Aim
There is an increasing evidence showing that species within various taxonomic groups have reticulate evolutionary histories with several cases of introgression events. Investigating the ...phylogeography of species complexes can provide insight into these introgressions, and when and where these hybridizations occurred. In this study, we investigate the biogeography of a widely distributed Western Palaearctic bat species complex, namely Myotis nattereri sensu lato. This complex exhibits high genetic diversity and in its western distribution range is composed of deeply diverged genetical lineages. However, little is known about the genetic structure of the eastern populations. We also infer the conservation and taxonomical implications of the identified genetic divergences.
Taxon
Myotis nattereri sensu lato including M. schaubi.
Location
Western Palaearctic.
Methods
We analysed 161 specimens collected from 67 locations and sequenced one mitochondrial and four nuclear DNA markers, and combined these with the available GenBank sequences. We used haplotype networks, PCA, t‐SNE and Bayesian clustering algorithms to investigate the population structure and Bayesian trees to infer the phylogenetic relationship of the lineages.
Results
We identified deeply divergent genetical lineages. In some cases, nuclear and mitochondrial markers were discordant, which we interpret are caused by hybridization between lineages. We identified three such introgression events. These introgressions occurred when spatially separated lineages came into contact after range expansions. Based on the genetic distinction of the identified lineages, we suggest a revision in the taxonomy of this species group with two possible new species: M. hoveli and M. tschuliensis.
Main conclusions
Our findings suggest that the M. nattereri complex has a reticulate evolutionary history with multiple cases of hybridizations between some of the identified lineages.
Secondary contacts can play a major role in the evolutionary histories of species. Various taxa diverge in allopatry and later on come into secondary contact during range expansions. When they meet, ...their interactions and the extent of gene flow depend on the level of their ecological differentiation and the strength of their reproductive isolation. In this study, we present the multilocus phylogeography of two cryptic whiskered bat species,
Myotis mystacinus
and
M. davidii
, with a particular focus on their putative sympatric zone. Our findings suggest that
M. mystacinus
and
M. davidii
evolved in allopatry and came into secondary contact during range expansions. Individuals in the area of secondary contact, in Anatolia and the Balkans, have discordant population assignments based on the mitochondrial and the nuclear datasets. These observed patterns suggest that the local
M. mystacinus
populations hybridized with expanding
M. davidii
populations, which resulted in mitochondrial introgression from the former. In the introgression area,
M. mystacinus
individuals with concordant nuclear and mitochondrial genotypes were identified in relatively few locations, suggesting that the indigenous populations might have been largely replaced by invading
M. davidii
. Changing environmental conditions coupled with ecological competition is the likely reason for this replacement. Our study presents one possible example of a historical population replacement that was captured in phylogeographic patterns.
The marbled polecat (
Vormela peregusna
) is a small mustelid that occurs from the Balkans to Mongolia and is listed as vulnerable under the International Union for Conservation of Nature's (IUCN) ...Red List. There are currently no efficient methods to monitor populations at a broad scale and most records come from opportunistic sightings. However, the elusive nature and unique pelage of the species often results in a lot of interest when sighted, with observations regularly being shared on social media platforms. Such records from social media can provide an extensive source of freely available information that could be used to inform the species’ distribution. In this study, we systematically collected marbled polecat records from five social media platforms by using a manual and automated search targeting the western range of the species. We identified 131 unique marbled polecat sightings originating mostly from Facebook, Instagram and Twitter. The records confirmed the species’ presence in 92 50-km grid cells within the study area and outperformed other sources, such as GBIF and scientific literature searches. The combination of all three datasets resulted in 133 presence points, which was sufficient enough to perform further habitat suitability modelling and reliable alpha hull range estimates. The social media search was well suited to clarify broad distribution patterns of marbled polecat, but did not detect the species in areas where its presence was most uncertain. The results of the modelling work, however, can be used to target further dedicated survey work for the species. The framework used in this study can be applied to provide more detailed information on distribution and occurrence patterns for other rare or under-studied species.
Studying hybrid zones that form between morphologically cryptic taxa offers valuable insights into the mechanisms of cryptic speciation and the evolution of reproductive barriers. Although hybrid ...zones have long been the focus of evolutionary studies, the awareness of cryptic hybrid zones increased recently due to rapidly growing evidence of biological diversity lacking obvious phenotypic differentiation. The characterization of cryptic hybrid zones with genome‐wide analysis is in its early stages and offers new perspectives for studying population admixture and thus the impact of gene flow. In this study, we investigate the population genomics of the Myotis nattereri complex in one of its secondary contact zones, where a putative hybrid zone is formed between two of its cryptic lineages. By utilizing a whole‐genome shotgun sequencing approach, we aim to characterize this cryptic hybrid zone in detail. Demographic analysis suggests that the cryptic lineages diverged during the Pliocene, c. 3.6 million years ago. Despite this ancient separation, the populations in the contact zone exhibit mitochondrial introgression and a considerable amount of mixing in nuclear genomes. The genomic structure of the populations corresponds to geographic locations and the genomic admixture changes along a geographic gradient. These findings suggest that there is no effective hybridization barrier between both lineages, nevertheless, their population structure is shaped by dispersal barriers. Our findings highlight how such deeply diverged cryptic lineages can still readily hybridize in secondary contact.
Identification of intraspecific conservation units and incorporating the distribution of genetic diversity into management plans are crucial requirements for assessing effective protection ...strategies. This study investigates the phylogeographic structures of 33 bat species present in the Near East in order to evaluate the conservation implications of their intraspecific genetic diversity both at regional and large-scale levels. To compare Anatolian populations with the European ones, we utilized two commonly used mitochondrial markers, Cytb and ND1, and analysed them together with the available sequences from GenBank. The management requirements of the identified clades and their taxonomical relations were evaluated by analysing their distributions and the levels of their genetic differentiations. In 12 species and the large
Myotis
complex, we identified a total of 15 genetically distinct populations found in the Near East, some of which might represent biologically distinct taxa. Comparing the phylogeographic patterns of different taxa indicates that three regions, the Balkans, the Caucasus, and the southern Anatolia, harbour genetically divergent populations and should have higher priority in conservation practices. Considering that Turkey has one of the richest bat fauna in the Mediterranean region and the Anatolian populations of various species are genetically distinct, protecting populations in Turkey is critically important for preserving the genetic diversity of the bats in the Western Palaearctic. Both regional and large-scale conservation strategies, which incorporate the distribution of genetic diversity, should be assessed and further ecological studies are needed to clarify the taxonomic relations of the identified clades.
Abstract
In the Western Palearctic, Myotis myotis comprises two morphologically and genetically distinct, Anatolian (eastern) and European (western), populations. The populations are parapatric with ...a narrow contact zone in Eastern Thrace. Anatolian M. myotis are larger than those in Europe and their size increases eastwards. Genotypes based on seven nuclear markers distinguish between eastern and western populations and indicate that gene flow between these populations is limited and asymmetric. Within a few hundred kilometres of Eastern Thrace, the Anatolian population consists almost entirely of individuals with distinctly eastern genotypes. The European population is composed of both distinctly western individuals and some admixed individuals. Mitochondrial DNA also differs between eastern and western M. myotis, with eastern and western populations of M. myotis sharing only one of 28 unique HVII haplotypes. We propose that partial reproductive isolation between M. myotis populations results from divergent selective forces. Genetically and morphologically, these populations satisfy the criteria of distinct evolutionary significant units. We suggest to expand the distributional range of the Levantine subspecies, M. m. macrocephalicus, to Anatolia and to recognize two subspecies in the species rank of Myotis myotis: M. m. myotis in Europe and M. m. macrocephalicus in Anatolia and Levant.
Two or more species are cryptic, if they are morphologically similar, biologically distinct, and misclassified as a single species. Cryptic species complexes were recently discovered within many bat ...species and we suspect that the bent-wing bat, Miniopterus schreibersii, found in Europe, northern Africa, and Asia Minor, could also form such a complex. Populations of M. schreibersii decline in most of the European countries and the species is currently listed as Near Threatened in the IUCN Red List. Finding that M. schreibersii is not a single species, but a species complex, would have a considerable impact on its conservation strategies, as the abundance of each component taxon would be much smaller than the one estimated for the nominal species.
Miniopterus schreibersii in Asia Minor consists of two genetically diverged lineages, which are reciprocally monophyletic on three mitochondrial DNA markers, have a diagnostic set of multilocus allele frequencies, and show a marked difference in their population structures. The lineages differ slightly in their size, wing shape, and echolocation call parameters. Although these differences are sufficient to discriminate between the lineages, they are not fully diagnostic in reference to individuals. We suggest that the lineages endured the major Northern Hemisphere glaciations in different glacial refugia and colonized Asia Minor after the last glacial maximum. The lineages are allopatric, which is neither delineated by the presence of geographical barriers nor associated with the specific climatic conditions, and which we link to competitive exclusion.
The distinctions between the lineages comply with most of the criteria required for species delineation imposed by various species concepts. Accordingly, we conclude that M. schreibersii in Asia Minor is represented by two cryptic species. Our results imply that the distributional range of the nominal species is almost exclusively limited to Europe and the coastal zones of Asia Minor. As populations of M. schreibersii seem to be much smaller than currently assumed, conservation strategies regarding this taxon need to be revised. The exact distributional range and the vulnerability of the suggested sister species to M. schreibersii is yet to be assessed.
We used both highly variable mitochondrial and nuclear loci to investigate the large mouse‐eared bat species complex in the Western Palaearctic to clarify their systematic position. Although ...mitochondrial lineages show no species segregation and some haplotypes are shared between Myotis myotis and Myotis blythii sensu lato, Bayesian clustering methods based on multilocus genotypes indicate highly concordant nuclear and morphological species assignment. These multilocus, nuclear analyses detected only a single putative F1 hybrid in the extensive areas of sympatry sampled, thus confirming the biological species status of M. myotis and M. blythii s.l. We propose that the strong cytonuclear discordance in these species complex results from a combination of prior spatial isolation of the two species in different glacial refugia, followed by a succession of mitochondrial introgression events that occurred during the eastward and westward expansions of M. myotis and of M. blythii, respectively. The nuclear markers further indicate the presence of a notable genetic discontinuity within M. myotis that broadly separates populations into an eastern and a western component with an overlap zone in the Balkans. This eastern and western discontinuity is also apparent in the mitochondrial lineages with the D haplogroup largely confined to samples found in Thrace and Asia Minor. None of these genetic discontinuities correspond to the distribution of the two commonly recognized M. myotis subspecies (myotis and macrocephalicus). We also show that distinct morphological subspecies within M. blythii (oxygnathus, omari, risorius and lesviacus) in Europe and the near‐East do not correlate with significant evolutionarily units, whether identified by mitochondrial or nuclear data and thus only represent local morphological variants with little taxonomic relevance.
Various mechanisms such as geographic barriers and glacial episodes have been proposed as determinants of intra-specific and inter-specific differentiation of populations, and the distribution of ...their genetic diversity. More recently, habitat and climate differences, and corresponding adaptations have been shown to be forces influencing the phylogeographic evolution of some vertebrates. In this study, we examined the contribution of these various factors on the genetic differentiation of the bent-winged bat, Miniopterus schreibersii, in southeastern Europe and Anatolia.
Our results showed differentiation in mitochondrial DNA coupled with weaker nuclear differentiation. We found evidence for restriction of lineages to geographical areas for hundreds of generations. The results showed that the most likely ancestral haplotype was restricted to the same geographic area (the Balkans) for at least 6,000 years. We were able to delineate the migration routes during the population expansion process, which followed the coasts and the inland for different nested mitochondrial clades. Hence, we were able to describe a scenario showing how multiple biotic and abiotic events including glacial periods, climate and historical dispersal patterns complemented each other in causing regional and local differentiation within a species.
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