A reinvestigation of phylogeny and divergence times of the Ablepharus kitaibelii species complex (Sauria, Scincidae) based on mtDNA and nuDNA genes

An expanded phylogeny of the genus Pseudamnicola (Gastropoda; Truncatelloidea; Hydrobiidae) across the Mediterranean Basin

The genus Pseudamnicola Paulucci, 1878, is commonly found throughout the Mediterranean region. The genus displays considerable levels of endemism, accompanied by notable systematic and taxonomic ambiguity. However, the application of molecular data has proven highly effective in clarifying taxonomy and unveiling the diversity of cryptic species within the genus. Therefore, we employed all cytochrome c oxidase subunit I sequence data available and generated new ones from Greece to infer the phylogeny of the genus throughout its Mediterranean range and estimate the divergence times as well as the ancestral area of diversification. Our phylogenetic and time-estimate analyses demonstrate that with 36 to 38 extant Pseudamnicola species and genetic divergences across species ranging from 0.5% to 11.9% on average, the genus underwent relatively recent diversification during late Miocene (6.53 Ma), and the primary speciation events occurred during Plio-Pleistocene. The Italian Peninsula and Islands and the Ionian Drainages as defined by the Freshwater Ecoregions of the World are the ancestral regions of the genus following two different dispersal routes. Our study contributes to deepening our understanding of Pseudamnicola phylogeny by using data from throughout its range for the first time. This phylogeny provides evidence and confirms previous studies that relatively recent habitat isolation, followed by founder and dispersal events, has been one of the primary reasons for the evolution of the genus Pseudamnicola in the Mediterranean basin.

Cryptic diversity and phylogeographic patterns of Mediodactylus species in the Eastern Mediterranean region

Cryptic diversity poses a great obstacle in our attempts to assess the current biodiversity crisis and may hamper conservation efforts. The gekkonid genus Mediodactylus, a well-known case of hidden species and genetic diversity, has been taxonomically reclassified several times during the last decade. Focusing on the Mediterranean populations, a recent study within the M. kotschyi species complex using classic mtDNA/nuDNA markers suggested the existence of five distinct species, some being endemic and some possibly threatened, yet their relationships have not been fully resolved. Here, we generated genome-wide SNPs (using ddRADseq) and applied molecular species delimitation approaches and population genomic analyses to further disentangle these relationships. Τhe most extensive nuclear dataset, so far, encompassing 2,360 loci and ∼ 699,000 bp from across the genome of Mediodactylus gecko, enabled us to resolve previously obscure phylogenetic relationships among the five, recently elevated, Mediodactylus species and to support the hypothesis that the taxon includes several new, undescribed species. Population genomic analyses within each of the proposed species showed strong genetic structure and high levels of genetic differentiation among populations.

Geographic Genetic Structure of Alectoris chukar in Türkiye: Post-LGM-Induced Hybridization and Human-Mediated Contaminations

Türkiye is considered an important evolutionary area for Chukar partridge (Alectoris chukar), since it is both a potential ancestral area and a diversification center for the species. Using 2 mitochondrial (Cty-b and D-loop) and 13 polymorphic microsatellite markers, we investigated the geographic genetic structure of A. chukar populations to determine how past climatic fluctuations and human activities have shaped the gene pool of this species in Türkiye. Our results indicate, firstly, that only A. chukar of the genus Alectoris is present in Türkiye (Anatolia and Thrace), with no natural or artificial gene flow from congenerics. Secondly, the geographic genetic structure of the species in Türkiye has been shaped by topographic heterogeneity, Pleistocene climatic fluctuations, and artificial transport by humans. Third, there appears to be three genetic clusters: Thracian, Eastern, and Western. Fourth, the post-LGM demographic expansion of the Eastern and Western populations has formed a hybrid zone in Central Anatolia (~8 kyBP). Fifth, the rate of China clade-B contamination in Türkiye is about 8% in mtDNA and about 12% in nuDNA, with the Southeastern Anatolian population having the highest contamination. Sixth, the Thracian population was the most genetically distinct, with the lowest genetic diversity and highest level of inbreeding and no China clad-B contamination. These results can contribute to the conservation regarding A. chukar populations, especially the Thracian population.

The evolutionary history of the relict scorpion family Iuridae of the eastern Mediterranean

Iuridae is a family of scorpions that exhibits a highly complex biogeographic and taxonomic history. Iuridae taxa are mainly found in Turkey and Greece, whereas a single species is found in northern Iraq. Several taxonomic revisions have been conducted on this family that initially comprised two genera. The latest taxonomic review, based on morphological and anatomical features, raised the number of Iuridae genera to four, and the number of species to 14. Sequence data from three molecular markers (COX1, 16S rDNA, ITS1) originating from numerous Iuridae taxa were analyzed within a phylogenetic framework. Divergence time-estimate analyses, species delimitation approaches and estimation of ancestral areas were implemented in order to: 1) reconstruct the phylogenetic relationships of the Iuridae taxa, 2) evaluate the morphological classifications, and 3) obtain insights into the biogeographic history of the family in the East Mediterranean. The multi-locus phylogeny clearly confirms an ancient division into two clades, Calchinae and Iurinae. Ancient patterns of isolation and dispersal are revealed. Both subfamilies are largely confined to the Anatolian peninsula and its few coastal islands; only the most derived genus Iurus has dispersed westward to Crete and Peloponnese. Based on our findings, three new genera of Iurinae (Metaiurus, Anatoliurus, and Letoiurus) are established. The genus Neocalchas emerges as one of the most ancient scorpion clades, with divergence time about 27 mya.

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.

A new ancient lineage of ablepharine skinks (Sauria: Scincidae) from eastern Himalayas with notes on origin and systematics of the group

The Himalayas represent a renowned biodiversity hotspot and an important biogeographic realm that has influenced origin and diversification of multiple taxa. A recent herpetological investigation of the eastern Himalayas of the Indian state of Arunachal Pradesh led to the discovery of a unique lineage of ablepharine skink, which is herein described as a new genus along with a new species. The findings are based an integrated taxonomic approach incorporating data from external morphology, microCT scans of the skull and molecular data. The molecular phylogeny of ablepharine skinks is also presented that suggests taxonomic amendments. Discovery of this unique lineage of skinks further highlights the biogeographic importance of the eastern Himalayas as a source for origin of several relic biota.

Nomenclature of supra-generic units within the Family Scincidae (Squamata)

The modern classification of skinks is based on a nomenclature that dates to the 1970s. However, there are a number of earlier names in the family group that have been overlooked by recent workers. These names are identified and their validity with respect to the International Code of Zoological Nomenclature investigated, along with their type genera. In most cases, use of these names to supplant junior synonyms in modern day use is avoidable by use of the Reversal of Precedence articles of the Code, but the names remain available in case of future divisions at the tribe and subtribe level. Other names are unavailable due to homonymy, either of their type genera or the stems from similar but non-homonymous type genera. However, the name Egerniini is replaced by Tiliquini, due to a limited timespan of use of Egerniini. A new classification of the Family Scincidae is proposed, providing a more extensive use of Code-regulated levels of classification, including tribes and subtribes, and a detailed synonymy provided for each taxonomic unit.

The roles of possible geographic barriers and geological events on the phylogeographic structure of the Eastern broad toothed field mouse (Apodemus mystacinus)

The Eastern broad toothed field mouse, Apodemus mystacinus, is a rodent species distributed in Turkey, the Middle East, and a few Aegean Islands. The aim of this study is to analyse the phylogeographic structure of A. mystacinus and possible causes of its differentiation, on the basis of mitochondrial and nuclear DNA sequences using a large number of new samples from Turkey. In this context, partial mitochondrial sequences of cytochrome b (Cytb), control region (D-loop) and a nuclear interphotoreceptor retinoid-binding protein (IRBP) gene were used to reveal the geographical differentiation among A. mystacinus populations and the validity of its subspecies. The estimated divergence times revealed that the first separation of A. mystacinus into three distinct groups (subspecies of A. mystacinus: A. m. mystacinus, A. m. smyrnensis, and A. m. euxinus) begun 0.641 Mya. The possible physical barriers in Anatolia such as high mountains and rivers could interrupt the gene flow between A. mystacinus populations. The results of the present study indicated that A. mystacinus might have used the high rocky areas along the Anatolian Diagonal as a dispersal way. Moreover, mitochondrial data in this study suggested for the first time that A. m. rhodius is synonymous with the nominative subspecies A. m. mystacinus.

Phylogenetic relationships amongst the snake-eyed lizards of the genus Ablepharus Fitzinger, 1823 (Sauria, Scincidae) in the Iranian Plateau based on mtDNA sequences

We recovered molecular phylogenetic relationships amongst species of the genus Ablepharus in Iran and Iraq. Partial sequences of three mitochondrial genes (cytochrome C oxidase subunit I – COI, 12S rRNA and 16S rRNA) were analysed. In addition, phylogenetic relationships and taxonomic evaluation of Ablepharus species in Cyprus, India, Greece, Turkey and Syria were performed using partial sequences of the 16S rRNA gene. Phylogenetic trees and estimated genetic distances showed that the Ablepharus populations of Iran and Iraq clustered into three distinct clades. One is found in northwest Iran (A. bivittatus in Ardabil, East and West Azerbaijan and Hamedan Provinces). The second clade, formed by A. chernovi, is found only in Uromia. The third and most heterogeneous clade is divided into two subclades, the first includes two lineages of Ablepharus in Khorasan Razavi and Semnan Provinces (A. pannonicus) and in eastern and south-eastern Iran (A. grayanus); the second subclade is distributed in the eastern part of Iraq and west and south-western Iran (Ablepharus sp.). Our analyses indicated that splitting of A. chernovi within the genus occurred in the early Miocene [about 22.5 million years ago (Mya)]. Ablepharus bivittatus diverged 15.2 Mya, in the middle Miocene. Ablepharus pannonicus diverged in the late Miocene (8.4 Mya) and A. grayanus separated in the late Miocene (6.7 Mya). The lineages of eastern Iraq and south-western Iran (Ablepharus sp.) diverged also in the late Miocene (7.0 Mya).

Morphological and genetic differentiation in the anguid lizard Pseudopus apodus supports the existence of an endemic subspecies in the Levant

The Levant represents one of the most important reptile diversity hotspots and centers of endemism in the Western Palearctic. The region harbored numerous taxa in glacial refugia during the Pleistocene climatic oscillations. Due to the hostile arid conditions in the warmer periods they were not always able to spread or come into contact with populations from more distant regions. One large and conspicuous member of the Levantine herpetofauna is the legless anguid lizardPseudopus apodus. This species is distributed from the Balkans to Central Asia with a portion of its range running along the eastern Mediterranean coast. Mitochondrial and nuclear DNA sequences, microsatellite genotypes, and morphology show that populations in this region differ from the two named subspecies and presumably had a long independent evolutionary history during the Quaternary. Here we describe the Levantine population as a new subspecies and present biogeographic scenarios for its origin and diversification. The new subspecies is genetically highly diverse, and it forms a sister lineage toPseudopusfrom the remaining parts of the range according to mtDNA. It is the largest-bodied of the three subspecies, but occupies the smallest range.

Phylogeographic analyses point to long-term survival on the spot in micro-endemic Lycian salamanders

Lycian salamanders (genus Lyciasalamandra) constitute an exceptional case of micro-endemism of an amphibian species on the Asian Minor mainland. These viviparous salamanders are confined to karstic limestone formations along the southern Anatolian coast and some islands. We here study the genetic differentiation within and among 118 populations of all seven Lyciasalamandra species across the entire genus’ distribution. Based on circa 900 base pairs of fragments of the mitochondrial 16SrDNA and ATPase genes, we analysed the spatial haplotype distribution as well as the genetic structure and demographic history of populations. We used 253 geo-referenced populations and CHELSA climate data to infer species distribution models which we projected on climatic conditions of the Last Glacial Maximum (LGM). Within all but one species, distinct phyloclades were identified, which only in parts matched current taxonomy. Most haplotypes (78%) were private to single populations. Sometimes population genetic parameters showed contradicting results, although in several cases they indicated recent population expansion of phyloclades. Climatic suitability of localities currently inhabited by salamanders was significantly lower during the LGM compared to recent climate. All data indicated a strong degree of isolation among Lyciasalamandra populations, even within phyloclades. Given the sometimes high degree of haplotype differentiation between adjacent populations, they must have survived periods of deteriorated climates during the Quaternary on the spot. However, the alternative explanation of male biased dispersal combined with a pronounced female philopatry can only be excluded if independent nuclear data confirm this result.

The biogeography of Elaphe sauromates (Pallas, 1814), with a description of a new rat snake species

Background

The rat snake genus Elaphe once comprised several dozens of species distributed in temperate through tropical zones of the New and Old World. Based on molecular-genetic analyses in early 2000s, the genus was split into several separate genera, leaving only 15 Palearctic and Oriental species as its members. One of the three species also occurring in Europe is Elaphe sauromates, a robust snake from the Balkans, Anatolia, Caucasus, Ponto-Caspian steppes, and Levant that has been suspected to be composed of two or more genetically diverse populations. Here, we studied the genetic structure and morphological variation of E. sauromates, aiming to better understand its inter-population relationships and biogeography, and subsequently revise its taxonomy.

Methods

We reconstructed the phylogeography and analyzed the genetic structure of E. sauromates populations originating from most of its geographic range using both mitochondrial (COI, ND4) and nuclear (C-MOS, MC1R, PRLR, RAG1) DNA gene fragments. We employed Maximum likelihood and Bayesian inference methods for the phylogenetic tree reconstructions, supplemented with species delimitation methods, analysis of haplotype networks, and calculation of uncorrected p-distances. Morphological variation in 15 metric and 18 meristic characters was studied using parametric univariate tests as well as multivariate general linearized models. In total, we analyzed sequences originating from 63 specimens and morphological data from 95 specimens of E. sauromates sensu lato.

Results

The molecular phylogeny identified two clearly divergent sister lineages within E. sauromates, with both forming a lineage sister to E. quatuorlineata. The genetic distance between them (5.80–8.24% in mtDNA) is similar to the distances among several other species of the genus Elaphe. Both lineages are also moderately morphologically differentiated and, while none of the characters are exclusively diagnostic, their combination can be used for confident lineage identification. Here, following the criteria of genetic and evolutionary species concepts, we describe the lineage from eastern Anatolia and parts of the Lesser and Great Caucasus as a new species E. urartica sp. nov.

Discussion

Elaphe urartica sp. nov. represents a cryptic species whose ancestors presumably diverged from their common ancestor with E. sauromates around the Miocene-Pliocene boundary. The intraspecific genetic structure indicates that the recent diversity of both species has been predominantly shaped by Pleistocene climatic oscillations, with glacial refugia mainly located in the Balkans, Crimea, and/or Anatolia in E. sauromates and Anatolia and/or the Caucasus in E. urartica sp. nov.

Phylogeography of Aegean green toads (Bufo viridis subgroup): continental hybrid swarm vs. insular diversification with discovery of a new island endemic

Background

Debated aspects in speciation research concern the amount of gene flow between incipient species under secondary contact and the modes by which post-zygotic isolation accumulates. Secondary contact zones of allopatric lineages, involving varying levels of divergence, provide natural settings for comparative studies, for which the Aegean (Eastern Mediterranean) geography offers unique scenarios. In Palearctic green toads (Bufo viridis subgroup or Bufotes), Plio-Pleistocene (~ 2.6 Mya) diverged species show a sharp transition without contemporary gene flow, while younger lineages, diverged in the Lower-Pleistocene (~ 1.9 Mya), admix over tens of kilometers. Here, we conducted a fine-scale multilocus phylogeographic analysis of continental and insular green toads from the Aegean, where a third pair of taxa, involving Mid-Pleistocene diverged (~ 1.5 Mya) mitochondrial lineages, earlier tentatively named viridis and variabilis, (co-)occurs.

Results

We discovered a new lineage, endemic to Naxos (Central Cyclades), while coastal islands and Crete feature weak genetic differentiation from the continent. In continental Greece, both lineages, viridis and variabilis, form a hybrid swarm, involving massive mitochondrial and nuclear admixture over hundreds of kilometers, without obvious selection against hybrids.

Conclusions

The genetic signatures of insular Aegean toads appear governed by bathymetry and Quaternary sea level changes, resulting in long-term isolation (Central Cyclades: Naxos) and recent land-bridges (coastal islands). Conversely, Crete has been isolated since the end of the Messinian salinity crisis (5.3 My) and Cretan populations thus likely result from human-mediated colonization, at least since Antiquity, from Peloponnese and Anatolia. Comparisons of green toad hybrid zones support the idea that post-zygotic hybrid incompatibilities accumulate gradually over the genome. In this radiation, only one million years of divergence separate a scenario of complete reproductive isolation, from a secondary contact resulting in near panmixia.

Electronic supplementary material

The online version of this article (10.1186/s12862-018-1179-0) contains supplementary material, which is available to authorized users.

A new population and subspecies of the critically endangered Anatolian meadow viper Vipera anatolica Eiselt and Baran, 1970 in eastern Antalya province

We report on a new population of Vipera anatolica from the Geyik Mountain Range in eastern Antalya Province, Turkey. It represents only the second known location, and is situated in a valley about 200 km east from the terra typica at Kohu Dağ in western Antalya Province. We compare both populations and, based on marked differences in morphology, habitat, genetics, and its geographically isolated location, we describe the recently discovered population as a new subspecies. Aspects of ecology, threats, and conservation needs are discussed.