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An understanding of the dynamics of bone growth is key to interpreting life‐history parameters of vertebrates. In this study, we used fluorochrome labels in captive leopard geckos (Eublepharis macularius) to track bone growth and intraskeletal variability from embryonic to adult growth stages. Thirteen individuals were administered fluorochromes from pre‐hatching to 4 years of age. The left tibia, fibula, femur, humerus, radius, and ulna were examined histologically and compared for differences in the number of labels within and between individuals at each sampled growth stage, and the amount of bone growth between labels was calculated. Results suggest that limb elements had differing growth rates; the fibula grew the fastest per day on average and the femur grew the slowest per day on average. All labels administered in ovo were still present in all limb elements in adults except for the tibia, suggesting growth marks are not lost in most elements and accurate calculations of growth rates could be performed in individuals up to 3 years old. All ex ovo labels were accounted for; however, when two fluorochromes were administered 3 weeks apart, the labels could not be differentiated from each other due to the new bone not being deposited at a quantifiable level. Overall, the tibia in leopard geckos is the least reliable limb bone to use for skeletochronology and the humerus, radius, and fibula preserve the longest growth record. This research highlights that, as in other extinct and extant animals, patterns of bone growth are not consistent across reptiles. This study adds to the growing body of knowledge on growth variability in reptiles. [ABSTRACT FROM AUTHOR]

The document "Contents Index to Volume 45" from the journal "Amphibia-Reptilia" covers a wide range of research topics related to amphibians and reptiles. It includes studies on mating strategies of frogs, the impact of fire on amphibians in the Pantanal ecoregion, and climbing performance of alligators. Additionally, the document explores issues such as lizard thermoregulation, crocodile nesting habitats, and snake fungal disease ecology. The research presented in this volume provides valuable insights into the diverse and complex ecosystems inhabited by these fascinating creatures. [Extracted from the article]

Skeletochronology was used to determine the ages of 30 loggerhead sea turtles (Caretta caretta) found in French Mediterranean waters. Histological sections were performed with 30 humeri collected on stranded C. caretta on the coast of Provence and the Gulf of Lion. Lines of arrested growth (LAGs) were used to evaluate age, considering only one period of arrested growth per year. Two successive LAGs delimit an interval that is proportional to the individual's body growth. In a first step, we created a skeletogram for each individual that identified its LAGs. Secondly, we measured the areas delineating successive intervals to determine individual growth patterns over the years. Two methods were used to deduce sea turtle age from histological sections: the correction factor (CF) method and the growth rate (GR) method, the latter using Von Bertalanffy growth function. Age estimations varied from 4.3 to 24.7 years (mean ± SD = 10.1 ± 4.8) with the CF method and from 6.2 to 25.6 years (mean ± SD = 12.2 ± 5.2) with the GR method, with no significant difference between the methods. The study sample was thus mostly composed of juveniles, which is also the most frequent life stage observed in the study area. The annual curved carapace length growth rate calculated with every LAG interval varied from 1.0 to 6.9 cm/year (mean ± SD = 3.5 ± 1.4, n = 115). High variability in interindividual growth rates were observed, which is of interest in understanding the complex lifecycle of these long-lived marine reptiles. [ABSTRACT FROM AUTHOR]

In this study, some life history characteristics (27 adult and 7 subadult specimens) of a highland population (Sütçüler) of the Lacerta pamphylica species in Isparta province of Türkiye were investigated by applying the skeletochronology method. The mean age and SVL values were 5.67 ± 0.50 years and 106.28 ± 2.25 mm in adult males and 5.33 ± 0.46 years and 102.65 ± 2.65 mm in adult females in the population. The age range varies between 3–10 years in males and 3–8 years in females. The age of subadult males and subadult females was 2 years. The presented study provides information on the age of the species Lacerta pamphylica for the first time. [ABSTRACT FROM AUTHOR]

Simple Summary: The main objective of this study was to provide the first information on the age structure of the critically endangered and endemic frog species, Rana tavasensis, in Türkiye. Age data are important in evaluating the dynamics of populations and effective conservation strategies should be addressed according to age-related parameters (e.g., longevity, mean age, growth rate, and age at maturity). Skeletochronology is an effective method for estimating the ages of amphibians, and using this method, we determined the mean age, longevity, and relationship between age and body size in both males and females of a R. tavasensis population in Çakıroluk, the terra-typica, located in Denizli province, Türkiye. The results of our study provides insights for taking feature measures to protect these frogs, whose number has progressively declined each year due to habitat loss and degradation. This study used skeletochronology to assess the relationships between age and body length among individuals in a population of the Tavas Frog (Rana tavasensis), located in the Çakıroluk plateau, Tavas district, Denizli province. The age varied from 3 to 12 years in both adult males and females. The age was 2 years in two subadult males, while it was 1 year in one juvenile specimen. The mean SVL and age of the adult individuals of the Çakıroluk population were 62.75 mm and 6.70 years in male specimens and 58.04 mm and 6.12 years in female specimens. A positive correlation was found between body size (SVL) and age in adult female and male individuals of the species. Because the number of individuals of the species is rapidly decreasing, species protection measures, based on knowledge related to the age structure and breeding features of these frogs, must be put into action urgently. [ABSTRACT FROM AUTHOR]

Body size is often a critical determinant of competitive ability and reproductive behavior. For example, small males characteristically lose contests with larger males and may be metabolically constrained from sustaining energetically demanding reproductive behaviors. Small males thus often utilize alternative reproductive tactics (ARTs) to maximize their reproductive success. How variation in body size among behavioral phenotypes arises can provide important insight into the maintenance of ARTs. For instance, smaller body sizes for males adopting ARTs may simply be a function of age, suggesting that the tactic is maintained by the periodic recruitment of young males into the population. Alternatively, body size differences among behavioral phenotypes that are unrelated to age suggest disparate growth rates that potentially arise as a consequence of variation in environmental conditions during development or genotypic differences between the phenotypes. Here we examine these alternative scenarios in the green treefrog, Dryophytes cinereus, using skeletochronological analysis combined with body size measures. As with many other anuran amphibians, male green treefrogs conditionally adopt a noncalling satellite mating tactic and attempt to intercept females attracted to the vocalizations of calling "host" males. We show that males adopting satellite behavior in natural choruses are smaller than calling males but do not represent a class of younger individuals, indicating that satellite males have lower growth rates than calling males. We also show that satellite males are in poorer condition than larger calling males, implicating energetic constraints in size‐related variation in mating tactic expression. Our work suggests that environmental conditions during development, genetic differences between phenotypes, or both, give rise to size discrepancies in behavioral phenotypes, neither of which have been previously explored in anurans. We discuss body size and condition differences between behavioral phenotypes in the context of energetic constraints and endocrine mediation of tactic expression in this species. [ABSTRACT FROM AUTHOR]

Age and body size in a lowland population of Lissotriton schmidtleri in the İstanbul Province of Türkiye were examined by applying the skeletochronology method. The age range varies between 5 to 11 years in males and 4 to 8 years in females. The mean age and SVL values were 8.1 years and 36.28 mm in males and 6.4 years and 37.72 mm in females. The mean SVL and age values showed a significant difference between the sexes. The present study showed sexual dimorphism and different life expectancy between sexes. The estimated potential reproductive lifespan was higher in males than females. [ABSTRACT FROM AUTHOR]

This study used skeletochronology to assess the relationships of age and body length of the individuals in a population of the Levant green lizard (Lacerta media), located in the Harmancık Village, Torul District, Gümüşhane Province. The mean age and SVL in the adult individuals of the Harmancık population were 101.57 ± 4.04 mm and 5.31 ± 1.34 years for all individuals (101.10 ± 3.61 mm and 5.31 ± 1.03 years in adult females and 102.09 ± 4.57 mm and 5.33 ± 1.67 years in adult males). The age range varied was 4-8 years in adult males and 4-7 years in adult females. The age of the subadult males and subadult females was at 3 years, while the age of the two juveniles was 2 years. A positive correlation was found between body size (SVL) and age in adult female and male individuals of the species. A male-biased sexual size dimorphism (SSD = -0.097) was observed. [ABSTRACT FROM AUTHOR]

The current study examines the growth pattern and lifestyle habits of the freshwater snapping turtles Chelydra and Macrochelys based on limb bone histology. Femora, humeri, and tibiae of 25 individuals selected from a range of ontogenetic stages were assessed to determine inter‐element and intraskeletal histological variation. Osteohistological assessment of multiple elements is consistent with overall moderate growth rates as revealed by the dominance of parallel‐fibered bone. However, the growth was cyclical as shown by deposition of multiple lines of arrested growths in the compacta. It appears that the bone tissue of C. serpentina is more variable through ontogeny with intermittent higher growth rates. M. temminckii appears to grow more slowly than C. serpentina possessing compact and thick cortices in accordance with their larger size. Overall, vascularization decreases through ontogeny with humeri and femora being well‐vascularized in both species. Contrarily, epipodials are poorly vascularized, though simple longitudinal and radial canals are present, suggesting differences in growth patterns when compared with associated diaphyseal sections. The tibiae were found to be the least remodeled of the limb bones and therefore better suited for skeletochronology for snapping turtles. Intra‐elementally, femora and humeri preserved higher cortical vascularity ventrally, suggestive of faster relative growth. We hypothesize that the differential growth pattern in limb bones of snapping turtles may relate to differential functional constraints, where forelimbs are operational in swimming while the hindlimbs provide stability. [ABSTRACT FROM AUTHOR]

Amphibians are not only an alternative source of vital protein for humans, but also one of the best bioindicators for ecological studies. In this study, we studied the age structure, body size, and mass of an amphibian species (Pelophylax ridibundus) by sampling from two different frog farms in Türkiye. The age ranged from 4 to 13 (mean: 7.1) years in the Adana site while the age varied from 1 to 12 (mean: 5.2) years in the İstanbul site. Body size ranged between 88.21 and 103.72 mm (mean: 94.99 ± 1.15 mm) in the Adana site and 45.96 and 103.25 mm (mean: 75.90 ± 3.01 mm) in the İstanbul site. The t-test confirmed that the average age, SVL, and weight of the Adana site were higher than those of İstanbul. Body size markedly increased with age and weight (SVL-age: r = 0.659, p < 0.01; SVL-weight: r = 0.877, p < 0.001) in the İstanbul site, while in the Adana site, body size correlated only with weight. In conclusion, our research uses skeletochronology to provide demographic characteristics of marsh frogs from two unexplored frog farms located in the west and south of Türkiye. [ABSTRACT FROM AUTHOR]

Age and growth-related parameters provide a better understanding of life-history adaptations and trade-offs and can be studied in the wild through capture-mark-recapture (CMR) or sclerochronology (i.e., skeletochronology and counting growth marks on hard structures). In chelonians, skeletochronology is limited to carcasses, CMR is limited by time and funding constraints, but counting shell growth annuli (SGA count) is a cheaper and faster alternative. A long-term CMR study in Testudo graeca from south-eastern Romania allowed us to compare the age estimated by the two sclerochronology methods using carcasses, and calibrate the results with data obtained from recaptured tortoises. We found that the accuracy of SGA counts significantly decreased with time (i.e., years between captures and older individuals). Skeletochronology showed the best results with long bones (i.e., ulna, radius, femur), but overall underestimated the age when compared to SGA counts; we obtained comparable results from these two methods in tortoises up to 17 years old. The oldest age estimated by skeletochronology alone was 28 years, 30 years by SGA counts, and 40 years by SGA counts when calibrated by CMR. The growth models using age estimations from both skeletochronology and SGA counts were similar, highlighting their usefulness in monitoring growth trajectories. Our study showed that while age estimation in tortoises is challenging, a combination of methods can improve its accuracy. [ABSTRACT FROM AUTHOR]

Understanding how age and body size vary across elevations can provide insights into the evolution of life‐history traits in animals. In the present study, we compared the demographic (using skeletochronology) and morphological traits of the Tibetan toad (Bufo tibetanus) between two populations from different elevational habitats (2650 vs. 3930 m). We found that (1) the mean age and body size of females were significantly greater than those of males in both populations; (2) both sexes of toads from the higher elevation tended to be significantly older in age and larger in body size; (3) there was a significant positive relationship between age and body size within each sex of the toad at both elevations; and (4) growth rates varied between the two populations, with the higher rate observed in the lower‐elevation population. Our results suggested that factors other than age, such as elevation‐associated temperature, influence the observed differences in body size between the two populations. Future research at a broader range of elevations should focus on these factors and evaluate their influence on animal growth patterns. [ABSTRACT FROM AUTHOR]

The life‐history traits of ectothermic animals can be influenced by many abiotic factors, including climate. As an ectothermic species, we questioned whether the life‐history characteristics of the orange‐tailed skink (Eumeces schneiderii) populations differ between two different environments/climates. Our findings showed that the average body size of lizards living in the Mediterranean climate zone was higher than those in the continental climate zone. However, although Mediterranean population had higher mean values regarding average age, there was no discernible difference between the two climate zone populations. When considering all populations collectively, it has been discovered that the species' maximum lifespan is 18 years. Body size notably increased with age in both populations. Through the utilization of the von Bertalanffy equation, the anticipated growth parameters portrayed a highly accurate connection between age and snout–vent length. In conclusion, lizards living in habitats characterized by milder Mediterranean climates were found to have larger body sizes than continental populations, but both populations were comparable in terms of mean age. This difference can be explained by several factors, including activation time, temperature, precipitation, food abundance, and the presence of predators. [ABSTRACT FROM AUTHOR]

In this study, the age structure and growth parameters of the Mediterranean house gecko, Hemidactylus turcicus (Linnaeus, 1758) were studied in Izmir Province (Western Anatolia, Türkiye). Our goal is to share with readers a small sampling of observations. In total 38 specimens (9 juveniles, 11 males, and 18 females) were captured and analysed in 2018. Age estimation was achieved based on histological skeletochronology using cross-sections of the femora, which suggested a mean age of 1.5 years for juveniles (1–2 years), 3.45 years (2–5 years) for males and 3.59 years (2–5 years) for females. Maximum age was estimated at 5 years. Age at sexual maturity was estimated at 2–3 years for both sexes, and a significant positive correlation was observed between size and age. [ABSTRACT FROM AUTHOR]

Information on habitat use among highly migratory green sea turtles is especially important for effective conservation – especially in urban habitats. However, long migration distances between sea turtle feeding grounds and nesting beaches make these long-lived marine reptiles difficult to study. Combining techniques, such as skeletochronology with stable isotope values from annual bone growth layers, can help determine life history traits and movement patterns of sea turtles. For one component of my capstone project, I helped members of the Marine Turtle Ecology and Assessment Program at the NOAA Southwest Fisheries Science Center take inventory of the East Pacific (EP) population of green turtles in San Diego Bay. Along with fieldwork, I worked in NOAA’s Marine Turtle Demography Laboratory prepping samples for stable isotope analysis. Finally, I analyzed data collected by NOAA to evaluate if trace elements found in bones, such as barium (Ba), magnesium (Mg), and strontium (Sr), could also be used toreconstruct transitions between oceanic and coastal life stages in sea turtles. For my capstone deliverable, I combined geographic maps, satellite telemetry data, stable isotope data, skeletochronology data, narrative text, and multimedia content to share case studies of well-known EP green sea turtles in an interactive, dynamic, and meaningful way. The long-term data stored in the bones of sea turtles, along with the information gained from multiple captures over time, has helped reconstruct movement patterns of these highly migratory reptiles. Through my ArcGIS Storymap, I can share this conservation success story - to give people hope, to inspire action, and to ensure the protection and continued success of these turtles and their habitat. I hope the turtle stories bring curiosity, and a better understanding of the amazing science that is improving conservation efforts for sea turtles around the globe.

Longevity is one of the most important characteristics in the life history of organisms. It is directly associated with growth, reproduction and age of sexual maturity. Despite this, little is known about longevity in South American anuran species, a region considered as a hotspot of world diversity. Thus, we carried out a literature review of publications on longevity of South American anurans that used the skeletochronology method to identify the main publication trends, as well as to point out the main information gaps and suggest future directions. We found clear biases when we analysed temporal, spatial and taxonomic patterns in publications on longevity: (i) studies are recent (mostly from 2015 onwards), (ii) bufonids and leptodactylids were the most studied groups, (iii) medium to large species are the most studied, (iv) species with wide geographic distribution, low risk of extinction, (v) the studies are concentrated in Brazil and Argentina, and (vi) most studies are in the Chaco biogeographical sub-region. We suggest that future work prioritizes little explored families and with high species diversity, small-bodied species, with restricted distribution, threatened with extinction, in order to expand the representation of different evolutionary lineages along the biogeographical units of South America.

Fossils provide an excellent opportunity to study and understand the evolution of insular environments free of human-made perturbations. Here, we evaluated the life-history traits and strategy of the extinct insular giant Prolagus sardus (Mammalia: Lagomorpha) by examining microscopically its fossilized bone tissues (osteohistology, skeletochronology, and quantitative geometry). For this task, a complete ontogenetic series of femora retrieved from the Late Pleistocene Grotta della Medusa (NW Sardinia, Italy) were analysed. Our results reveal that: (i) P. sardus ' pups were weaned at large size; (ii) the species' maturation was delayed in its life cycle; and (iii) P. sardus lived longer than expected for its size. Hence, the giant P. sardus should have a slow pace of life triggered by the low levels of extrinsic mortality of the insular habitat. On the other hand, bone tissue differences between P. sardus and Ochotona were found in the vascularization, slow- growing bone presence, and cortical and medullary growth trajectories. The results obtained in this study concur with the eco-evolutionary responses described to date in extinct insular lagomorphs, as well as provide new empirical evidence about the phenomenon known as 'insular gigantism' as a pattern of evolution of small-sized mammals in genuine insular ecosystems. [ABSTRACT FROM AUTHOR]

Horticulture poses a significant ecological risk, as agrochemicals are applied more frequently and in larger quantities per unit of production compared to extensive crop fields. The native amphibian Rhinella arenarum serves as a reliable bioindicator of environmental health. This study aimed to assess genocytotoxic damage and demographic life history traits of R. arenarum inhabiting horticultural environments. Sampling was conducted in suburban sites in central Argentina: H1 and H2 (sites associated with horticultural activity) and a reference site, RS. Environmental parameters were recorded, and the frequency of micronuclei (Mn), nuclear abnormalities (ENA), and indicators of cytotoxic damage were determined in tadpoles and adults. Demographic variables (age at maturity, longevity, potential reproductive lifespan, size at maturity, modal lifespan) were calculated. The highest nitrate and phosphate values, along with low dissolved oxygen values, were recorded at sites H1 and H2. Organisms inhabiting horticultural environments exhibited higher frequencies of Mn and ENA, surpassing those recorded in previous studies on tadpoles from sites with extensive crop production. Size at maturity and age at maturity of females, as well as size at maturity, longevity, mean age, and mean adult SVL of males, were lower in horticultural sites. The results support the hypothesis that anuran populations inhabiting horticultural environments demonstrate a diminished health status attributed to subpar environmental quality. Monitoring endpoints at different biological levels provides information on the ecotoxicological risk for amphibians and human populations inhabiting nearby areas. [ABSTRACT FROM AUTHOR]

Abstract The life‐history traits of ectothermic animals can be influenced by many abiotic factors, including climate. As an ectothermic species, we questioned whether the life‐history characteristics of the orange‐tailed skink (Eumeces schneiderii) populations differ between two different environments/climates. Our findings showed that the average body size of lizards living in the Mediterranean climate zone was higher than those in the continental climate zone. However, although Mediterranean population had higher mean values regarding average age, there was no discernible difference between the two climate zone populations. When considering all populations collectively, it has been discovered that the species' maximum lifespan is 18 years. Body size notably increased with age in both populations. Through the utilization of the von Bertalanffy equation, the anticipated growth parameters portrayed a highly accurate connection between age and snout–vent length. In conclusion, lizards living in habitats characterized by milder Mediterranean climates were found to have larger body sizes than continental populations, but both populations were comparable in terms of mean age. This difference can be explained by several factors, including activation time, temperature, precipitation, food abundance, and the presence of predators.

Abstract Understanding how age and body size vary across elevations can provide insights into the evolution of life‐history traits in animals. In the present study, we compared the demographic (using skeletochronology) and morphological traits of the Tibetan toad (Bufo tibetanus) between two populations from different elevational habitats (2650 vs. 3930 m). We found that (1) the mean age and body size of females were significantly greater than those of males in both populations; (2) both sexes of toads from the higher elevation tended to be significantly older in age and larger in body size; (3) there was a significant positive relationship between age and body size within each sex of the toad at both elevations; and (4) growth rates varied between the two populations, with the higher rate observed in the lower‐elevation population. Our results suggested that factors other than age, such as elevation‐associated temperature, influence the observed differences in body size between the two populations. Future research at a broader range of elevations should focus on these factors and evaluate their influence on animal growth patterns.

This study used skeletochronology to assess the relationships between age and body length among individuals in a population of the Tavas Frog (Rana tavasensis), located in the Çakıroluk plateau, Tavas district, Denizli province. The age varied from 3 to 12 years in both adult males and females. The age was 2 years in two subadult males, while it was 1 year in one juvenile specimen. The mean SVL and age of the adult individuals of the Çakıroluk population were 62.75 mm and 6.70 years in male specimens and 58.04 mm and 6.12 years in female specimens. A positive correlation was found between body size (SVL) and age in adult female and male individuals of the species. Because the number of individuals of the species is rapidly decreasing, species protection measures, based on knowledge related to the age structure and breeding features of these frogs, must be put into action urgently.

We present the first data on the life history traits and growth patterns of Boana riojana from 35 individuals belonging to two populations in central Argentina. We determined age using skeletochronology and analyzed morphometric variables in relation to these ages. The mean snout-vent length of sexually mature males was 53.7 mm, with an average age of 2.4 years. The species had a maximum longevity of four years, and the minimum age at sexual maturity was two years, which was consistent across both populations. Body size and age showed a positive correlation. The von Bertalanffy growth equation revealed an asymptotic snout-vent length of 59.7 mm and a growth coefficient of 0.87. Additionally, a decline in growth rate was observed from the second to the third year of age. We found no significant differences in the variables between both populations. In conclusion, determining the individual age of different populations of B. riojana has, for the first time, allowed us to establish the life history traits of the species. [ABSTRACT FROM AUTHOR]

The age, growth, and fertility of two populations of Ablepharus bivittatus in the Talysh Mountains are presented. Altogether, 59 individuals were studied from two localities in the Ardabil Province, Iran, one being the village of Khanegah-e-Oliya in Namin region and the other the village of Majara in Khalkhal region. The age of the lizards was determined using skeletochronology. The average age in females was 3.6 ± 1.15 years (maximum of six years), in males 2.6 ± 1.24 (maximum of five years). The sections of tubular bones of many individuals were noted to have lines of arrested growth corresponding to hibernation and aestivation. Lizards grow intensely during the first three years of life, but then their growth slows down. Animals in the age groups of three years and older do not differ in body length. The age of pregnant lizards is 2–5 years, on average, 3.7 ± 0.91 years. The fertility of females does not depend on age. [ABSTRACT FROM AUTHOR]

Terentiev's frog (Pelophylax terentievi) is one of the least studied representatives of the genus. The results of studying the age structure and growth of this species based on skeletochronology, as well as the results of fertility assessment, are presented for the first time. Altogether, 36 specimens from the vicinity of Shahritus, Khatlon region, southern Tajikistan were studied. In all individuals, lines of arrested growth were found in the cross sections of bones. The age averaged 3.5 ± 0.98 years in females compared to 4.1 ± 1.38 years in males, and the maximum age was five and six years, respectively. Adult females and males did not differ in body length, but the former were able to reach a longer body during their lifetime (SVLmax is 99.16 mm for females and 62.84 mm for males), while their growth coefficient (k) was significantly lower than that of males (0.182 and 0.549, respectively). Females were characterized by lower rates of estimated survival (S is 0.72 in females and 0.77 in males) and life expectancy (ESP is 4.11 years in females and 4.86 years in males). Frogs reach sexual maturity at the age of three or four years, and their absolute fertility is 138–3317 eggs per female. [ABSTRACT FROM AUTHOR]

Aim: Physiological and metabolic performance are key mediators of the functional response of species to environmental change. Few environments offer such a multifaceted array of stressors as high‐altitude habitats, which differ markedly in temperature, water availability, UV radiation and oxygen pressure compared to low‐altitude habitats. Species that inhabit large altitudinal gradients are thus excellent models to study how organisms respond to environmental variation. Location: Tenerife island, Canary Islands archipelago (Spain). Taxon: Tenerife lizard (Gallotia galloti, Lacertidae). Methods: We integrated data on age structure, thermal and hydric regulatory behaviour and four metabolic and stress‐related biomarkers for an insular lizard that inhabits an extreme altitudinal range (sea level to 3700 m a.s.l.), to understand how an ectotherms' age, ecophysiology and metabolism can be affected by extreme environmental variation. Results: We found marked differences in metabolic stress markers associated with altitude (particularly in the abundance of carbonyl metabolites and relative telomere length), but without a linear pattern along the altitudinal cline. Contrary to expectations, longer telomeres and lower carbonyl content were detected at the highest altitude, suggesting reduced stress in these populations. Evaporative water loss differed between populations but did not follow a linear altitudinal gradient. Lizard age structure or thermal physiological performance did not markedly change across different altitudes. Mixed signals in life‐history and thermal ecology across populations and altitude suggest complex responses to variable conditions across altitude in this species. Main Conclusions: Our integrative study of multiple functional traits demonstrated that adaptation to highly divergent environmental conditions in this lizard is potentially linked to an interplay between plasticity and local adaptation variably associated with different functional traits. [ABSTRACT FROM AUTHOR]

Simple Summary: Knowledge of life history traits is crucial for understanding population dynamics, biodiversity declines, and conservation management decisions. Here, we quantified the age structure and body size of the plateau brown frog (Rana kukunoris) in the Jiuzhaigou National Nature Reserve (JNNR), providing the first data about the life history traits of this species in this region. Subsequently, we compared the maximum longevity, age at sexual maturity (ASM), average age, and average snout–vent length (SVL) with those of 28 reported populations, and we examined the climatic influences on these four key life history traits. Notably, the maximum longevity in the JNNR population is 8 years, reaching the reported maximum longevity of this species. As elevation increases, the average age and ASM also increase. However, the average SVL initially increases before decreasing when above an elevation of 3000 m, which does not support Bergmann's rule. Climatic factors, particularly temperature and UV-B, have discriminative effects on the life history variations of R. kukunoris. Our results will contribute to a deeper understanding of the diverse life history strategies and the related driving forces within a species. Jiuzhaigou National Nature Reserve (JNNR) is a renowned World Biosphere Reserve and UNESCO-designated World Nature Heritage Site. The age structure and body size of a population are crucial for assessing the quality of habitats in which a population lives and are essential for the vertebrate conservation and management, especially for amphibians. Unfortunately, information about the life history traits of amphibians is currently unavailable in JNNR. Herein, we first estimated the age structure and body size of Rana kukunoris, which is endemic to the Eastern Qinghai-Xizang Plateau. Then, we compared our data with 28 reported populations along an elevation gradient (1797–3450 m) and investigated how life history traits respond to climatic variations. Our results indicated the following: (1) For individuals from JNNR, the maximum longevity is 8 years, age at sexual maturity (ASM) is 2 years, suggesting a favorable ecological environment in JNNR. Notably, females are significantly larger than males due to the age factor. (2) The average age and ASM show a positive correlation with elevation. However, when the elevation exceeds 3000 m, the average SVL initially increases and then decreases due to the harsh environmental conditions at higher elevation. (3) Temperature and/or UV-B have a significant impact on the average age, ASM, and average SVL variations of R. kukunoris, suggesting adaptive potential of this species via life history variations in light of environmental changes. These accounts provide antecedent information about the life history traits of amphibians in JNNR, and provide insights into the driving factors of the life history variations of the plateau brown frog. [ABSTRACT FROM AUTHOR]

Using skeletochronology, we assessed the relationships of age and body size (SVL) in individuals from a population of the agile frog Rana dalmatina near the village of Özyurt, North-western Türkiye. The mean age and SVL of adult frogs were 4.50 ± 0.38 years and 61.54 ± 1.31 mm (6.46 ± 0.33 years and 67.86 ± 1.00 mm in females and 3.00 ± 2.71 years and 56.70 ± 1.26 mm in males, respectively). Intersexual differences in body size were female-biased (SSD = 0.196) while the age ranged between 4-8 years in females and 2-6 years in males. There was a positive correlation between body size and age (i.e., larger frogs were older) in both female and male individuals of this species. [ABSTRACT FROM AUTHOR]

Bufo verrucosissimus is an endangered species in the Russian Federation. One of the largest protected areas where B. verrucosissimus is preserved is the Caucasian State Nature Biosphere Reserve. The paper presents data on age structure and growth of B. verrucosissimus collected in the Caucasian State Nature Biosphere Reserve in 1987–1990 and stored in the collection of Sochi National Park. The age of 16 females and 51 males was determined using the method of skeletochronology. The age of adult females was 6–10 years (on average 7.9 years), and males 2–9 years (on average 5.8 years). Females were statistically significantly superior to males in average age. In terms of body length, significant differences between males and females where noted in groups of seven- and ten-year-old animals. The body length of studied animals (60.8–116.4 mm for females and 61.2–86.3 mm for males) corresponds to the size of adult toads from other localities in the North Caucasus. Females grow evenly throughout their lives, while the growth of males slows down significantly after reaching puberty. Males were able to reach the maximum body length faster than females (the growth coefficient was 0.722 for males and 0.163 for females). According to the von Bertalanffy equation, the maximum possible body length was 130.9 mm for females and 74.6 mm for males.

Knowing the age of individuals in a population is crucial to devise appropriate conservation strategies, especially on endangered long-lived species such as sea turtles. Sea turtles do not have external morphologic characters that indicate their age; therefore, age has been estimated by indirect methods such as biometric measurements or skeletochronological analysis. Previous skeletochronological studies have determined that sea turtle age can be estimated with skeletal growth marks (GMs) produced by annual seasonality. This study focused on the skeletochronological analysis of known-age loggerheads reared under seminatural conditions, showing that sea turtles kept under natural photoperiod and seawater temperature seasonality and fed periodically, did not present visible GMs. However, the animals suffering health problems affecting their growth did exhibit GMs. This suggests that skeletochronological studies in sea turtles must be taken with caution at least at early life stages and for the northeast Atlantic loggerhead population. Additionally, this study showed that seawater temperature seasonality strongly influences sea turtles' growth rates. [ABSTRACT FROM AUTHOR]

Central European water frog Pelophylax esculentus is a hybrid that lives sympatrically and forms genetic systems with one of its parental species, in this case L-E (P. lessonae - P. esculentus). Hybrids are restored in each generation due to hybridogenesis, a unique mode of hemiclonal reproduction. We investigated changes in the species composition, mate choice, and genome transmission in naturally formed pairs in the L-E hybridogenetic system from the Raków fish pond complex (SW Poland). Our observations showed that the genetic system remained the same for over a decade but the share of the taxa and the sex ratios within the species changed. The frequency of P. lessonae decreased by about 20% in favor of P. esculentus. The proportion of males to females of P. lessonae increased twofold and of P. esculentus fourfold. We also found that the stability of the L-E population was ensured by a specific female mate choice pattern with the dominance of homotypic P. lessonae and heterotypic ♀P. esculentus × ♂P. lessonae pairs (almost 90% of the pairs collected from nature). The youngest females and males that formed a successful amplexus were 3 years old. We noted a male-male competition manifested by the exclusion of young males (before the third hibernation) from the participation in the mating. An analysis of genome transmission to gametes revealed that females P. lessonae transmitted Lx, while P. esculentus transmitted the Rx and/or Lx genomes. Males of P. lessonae transmitted the Lx or Ly genomes, while P. esculentus transmitted the Lx, Ly, and/or Rx genomes. The high proportion of the L genomes transferred to gametes enables both the restoration of the parental species P. lessonae and the regular renewal of a new generation of hybrids. Significance statement: Central European water frog complex includes two species: Pelophylax ridibundus (genotype RR) and P. lessonae (LL), and their natural hybrid, P. esculentus (RL). Hybrid individuals of both sexes reproduce due to a specific mode of reproduction, i.e., hybridogenesis, in which hybrids eliminate one of the parental genomes (R or L) from the germ line prior to meiosis and transmit the other one (not recombined, i.e., clonal) to the gametes. The hybrids live in mixed populations with one of the parental species and are restored in each generation. This, in turn, allows a kind of balance to be maintained in a population due to specific mate choice and genome transmission. Our research showed that the stability of the studied population was ensured by female preference to P. lessonae and male-male competition manifested by the exclusion of males under 3 years of age from the participation in the mating. [ABSTRACT FROM AUTHOR]

Simple Summary: The Asian common toad Duttaphrynus melanostictus represents a serious threat to the biodiversity of Madagascar, where it was introduced in around 2010. Here, we study some traits of its life history, including its body size, age structure, and age at sexual maturity based on individuals sampled at different sites of Toamasina, on the east coast of Madagascar, in 2016, 2018, and 2019. The individuals studied here were larger, although no longer-living, with respect to individuals of the native populations in SE Asia. In the invasive population of Madagascar, the males were significantly smaller and younger than the females when data from different sites were pooled. However, when data are analyzed separately, this was true only for one site. The maximum age ascertained in this study is 3 years in males and 6 years in females. Males and females reach sexual maturity after the first and second year of age, respectively. Further studies on the life history traits of the population of D. melanostictus in Madagascar can be relevant for the management of this invasion as well as to better understand the biology of the species. We analyzed the body length, age structure, and age at sexual maturity of the invasive Asian common toad Duttaphrynus melanostictus from different sites in Toamasina, east Madagascar. We used skeletochronology as a proxy for age estimation, while gonads were histologically analyzed to determine the age of sexual maturity. The analysis of pooled age data from three sites investigated in 2016 showed that both sexes were larger, although not older, than those of native populations. For the individuals from Madagascar, the males were significantly smaller and younger (mean ± SD, SVL: 71.4 ± 1.6 mm; age: 1.8 ± 0.7 years) than the females (SVL: 78.42 ± 1.9 mm; age: 2.7 ± 1.3 years), when the data were pooled, but when the data were analyzed separately for each of the three sites, similar results were obtained only for one site. The oldest recorded male and female were 3 and 6 years old, respectively. Gonadal histology showed that the males and females reach sexual maturity after the first and second years of age, respectively. Further studies are needed to understand if the larger size and faster growth rates observed in the invasive population of D. melanostictus in Madagascar are a consequence of more favorable environmental conditions with respect to the native range (e.g., the availability of larger trophic niches, a lack of competitors, and lower predatory pressure), and we suggest to extend the monitoring of these life history traits to understand how they might influence the invasion. [ABSTRACT FROM AUTHOR]

Knowledge of life history is important for understanding population ecology. The genus Diploderma is one of the most diverse genera in the family Agamidae, and no data on the life history traits of Diploderma species have been reported to date. Here, the age and growth of a population of D. micangshanense were revealed using skeletochronology for the first time. Females have greater snout-vent length (SVL) than males, but the mean SVL did not significantly differ between the sexes. Age ranged from one to four years in both sexes, and mean ages were 2.24 ± 0.10 years for males and 2.28 ± 0.12 years for females. No significant sexual differences were detected in either age structure or mean age. Age and body size were significantly positively correlated in both sexes. The growth coefficient k (males: 0.510; females: 0.441) and growth rate (males: 4.33 ± 0.38; females: 4.91 ± 0.39) were similar in both sexes. These results have implications for the population dynamics and management of this species. [ABSTRACT FROM AUTHOR]

In this study, comparison of body size and age structure of two populations of Lissotriton schmidtleri from two different altitudes (Efes, 5 m and Karagöl, 816 m a.s.l.) was carried out. We applied phalangeal skeletochronology to obtain the age of adults by counting the lines of arrested growth (LAGs) in phalangeal cross-sections. Female-biased sexual dimorphism was observed in both populations. Both male and female individuals in Efes and Karagöl populations reached sexual maturity at the age of 2. The maximum age or longevity was calculated as 10 years in males and 8 years in females. Considering all individuals, Karagöl population was found to be older than Efes population. For both populations, a significant positive correlation was found between age and size in males and females. [ABSTRACT FROM AUTHOR]

In this study, we described age structure, body size, body mass and the relationships among these parameters for a population of P. caucasicus from Lake Borçka Karagöl, Artvin, Turkey. The mean SVL with standard error was 45.87 mm ± 0.55 (range: 39.98-50.28 mm) and the mean weight with standard error 8.81 g ± 0.39 (range: 6.10-11.47 g) in females whereas 48.16 mm ± 0.45 (range: 43.64-54.78 mm) and 11.32 ± 0.25 (range: 9.56-14.80 g) in males, respectively. We found a significant male-biased difference reflecting sexual dimorphism and statistically significant positive relationships between these variables. According to the results, the age ranged between 2-5 years in females and 2-6 years in males. The mean age distributions significantly differed between the sexes (females: 3.28 years ± 0.19; males: 3.94 years ± 0.20). The mean ages and maximal ages were found identical to the previously reported results from Turkey, but the mean ages were higher than in Georgian populations. Von Bertalanffy growth models demonstrated similar curves, and the growth rate was faster up to 3 years in both sexes. To conclude, this study was the first to determine age structure and growth patterns in Borçka Karagöl population and weight data for P. caucasicus was presented for the first time in the literature. [ABSTRACT FROM AUTHOR]

Here we examine the tibial microstructure of modern and fossil angulate tortoises to assess the histology and growth from the late Miocene–early Pliocene, Pleistocene through to modern forms. The cross-sections of all the tibiae sampled revealed highly vascularized, uninterrupted, fibrolamellar bone tissue during early ontogeny, which suggests that early growth was fast. However, later in ontogeny, growth was slower, as indicated by the deposition of parallel-fibred bone tissue in the outer cortex, and even ceased periodically, as indicated by lines of arrested growth. Comparative analyses of the growth rates of the tortoises from different time periods showed that the tortoises from the late Miocene–early Pliocene Langebaanweg locality and from Diepkloof Rock Shelter had relatively slower growth rates under less optimal growth conditions. Additionally, these prehistoric specimens show extensive remodelling, and several generations of secondary osteons further suggest functional and/or metabolic stresses on the skeleton. Palaeoenvironmental reconstructions suggest that it was mostly cooler and drier with seasonal fluctuations in late Miocene–early Pliocene, and it is likely that Chersina responded to these conditions by having a lower rate of growth as compared with their modern counterparts, which thrive in the current prevailing more favourable Mediterranean type of climate.

Skeletochronology is a reliable method for estimating the age and growth rate of many ectothermic vertebrates, including amphibians. The Levant green frog, Pelophylax bedriagae (Ranidae), is a relatively large frog distributed in the western and northern parts of Iran. The age structure of Pelophylax bedriagae was determined by examining 52 females and 39 males collected from Kohgilouyeh and Bouyerahmad Provinces (Yasouj and Basht). The age range of the two populations is three to 10 years. The maximum age for males and females is 10 and eight years, respectively. The highest age distribution for males is six years (17.6%) and four and six years (15.4%) for females. On average, males (6.2±1.4 years) are older than females (5.2±1.3 years). Male and female body size is correlated with age within both populations. However, despite being significantly different in average body size, the average age of the two populations (Yasouj vs. Basht) is not significantly different. [ABSTRACT FROM AUTHOR]

Age estimation of the juvenile stage of Varanus salvator bivittatus using limb bones, namely the big long tubular bones (femur, tibia, humerus) and the small long tubular bones (fibula, radius, ulna, phalanx), was performed using the skeletochronological method. Samples were from Java Island, Indonesia and provided by the pet exporters. Lines of arrested growth (LAG) were present and the first growth mark was visible on a female with a snout-vent length (SVL) of 18.8 cm, and a male with SVL of 19.3 cm. The process of resorption begins in the juvenile stage, and resorption occurs in all long tubular bones. Inside the big long tubular bones, resorption begins earlier and is more extensive than in the small long tubular bones, and in one individual with SVL 25.0 cm, the endosteal bone had completely eroded in all big tubular bones. Resorption also occurred in the small long tubular bones; however, on one individual with an SVL of 25.0 cm, the remaining endosteal bone was still visible only in fibula bone. Linear regression analysis resulted in a weak correlation, statistically insignificant between the SVL and the diameter of the marrow cavity (d) in the fibula bone, while in other bones the correlations were strong and statistically significant (p < 0.005). Among seven tubular bones, the resorption rate in the fibula bone was the lowest but very high in the phalanx bone. Radial osteon formation has occurred in the smallest individual with SVL 14.4 cm to the biggest one with SVL 25.0 cm, and radial osteon density increases with increased SVL. There was no radial osteon in fibula and phalanx bones in any sampled specimen. In general, there were no significant differences in bone diameter (D), marrow cavity diameter (d) and bone thickness (MP) in all long tubular bones in both male and female individuals, and the density of radial osteon on some tubular bones was influenced by body length, but not by sex. [ABSTRACT FROM AUTHOR]

Parasites can directly affect host survival by causing cryptic costs that may occur in species when mortality does not take place or is less evident. Costs can be present in differently life history stages or age cohorts or cause age-dependent effects. Here we investigate the effects of chytridiomycete fungus Batrachochytrium dendrobatidis , (Bd), that causes one of the main infectious diseases implicated in numerous mass mortalities and population declines in the class of Amphibia, including in one of the rarest and most threatened salamander in Europe, the endemic Sardinian brook newt Euproctus platycephalus. This species is known to be infected by Bd since 2006, without evident direct cost or mass mortality events being observed. During 5 years of sampling (2007-2011), we captured 273 newts in the main infected area of the Limbara Mountain in the North of Sardinia, and, through epidemiological and age analyzes, we assess that Bd directly affected juvenile recruitment, and it is related to difficulties in the development of the species, with an impact on the females growth. [ABSTRACT FROM AUTHOR]

Knowledge on life history traits and population dynamics of amphibians from northeastern Anatolia is limited. This results in a heavy reliance on published data regarding the European and Caucasian counterparts of the Anatolian populations in local conservation studies. The present study evaluated the phenology, age structure, population size, and population structure of the amphibian community in Lake Çıldır, northeastern Anatolia, Turkey. The site was surveyed between April 2017 and July 2019, detecting the presence of Bufo verrucosissimus, Bufotes viridis sitibundus, Pelophylax ridibundus, and Rana macrocnemis. The estimated population size ranged from 553 to 789 individuals for P. ridibundus and from 404 to 655 individuals for R. macrocnemis. The estimated mean capture probability was 0.09-0.10 for P. ridibundus and 0.08-0.11 for R. macrocnemis. The mean survival rates were estimated at 0.40-0.60 for P. ridibundus and 0.24-0.56 for R. macrocnemis. A male-biased sex ratio was observed for all species. The mean age was estimated at 5.28 years (2-9) for P. ridibundus, 4.32 years (2-6) for R. macrocnemis, and 5.55 years (3-9) for B. viridis sitibundus. Depending on weather conditions, the amphibian species emerged from brumation in the second half of April, and the breeding period took place between the end of April and June. The metamorphosis was attained in 55-125 days for P. ridibundus, 44-124 days for R. macrocnemis, and 56-128 days for B. viridis sitibundus, depending on weather conditions. The amphibian community of Lake Çıldır comprises healthy frog and toad populations, whose primary threats appear to be weather fluctuations and climate change. In contrast to their western Anatolian conspecifics, the studied amphibians suffered limited habitat loss and degradation, rendering them effective candidates as indicator species for climate change studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding variations in the morphology and age of animals along a geographical gradient may aid in our comprehension of the evolution of these animals. In this view, we studied variation in the age and body size of Andrew's toad (Bufo andrewsi) across 31 populations along a geographical gradient. The results revealed that along with a decrease in the annual mean temperature, the age structure increased, whereas body size did not indicate an increasing trend, showing no support for Bergmann's rule. Precipitation seasonality negatively correlated with longevity and mean age, whereas precipitation of the driest month positively correlated with body size. Moreover, we also found that UV-B seasonality positively correlated with age structure traits and body size. The present study provided critical cues that explain the considerable variability observed in the ecogeographic patterns among Andrew's toads. Environmental variation likely modifies the life-history traits of vertebrates. As ectothermic vertebrates, it is possible that the body size of amphibians is impacted by environmental conditions. Here, we firstly quantified age and body size variation in the Andrew's toad (Bufo andrewsi) across the Hengduan Mountains. Then, we examined the environmental correlates of this variation based on the literature and our unpublished data on the age and body size of the Andrew's toad from 31 populations distributed in southwestern China. Although our analysis revealed significant variations in age and body size across B. andrewsi populations, neither latitude nor altitude correlated with this variability in age and body size. We found that age at sexual maturity, mean age, and longevity increased with decreasing annual mean temperature, whereas age at sexual maturity increased with decreasing temperature seasonality, implying that temperature was a crucial habitat characteristic that modulated age structure traits. Moreover, we revealed positive associations between age structure and UV-B seasonality, and negative relationships between both mean age and longevity and precipitation seasonality. We also found that body size increased with increasing precipitation in the driest month and UV-B seasonality. However, body size did not covary with temperature, signifying no support for Bergmann's rule. These findings help us to understand amphibians' abilities to adapt to environmental variation, which is particularly important in order to provide a theorical basis for their conservation. [ABSTRACT FROM AUTHOR]

Habitat conditions drive the growth rate and the age structure of near-threatened species of Caucasian parsley frog (Pelodytes caucasicus). We studied the age structure and the growth parameters of the Caucasian parsley frogs obtained from four regions of Anatolia, that is, Giresun, Trabzon, Rize, and Artvin. Our results revealed a lower growth rate among the frogs residing in anthropogenic areas (Cımbırtlık, Giresun; Çat, Rize) compared to those living in the conservative areas (Hıdırnebi, Trabzon; Karagöl, Artvin). Also, the lowest values for age structure and the snout-vent length (SVL) were found in anthropogenic areas. Since P. caucasicus is categorized as "Near-Threatened" by the International Union for Conservation of Nature (IUCN) and the Red Data Books of some countries, we must manage protected areas and plan future conservation action for this species. [ABSTRACT FROM AUTHOR]

Some life-history traits (e.g. body size, SSD and age) of the Danford's lizard Anatololacerta danfordi were studied applying skeletochronology techniques to the phalangeal bones (n = 33). The mean of the snout-vent-length (SVL) was 59.02 ± 1.07 mm in females and 62.17 ± 1.38 mm in males. The mean SVL was not significantly different between sexes. Sexual size dimorphism was weakly expressed in the slightly bigger SVL of the males (SDI = -0.053). Sexual maturity was attained between the second and the fourth year of life in both sexes. The age ranged from 2 to 6 years in females and from 3 to 8 years in males. The means of age were 4.29 ± 0.31 LAGs in female specimens and 4.63 ± 0.37 LAGs in male specimens. The mean age was not significantly different between the sexes. [ABSTRACT FROM AUTHOR]

Jiuzhaigou National Nature Reserve (JNNR) is a renowned World Biosphere Reserve and UNESCO-designated World Nature Heritage Site. The age structure and body size of a population are crucial for assessing the quality of habitats in which a population lives and are essential for the vertebrate conservation and management, especially for amphibians. Unfortunately, information about the life history traits of amphibians is currently unavailable in JNNR. Herein, we first estimated the age structure and body size of Rana kukunoris, which is endemic to the Eastern Qinghai-Xizang Plateau. Then, we compared our data with 28 reported populations along an elevation gradient (1797–3450 m) and investigated how life history traits respond to climatic variations. Our results indicated the following: (1) For individuals from JNNR, the maximum longevity is 8 years, age at sexual maturity (ASM) is 2 years, suggesting a favorable ecological environment in JNNR. Notably, females are significantly larger than males due to the age factor. (2) The average age and ASM show a positive correlation with elevation. However, when the elevation exceeds 3000 m, the average SVL initially increases and then decreases due to the harsh environmental conditions at higher elevation. (3) Temperature and/or UV-B have a significant impact on the average age, ASM, and average SVL variations of R. kukunoris, suggesting adaptive potential of this species via life history variations in light of environmental changes. These accounts provide antecedent information about the life history traits of amphibians in JNNR, and provide insights into the driving factors of the life history variations of the plateau brown frog.

Ontogeny, temporal strategies and the reproductive cycle are basic aspects of a species' life history and can provide us with information about the current status and future trends of a population. Here, we present data on reproductive biology, influence of environmental factors on male and female reproductive parameters and intra- and interspecific comparisons regarding these parameters, as well as unpublished data on age at sexual maturity and longevity of the syntopic and phylogenetically close frogs Physalaemus cuvieri – dog frog –, Physalaemus riograndensis – Rio Grande frog – and Pseudopaludicola falcipes – Hensel's swamp frog –, in southern Brazil. Accordingly, we used morphoanatomical and histological analyses, whose results were associated with climatological environmental variables (temperature, rainfall, relative humidity and photoperiod). Our results indicate that although they are phylogenetically close and that they co-occur in reproductive environments, the species differ in terms of reproductive cycle and in how environmental variables affect reproductive parameters between the sexes: photoperiod was the most important environmental factor for males and females of P. falcipes , while air humidity was more important for P. cuvieri. The age aspects also varied between the species, where sexual maturity was reached later in the Physalaemus species and the greatest longevity recorded for P. cuvieri. In addition, we found that there was intersexual and interspecific variation in the patterns measured, reflecting intrinsic differences in reproductive strategies and modes. Such studies are of paramount importance, as they serve as a basis for further research, in addition to allowing comparisons and/or possible generalizations about the evolutionary meaning of reproductive strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: Amphibians have weak dispersal abilities and are sensitive to environmental changes, resulting in their disproportionately high risk of extinction, with many species' populations rapidly declining. Therefore, it is critical for amphibian conservation to understand their adaptive potential by exploring how amphibians respond to environmental changes based on morphological variations. Our results showed that morphological traits of Feirana taihangnica significantly differed among ages. Along with the increase in annual mean temperature, snout-vent length showed an anti-hump trend, indicating no support for Bergmann's rule. Mean ultraviolet-B of the highest and lowest months were positively and negatively correlated with head width, thigh length and tibia width, respectively. The present study can help understand the effects of environmental changes on morphological variations of this mountain frog species and its adaptive potential, providing important implications for species conservation. The Taihangshan swelled-vented frog (Feirana taihangnica), an endemic species to the Qinling Mountains, central China, has experienced a dramatic population decline over the last few decades. The aim of this work was to quantify morphological variation in F. taihangnica across the Qinling Mountains and examine environmental correlates of this variation of morphological traits. We implemented a hierarchical partitioning to estimate the independent contribution of each environmental variable on morphological variations. Temperature seasonality was the greatest contributor in variations of snout-vent length (SVL) and head width, and ultraviolet-B (UV-B) radiation of the lowest month was the most influential on both thigh length and tibia width. Then, we used generalized additive models to analyze the relationship between each environmental factor and morphological trait variations. Along the increasing of annual mean temperature, SVL decreased firstly and then increased, indicating no support for Bergmann's rule. Furthermore, SVL was negatively correlated with annual precipitation, while positively with temperature seasonality. The mean UV-B of the highest and lowest months was positively and negatively correlated with head width, thigh length and tibia width, respectively. The results of this study help us to understand adaptive potential of this mountain frog species via morphological variations in the light of environmental changes. [ABSTRACT FROM AUTHOR]

Individual age and population age composition are the major concerns of ecologists, evolutionary biologists and conservation biologists. In amphibians, skeletochronology—counting the number of lines of arrested growth deposited in the bone tissue, is the dominant method to determine actual age of an individual. Since 1970s, age data of the ectothermic taxa have been accumulated and increasingly used in comparative studies. Here we make a global assessment for the availability of the data, based on a collection of 369 published papers. For a specific species, more males than females were sampled. Among the extant 8146 amphibian species, only 266 (3.3%) have been skeletochronologically investigated. Of these studied species, 2 (0.9% of 214) belong to caecilians, 56 (7.6% of 740) salamanders and 208 (2.9% of 7192) anurans. A complete paucity of data was seen in 80%, 50%, and 54% of families in the corresponding orders. More temperate species than tropical species were sampled, while the proportion of Palearctic species studied was higher than that in the other 5 biogeographical realms. Species inhabiting semi‐aquatic niche were more likely to be studied than fossorial or plant dwellers. Age information of multiple populations (2–48) was available for species with a broad distribution, accounts for 61% of salamander and 43% of anuran species studied. Because these gaps in demographic knowledge can limit our understanding of questions ranging from life history evolution, population dynamics to conservation, we encourage herpetologists to pay more efforts on filling them. [ABSTRACT FROM AUTHOR]

Loggerhead turtles, Caretta caretta, born on the nesting beaches of the Northwest Atlantic Ocean (US eastern coast) undertake a transoceanic migration immediately after birth, traveling eastward in association with the Gulf Stream and reaching the coasts of Europe and northwestern Africa when two or three years old and 20-30 cm in curve carapace length. Once there, they may remain in the eastern Atlantic or enter the Mediterranean Sea before eventually returning to the western Atlantic several years later. However, the timing of entry into the Mediterranean and the length of the period spent inside are poorly known. To study this, skeletochronology was combined with the analysis of the stable isotope ratios of oxygen (δ 18 O), carbon (δ 13 C) and nitrogen (δ 15 N) in the cortical bone of the humerus of 31 juvenile loggerhead turtles of Northwest Atlantic origin found dead stranded in the Balearic Islands. Incremental bone layers were sampled to assess changes in habitat through the movement across isotopically distinct water masses and the existence of any ontogenetic change in the diet. Although the incremental layers corresponding to the very first years of live were missing in all individuals, the wide range of δ 18 O values of the remaining layers suggested that these juveniles moved between water masses differing in salinity, from the eastern Atlantic, the western Mediterranean, and the much saltier eastern Mediterranean, without any consistent temporal pattern. Nevertheless, upon reaching ten years old, loggerhead turtles seem to settle in low salinity areas of the western Mediterranean, such as the Algerian Basin or the Alboran Sea, likely preparing for their return towards their natal beaches in the Northwest Atlantic. Finally, the changes observed in the δ 13 C and δ 15 N values were small, suggesting only minor ontogenetic changes in their diet throughout the analysed life stages., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Luis Cardona reports financial support was provided by Ministerio de Ciencia, Innovación y Universidades, Spain. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Courtship acoustic displays in anuran amphibians are energetically costly and risky, but have a major role in mating success since they encode relevant information regarding the caller’s identity and status. Age and size are essential traits shaping fitness, reproductive success and life-history strategies, and thus are expected to also have a role in courtship displays. We tested this assumption in a species of nest-building frogs, Leptodactylus bufonius, in northern Argentina. We conducted the first detailed quantitative description of the males’ mating calls and assessed the effects of biological traits (i.e., body size parameters and individual age) and local climate (i.e., air temperature and humidity) on the main acoustic features of these calls (i.e., call duration, inter-call duration, dominant frequency, and dominant frequency modulation). The calls were short (mean ± SE, 0.163 ± 0.004 s), whistle-like, single notes with harmonic structure. The dominant frequency (1381.7 ± 16.2 Hz) decreased with arm length (χ2 = 5.244, df = 1, p = 0.022) and had an upward modulation (456.4 ± 11.0 Hz) which increased with age (χ2 = 4.7012, df = 1, p = 0.030). Call duration and dominant frequency were the most static parameters at intra-individual level, indicating their role in individual recognition. Temperature and humidity shaped the temporal acoustic parameters, and the dominant frequency. Our findings suggest that the acoustic features of the mating calls in amphibians could promote female mate choice in relation to both size and age and open up new questions for future research: are females more attracted to older males, and what are the specific costs and benefits? We suggest that mating calls may direct female preferences toward males of certain size and age classes, ultimately shaping the life-history strategies in a given population. Finally, we found discrepancies in the mating calls of L. bufonius recorded from Corrientes and those previously described from other populations, which suggests that multiple species may have been recorded under the same name.

We analyzed the body length, age structure, and age at sexual maturity of the invasive Asian common toad Duttaphrynus melanostictus from different sites in Toamasina, east Madagascar. We used skeletochronology as a proxy for age estimation, while gonads were histologically analyzed to determine the age of sexual maturity. The analysis of pooled age data from three sites investigated in 2016 showed that both sexes were larger, although not older, than those of native populations. For the individuals from Madagascar, the males were significantly smaller and younger (mean ± SD, SVL: 71.4 ± 1.6 mm; age: 1.8 ± 0.7 years) than the females (SVL: 78.42 ± 1.9 mm; age: 2.7 ± 1.3 years), when the data were pooled, but when the data were analyzed separately for each of the three sites, similar results were obtained only for one site. The oldest recorded male and female were 3 and 6 years old, respectively. Gonadal histology showed that the males and females reach sexual maturity after the first and second years of age, respectively. Further studies are needed to understand if the larger size and faster growth rates observed in the invasive population of D. melanostictus in Madagascar are a consequence of more favorable environmental conditions with respect to the native range (e.g., the availability of larger trophic niches, a lack of competitors, and lower predatory pressure), and we suggest to extend the monitoring of these life history traits to understand how they might influence the invasion.

Ponds in agricultural landscapes are often used by amphibians as breeding habitat. However, the characteristics of agricultural ponds and especially the surrounding area are usually said to be suboptimal for many amphibian species. Using suboptimal habitats might allow a species’ survival and reproduction, but can have negative consequences at the individual and population level. In the present study, we investigated Palmate Newt (Lissotriton helveticus) populations from an intensive wine-growing region in southern Germany and compared them with populations located in a nearby forested area in terms of biometric traits, age and genetic structure. By analyzing over 900 adult newts from 11 ponds, we could show that newts reproducing in forest ponds were larger than newts reproducing in agricultural ponds. We did not find differences in the newt age and growth rate between habitat types. Therefore, differences in the body size of newts might already existed in larvae and/or juveniles, what might be related to a lower habitat quality for larvae and/or juveniles in the agricultural landscape. Body mass, body condition and sexual dimorphic traits (length of the caudal filament and max. height of the tail) correlated with body size, but no additional effect of the habitat type was found. The analysis of microsatellites revealed a higher genetic diversity in forest ponds. However, no clear sign of inbreeding was observed in any agricultural population, suggesting some degree of gene flow between them. We conclude, that agricultural ponds can be suitable habitats for the Palmate Newt and that conservation effort should aim to preserve them. The observed effects on body size indicate the need to increase the quality of the aquatic and terrestrial habitat for early life stages of this newt species in agricultural landscapes. [ABSTRACT FROM AUTHOR]