We describe a new species of hylid frog, Scinax peixotoi, from Queimada Grande Island, southeastern Brazil. The new species belongs to the Scinax perpusillus species group, in which all known forms inhabit bromeliads, and is diagnosed by the following set of characters: moderate-size (males 18.8-20.7 mm SVL, females 22.4-25.1 mm SVL); canthus rostralis distinct; dorsal skin slightly rugose; and a distinct advertisement call with relatively low dominant frequency. The new species is known from a single population on Queimada Grande, an island of 43 ha, approximately 33 km distant from the coast of São Paulo State, where it inhabits scattered patches of bromeliads. The highly specialized and patchy habitat of S. peixotoi, associated with its small range size, make this species highly susceptible to stochastic or anthropogenic habitat disturbances, which could lead it to extinction. Copyright © 2007 Magnolia Press. 13914755Brasil (2002). Sistema Nacional de Unidades de Conservação. Ministério do Meio Ambiente, BrasíliaCei, J.M. (1980). Amphibians of Argentina. Monit. Zool. Ital. (n.s.) Monogr. 2, 1-609Duellman, W.E., Wiens, J.J., The status of the hylids frog genus Ololygon and the recognition of Scinax Wagler, 1830 (1992) Occasional Papers of the Museum of Natural History, University of Kansas, 151, pp. 1-23Duellman, W.E., I. De La Riva & Wild, F.R. (1997) Frogs of the Hyla armata and Hyla pulchella groups in the Andes of South America with definitions and analysis of phylogenetic relationships of Andean groups of Hyla. Scientific Papers, Natural History Museum of the University of Kansas, 3, 1-41Faivovich, J., A cladistic analysis of Scinax (Anura:Hylidae) (2002) Cladistics, 18, pp. 367-393Heyer, W.R., Rand, A.S., da Cruz, C.A.G., Peixoto, O.L., Nelson, C.E., Frogs of Boracéia (1990) Arquivos de Zoologia, 31, pp. 231-410. , S. PauloIUCN, (1994) Guidelines for protected area management categories. IUCN, Gland. Lutz, B. (1973). Brazilian species of Hyla. University of Texas Press, Austin & LondonMarques, O.A.V., Martins, M., Sazima, I., A jararaca da Ilha da Queimada Grande (2002) Ciência Hoje, 31, pp. 56-59Marques, O.A.V., Martins, M., Sazima, I., A new insular pitviper from Brazil, with comments on the evolutionary biology and conservation of the Bothrops jararaca group (Serpentes, Viperidae) (2002) Herpetologica, 58, pp. 303-312Martin, L., Mörner, N.A., Flexor, J.M., Suguio, K., Fundamentos e reconstrução de antigos níveis marinhos do Quartenário. Boletim do Instituto de Geociências (1986) Publicação Especial, 4, pp. 1-161Myers, C.W., Duelmann, E., A new species of Hyla from Cerro Colorado, and other tree frog records and geographical notes from western Panama (1982) American Museum Novitates, 2752, pp. 1-32Oliveira, F.B., Navas, C.A., Plant selection and seasonal patterns of vocal activity in two population of Bromeligen treefrog Scinax perpusillus (AnuraHylidae) (2004) Journal of Herpetology, 38 (3), pp. 331-339Peixoto, O.L. (1986) Espécies bromelígenas do gênero Ololygono grupo perpusilla (Amphibia. Anura, Hylidae). Tese de Doutorado, Inst. Biociências, Universidade de São Paulo, São Paulo, BrasilPeixoto, O.L., Caracterização do grupo "perpusillus" e revalidação da posição taxonômica de Ololygon perpusilla perpusilla e Ololygon perpusilla v-signata (Amphibia, Anura, Hylidae) (1987) Arquivos da Universidade Federal Rural do Rio de Janeiro, Itaguaí, 10 (1/2), pp. 37-49Peixoto, O.L., Sobre o "status" taxonômico de Hyla catharinae alcatraz B. Lutz 1973, com a descrição de uma nova espécie para o grupo "perpusilla" (Amphibia, Anura, Hylidae) (1988) Acta Biologica Leopoldesia, 10, pp. 253-267Peixoto, O.L., Duas novas espécies de Ololygon do Grupo "perpusilla" (Amphibia, Anura, Hylidae) (1988) Arquivos da Universidade Federal Rural do Rio de Janeiro, Itaguaí, 10, pp. 27-37Peixoto, O.L., Uma nova espécie de Scinax do grupo "perpusillus" para Santa Teresa, Estado do Espírito Santo, Brasil (Amphibia, Anura, Hylidae). Boletim do Museu Biológico Mello Leitão (N (2002) Sér.),13, pp. 7-15Pombal Jr., J.P., Bastos, R.P., Vocalizações de Scinax perpusillus (A. Lutz & B. Lutz) e S. arduous Peixoto (Anura, Hylidae), com comentários taxonômicos (2003) Revista Brasileira de Zoologia, 20 (4), pp. 607-610Rabinowitz, D., Cairns, S., Dillon, T., Seven forms of rarity and their frequency in the flora of the British Isles (1986) Conservation biology, the science of scarcity and diversity, pp. 182-204. , Pp, Soulé, M. E, ed, Sinauer, Sunderland, MassSavage, J.M., Heyer, W.R., Variation and distribution in tree-frog genus Phyllomedusa in Costa Rica, Central America. Beitr (1967) Neotropical Fauna, 5, pp. 111-131Souza, C.R.D.G., Suguio, K., Oliveira, A.M.D.S., Oliveiria, P.E., (2005) Quaternário do Brasil. Holos Editora, , Ribeirão Preto, SP, Brazil