The Near East as a cradle of biodiversity: A phylogeography of banded newts (genus Ommatotriton) reveals extensive inter- and intraspecific genetic differentiation

Abstract

The banded newt (genus Ommatotriton) is widely distributed in the Near East (Anatolia, Caucasus and the Levant) - an understudied region from the perspective of phylogeography. The genus is polytypic, but the number of species included and the phylogenetic relationships between them are not settled. We sequenced two mitochondrial and two nuclear DNA markers throughout the range of Ommatotriton. For mtDNA we constructed phylogenetic trees, estimated divergence times using fossil calibration, and investigated changes in effective population size with Bayesian skyline plots and mismatch analyses. For nuDNA we constructed phylogenetic trees and haplotype networks. Species trees were constructed for all markers and nuDNA only. Species distribution models were projected on current and Last Glacial Maximum climate layers. We confirm the presence of three Ommatotriton species: O. nesterovi, O. ophryticus and O. vittatus. These species are genetically distinct and their most recent common ancestor was dated at ∼25Ma (Oligocene). No evidence of recent gene flow between species was found. The species show deep intraspecific genetic divergence, represented by geographically structured clades, with crown nodes of species dated ∼8-13Ma (Miocene to Early Quaternary); evidence of long-term in situ evolution and survival in multiple glacial refugia. While a species tree based on nuDNA suggested a sister species relationship between O. vittatus and O. ophryticus, when mtDNA was included, phylogenetic relationships were unresolved, and we refrain from accepting a particular phylogenetic hypothesis at this stage. While species distribution models suggest reduced and fragmented ranges during the Last Glacial Maximum, we found no evidence for strong population bottlenecks. We discuss our results in the light of other phylogeographic studies from the Near East. Our study underlines the important role of the Near East in generating and sustaining biodiversity.

Fossil amphibians and reptiles from the Neogene locality of Maramena (Greece), the most diverse European herpetofauna at the Miocene/Pliocene transition boundary

“…The genus Ommatotriton is represented in Maramena on the basis of vertebral and appendicular material, and this occurrence represents an interesting find. Extant species of this genus are currently distributed in the Middle East, eastern Anatolia, and the Caucasus (Riemsdijk et al, 2017), where the data on the palaeoherpetofauna are extremely scarce. As such, if our identification is correct, then the new Maramena specimens represent the first reliable finds of Ommatotriton in the fossil record and accordingly extend that lineage back to the latest Miocene/earliest Pliocene and widen its geographic distribution.…”

Molecular data reveal the hybrid nature of an introduced population of banded newts (Ommatotriton) in Spain

“…For the nuclear markers, haplotype networks were built using PopArt 1.7 (Bandelt et al 1999;Leigh et al 2016). Species distribution models for O. ophryticus and O. nesterovi, based on bioclimatic values and presented in van Riemsdijk et al (2017), and an additional model combining distribution data for both species were projected onto current climate layers of northern Iberia, to approximate the suitable area in the introduced range and the invasive potential of the exotic population.…”

Landscape determinants of genetic differentiation, inbreeding and genetic drift in the hazel dormouse (Muscardinus avellanarius)

“…For the nuclear markers, haplotype networks were built using PopArt 1.7 (Bandelt et al 1999;Leigh et al 2016). Species distribution models for O. ophryticus and O. nesterovi, based on bioclimatic values and 1 3 presented in van Riemsdijk et al (2017), and an additional model combining distribution data for both species were projected onto current climate layers of northern Iberia, to approximate the suitable area in the introduced range and the invasive potential of the exotic population.…”