Evolution of the African slippery frogs (Anura: Conraua), including the world’s largest living frog |
| |
Authors: | David C Blackburn Stuart V Nielsen Michael F Barej Joseph Doumbia Mareike Hirschfeld N’Goran G Kouamé Dwight Lawson Simon Loader Caleb Ofori-Boateng Edward L Stanley Mark-Oliver Rödel |
| |
Institution: | 1. Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA;2. Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany;3. ONG EnviSud Guinée, Conakry, Guinea;4. Université Jean Lorougnon Guédé, Daloa, Ivory Coast;5. Oklahoma City Zoo and Botanical Garden, Oklahoma City, OK, USA;6. Natural History Museum, London, UK;7. 1CSIR-Forestry Research Institute of Ghana, Kumasi, Ghana |
| |
Abstract: | Although Conraua goliath is well known as the largest living frog species, the diversity and evolution of the genus Conraua across sub-Saharan Africa remain poorly understood. We present multilocus phylogenetic analyses of the six currently recognized species that provide insights into divergence times, biogeography, body size evolution and undescribed species. An analysis of divergence times demonstrates that crown-group Conraua arose some time during the latest Oligocene to mid-Miocene followed by divergence into major lineages in the mid-Miocene that may reflect the fragmentation of widespread tropical forests in Africa that began at this time. We find three pairs of sister species, C. crassipes + C. beccarii, C. alleni + C. derooi and C. goliath + C. robusta, each of which diverged during the Miocene. These relationships reject phylogenetic hypotheses based solely on biogeography as the geographically peripheral C. beccarii from north-eastern Africa is nested within western African species and the Central African species do not form a clade. Our species delimitation analyses provide support for undescribed species in C. alleni, C. beccarii and C. derooi, and possibly C. crassipes, suggesting that the current taxonomy substantially underestimates species diversity. There is no clear directional trend of either increasing or decreasing body size in Conraua and the three largest species do not form a clade. With a robust phylogenetic hypothesis in hand, further field-based studies are needed to understand the evolution of morphology and life history in this charismatic African anuran clade. |
| |
Keywords: | body size evolution divergence dating Goliath Frog phylogenetics species delimitation |
|
|