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The Mascarene ridged frog, Ptychadena mascareniensis , is a species complex that includes numerous lineages occurring mostly in humid savannas and open forests of mainland Africa, Madagascar, the Seychelles, and the Mascarene Islands. Sampling across this broad distribution presents an opportunity to examine the genetic differentiation within this complex and to investigate how the evolution of bioclimatic niches may have shaped current biogeographic patterns. Using model-based phylogenetic methods and molecular-clock dating, we constructed a time-calibrated molecular phylogenetic hypothesis for the group based on mitochondrial 16S rRNA and cytochrome b ( cytb ) genes and the nuclear RAG1 gene from 173 individuals. Haplotype networks were reconstructed and species boundaries were investigated using three species-delimitation approaches: Bayesian generalized mixed Yule-coalescent model (bGMYC), the Poisson Tree Process model (PTP) and a cluster algorithm (SpeciesIdentifier). Estimates of similarity in bioclimatic niche were calculated from species-distribution models ( maxent ) and multivariate statistics (Principal Component Analysis, Discriminant Function Analysis). Ancestral-area reconstructions were performed on the phylogeny using probabilistic approaches implemented in BioGeoBEARS. We detected high levels of genetic differentiation yielding ten distinct lineages or operational taxonomic units, and Central Africa was found to be a diversity hotspot for these frogs. Most speciation events took place throughout the Miocene, including “out-of-Africa” overseas dispersal events to Madagascar in the East and to São Tomé in the West. Bioclimatic niche was remarkably well conserved, with most species tolerating similar temperature and rainfall conditions common to the Central African region. The P. mascareniensis complex provides insights into how bioclimatic niche shaped the current biogeographic patterns with niche conservatism being exhibited by the Central African radiation and niche divergence shaping populations in West Africa and Madagascar. Central Africa, including the Albertine Rift region, has been an important center of diversification for this species complex. [ABSTRACT FROM AUTHOR]

Abstract: The family Microhylidae has a large circumtropic distribution and contains about 400 species in a highly subdivided taxonomy. Relationships among its constituent taxa remained controversial due to homoplasy in morphological characters, resulting in conflicting phylogenetic hypotheses. A phylogeny based on four nuclear genes (rag-1, rag-2, tyrosinase, BDNF) and one mitochondrial gene (CO1) of representatives of all currently recognized subfamilies uncovers a basal polytomy between several subfamilial clades. A sister group relationship between the cophylines and scaphiophrynines is resolved with moderate support, which unites these endemic Malagasy taxa for the first time. The American members of the subfamily Microhylinae are resolved to form a clade entirely separate from the Asian members of that subfamily. Otophryne is excluded from the subfamily Microhylinae, and resolved as a basal taxon. The placement of the Asian dyscophine Calluella nested within the Asian Microhyline clade rather than with the genus Dyscophus is corroborated by our data. Bayesian estimates of the divergence time of extant Microhylidae (47–90Mya) and among the subclades within the family are discussed in frameworks of alternative possible biogeographic scenarios. [Copyright &y& Elsevier]