The Amphibians of the Gulf of Guinea Oceanic Islands

AbstractThis chapter reviews the diversity, evolutionary relationships, ecology, and conservation of the Gulf of Guinea oceanic islands’ endemic caecilian and anuran fauna. A total of nine amphibian species (representing five families) are known from São Tomé and Príncipe islands, all of which are endemic. No amphibians have been reported from Annobón. Taxonomic research on this group of animals began in the second half of the nineteenth century with subsequent refinement following the advent of molecular techniques. The presence of several amphibians from distinct evolutionary lineages is unexpected for oceanic islands and has motivated several biogeographic studies to reconstruct the evolutionary histories of these enigmatic species. Yet, the continental source for many of the islands’ amphibians remains unknown. The amphibians of São Tomé and Príncipe also exhibit intriguing phenotypic diversity for addressing long-standing hypotheses in evolutionary biology, including body size evolution and gigantism on islands, intraspecific variation and interspecific divergence in coloration, and reproductive and dietary niche partitioning. Recent studies have confirmed the presence of the fungal pathogen Batrachochytrium dendrobatidis in amphibian communities on both São Tomé and Príncipe, but it is unclear whether this pathogen is negatively impacting local populations. Most of the Gulf of Guinea oceanic island endemic amphibians are incredibly abundant and widespread, occurring in primary forest, secondary forest, and agricultural habitats across the islands. Three anuran species (Hyperolius thomensis, Leptopelis palmatus, Ptychadena newtoni) have more limited distributions and/or more specialized ecologies; consequently, additional land-use change poses a threat to the long-term persistence of these taxa.