One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures -the world's so-called biodiversity hotspots. Although the distribution of Puddle frogs of the genus Occidozyga in South and Southeast Asia includes five biodiversity hotspots, the available data on phylogeny, species diversity, and biogeography are surprisingly patchy. Samples analyzed in this study were collected throughout Southeast Asia, with a primary focus on Sundaland and the Philippines. A mitochondrial gene region comprising ~ 2000 bp of 12S and 16S rRNA with intervening tRNA Valine and three nuclear loci (BDNF, NTF3, POMC) were analyzed to obtain a robust, time-calibrated phylogenetic hypothesis. We found a surprisingly high level of genetic diversity within Occidozyga, based on uncorrected p-distance values corroborated by species delimitation analyses. This extensive genetic diversity revealed 29 evolutionary lineages, defined by the > 5% uncorrected p-distance criterion for the 16S rRNA gene, suggesting that species diversity in this clade of phenotypically homogeneous forms probably has been underestimated. The comparison with results of other anuran groups leads to the assumption that anuran species diversity could still be substantially underestimated in Southeast Asia in general. Many genetically divergent lineages of frogs are phenotypically similar, indicating a tendency towards extensive morphological conservatism. We present a biogeographic reconstruction of the colonization of Sundaland and nearby islands which, together with our temporal framework, suggests that lineage diversification centered on the landmasses of the northern Sunda Shelf. This remarkably genetically structured group of amphibians could represent an exceptional case for future studies of geographical structure and diversification in a widespread anuran clade spanning some of the most pronounced geographical barriers on the planet (e.g., Wallace's Line). Studies considering gene flow, morphology, ecological and bioacoustic data are needed to answer these questions and to test whether observed diversity of Puddle frog lineages warrants taxonomic recognition.

The current account presents the results of a 14-day amphibian survey at Maliau Basin Conservation Area (MBCA). With a total of approximately 170 man-hrs, 44 species were detected at four study sites during the field period; four more species were later discovered outside the two-week campaign. The results are compared to the results of previous surveys. Apart from adults, we present the first photographic documentation of the larval stages ofChiromantisinexpectatusand BorneanPhrynoidisjuxtaspera, along with a brief tadpole description; the better-known tadpoles of four more species were recorded. The results of our expedition suggest that nine more species are present at MBCA than reported by previous studies. We present an updated list of known species in the MBCA, comprising 61 species. The species accumulation curve over the 14 days period of the core survey did not show signs of asymptotic saturation. We conclude that the definitive species number for MBCA amphibians has the potential to increase with more thorough surveys in the future.

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