Kurtuluş Olgun

Age, size and growth of the southern crested newt Triturus karelinii (Strauch 1870) in a population from Bozdag (Western Turkey)

We studied the characteristics of bone growth assessed by skeletochronology in a southern crested newt Triturus karelinii (Urodela) population from Western Turkey. The timing and patterns of bone arrested growth were observed using the phalanges of juveniles and adults that were caught in spring at a breeding site. A metamorphosis line was found in the juveniles. In some adults, a classical succession of single lines of arrested growth was observed in about 50% of the cross sections. However, the other adults exhibited a succession of double lines of arrested growth in their phalanges. Due to the arid summer and cold winter climate in the Bozdag region (1200 m a.s.l.), we argue that in this last case, the lines of arrested growth were deposited during both the summer (aestivation) and winter (wintering). Body length, age and growth were similar in males and females. The age of maturity was 3 to 4 years old and longevity was 8 and 11 years in males and females respectively. Body length and age among taxonomically related large bodied newts of the T. cristatus complex were reported from populations experiencing various environmental conditions. Body length and age at maturity were similar to that observed in other newt species. However, longevity seems to be lower than expected in the T. karelinii studied population. We hypothesized that the arid climate of Bozdag could cause a higher mortality risk during the terrestrial phase of the life cycle. Studying more populations exposed to various conditions is clearly needed to assess interpopulational variation of these life-history traits in this newt species.

Gregarious behaviour in a salamander: attraction to conspecific chemical cues in burrow choice

Gregarious behaviour (i.e. living in groups in contrast to a solitary life) is commonly observed in mammals, but rarely documented in amphibians. Environmental features and/or animal mutual attractions can promote the formation of aggregations that may both reduce the risks of dehydration and predation and increase mate access and fitness. Luschan’s salamander (Mertensiella luschani) lives in permanently arid Mediterranean environments; individuals shelter in cracks and crevices and leave only during favourable periods. In this study we examined the role of chemical tracks, in self and conspecific recognition (i.e. gregarious/solitary behaviour), on the social structure of this species. Our results show that juveniles and adults of both sexes use chemical scents deposited on substrate to relocate their shelter. In contrast to numerous other salamander species, Luschan’s salamanders also use social information, conveyed by conspecific scents, to identify a safe shelter. Furthermore, this scent marking does not play a role in sexual attraction but allows sex discrimination. This species exhibits gregarious behaviour (i.e. conspecific attraction) as a possible adaptation to dry environments. We discuss both ultimate and proximate factors in the evolution from a solitary to a gregarious life.

Taxonomy of the banded newt, Triturus vittatus : morphological and allozyme data

We studied the number of rib-bearing vertebrae, eight morphometric characters and 36 protein loci in three subspecies of the banded newt, Triturus vittatus from the Near and Middle East. The number of rib-bearing vertebrae ranged from 12 to 15. Modal count was 13 in T. v. cilicensis , T. v. vittatus and T. v. ophryticus in the western part of the range and 14 in the eastern part of the T. v. ophryticus range. Significant differences were found between groups ( cilicensis plus vittatus , western ophryticus , eastern ophryticus ). Significant differences in shape were observed comparing T. vittatus with T. karelinii and T. montandoni , but not among T. v. vittatus , T. v. cilicensis and T. v. ophryticus . Genetic differentiation within T. v. ophryticus reached D Nei = 0.24, which was similar to the distance observed between T. v. vittatus and T. v. cilicensis ( D Nei = 0.18). The two groups clustered at D Nei = 0.58. We discuss the question whether T. v. ophryticus should be raised to species level.

AGE, SIZE AND GROWTH IN TWO POPULATIONS OF THE SOUTHERN CRESTED NEWT, TRITURUS KARELINII (STRAUCH 1870) FROM DIFFERENT ALTITUDES

Abstract We measured body size of individuals from two populations of the southern crested newt, Triturus karelinii, from two localities at different altitudes (7 m, Klaros and 1373 m, Reşadiye) in Turkey. Lines of arrested growth (LAGs) recorded in phalanges were used to estimate the age of juveniles and adults. Females were on average larger than males in Klaros, and males were on average larger than females in Reşadiye. Our results did not follow the Bergmanns rule and developmental temperature-size rule: for both sexes, the individuals of lowland population were larger than the individuals of highland population. Significant differences were found between the populations in terms of mean SVL (snout–vent length). The average age was calculated as 6.14 ± 1.51 and 6.16 ± 1.46 yr in Klaros and 5.30 ± 1.20 and 5.76 ± 1.26 yr in Reşadiye, for males and females respectively. No significant differences were found between the age distributions of the females in both populations. Both sexes from lowland population had age distributions that were similar to their counterparts from highland population. The growth curves for T. karelinii populations were well described in a Von Bertalanffy growth model. K was not significantly different between the sexes. However, SVLmax was significantly larger in females than males in both populations

A genomic footprint of hybrid zone movement in crested newts

Speciation typically involves a stage in which species can still exchange genetic material. Interspecific gene flow is facilitated by the hybrid zones that such species establish upon secondary contact. If one member of a hybridizing species pair displaces the other, their hybrid zone would move across the landscape. Although theory predicts that moving hybrid zones quickly stagnate, hybrid zones tracked over one or a few decades do not always follow such a limitation. This suggests that hybrid zones have the potential to traverse considerable distances over extended periods of time. When hybrid zones move, introgression is predicted to result in biased gene flow of selectively neutral alleles, from the receding species into the advancing species. We test for such a genomic footprint of hybrid zone movement in a pair of crested newt species (genus Triturus) for which we have a priori support for westward hybrid zone movement. We perform a multilocus phylogeographical survey and conduct Bayesian clustering analysis, estimation of ancestry and heterozygosity, and geographical cline analysis. In a 600 km wide area east of the present day hybrid zone a genomic footprint constitutes empirical evidence consistent with westward hybrid zone movement. The crested newt case suggests that hybrid zone movement can occur over an extensive span of time and space. Inferring hybrid zone movement provides fundamental insight into historical biogeography and the speciation process, and we anticipate that hybrid zones will prove to be far more mobile than currently appreciated.

Body size and age structure of Pelophylax ridibundus populations from two different altitudes in Turkey

We estimated differences in body size and age structure of two populations of Pelophylax ridibundus living at different altitudes in Turkey, one from Dortyol (6 m a.s.l.) and the other from Karagol (1480 m a.s.l.). Their age structure was determined by skeletochronology performed on the LAGs (lines of arrested growth) of the phalanges. While ages ranged from 2 to 8 years for males and from 2 to 7 years for females in Karagol, in Dortyol the ages ranged from 4 to 11 years for males, and 3 to 7 years for females. Sexual size dimorphism was only found in the Dortyol population. Larger females tend to be found in hotter climates (Dortyol) but reach maturity later (3-4 years) than the highland population (2 years). A significant relationship between age and snout-vent length (SVL) was found for both sexes and populations with the exception of females in Dortyol.

Body size and age structure of a breeding population portion of the Urmia salamander, Neurergus crocatus Cope, 1862 (Caudata: Salamandridae)

Abstract Recently, the Urmia salamander, Neurergus crocatus Cope, 1862 was classified as a vulnerable species. The age structure of a breeding population portion of N. crocatus from Turkey was studied by using skeletochronology performed on the phalanges. According to the analysis of the age structure based on counting lines of arrested growth (LAGs), ages ranged from 5 to 14 years (mean = 9.4 ± 2.3 years) for males and from 8 to 17 years (mean = 11.6 ± 2.2 years) for females in N. crocatus. The mean snout–vent length was 69.2 ± 3.6 mm in males and 76.2 ± 3.8 in females. The sexual dimorphism index was 0.10. The difference between the sexes in age and size was statistically significant.

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

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.

First comprehensive insights into nuclear and mitochondrial DNA based population structure of Near East mountain brook newts (Salamandridae: genus Neurergus) suggest the resurrection of Neurergus derjugini

Due to their extraordinary coloration, mountain brook newts of the genus Neurergus found in the Near East have fascinated herpetologists since their initial description more than 150 years ago. Although the monophyly of Neurergus newts within the Salamandridae has been unambiguously shown for mitochondrial genes, and recent comprehensive molecular phylogenies placed Neurergus as a sister taxon of banded newts (genus Ommatotriton), we know almost nothing about the structure and relatedness of populations at the intraspecific level. In this study, we therefore analysed sequence variation of a mitochondrial DNA segment (covering a partial region of the control region and the 12S ribosomal RNA) from more than 100 individuals and of two nuclear genes (KIAA and SACS) for a representative subset of individuals originating from nine distinct populations, representing N. strauchii, N. crocatus and N. microspilotus. We also studied individuals of N. derjugini, a taxon that has long been synonymized as N. crocatus, and of which individuals have not been accessible to the scientific community since its original description in 1916. Our results suggest high genetic diversity of populations within species for the mitochondrial DNA marker, while the resolution of applied nuclear genes did not go beyond the level of species. For N. strauchii and N. crocatus, two species that inhabit the largest geographic ranges within the genus, we found a high proportion of diversity both within and between populations for the mitochondrial control region. Individuals of N. microspilotus and N. derjugini only displayed considerable genetic differentiation for one nuclear gene (SACS), while only very little or none genetic differentiation could be found for the mitochondrial control region and the KIAA gene, respectively. As both taxa are also morphologically not well differentiated, we suggest on the basis of the current dataset to taxonomically synonymize N. microspilotus due to priority reasons as N. derjugini. It can be therefore concluded that the most accurate taxonomy of the genus Neurergus should consider N. crocatus, N. strauchii, N. kaiseri and N. derjugini as valid taxonomic units at the species level.

The distributions of the six species constituting the smooth newt species complex ( Lissotriton vulgaris sensu lato and L. montandoni ) – an addition to the New Atlas of Amphibians and Reptiles of Europe

The ‘smooth newt’, the taxon traditionally referred to as Lissotriton vulgaris , consists of multiple morphologically distinct taxa. Given the uncertainty concerning the validity and rank of these taxa, L. vulgaris sensu lato has often been treated as a single, polytypic species. A recent study, driven by genetic data, proposed to recognize five species, L. graecus , L. kosswigi , L. lantzi , L. schmidtleri and a more restricted L. vulgaris . The Carpathian newt L. montandoni was confirmed to be a closely related sister species. We propose to refer to this collective of six Lissotriton species as the smooth newt or Lissotriton vulgaris species complex. Guided by comprehensive genomic data from throughout the range of the smooth newt species complex we 1) delineate the distribution ranges, 2) provide a distribution database, and 3) produce distribution maps according to the format of the New Atlas of Amphibians and Reptiles of Europe, for the six constituent species. This allows us to 4) highlight regions where more research is needed to determine the position of contact zones.