Evolution in the South American ‘Lost World’: insights from multilocus phylogeography of stefanias (Anura, Hemiphractidae, Stefania)

Abstract

Aim To investigate the influence of tepuian geomorphology on species diversification in the Pantepui biogeographical region based on the phylogenetic relationships and divergence times of tepui‐endemic clades of stefania frogs (Stefania, Hemiphractidae). Location The ‘tepuis’ and uplands/lowlands of the Pantepui biogeographical region of northern South America, one of the least accessible and least studied areas in the world. Methods Two mitochondrial and two nuclear DNA sequences from 60 individuals of Stefania from 24 localities in Pantepui were employed to infer phylogenetic affinities and estimate divergence times within the genus using both concatenation and species tree analyses. Ancestral areas were inferred using multiple models in a common likelihood framework. Results Phylogenetic analyses revealed high diversity in the genus Stefania with 10 candidate species in the Eastern Pantepui District. Four strongly supported clades are recovered in the area, one being exclusively composed of microendemics on isolated tepui summits. Biogeographical analyses suggest episodes of fragmentation of widespread tepuian ancestors from the onset of diversification of the genus, estimated in the Oligocene (c. 26 Ma), therefore suggesting a neglected vicariant model of Pantepui evolution, the Plateau Theory. Main conclusions Although our results suggest that vicariance played an important role in the diversification of Stefania, speciation in Pantepui followed an intricate pattern implying multiple nonexclusive processes. Vicariance and dispersal likely influenced diversification patterns of the Pantepui fauna, possibly according to the following sequence: (1) Cenozoic vicariance; (2) reorganization of species diversity due to periods of climatic instability; (3) recent invasions (Pleistocene) of widespread upland taxa.

Fish biogeography in the “Lost World” of the Guiana Shield: Phylogeography of the weakly electric knifefish Gymnotus carapo (Teleostei: Gymnotidae)

“…Based on a rate of mitochondrial sequence divergence of approximately 1% per million years, this would provide an age estimate of 1.5 Myr for the divergence of upland G. carapo from nearby lowland populations. This suggests that G. carapo is a more recent addition to the fauna of upland Guiana, in line with ages of some amphibians found on tepui summits (Kok et al, 2012(Kok et al, , 2016. Based on these results, we suggest that upland Guianas ichthyofauna consist of a mosaic of relatively ancient endemics combined with more recent arrivals like G. carapo.…”

Conceptual and statistical problems with the DEC+J model of founder‐event speciation and its comparison with DEC via model selection

“…(), Skeels and Cardillo () and Kok et al. (). The application of model selection in these cases appears to be motivated by the same reasons one selects among models of nucleotide evolution for phylogeny reconstruction: that the best‐fit model is necessary for accurate inferences.…”

“…For simple inference of ancestral ranges on a fixed phylogeny, a DEC-based model may be defensible if statistical model selection is not used to justify the choice, and it is understood that inferences about cladogenetic range inheritance lack any relation to time, normally a fundamental axis of evolutionary models. et al (2016), Givnish et al (2016), Skeels and Cardillo (2017) and Kok et al (2017). The application of model selection in these cases appears to be motivated by the same reasons one selects among models of nucleotide evolution for phylogeny reconstruction: that the best-fit model is necessary for accurate inferences.This trend is unfortunate for two reasons: first, DEC+J is a poor model of founder event speciation, and second, unlike nucleotide models, DEC and DEC+J cannot be compared using standard…”

The use of bioacoustics in anuran taxonomy: theory, terminology, methods and recommendations for best practice

“…The application of molecular genetics and its integration into taxonomic research on anurans has revealed a tremendous amount of hidden diversity, particularly in the most species-rich tropical regions (e.g., Köhler et al 2005a;Stuart et al 2006;Fouquet et al 2007;Crawford et al 2010Crawford et al , 2013Funk et al 2012;Barej et al 2015;Kok et al 2017). A great part of this uncovered diversity is considered to represent different species (Fouquet et al 2007;Vieites et al 2009).…”