Diversification of montane species via elevation shifts: the case of the Kaçkar cricketPhonochorion(Orthoptera)

Abstract

Localized up‐down altitudinal shifts and subsequent isolation–admixture of montane species in response to glacial cycles has been proposed as a mechanism for the high diversity along Anatolian mountains. However, specific predictions of the proposed mechanism (the elevation shift model) have yet to be tested. Here, we provide a first assessment of this model for promoting inter‐ and intraspecific genetic diversity in the bush‐cricket genus Phonochorion endemic to the West Lesser Caucasus hotspot. Mitochondrial genes were analysed by Bayesian Markov Chain Monte Carlo inferences and coalescent simulations. Timing of diversification was estimated using a multispecies coalescent model. Divergence with gene flow was tested using an isolation with migration model. Population genetic parameters and genetic structuring were determined using Bayesian coalescent methods and spatial analysis. Demographic history was assessed using mismatch distributions and extended Bayesian skyline plots. Speciation events corresponded both to the Miocene and Pleistocene while intraspecific divergence was Pleistocene based. There was evidence for moderate levels of gene flow between species during diversification; however, incomplete lineage sorting could explain the data as well as gene flow. Overall diversification patterns within the genus Phonochorion agree with the predictions of the elevations shift model. Genetic patterns of diversification were driven mainly by Pleistocene glacial cycles and reflected the nature and distribution of sky islands. There was also some albeit weak evidence of demographic expansions coinciding with glacial cooling. However, evidence for divergence with gene flow was inconclusive.

Phylogeography and taxonomy of the Psorodonotus caucasicus (Orthoptera, Tettigoniidae) group: independent double invasion of the Balkans from the Caucasus

“…However, the intraspecies genetic structuring of species other than P. ebneri began after the MPT (800 ka) or after the initiation of intense glaciation periods of late Pleistocene. Contrary to general wisdom that the last four glacial cycles drove speciation within Anatolian lineages, the radiation patterns of the PCG and other mountanious Anatolio‐Balkan lineages suggest the occurrence of radiation during an earlier period (Gündüz et al , ; Ahmadzadeh et al , ; Sağlam et al , ; Kaya et al , , ; Çıplak et al , ; Chobanov et al , ). The SDMs for the PCG support this hypothesis, too.…”

Budding speciation via peripheral isolation: the Psorodonotus venosus (Orthoptera, Tettigoniidae) species group example

“…Following the range retractions, peripherally isolated remnants diverged into the present bud species on mountain summits, as assumed by the rear/leading edge concept (Çıplak ; Hampe & Petit ) and as observed in other Anatolian lineages (Sağlam et al . ; Korkmaz et al . ; Çıplak et al .…”

“…; Sağlam et al . ), and the summits there considered to be intrarefugial arctic poles during glacials and as sky‐islands during interglacials for the mountainous populations (Çıplak ; ; Çıplak et al . ) because the peaks over 1800 m were glaciated during cold periods (Sarikaya et al .…”

Phylogeny, diversification and biogeographic implications of the eastern Mediterranean endemic genus Ricotia (Brassicaceae)

“…(Parolly & al., 2010) and Arabis alpina L. (Ansell & al., 2011;Karl & al., 2012), although this region has been suggested to represent the cradle of the family (Franzke & al., 2011a). Only few other studies explored the biogeographic history of Anatolian plants (e.g., Jakob & al., 2007;Font & al., 2009), but several animal groups are better represented (e.g., Bilgin & al., 2006;Akın & al., 2010;Çıplak & al., 2010;Gür, 2013;Kaya & al., 2013;Sağlam & al., 2014). Therefore, more studies are needed in this area to understand both historical biogeographic patterns and the evolution of ecologically important plant characters.…”