In recent years many cases of hybridization and introgression became known for chelonians, requiring a better understanding of their speciation mechanisms. Phylogeographic investigations offer basic data for this challenge. We use the sister species Mauremys caspica and M. rivulata, the most abundant terrapins in the Near and Middle East and South‐east Europe, as model. Their phylogeographies provide evidence that speciation of chelonians fits the allopatric speciation model, with both species being in the parapatric phase of speciation, and that intrinsic isolation mechanisms are developed during speciation. Hybridization between M. caspica and M. rivulata is very rare, suggesting that the increasing numbers of hybrids in other species are caused by human impact on environment (breakdown of ecological isolation). Genetic differentiation within M. caspica and M. rivulata resembles the paradigm of southern genetic richness and northern purity of European biota. However, in west Asia this pattern is likely to reflect dispersal and vicariance events older than the Holocene. For M. caspica three distinct Pleistocene refuges are postulated (Central Anatolia, south coast of Caspian Sea, Gulf of Persia). Morphologically defined subspecies within M. caspica are not supported by genetic data. This is one of the few studies available about the phylogeography of west and central Asian species.
More than two third area of our planet is covered by oceans and assessment of marine biodiversity is a challenging task. With the increasing global population, there is a tendency to exploit marine resources for food, energy and other requirements. This puts pressure on the fragile marine environment and necessitates sustainable conservation efforts. Marine species identification using traditional taxonomical methods is often burdened with taxonomic controversies. Here we discuss the comparatively new concept of DNA barcoding and its significance in marine perspective. This molecular technique can be useful in the assessment of cryptic species which is widespread in marine environment and linking the different life cycle stages to the adult which is difficult to accomplish in the marine ecosystem. Other advantages of DNA barcoding include authentication and safety assessment of seafood, wildlife forensics, conservation genetics and detection of invasive alien species (IAS). Global DNA barcoding efforts in the marine habitat include MarBOL, CeDAMar, CMarZ, SHARK-BOL, etc. An overview on DNA barcoding of different marine groups ranging from the microbes to mammals is revealed. In conjugation with newer and faster techniques like high-throughput sequencing, DNA barcoding can serve as an effective modern tool in marine biodiversity assessment and conservation.
The West Asian stripe-necked terrapin Mauremys caspica is widespread throughout the Middle East-a region for which only few phylogeographic studies are available. Due to landscape alteration, pollution and intensification of water management, M. caspica is increasingly threatened. However, genetic diversity among and within populations is poorly known, impeding the identification of management units. Using a nearly rangewide sampling, we analyzed 14 microsatellite loci and mtDNA sequences in order to gain insight into the population structure and history of M. caspica.In agreement with a previous study, we found two clusters of mitochondrial haplotypes, with one cluster distributed in the east and the other in the west of the range. However, our microsatellite data suggested a more pronounced geographical structuring. When null alleles were coded as recessive with STRUCTURE 2.3.2, three clusters were revealed, with one cluster matching roughly the range of the western mitochondrial cluster, and the composite ranges of the two other microsatellite clusters correspond to the distribution of the eastern mitochondrial cluster. Naïve STRUCTURE analyses without correction for null alleles were congruent with respect to the two eastern microsatellite clusters, but subdivided the western cluster into two units, with an additional geographical divide corresponding to the 'Anatolian diagonal'-a wellknown high mountain barrier impeding exchange between western and eastern taxa. In naïve analyses, the westernmost microsatellite cluster (from Central Anatolia) is quite isolated from the others, and its distinctness is also supported by fixation indices resembling the values among the other three clusters. One of the two eastern clusters is distributed in the Caucasus region plus Iran, and terrapins from Saudi Arabia and Bahrain constitute the second eastern cluster, supporting Electronic supplementary material The online version of this article (
U. (2017). Unexpected hybridization patterns in Near Eastern terrapins (Mauremys caspica, M. rivulata) indicate ancient gene flow across the Fertile Crescent. -Zoologica Scripta, 46, 401-413.Recent studies indicate that hybridization in animals occurs more frequently than previously thought and that it may play an important evolutionary role. Chelonians are capable of extensive hybridization, raising the question how chelonian species evolve and maintain genetic integrity despite hybridization. Here, we use two sister species with parapatric distribution, Mauremys caspica and M. rivulata, as our model. These taxa are estimated to have diverged some 5.3-7.0 million years ago. Using rangewide sampling and 13 unlinked polymorphic microsatellite markers, five nuclear loci and one mitochondrial gene, we show that hybridization is rare along the contact zone of the two species in Turkey. However, we discovered an unexpected hybrid swarm in the southern Levant that has been hitherto identified with M. rivulata. This hybrid swarm is separated from the inland species M. caspica by a 700-km-wide distribution gap corresponding to the Syrian Desert. Ecological palaeomodelling suggests that during more humid climatic episodes in the Last Glacial Maximum and mid-Holocene, the current contact zone extended into the southern Levant, facilitating the establishment of the now isolated hybrid swarm. Our results support that there is not necessarily a general hybridization pattern in a given species couple and that the extent of gene flow may differ considerably in different parts of the distribution range. Moreover, our results highlight that studies on hybridization should not focus only on extant contact and hybrid zones, but should use rangewide sampling to detect signals of ancient hybridization that might otherwise be missed.
We undertook breeding surveys between 2010 and 2011 to assess the status of breeding birds on 16 islands in the northern Saudi Arabia. Sixteen bird species were found breeding at three different seasons; i.e. winter (Osprey), spring (Caspian and Saunder's Terns), and summer (Lesser Crested, White-cheeked, Bridled Terns). It is postulated that food availability is an important factor influencing the breeding of seabirds in the northern Saudi Arabian Red Sea. Several species laid eggs earlier in northern parts of the Red Sea than in southern parts. The predicted increases in temperatures (Ta ) could have a negative effect on species survival in the future, especially on those whose nests that are in the open. Finally, disturbance, predation and egg collection were probably the main immediate threats affecting the breeding seabird species in the northern Red Sea.
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