Amphibians of La Escalera Region, Southeastern Venezuela: Taxonomy, Ecology, and Biogeography

Abstract

Data are presented on the characteristics and natural history of 57 species of anuran amphibians from a transect from El Dorado in humid tropical forest across the Sierra de Lema to the Gran Sabana, Estado de Bolivar, Venezuela. Allophryne nithveiii, Phyllomedusa tomopterrm, and Elachistocleis sp. are reported for the first time from Venezuela. Descriptions and illustrations of tad- poles are presented for Colostethus parkerae, Hyla multifasciata, Leptodactyhis longirostris, L. rugosus, and L. sabnnensis. Descriptions and illustrations of advertisement calls are presented for Bufo granulosus, Hyla lemai, H. miiiuscula, H. miinita, H. multifasciata, Phyllomedusa hypocondrialis, Leptodactyhis rugosus, Phifsalaemus enesefae, Cteuophryne geayi, and Elachistocleis sp. Analysis of utilization of calling sites by anurans in five communities shows greater overlap of calling sites with size of adult males in humid tropical forest than in very humid lower montane forest and grassland on the Gran Sabana. Few species are distributed throughout the elevational transect, but some species that occur in savannas in the lowlands also occur on the Gran Sabana. Comparison of the anuran faunas at 12 sites in the Guianan region reveals that the fauna in the humid tropical forest in the lowlands to the north of the Sierra de Lema contains a mixture of forest-dwelling and savanna-inhabiting species, and that the fauna in the very humid lower montane forest on the northern slopes of the Sierra de Lema is primarily a mixture of endemics and species shared with the Gran Sabana. Significant negative correlations between dis- tances between sites and coefficients of biogeographic resemblance exist among sites in savannas, between sites in savannas and lowland rainforest, and between sites in savannas and cloud forest.