Altitude impacts body size but not age in a gecko

Animals' age and size-related life-history traits are influenced by a variety of factors. In connection with climate, the effect of altitude on demographic parameters may differ among different populations of the same species. In the present study, it was analyzed that how body size and longevity of the Asia Minor thin-toed gecko, Mediodactylus heterocercus (Blanford, 1874), vary along with an elevational gradient in Turkey. For this purpose, a total of 138 (52 males, 75 females, and 11 young) M. heterocercus specimens from 11 different populations were analyzed. Populations at inter-mediate altitude had shorter lifespans than in both low and high elevations (marginal environments). Furthermore, the adult life expectancy (ESP), which indicates the expected lifespan of individuals having sexual maturity, was higher in high altitude populations (ESP: 6.59 years) than in intermediate populations (ESP: 5.40 years) and low altitude populations (ESP: 6.01 years). The results of the study suggest that Asia Minor thin-toed geckos' body size increases with altitude, but their age does not.

Age structure and body size of the endangered species Darevskia bendimahiensis (Schmidtler, Eiselt & Darevsky, 1994) from eastern Turkey (Squamata, Sauria, Lacertidae)

The life-history traits of the parthenogenetic lizard Darevskiabendimahiensis were studied by skeletochronology in a population inhabiting highlands in Çaldıran, Van, Turkey. Endosteal resorption was observed in 18 specimens (55%). The mean age was 4.91 ± 0.19 SD years. The mean snout-vent length (SVL) was 51.11 ± 1.15 SD mm. The age at sexual maturity was estimated as 3 years. Longevity was 7 years. Snout-vent length and age were positively correlated (Spearman’s correlation; r = 0.797, P = 0.000). The aim of this study is to contribute to the future conservation activities for this endangered species.

Development of sexual dimorphism in two sympatric skinks with different growth rates

Sexual size dimorphism (SSD) is widespread in animals, especially in lizards (Reptilia: Squamata), and is driven by fecundity selection, male-male competition, or other adaptive hypotheses. However, these selective pressures may vary through different life history periods; thus, it is essential to assess the relationship between growth and SSD. In this study, we tracked SSD dynamics between a "fading-tail color skink" (blue tail skink whose tail is only blue during its juvenile stage: Plestiodon elegans) and a "nonfade color" tail skink (retains a blue tail throughout life: Plestiodon quadrilineatus) under a controlled experimental environment. We fitted growth curves of morphological traits (body mass, SVL, and TL) using three growth models (Logistic, Gompertz, and von Bertalanffy). We found that both skinks have male-biased SSD as adults. Body mass has a higher goodness of fit (as represented by very high R 2 values) using the von Bertalanffy model than the other two models. In contrast, SVL and TL for both skinks had higher goodness of fit when using the Gompertz model. Two lizards displayed divergent life history tactics: P. elegans grows faster, matures earlier (at 65 weeks), and presents an allometric growth rate, whereas P. quadrilineatus grows slower, matures later (at 106 weeks), and presents an isometric growth rate. Our findings imply that species- and sex-specific trade-offs in the allocation of energy to growth and reproduction may cause the growth patterns to diverge, ultimately resulting in the dissimilar patterns of SSD.

Phylogeography of the red-bellied lizard, Darevskia parvula in Turkey

The groups of red-bellied lizards had a small distribution area in the Pontic zone. The several studies performed on these lizard groups are based on taxonomy and systematics. Although there were several taxonomic or systematic researches on some species of this group, the phylogeographical pattern and species disturbing boundaries of this group is still not clear. In the present study, we aimed to resolve the taxonomic and phylogenetic relationships of the red-bellied lizards in Turkey, based on two combined mitochondrial gene fragments and one protein-coding nuclear gene (rag1). Also, we evaluated ecological niches differentiations among red-bellied lizard groups. The mitochondrial DNA genes were found to be highly polymorphic in this group. One hundred and one variable nucleotide sites were detected on the combined gene sequences. According to phylogenetic trees based on the maximum likelihood (ML) and Bayesian inference (BI), the red-bellied lizards group have three species groups; Darevskia parvula, D. adjarica and unnamed Darevskia sp. (candidate species for Darevskia genus). This situation was supported by high bootstrap and posterior probability values in the trees of mitochondrial DNA gene fragments. However, no genetic variation was detected according to nuclear DNA (rag1) sequence. Because the species groups have no overlaps in terms of their ecological niches, ecological niche modelling (ENM) results revealed differences among the groups of D. parvula, D. adjarica, and unnamed Darevskia sp. Besides, we detected no geographical overlaps among three species groups, since there were geographical isolation zones among the species groups of red-bellied lizard.

Age and growth of the common wall lizard, Podarcis muralis (Laurenti, 1768)

The present study was designed to compare the life history traits of two Podarcis muralis populations located at sites of different elevation. The age at maturity was similar in both populations, whereas longevity was found to be lower in the lowland one (Dereköy). The males and females of both populations had a similar snout-vent length (SVL) and mean age. Sexual size dimorphism (SSD) was weak in the highland population, males being slightly larger than females, whereas a strong male-biased SSD was observed in the lowland one. The growth coefficient (k) and growth rates were similar in both populations. This study indicates that the age at maturation (2-3 years) and growth rates (2.37 mm/year) are similar in two populations of P. muralis exposed to different climatic and environmental conditions. Longevity was slightly higher in the highland population (16 years) compared to the lowland one (14 years).

Demographic life history traits in a population of a critically endangered species, Darevskia dryada (Darevsky & Tuniyev, 1997)

Knowing the age structure of endangered species is important in order to contribute to future conservation studies for such species. In this context, we investigated age structure, age at sexual maturity, potential reproductive lifespan and longevity in a population of the Charnali lizard, Darevskia dryada, an endangered species from Turkey. The results show that the Charnali lizard has a longer life span than other lizards of the genus Darevskia that live in the same region. We estimated that these lizards attain their sexual maturity at the age of one or two years and the potential reproductive life span for males and females is six and five years, respectively. As in many other lizards, the Charnali lizard exhibited a low-level male-biased sexual dimorphism in terms of increased size. We believe that this study, in which prior information related to the Charnali lizard is shared, will contribute to future conservation activities for this critically endangered species.

Body size and age structure of the endangered Clark’s lizard (Darevskia clarkorum) populations from two different altitudes in Turkey

We investigated age structure, body size and longevity in two breeding populations ofDarevskia clarkoruminhabiting altitudes ranging from 450 m a.s.l. (Kamilet) to 2250 m a.s.l. (Başyayla) in Turkey by skeletochronology performed on the phalanges. The mean age was found to be 6 years in the Kamilet population and 7 years in the Başyayla population. The maximum life span was 10 years in the lowland population while it was 12 years in the highland population. Age at sexual maturity of both males and females was 1-2 years in the lowland population while it was 2-3 for both sexes in the highland population. Both age and SVL of specimens from the Kamilet population were significantly different between the sexes while age and SVL did not differ significantly between the sexes in Başyayla population. As a conclusion, we observed that the mean age, longevity and age at maturity were increased by altitude while there was a decrease based on the mean SVL in the highland population ofD. clarkorum. Our data on body size, longevity and age at sexual maturity may contribute to conservation efforts for this endangered species.