rocha et al. (2009) updated the previous reptile list of Rocha & van Sluys (2006) by adding representatives of the Orders Crocodylia (one species of caiman) and Chelonia (three species of marine turtles) and three more species of Squamata (the lizards Anolis punctatus and Tropidurus torquatus and the snake Corallus hortulanus), as well as providing the first amphibian list for the area.However, no museum vouchers or photos were provided along with those lists.Later, Winck et al. (2011) gave details about the records of Anolis punctatus and Tropidurus torquatus, providing voucher numbers for both taxa.Bittencourt-Silva & Silva (2013) compiled amphibian lists for some islands in the Angra dos Reis Bay, on the Rio de Janeiro coast, including Ilha Grande, providing voucher numbers for most records (except for Cycloramphus fuliginosus Tschudi, 1838) and adding seven species to the previous list of Rocha et al. (2009).Considering all those studies, the herpetofaunal list of Ilha Grande currently includes 32 reptiles (including sea turtles) and 32 amphibians (all of them anurans).
Since 1995 a research team from the Laboratório de Vertebrados of the Departamento de Ecologia from Universidade do Estado do Rio de Janeiro has conducted fieldwork at Ilha Grande (Rocha et al., 2009).Part of the results of those efforts have produced the herpetofaunal lists of Rocha & van Sluys (2006) and Rocha et al. (2009).But, since the publication of these lists, the ongoing studies of our team have added more species records to the island's herpetofauna.Thus, in the present article we provide an update to the knowledge of amphibians and reptiles occurring in Ilha Grande, based on both primary and secondary data.

Study area
Ilha Grande (23°04'31" -23°13'36"S; 44°05'27" -44°22'43"W) lies on the southern coast of the state of Rio de Janeiro, inside Ilha Grande Bay, and belongs to the municipality of Angra dos Reis (Fig. 1).Its last connection with the continent has been around 5,100 years ago (Gama et al., 2009), and its nearest point to the mainland is currently separated from it by ca. 2 km of sea.It contains two terrestrial conservation units of integral protection: Parque Estadual da Ilha Grande (PEIG), with 12,052 ha, and Reserva Biológica da Praia do Sul (RBEPS), with 3,502 ha (INEA, 2013).The vegetation of Ilha Grande is part of the Atlantic Forest that covers the Serra do Mar region; the predominant type of vegetation is Dense Umbrophilous Forest, with other types of formation such as restingas (coastal habitats with sandy soils and xerophyllous vegetation), flooded forests and mangroves being also present, in a smaller scale (Alho et al., 2002;Callado et al., 2009).The climate of Ilha Grande is wet and warm, with total annual rainfall around 2,200 mm at the coastal lowland areas, and mean annual temperature of 21°C (INEA, 2013).

Data collection
To provide an update of the previous information regarding amphibian and reptile species occurring in Ilha Grande, we used primary data from our own fieldwork, supplemented with secondary data (obtained from the literature and from institutional collections).Primary data were obtained from field research conducted along 21 years  by the Laboratório de Vertebrados do Departamento de Ecologia da Universidade do Estado do Rio de Janeiro.Most of the fieldwork has been carried out in the surroundings of the Vila Dois Rios village (23°11'09"S, 44°11'26"W) and along forest trails leading from there to other parts of the island.But some intensive collecting has been conducted more recently (2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) in other portions of the island such as Pico do Papagaio mountain, Lopes Mendes beach, and the Reserva Biológica Estadual da Praia do Sul.In the latter locality, systematic samplings were carried out between 2012 and 2014 on both restinga (23°10'29"S, 44°17'56"W) and umbrophilous forest (23°10'25"S, 44°18'45"W) formations using two sampling methodologies: time-constrained (one hour per person) visual searches (Crump & Scott Jr., 1994) and quadrat sampling (Jaeger & Inger, 1994).Visual surveys totaled 408 h of sampling (204 h each on restinga and forest) and quadrat sampling was performed using 80 plots of 16 m² (4 m × 4 m) set with nylon mesh fences on the floor of the forest and restinga (40 plots on each habitat), totaling 1,280 m² of sampled area.
Regarding secondary data, we sought records of specimens of amphibians and reptiles from Ilha Grande deposited in herpetological collections of different institutions in the state of Rio de Janeiro, as well as published records from the literature.More specifically, we searched the catalogs of the collections of the Museu Nacional (MNRJ), the Universidade Federal Rural do Rio de Janeiro (RU), the Universidade Federal do Rio de Janeiro (ZUFRJ) and the Universidade Federal do Estado do Rio de Janeiro (UNIRIO).The site "Species Link" (www.splink.cria.org.br) was also accessed in order to verify the existence of specimens from Ilha Grande in other institutional collections, namely those of the Instituto Butantan (IBSP), of the Departamento de Zoologia de São José do Rio Preto (DZSJRP), and the Célio F.B. Haddad amphibian collection (CFBH) of the Universidade Estadual Paulista, all in the state of São Paulo.We also sought records in published articles and books in different databases for bibliographic research, such as ISI Web of Science (www.portal.isiknowledge.com),Scopus, Wilson Web, Biological Abstracts (www.periodicos.capes.gov.br) and SciELO -Scientific Electronic Library Online (www.scielo.br).
In order to evaluate the occurrence of the amphibian and reptile species within Ilha Grande, we aimed to obtain the locations of occurrence on the island as accurately as possible for specimens in scientific collections and also from the literature, when such data was available.All records without identification at the specific level were disregarded, except for those involving individuals believed to belong to undescribed taxa or when such unidentified specimens were the only members of a given genus recorded at the area.The same applied for specimens identified through the taxonomic artifices "gr.", "cf." and "aff.".Nomenclature used throughout the text follows Segalla et al. (2016) and Frost (2017) for amphibians, and Costa & Bérnils (2015) for reptiles, unless otherwise noted.

RESULTS AND DISCUSSION
The records we obtained for the non-marine herpetofauna of Ilha Grande indicated presently the occurrence of a total of 74 species, being 34 amphibians (all of them anurans) and 40 reptiles (27 snakes, 11 lizards, one amphisbaenian and one crocodilian) (Table 1).Our survey added 14 species to the herpetofaunal list of Ilha Grande, being three of amphibians (Ischnocnema bolbodactyla, Leptodactylus flavopictus and Leptodactylus latrans; Fig. 2) and eleven of reptiles [Boa constrictor, Dipsas albifrons, D. alternans, D. indica (Fig. 3A), Echinantera cephalostriata (Fig. 3B), Erythrolamprus aesculapii, Liotyphlops wilderi, Mastigodryas bifossatus, Ophiodes cf.striatus, Philodryas olfersii and Xenodon merremi] (see Appendix 1 for voucher specimens).Additionally, one species (the frog Cycloramphus fuliginosus; see below) is herein removed from the previous list.We also confirm the occurrence of the snake Corallus hortulanus in the island on the basis of vouchered specimens in collections (see Appendix 1) and one individual photographed (but not collected) in the Vila do Aventureiro village during our fieldwork (Fig. 4).
The amphibian richness presently registered for Ilha Grande corresponds to 3.1% of the amphibian species known to occur in Brazil (Segalla et al., 2016), to 6.3% of the species known from the Atlantic Forest domain (Haddad et al., 2013) and to ca. 18% of the species reported for the state of Rio de Janeiro (Rocha et al., 2004a;Vrcibradic et al., 2011).The richness of non-marine reptiles occurring in Ilha Grande corresponds to ca. 5% of that of Brazil (Costa & Bérnils, 2015), to 19% of that of the Atlantic Forest (Martins & Molina, 2008) and to ca. 30% of that of the state of Rio de Janeiro (Rocha et al. 2004a;Vrcibradic et al., 2011).These numbers indicate that Ilha Grande is an important reservoir of the biodiversity of Atlantic rainforest amphibians and reptiles and point out the importance of the conservation of the different environments along the island landscape.Rocha et al. (2009) remarked that the Park Management Directive Plan (UFRRJ/IEF/PRONATURA, 1992) of the PEIG cited three amphibian species not present in their list: Leptodactylus ocellatus (Linnaeus, 1758) (currently L. latrans), Hyla albofrenata Lutz, 1924 (currently Aplastodiscus albofrenatus) and Ololygon perpusilla (Lutz & Lutz, 1939).The occurrence of L. latrans in Ilha Grande is here confirmed through both primary and secondary data.The record of A. albofrenatus was almost certainly based on A. eugenioi, a taxon that had not yet been described at the time of the report and was then considered as part of A. albofrenatus (see Carvalho-e-Silva & Carvalho-e-Silva, 2005).Finally, the record of Ololygon perpusilla is probably referable to an apparently undescribed species of the O. perpusilla group (referred to as Scinax gr.perpusillus by Bittencourt-Silva & Silva, 2013).
Two of the species reported as new records in our study have been recorded only through photographs, as physical specimens could not be secured.This was the case of the frog Leptodactylus flavopictus (whose record was based on a specimen that evaded capture) and of the snake Dipsas indica.The latter species was recorded by a colleague who photographed one specimen but could not collect it since he did not have a collecting permit.A previous record based only on a photograph was that of the toad Rhinella icterica reported by Bittencourt-Silva & Silva ( 2013).Since all those species are relatively large-bodied and can be easily told apart from other congeners occurring in the Atlantic Forest of southeastern Brazil, it was possible to identify them accurately from the images.
The oldest representative of the Ilha Grande herpetofauna found by us in the scientific collections surveyed was an individual of the cycloramphid frog Thoropa miliaris collected in Praia do Sul in 1941, which is currently deposited in the amphibian collection of Museu Nacional (MNRJ 58941; collector unknown).There are other specimens of various amphibian and reptile taxa in the collections of Museu Nacional and Universidade Federal do Rio de Janeiro that have been collected in the 1940s by the German ornithologist Helmut Sick, during his stay at the prison of Vila dos Dois Rios village between 1942 and 1945 (Vuilleumier, 1998).Some of those specimens constitute the sole representatives of their species recorded so far for Ilha Grande, like the glass frog Vitreorana eurygnatha, the lizard Ophiodes cf.striatus, and the snakes Boa constrictor, Dipsas alternans, Erythrolamprus aesculapii, Liotyphlops wilderi and Mastigodryas bifossatus.The fact that no further specimens of those taxa have been collected in the island in over seven decades may have a number of different causes, such as: low density of those taxa in Ilha Grande, low detectability (e.g., in the case of the fossorial snake Liotyphlops), occurrence of those taxa in undersampled regions of the island, local extinction and/or possible mislabeling of specimens (see below).
The knowledge about the Ilha Grande herpetofauna has been amassed over the last seven decades, starting with the first deposits in scientific collections of specimens collected in the 1940s.There has been a consistent increase in the last two decades since the creation of the Centro de Estudos Ambientais e Desenvolvimento Sustentável of the Universidade do Estado do Rio de Janeiro (CEADS/UERJ) in 1996, which is located in Vila Dois Rios village.The creation of CEADS allowed the development of new research projects with various groups of fauna and flora of the island (Callado et al., 2009;Rocha et al., 2009).However, the logistical facility provided by the CEADS potentially promoted a bias in the research on herpetofauna (and also on other groups of animals and plants), concentrating most of the studies in the forests around Vila Dois Rios village, on the seaward side of the island.Indeed, Vila Dois Rios was the locality with the highest number of herpetofaunal species recorded for Ilha Grande (see Fig. 1).

Amphibia
Chiasmocleis -Specimens of this genus recorded at Ilha Grande have been usually referred as Chiasmocleis sp.(Rocha et al., 2000(Rocha et al., , 2001(Rocha et al., , 2004a(Rocha et al., , 2009;;Ariani et al., 2006;van Sluys et al., 2007;Goyannes-Araújo et al., 2015).Rocha et al. (2004a) and Goyannes-Araújo et al. (2015) commented that the Chiasmocleis from Ilha Grande was an undescribed species.Bittencourt-Silva & Silva (2013), on the other hand, referred to the species occurring in Ilha Grande as C. carvalhoi (now C. lacrimae; see Peloso et al., 2014).Tonini et al. (2014), in a molecular phylogenetic analysis of the C. lacrimae and C. capixaba complexes, used DNA sequences of three specimens of Chiasmocleis from "Angra dos Reis, Rio de Janeiro" housed at the herpetological collection of the Universidade Federal Rural do Rio de Janeiro.Those specimens (RU 7003-05; referred as RN 7003-05 in Tonini et al., 2014) are actually from Ilha Grande, and are determined as Chiasmocleis gr.carvalhoi in that collection's catalog (curiously, they are not listed in the Appendix I of Bittencourt-Silva & Silva, 2013).In Tonini et al.'s (2014) phylogeny their DNA sequences grouped with other samples from the states of Rio de Janeiro and São Paulo in a clade that those authors considered to be assignable to C. lacrimae (sensu strictu).Thus, the species of Chiasmocleis that occurs in Ilha Grande can be referred to C. lacrimae (assuming that only one species of that genus occurs there).Rocha et al. (2009) and Bittencourt-Silva & Silva (2013) listed two species of the genus Cycloramphus for Ilha Grande: Cycloramphus boraceiensis and C. fuliginosus.In the Appendix of their article, Bittencourt-Silva & Silva (2013) cite a voucher number for C. boraceiensis but none for C. fuliginosus, instead referring to the citation by Rocha et al. (2009) to justify its presence on the list (indeed, C. fuliginosus is the only species in their list for which no voucher specimens are mentioned).The specimen cited in that work (MNRJ 48118) was checked by the authors at the collection of the Museu Nacional.The name C. boraceiensis was written in the label inside the vial in which it is kept, but in the museum catalog this same specimen is referred as C. fuliginosus.Thus, it seems that the records of two species of Cycloramphus for Ilha Grande are based on a single specimen.Cycloramphus boraceiensis is the only species of the genus previously reported for Ilha Grande (Heyer, 1983).Heyer's (1983) record of this species for the island is based on an individual in the Museu Nacional (MNRJ 2241, also examined by us) that had been collected by H. Sick in 1944.During fieldwork at the RBEPS one of us (FBST) collected three individuals of Cycloramphus (subsequently deposited at the Museu Nacional under the numbers MNRJ 89138-40).Using Heyer's (1983) dichotomic key to the species of Cycloramphus known at the time and making direct comparisons with MNRJ 2241 we were able to confirm the identification of MNRJ 48118 as C. boraceiensis and to determine that our three new specimens were C. boraceiensis as well.Thus, it seems that C. boraceiensis is currently the only species of the genus known to occur at Ilha Grande and, therefore, C. fuliginosus should be excluded from the island's list of amphibians.

Cycloramphus -Both
Ischnocnema -Ischnocnema octavioi was first reported for Ilha Grande by Rocha et al. (2000Rocha et al. ( , 2001)), but that record was later found to be based on two misidentified specimens of I guentheri (Vrcibradic et al., 2008).Bittencourt-Silva & Silva (2013) reported the occurrence of I octavioi in Ilha Grande based on a third specimen, MNRJ 60158 (the two previously mentioned specimens, MNRJ 47972-73, were correctly listed by them under I guentheri).The specimen MNRJ 60158 was collected by a colleague and is, in fact, I octavioi, which confirms the occurrence of this species in the island.
Physalaemus -There were two specimens at the Museu Nacional determined as Physalamus angrensis (MNRJ 56473-74), having been collected at Praia do Sul.Those specimens were re-examined and re-identified as young individuals of Physalaemus signifer (M.Woitovicz-Cardoso, pers.comm.), a relatively common species in Ilha Grande, where it occurs in various localities, including the RBEPS (Table 1).

Reptilia
Ophiodes -The lizard genus Ophiodes is currently a problematic taxon, requiring a comprehensive review.One individual at the collection of Museu Nacional is labeled Ophiodes fragilis (Raddi, 1820).The name O. fragilis has been widely used for specimens from southeastern Brazil and portions of Argentina and Paraguay (Pizzatto, 2005;Avila et al., 2013;Cacciali & Scott, 2015).Nevertheless, a proper redescription and revalidation of O. fragilis has not yet been published (Costa & Bérnils, 2015).Thus, we follow Montechiaro et al. (2011) and take a conservative stance by referring to the specimen from Ilha Grande as Ophiodes cf.striatus.

Thamnodynastes -Snakes from the genus
Thamnodynastes from Ilha Grande present another taxonomic problem.They have been referred to as Thamnodynastes strigilis by Ariani et al. (2006) and Rocha et al. (2009), and as Thamnodynastes cf.strigilis by Rocha & van Sluys (2006), but T. strigilis is currently considered a synonym of T. pallidus, a species that does not occur in southeastern Brazil (Bailey et al., 2005).The name T. nattereri (or T. cf.nattereri) have also been recently attributed to the Atlantic Forest Thamnodynastes commonly referred to "strigilis" or "cf.strigilis" in the literature (Dorigo et al., 2014;Franco et al., 2017).Indeed, the specimens from Ilha Grande deposited in the institutional collections we surveyed are all labeled as either T. cf.nattereri, Thamnodynastes sp., or (in one case) T. pallidus nattereri.
For the present list we conventionally follow the most recent authors and attribute the name Thamnodynastes cf.nattereri for the specimens from Ilha Grande, though we are aware that this is a provisional designation, given the current nomenclatural problems involving the epithet "nattereri" (Franco & Ferreira, 2002;Bellini et al., 2014;Dorigo et al., 2014;Franco et al., 2017).

Probable erroneous records
Some of the records from Ilha Grande based on secondary data are problematic, as the species involved are not known to occur in the state of Rio de Janeiro or even in the Atlantic Forest biome.We believe those records contain erroneous information and, therefore, they were not included in the list.This is the case of two lizard specimens at the reptile collection of the Museu Nacional.One of them (MNRJ 19748), referred to Anolis auratus in the museum's catalog, has been collected in 1986 by the personnel of the "Projeto Ilha Grande".Unfortunately, that specimen could not be located at the museum's collection, so we could not verify its identity.Nevertheless, since A. auratus is a species confined to the Amazon region (Ávila-Pires, 1995), we assume the specimen must have been misidentified.The other problematic specimen is MNRJ 15512, identified as Tropidurus spinulosus and collected by H. Sick in 1944, according to the catalog.That specimen was examined by us and is indeed a member of the T. spinulosus group.However, species of the T. spinulosus group do not occur in the Atlantic for- ests of southeastern Brazil (Carvalho, 2013(Carvalho, , 2016)), which indicates that the locality of collection given for MNRJ 15512 is probably erroneous.

Conservation issues
Among the herpetofauna species recorded for Ilha Grande, amphibians had a high rate of endemism for the Atlantic Forest Biome (94% of the species were endemic).This high degree of endemism is characteristic of the amphibian fauna of this biome, in which 88% of the species are endemic according to Haddad et al. (2013).Regarding reptiles, 12 species were endemic to the Atlantic Forest (five lizards and seven snakes), representing about a third of the species recorded for the island.
In spite of the high rate of endemism among amphibians, most species are categorized as being of "Least Concern" in terms of their conservation status in the global scope (according to criteria of the IUCN -International Union for the Conservation of Nature).The only species from Ilha Grande included in an actual threat category by the IUCN is Chiasmocleis lacrimae, which is currently considered as "Endangered", mainly due to habitat degradation within its area of occurrence and the presumed trend for decline of its populations [see Stuart et al., 2008 (as C. carvalhoi)].The only other species of the Ilha Grande herpetofauna not categorized as "Least Concern" is the hylodid Hylodes fredi, a species endemic to the island, which is considered as "Data Deficient" (DD) due to the lack of information on "its extent of occurrence, area of occupancy, status and ecological requirements" (Angulo, 2008).Nevertheless, we caution that, in terms of conservation, particular attention should be paid to hylodids, as well as to any other species whose life is restricted to forest streams, as we believe those species are particularly vulnerable to environmental disturbances.Hylodids have had their real threat status underestimated since the current form of extinction risk assessment by IUCN for species restricted to streams seems to overestimate the actual area of occupation for these species which is likely much more spatially limited (Almeida-Gomes et al., 2014).The other frog species endemic to Ilha Grande, the odontophrynid Proceratophrys tupinamba, is not yet categorized by IUCN, probably because its description is relatively recent (Prado & Pombal Jr., 2008).However, we think these two species that occur only in Ilha Grande carry conservation concern because they have a very restricted distribution and depend on the effective conservation of that particular insular environment.
Among the reptiles, only two species of lizards (Salvator merianae and Tropidurus torquatus), three of snakes (Siphlophis pulcher, Xenodon neuwiedii and Bothrops jararacussu) and one crocodilian (Caiman latirostris) are categorized by the IUCN, but all in the category of "Least Concern".The broad-snouted caiman (C.latirostris), although believed to be an introduced species in Ilha Grande (INEA, 2013), is the only taxon on the island that is included in the Rio de Janeiro state list of threatened fauna (classified as "Endangered"; Bergallo et al. 2000).However, at the national level, none of the species of the Ilha Grande reptile fauna is categorized as having a conservation risk (Haddad, 2008;Martins & Molina, 2008).
In conclusion, our data indicated that Ilha Grande houses a considerable portion of Atlantic Forest amphibian and reptile diversity together with a predominance of species endemic to this biome, plus a few species endemic to that island.This indicates that Ilha Grande is an important reservoir of both biodiversity and endemism of amphibians and reptiles of the Atlantic Forest of southeastern Brazil, which points out the importance of the conservation of this island and its different habitats along the insular landscape.We also point out that several portions of Ilha Grande remain unexplored, particularly in respect to the herpetofauna (as is evident from Fig. 1), and that still more species of amphibians and reptiles are likely to be added to the present list if field surveys in that island are intensified.