The effects of the Late Quaternary glacial-interglacial cycles on Anatolian ground squirrels: range expansion during the glacial periods?

Identifying the Past, Present, and Future Distribution Patterns of the Balkan Wall Lizard (Sauria: Lacertidae: Podarcis tauricus) by Ecological Niche Modelling

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Complete mitogenomes of Turkish tree squirrels, Sciurus anomalus and S. vulgaris, (Sciuridae: Rodentia: Mammalia) and their phylogenetic status within the tribe Sciurini

The genus Sciurus, a member of the family Sciuridae, is widely distributed in the Holarctic region. To better understand mitogenomic characteristics and to reveal internal phylogenetic relationships of the genus, 20 complete mitogenomes of Turkish tree squirrels were successfully sequenced for the first time, including 19 for S. anomalus (from 16,505 bp to 16,510 bp) and one for S. vulgaris (16,511 bp). The mitogenomes of two species were AT-biased. All tRNAs for two species displayed a typical clover-leaf structure, except for tRNA^Ser(AGY). The tRNA Serine1 (S1)-GCT structure lacked the dihydrouridine (DHU) loop and stem. Based on mitogenomic dataset for phylogeny of Sciurinae, phylogenetic analyses (Bayesian Inference and Maximum Likelihood) did not support monophyly of Sciurus and proposed that S. anomalus, the most basal taxa in the Sciurini tribe, had at least five mitogenome lineages, which were also supported by network analysis. The dissimilarities among the five linegaes of S. anomalus ranged from 0.0042 (0.42%) to 0.0062 (0.62%) using K2P sequence pairwise distances. In addition to this mitogenomic analysis result, phylogenetic analyses using the CYTB + D-loop dataset proposed the existence of at least nine lineages for S. anomalus, which was different than those of the previous studies. The current study proposed that the use of mitogenomic data for reconstructing the phylogeny of Turkey' Sciurus holds an important value for revealing evolutionary relationships.

The story of a rock-star: multilocus phylogeny and species delimitation in the starred or roughtail rock agama, Laudakia stellio (Reptilia: Agamidae)

Situated at the junction of three continents, Europe, Asia and Africa, the Eastern Mediterranean is an ideal region to study the effects of palaeogeography, ecology and long human presence on animal evolution. Laudakia stellio (Squamata: Agamidae) is found across this region and offers an excellent opportunity for such studies. The high morphological variation across their range suggests that these lizards might represent a species complex. This is the first study exploring their evolutionary history, using molecular markers and individuals from all described subspecies. We employed the latest phylogenetic and species-delimitation methods to identify all distinct evolutionary lineages, their genetic variation and divergence times. The phenotypical diversity of L. stellio matches its genetic differentiation: almost all subspecies correspond to well-supported retrieved subclades and additional distinct lineages representing intermediate morphs have been retrieved. ‘Laudakia stellio’ represents three distinct evolutionary entities that diverged during the Plio-Pleistocene transition, which we propose as distinct species. One includes Greek and Turkish populations, as well as cryptic Anatolian lineages. The second comprises all other Near East populations and the third is endemic to Cyprus. Our results indicate a role of humans in shaping present distribution patterns, and highlight the importance of the Aegean, Anatolia and the Levant as glacial refugia and diversity hotspots.

Phylogeographic analysis of shrubby beardtongues reveals range expansions during the Last Glacial Maximum and implicates the Klamath Mountains as a hotspot for hybridization

Quaternary glacial cycles often altered species' geographic distributions, which in turn altered the geographic structure of species' genetic diversity. In many cases, glacial expansion forced species in temperate climates to contract their ranges and reside in small pockets of suitable habitat (refugia), where they were likely to interact closely with other species, setting the stage for potential gene exchange. These introgression events, in turn, would have degraded species boundaries, making the inference of phylogenetic relationships challenging. Using high-throughput sequence data, we employed a combination of species distribution models and hybridization tests to assess the effect of glaciation on the geographic distributions, phylogenetic relationships, and patterns of gene flow of five species of Penstemon subgenus Dasanthera, long-lived shrubby angiosperms distributed throughout the Pacific Northwest of North America. Surprisingly, we found that rather than reducing their ranges to small refugia, most Penstemon subgenus Dasanthera species experienced increased suitable habitat during the Last Glacial Maximum relative to the present day. We also found substantial evidence for gene exchange between species, with the bulk of introgression events occurring in or near the Klamath Mountains of southwestern Oregon and northwestern California. Subsequently, our phylogenetic inference reveals blurred taxonomic boundaries in the Klamath Mountains, where introgression is most prevalent. Our results question the classical paradigm of temperate species' responses to glaciation and highlight the importance of contextualizing phylogenetic inference with species' histories of introgression.

The Quaternary range dynamics ofNoccaea iberidea(Brassicaceae), a typical representative of subalpine/alpine steppe communities of Anatolian mountains

The responses of Anatolian plants to global climate change have been poorly investigated. In this study, we aimed to understand how climatic oscillation during the Quaternary period helped to shape the current distribution patterns of the Anatolian endemic Noccaea iberidea, a typical representative of tragacanthic (thorny cushion) steppe communities of Anatolia. We used ecological niche modelling combined with statistical phylogeography, based on nuclear ribosomal ITS and plastidic trnL-F and trnS-ycf9 regions. Both the structure of the haplotype networks and the results of the extended Bayesian skyline plot analysis clearly indicated that N. iberidea has been through a recent population expansion. This interpretation was also supported by ecological niche modelling analysis, which showed that the availability of areas of high suitability expanded from the Last Interglacial to the Last Glacial Maximum, suggesting that N. iberidea might have expanded its range during the glacial periods. In conclusion, the study improves our understanding of the demographic history and responses of steppe plant communities of Anatolia to global climate changes through the Late Quaternary glacial–interglacial cycles, which in turn might aid in the development of future conservation strategies.

Dynamics behind disjunct distribution, hotspot-edge refugia, and discordant RADseq/mtDNA variability: insights from the Emei mustache toad

Background

The distribution of genetic diversity and the underlying processes are important for conservation planning but are unknown for most species and have not been well studied in many regions. In East Asia, the Sichuan Basin and surrounding mountains constitute an understudied region that exhibits a “ring” of high species richness overlapping the eastern edge of the global biodiversity hotspot Mountains of Southwest China. We examine the distributional history and genetic diversification of the Emei mustache toad Leptobrachium boringii, a typical “ring” element characterized by disjunct ranges in the mountains, by integrating time-calibrated gene tree, genetic variability, individual-level clustering, inference of population splitting and mixing from allele frequencies, and paleoclimatic suitability modeling.

Results

The results reveal extensive range dynamics, including secondary contact after long-term isolation via westward dispersal accompanied by variability loss. They allow the proposal of a model that combines recurrent contractions caused by Quaternary climatic changes and some failed expansions under suitable conditions for explaining the shared disjunct distribution pattern. Providing exceptional low-elevation habitats in the hotspot area, the eastern edge harbors both long-term refugial and young immigrant populations. This finding and a synthesis of evidence from other taxa demonstrate that a certain contributor to biodiversity, one that preserves and receives low-elevation elements of the east in this case, can be significant for only a particular part of a hotspot. By clarifying the low variability of these refugial populations, we show that discordant mitochondrial estimates of diversity can be obtained for populations that experienced admixture, which would have unlikely left proportional immigrant alleles for each locus.

Conclusions

Dispersal after long-term isolation can explain much of the spatial distribution of genetic diversity in this species, while secondary contact and long-term persistence do not guarantee a large variation. The model for the formation of disjunct ranges may apply to many other taxa isolated in the mountains surrounding the Sichuan Basin. Furthermore, this study provides insights into the heterogeneous nature of hotspots and discordant variability obtained from genome-wide and mitochondrial data.

Phylo-comparative analyses reveal the dual role of drift and selection in reproductive character displacement

When incipient species meet in secondary contact, natural selection can rapidly reduce costly reproductive interactions by directly targeting reproductive traits. This process, called reproductive character displacement (RCD), leaves a characteristic pattern of geographic variation where divergence of traits between species is greater in sympatry than allopatry. However, because other forces can also cause similar patterns, care must be given in separating pattern from process. Here we show how the phylo-comparative method together with genomic data can be used to evaluate evolutionary processes at the population level in closely related species. Using this framework, we test the role of RCD in speciation of two cricket species endemic to Anatolian mountains by quantifying patterns of character displacement, rates of evolution and adaptive divergence. Our results show differing patterns of character displacement between species for reproductive vs. non-reproductive characters and strong patterns of asymmetric divergence. We demonstrate diversification results from rapid divergence of reproductive traits towards multiple optima under the dual influence of strong drift and selection. These results present the first solid evidence for RCD in Anatolian mountains, quantify the amount of drift and selection necessary for RCD to lead to speciation, and demonstrate the utility of phylo-comparative methods for quantifying evolutionary parameters at the population level.

Foraging ecology of Eurasian lynx populations in southwest Asia: Conservation implications for a diet specialist

Intraspecific variation in key traits of widespread species can be hard to predict, if populations have been very little studied in most of the distribution range. Asian populations of the Eurasian lynx (Lynx lynx), one of the most widespread felids worldwide, are such a case in point. We investigated the diet of Eurasian lynx from feces collected Mediterranean, mixed forest-steppe, and subalpine ecosystems of Turkey. We studied prey preferences and functional responses using prey densities obtained from Random Encounter Modelling. Our analysis revealed that the main prey was brown hare (Lepus europaeus) in all three areas (78%-99% of biomass consumed) and lynx showed a strong preference for brown hare (Chesson's selectivity index, α = 0.90-0.99). Cannibalism contributed at least 5% in two study areas. The type II functional response of lynx populations in Turkey was similar to the Canada lynx (Lynx canadensis) and daily food intake in grams per lynx matched that of Canada lynx and Iberian lynx (Lynx pardinus), both lagomorph specialists, rather than those of Eurasian lynx from Europe. Therefore, lynx in Turkey may be better described as a lagomorph specialist even though it coexists with ungulate prey. We suggest that ungulate-based foraging ecology of Eurasian lynx in Europe may be a recent adjustment to the availability of high densities of ungulates and cannot be representative for other regions like Turkey. The status of lagomorphs should become an essential component of conservation activities targeted at Eurasian lynx or when using this species as a flagship species for landscape preservation.

Genetic characterization of the Turkish gray hamster (Cricetulus migratorius) based on mitochondrial cytochrome b and 12S rRNA sequences

Although genetic diversity and phylogenetic status of the gray hamster (Cricetulus migratorius) have been investigated from different regions in previous studies, genetic data on this species from Turkey are still lacking, since previous data have been based on a limited number of gray hamsters sampled across the Anatolian part of Turkey. The aim of this study was to determine the genetic diversity of the Anatolian population and to reveal the phylogenetic relationships among the Anatolian population and conspecific populations of the gray hamster. The complete and partial fragments of mitochondrial Cyt b and 12S rRNA from the 20 Turkish samples were amplified and sequenced. Ten 12S rRNA (901 bp) and 15 Cyt b (1140 bp) haplotypes found in this work were not previously reported. Based on Bayesian, Maximum Likelihood, Neighbour-Joining and Median-Joining network analyses by using mitochondrial data under the name Cricetulus, the results of phylogenetic and network analyses indicated that there was a deep separation among the distinct lineages within the genus Cricetulus. When considering the position of the Turkish haplotypes in median joining network, the Anatolian part of Turkey may have hosted a source population of the gray hamster for expansion to adjacent regions in the past period. Additionally, the Anatolian population of gray hamster had relatively high haplotype diversity and the present study propounded the importance of data obtained from the Anatolian population of gray hamster to reveal the phylogenetic relationships among conspecific populations of the gray hamster.

An endemic rat species complex is evidence of moderate environmental changes in the terrestrial biodiversity centre of China through the late Quaternary

The underlying mechanisms that allow the Hengduan Mountains (HDM), the terrestrial biodiversity centre of China, to harbour high levels of species diversity remain poorly understood. Here, we sought to explore the biogeographic history of the endemic rat, Niviventer andersoni species complex (NASC), and to understand the long-term persistence of high species diversity in this region. In contrast to previous studies that have proposed regional refuges in eastern or southern of the HDM and emphasized the influence of climatic oscillations on local vertebrates, we found that HDM as a whole acted as refuge for the NASC and that the historical range shifts of NASC mainly occurred in the marginal regions. Demographic analyses revealed slight recent population decline in Yunnan and south-eastern Tibet, whereas of the populations in Sichuan and of the entire NASC were stable. This pattern differs greatly from classic paradigms of temperate or alpine and holarctic species. Interestingly, the mean elevation, area and climate of potential habitats of clade a (N. excelsior), an alpine inhabitant, showed larger variations than did those of clade b (N. andersoni), a middle-high altitude inhabitant. These species represent the evolutionary history of montane small mammals in regions that were less affected by the Quaternary climatic changes.