Giant Tree Frog diversification in West and Central Africa: Isolation by physical barriers, climate, and reproductive traits.

Secondary sympatry amongst sister lineages is strongly associated with genetic and ecological divergence. This pattern suggests that for closely related species to coexist in secondary sympatry, they must accumulate differences in traits that mediate ecological and/or reproductive isolation. Here, we characterized inter- and intraspecific divergence in three giant tree frog species whose distributions stretch across West and Central Africa. Using genome-wide single-nucleotide polymorphism data, we demonstrated that species-level divergence coincides temporally and geographically with a period of large-scale forest fragmentation during the late Pliocene. Our environmental niche models further supported a dynamic history of climatic suitability and stability, and indicated that all three species occupy distinct environmental niches. We found modest morphological differentiation amongst the species with significant divergence in tympanum diameter and male advertisement call. In addition, we confirmed that two species occur in secondary sympatry in Central Africa but found no evidence of hybridization. These patterns support the hypothesis that cycles of genetic exchange and isolation across West and Central Africa have contributed to globally significant biodiversity. Furthermore, divergence in both ecology and reproductive traits appear to have played important roles in maintaining distinct lineages. At the intraspecific level, we found that climatic refugia, precipitation gradients, marine incursions, and potentially riverine barriers generated phylogeographic structure throughout the Pleistocene and into the Holocene. Further studies examining phenotypic divergence and secondary contact amongst these geographically structured populations may demonstrate how smaller scale and more recent biogeographic barriers contribute to regional diversification.

La sympatrie secondaire parmi les espèces sœurs est fortement associée à la divergence génétique et écologique. Ce modèle suggère que pour que des espèces étroitement liées coexistent en sympatrie secondaire, elles doivent accumuler des différences dans les traits qui contribuent à l'isolement écologique ou reproductif. Ici, nous avons caractérisé la divergence inter- et intra-spécifique chez trois espèces de grenouilles arboricoles géantes dont les distributions s'étendent à travers l'Afrique de l'Ouest et Centrale. Avec des données génétiques, nous avons démontré que la divergence au niveau des espèces coïncide temporellement et géographiquement avec une période de fragmentation forestière à la fin du Pliocène. Nos modèles de niches environnementales ont soutenu une histoire dynamique de stabilité climatique, et ont indiqué que les trois espèces occupent des niches environnementales distinctes. Nous avons trouvé une différenciation morphologique modeste parmi les trois espèces mais une divergence significative dans le diamètre du tympan et les cris des mâles. De plus, nous avons confirmé que deux espèces sont présentes en sympatrie secondaire en Afrique Centrale mais n'avons trouvé aucune preuve d'hybridation. Ces résultats soutiennent l'hypothèse que les cycles d'échange génétique et d'isolement à travers l'Afrique de l'Ouest et Centrale ont contribué à une profonde concentration de biodiversité dans la région. De plus, la divergence des traits écologiques et reproducteurs semble avoir joué un rôle important dans le maintien de lignées distinctes. Au niveau intra-spécifique, nous avons constaté que les refuges climatiques, les gradients de précipitation, les incursions marines et potentiellement les barrières fluviales ont généré une structure phylogéographique pendant le Pléistocène et jusqu'à l'Holocène. Des études examinant la divergence phénotypique et le contact secondaire entre ces populations géographiquement structurées pourraient démontrer comment des barrières biogéographiques à échelle plus petite et plus récentes contribuent à la diversification régionale.

A new species of feather-tailed leaf-toed gecko, Kolekanos Heinicke, Daza, Greenbaum, Jackman, Bauer, 2014 (Squamata, Gekkonidae) from the poorly explored savannah of western Angola.

We here describe a new species of feather-tailed leaf-toed gecko, Kolekanos, from southern Benguela Province, Angola, based on morphological and osteological evidence, supported by phylogenetic analysis of mitochondrial data. The new species adds to the rapidly growing and newly-recognised endemic biodiversity of Angola, doubling the number of Kolekanos species, breaking the pattern observed within other closely-related African members of a clade of circum-Indian Ocean leaf-toed geckos - Ramigekko, Cryptactites and Afrogecko - all of which are presently monotypic. The new species is easily distinguished from K.plumicaudus, based on spine-like (as opposed to feather-like) scales on the margins of the original tail. Phylogenetic analyses also recovered the new taxon as monophyletic, with a well-supported sister relationship to K.plumicaudus, from which it differs by a substantial 24.1% NADH-dehydrogenase subunit 2 mitochondrial gene uncorrected p-distance.

Taxonomical review of Prosymnaangolensis Boulenger, 1915 (Elapoidea, Prosymnidae) with the description of two new species.

African Shovel-snout snakes (Prosymna Gray, 1849) are small, semi-fossorial snakes with a unique compressed and beak-like snout. Prosymna occur mainly in the savanna of sub-Saharan Africa. Of the 16 currently recognised species, four occur in Angola: Prosymnaambigua Bocage, 1873, P.angolensis Boulenger, 1915, P.frontalis (Peters, 1867), and P.visseri FitzSimons, 1959. The taxonomical status and evolutionary relationships of P.angolensis have never been assessed due to the lack of genetic material. This species is known to occur from western Angola southwards to Namibia, and eastwards to Zambia, Botswana and Zimbabwe. The species shows considerable variation in dorsal colouration across its range, and with the lower ventral scales count, an 'eastern race' was suggested. In recent years, Prosymna material from different parts of Angola has been collected, and with phylogenetic analysis and High Resolution X-ray Computed Tomography, the taxonomic status of these populations can be reviewed. Strong phylogenetic evidence was found to include the angolensis subgroup as part of the larger sundevalli group, and the existence of three phylogenetic lineages within the angolensis subgroup were identified, which each exhibit clear morphological and colouration differences. One of these lineages is assigned to the nominotypical P.angolensis and the other two described as new species, one of which corroborates the distinct eastern population previously detected. These results reinforce that a considerable part of Angolan herpetological diversity is still to be described and the need for further studies.

ResumoAs cobras-de-focinho-de-pá africanas (Prosymna) são pequenas cobras semi-fossoriais com um focinho único, achatado e em forma de bico, que ocorrem principalmente na savana da África subsaariana. Das 16 espécies actualmente reconhecidas, quatro existem em Angola: Prosymnaambigua Bocage, 1873, P.angolensis Boulenger, 1915, P.frontalis (Peters, 1867), e P.visseri FitzSimons, 1959. O estatuto taxonómico e as relações evolutivas de P.angolensis nunca foram avaliados devido à falta de material genético. A espécie ocorre desde o oeste de Angola, para sul até a Namíbia, e para este em direcção à Zâmbia, Botswana e Zimbábue. Na sua área de ocorrência, esta espécie tem variação principalmente na coloração dorsal, e com base no menor número de escamas ventrais, foi sugerida a existência de uma raça oriental. Recentemente foi amostrado material de Prosymna de várias partes de Angola, e com recurso a análises filogenéticas e a tomografia computadorizada de raios-X de alta resolução, foi possível rever o estatuto taxonómico destas populações. Encontrámos fortes evidências filogenéticas para incluir o subgrupo angolensis como parte do grupo sundevalli. Revelámos a existência de três linhagens filogenéticas no subgrupo angolensis. Atribuímos uma dessas linhagens ao P.angolensis nominotípico, e descrevemos as outras duas como espécies novas, uma das quais corrobora a população oriental previamente detectada. Estes resultados reforçam a ideia de que uma parte considerável da diversidade herpetológica angolana está ainda por descrever, e a necessidade de mais estudos.

A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola.

A new species of red toad, from the previously monotypic genus Schismaderma, is described. The new species was found in Malanje Province, and seems endemic to central Angola, occurring approximately 500 km west of the closest known records of Schismaderma carens. Unusual adult colouration and geographical distance to remaining S. carens populations suggested specific differentiation. In an integrative approach, we compared the red toads from central Angola with S. carens from across the entire range, including molecular data, morphology of adults and tadpoles, and male advertisement calls. Phylogenetic analysis based on mitochondrial (12S, 16S, COI) and nuclear (CXCR4, RAG1) markers, retrieved the Angolan clade as monophyletic, and revealed intra-specific substructuring among the remaining Schismaderma. Genetic distances supported specific differentiation of the central Angolan material compared with other S. carens. Adults from the new Angolan species have bolder ventral patterning and smaller body size than S. carens. No obvious differences were detected between the tadpoles and the advertisement calls of the two Schismaderma species. This discovery adds to the knowledge of the herpetofauna of the Angolan Miombo woodlands, a poorly understood ecoregion, and likely more biodiverse than previously assumed. The result of past river basin dynamics in central Angola likely led to the evolution of this new species of Schismaderma.