Pelobates Syriacus Research Articles

Annual climatic fluctuations and short-term genetic variation in the eastern spadefoot toad

In addition to variations on the spatial scale, short- and long-term temporal variations, too, can impose intense selection on the overall genetic diversity and composition of a population. We hypothesized that the allelic composition in populations of the eastern spadefoot toad (Pelobates syriacus) would change among successive years in accordance with the short-term changes in environmental conditions. Surprisingly, the effect of short-term climate fluctuations on genetic composition have rarely been addressed in the literature, and to our knowledge the effect of annual climatic fluctuations have not been considered meaningful. Our findings show that climatic variation among successive years, primarily the amount of rainfall and rainy days, can significantly alter both microsatellite allelic composition and diversity. We suggest that environmental (i.e. fluctuating) selection is differential across the globe, and that its intensity is expected to be greatest in regions where short-term climatic conditions are least stable.

Early Pleistocene amphibians and squamates from Copăceni (Dacian Basin, southern Romania)

This paper describes an Early Pleistocene amphibian and squamate assemblage from the Dacian Basin, southern Romania. The fossil sample allows for the identification of a moderately diverse assemblage, which includes representatives of 13 genera of the families Salamandridae (Lissotriton vulgaris, Triturus sp.), Bombinatoridae (Bombina sp.), Hylidae (Hyla aff. Hyla arborea), Bufonidae (Bufo bufo), Pelobatidae (Pelobates syriacus), Ranidae (Ranidae indet., Pelophylax sp., Rana ?temporaria, Rana sp.), Lacertidae (Lacertidae indet.), Anguidae (Pseudopus sp.), Natricidae (Natrix natrix), and Colubridae (Coronella austriaca, Zamenis longissimus). The taxonomic composition of the Early Pleistocene amphibian and squamate assemblage from Copăceni is similar to the one reported from other Romanian sites of the same age, and also to that of Recent Romanian herpetofaunas. The amphibian and squamate assemblage from Copăceni supports the existence of a permanent freshwater body, of neighbouring forests or shrubberies, and thick soil, in an Early Pleistocene climate that was warmer than the present one.

Sexual dimorphism in digit length ratios of the second to fourth digits (2D:4D) in two species of green toads (Pelobates syriacus Boettger, 1889 and Bufo viridis (Laurenti, 1768))

Sexual dimorphism in digit length ratios of the second to fourth digits (2D:4D) in two species of green toads (Pelobates syriacus Boettger, 1889 and Bufo viridis (Laurenti, 1768))

Out of the ground: two coexisting fossorial toad species differ in their emergence and movement patterns

Understanding the way species with similar niches can coexist is a challenge in ecology. The niche partitioning hypothesis has received much support, positing that species can exploit available resources in different ways. In the case of secretive species, behavioural mechanisms of partitioning are still poorly understood. This is especially true for fossorial frogs because individuals hide underground by day and are active only during the night. We investigated the nocturnal activity and tested the niche partitioning hypothesis in two syntopic fossorial spadefoot toads (Pelobates fuscus and Pelobates syriacus) by examining interspecific variation in emergence from the soil. We employed a night vision recording system combined with video tracking analyses in a replicated laboratory setting to quantify individual movement patterns, a procedure that has not been used until now to observe terrestrial amphibians. Most individuals appeared on the surface every night and returned to their original burrow (about 60% of the times), or dug a new one around morning. There was a large temporal overlap between the two species. However, P. syriacus was significantly more active than P. fuscus in terms of total distance covered and time spent moving, while P. fuscus individuals left their underground burrow more frequently than P. syriacus. Consequently, P. fuscus adopted more of a sit-and-wait behaviour compared to P. syriacus, and this could facilitate their coexistence. The use of night video tracking technologies offered the advantage of individually tracking these secretive organisms during their nocturnal activity period and getting fine-grained data to understand their movement patterns.

New records of fire-bellied toad (Bombina bombina (Linnaeus, 1761)) and common spadefoot toad (Pelobates fuscus (Laurenti, 1768)) in Serbia

Species' distribution data are substantial basic for future research in the areas of systematics, ecology, biogeography and especially conservation biology. Rapid worldwide declines of amphibians have emphasized a need for more precise data about their distribution at the regional and national levels, especially in countries with poor distributional data (e.g. Margules et al. 2002). Regarding both the geographical location as well as the elevation gradient, the entire territory of Serbia is inhabited by amphibians. General distribution pattern of all Serbian amphibians has been published only recently (Vukov et al. 2013), but without precise locations. As concerned to Anuras, overview of precise distribution exists for only few species, e. g. Pelobates fuscus and Pelobates syriacus (Džukić et al. 2005, 2008), while for all other species of frogs and toads in Serbia, comprehensive and detailed distribution data are not available.

First record of Pelobates syriacus (Anura, Amphibia) in the early Pleistocene of Italy

Spadefoot toads (Pelobatidae, Anura) are rare in the Italian fossil record, being previously recorded only in the late Pliocene of Arondelli (Piedmont Region, northwestern Italy) and in the early Pleistocene of Pirro Nord P21 (Apulia, southeastern Italy). Here we describe for the first time abundant fossil remains of Pelobates syriacus from the lower Pleistocene fissure of Pirro Nord P13 (Apulia, southeastern Italy). These fossils shed new light on the palaeobiogeographical history of Pelobates in the Apennine Peninsula and are the first fossil evidence in Italy for P. syriacus, which currently lives in the southeastern Balkan Peninsula, Caucasus and the Middle East. This extralimital Italian occurrence suggests that P. syriacus has good dispersal abilities, when favourable conditions exist. Dispersal routes to reach the Apennine Peninsula during the early Pleistocene may have been favoured by a low level of the Adriatic Sea during a cold interval, furnishing a new habitat suitable for P. syriacus.

Life Cycle of Tree Frogs (Hyla savygnyi) in Semi-Arid Habitats in Northern Israel

The life cycle of tree frogs (Hyla savygnyi) in localities of various habitats in northern Israel in the Upper Galilee and Golan Heights (annual rainfall range of 500-1,000 mm) and the Hula Valley, ranging from 212 to 740 m above sea level (ASL), was studied. Tree frogs were observed around winter rain pools, springs and streams. Fifty-one different breeding places were monitored. Only ponds and springs having stable non-flowing water are used by tree frogs for reproduction and are where larvae can metamorphose. The male call in the breeding places attracts the female, who then comes to the male, and breeding occurs underwater. Breeding time in Israel varies according to location and geographical and ecological conditions. It takes place in March-April in northern Israel, the Upper Galilee, the Golan Heights and the Hula Valley. In various breeding places, larvae grow between April and June. Apparently tree frog larvae adapt to breeding places where stable water is found, such as in ponds or springs, but not to breeding places with flowing water such as streams or rivers. Various Anuran and Urodela larvae were found in the same breeding sites where the larvae of H. savygnyi were found, including Pseudepidalea Viridis, Rana bedriagae, Pelobates syriacus, Salamandra infraimmaculata and Triturs vittatus. Following metamorphosis, H. savygnyi adapt to terrestrial life in semi-arid habitats, and is found on plants or in hiding places under rocks and in holes to prevent dehydration particularly during hot and dry weather. The ability to change color helped the frogs to hide in various substrates. The rate of water loss of terrestrial H. savygnyi during dehydration is around 50% of body weight. Plasma osmolality increased from 200 mOsm/kg to about 450 mOsm/kg, which helped the tree frog to survive in semi-arid habitats.

Diversity, Threats, and Conservation of the Terrestrial and Freshwater Herpetofauna of Jordan

In this review, we identified the diversity of the freshwater and terrestrial herpetofauna of Jordan that consists of a total of 103 species of extant reptiles (100 species and subspecies) and amphibians (3 species). Two amphibian species became extinct within the past thirty years ( Triturus vittatus and Pelobates syriacus ). Four categories of threats affecting amphibians and reptiles were identified (Habitat loss and degradation, water issues, human disturbance and related activities, and legislations and public awareness) along with supportive examples for each category of threats. Key species that requires urgent protection includes Hemidactylus mindiae , Acanthodactylus ahmaddisii , Chalcides guentheri , Phoenicolacerta kulzeri khazaliensis , Lacerta media , Platyceps elegantissimus , Platyceps sinai , Telescopus hoogstraali , and Macrovipera lebetina due to their limited distribution, and Uromastyx aegyptia , Chalcides sepsoides , Scincus scincus meccensis , Trapelus persicus fieldii , and Testudo graeca due to habitat loss. The status of herpetofauna in Jordan is still far from being completely understood. Nevertheless, the lack of conservation measures and low public concern makes amphibians and reptiles extremely vulnerable in the near future.

Climate-induced shifts in the niche similarity of two related spadefoot toads (genus Pelobates)

Of the four species encompassing the genus Pelobates, only two overlap along a narrow contact zone, i.e., Pelobates fuscus and Pelobates syriacus. Our study investigated the shifts in niche similarity of these two closely related species from the Last Interglacial towards the end of the twenty-first century. We computed climatic suitability models using Maxent and projected them onto future and past climates. We used fossil occurrences to test the predictive accuracy of past projections. Niche similarity was assessed between the studied species using Schoener’s D index and a background similarity test. Finally, we evaluated niche differentiation by contrasting the species occurrences using a logistic regression analysis. The ecological niches are slightly extended outside the present geographical ranges in the Caucasus and the Balkans, south for P. fuscus and north and west for P. syriacus, suggesting that their present distribution is not at equilibrium with the climate. The Last Interglacial distribution of P. fuscus included British Isles and broad areas in western, central, and northern Europe, while P. syriacus extended northwards in the Balkans. The validation with fossil records revealed good predictive performance (omission error = 4.1 % for P. fuscus and 16.6 % for P. syriacus). During the Last Glacial Maximum, climatic suitability persisted in refugia in southern Europe, Pannonian Basin, and Caucasus for P. fuscus, and Israel, southern Balkans, and Caucasus for P. syriacus. Present potential distributions revealed a low similarity of species’ ecological niches, comparable with Last Interglacial, but projections towards 2080 revealed a sharp increase.

When Males Are Larger than Females in Ecthotherms: Reproductive Investment in the Eastern Spadefoot Toad Pelobates syriacus

The way animals allocate resources to growth and reproduction is of major importance in understanding life-history trade-offs. Because the investment in reproduction of the two sexes differs, comparing the costs and the reproductive strategies adopted offers an insight into the evolutionary forces that shaped them. In the Eastern Spadefoot Toad, Pelobates syriacus the males are larger than females in body length, but not in body mass. We studied the reproductive effort and output in a population of P. syriacus from the Danube Delta Biosphere Reserve (Romania), during two consecutive years (2010 and 2011). Body mass loss during mating and egg deposition in females averaged 27%, while in males it was 3.9%. Body mass loss in females was proportional with size, with larger females losing more weight than smaller ones. Initial body mass and body mass loss during reproduction were significantly correlated with clutch size, but egg size was not correlated to female size or body mass loss. Year had a significant effect on body size in both sexes, suggesting high plasticity and the effect of local environmental factors on growth and reproduction. Age of adults ranged between 2–12 years and did not differ significantly between sexes. A nonrandom, but not completely assortative, mating was observed, with the age and body size of paired animals slightly positively correlated, indicating an explosive breeder reproductive strategy.

CHROMATOPHORE STUDIES VIII. THE OCCURRENCE OF GIANT MELANOPHORES IN THE EPIDERMIS OF PELOBATES

ABSTRACT Multinucleate giant melanophores developed in the epidermis of hypophysectomized tadpoles of Pelobates syriacus after implantation of a hypophysis into the tail. These cells, containing from 2–6 nuclei and reaching a maximum length of 365μ, are more branched than normal cells and their surface is also always much larger than that of normal cells of equal age.

Genetic Variation among various populations of spadefoot toads (<i>Pelobates syriacus</i>, Boettger, 1869) at breeding sites in northern Israel

A genetic study was carried out on spadefoot toads (Pelobates syriacus) from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic variation based on five DNA polymorphisms and for RAPD PCR. The nucleotide sequences of the mitochondrial DNA fragments were determined from a 460 bp clone of cytochrome b and a 380 bp clone of 12S (GenBank accession numbers, FJ595199-FJ59-5203). No genetic variation was found among the populations with regard to 12S. According to the analysis of five sequences using Arlequin software, there was a high gene identity among the populations (98.7%-99.6%). Both populations, Elrom Pond breeding site, at the highest altitude and Fara Pond, at the lowest, had the lowest identities as compared to other populations. The DNA variation among P. syri-acus populations from various breeding sites, according to band sharing (BS), when using the OP-4 primer, was 0.92-1.00. Similarity was low between the population of Elrom Pond and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS), as well as between the population of Fara Pond at the lowest altitude, and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS). Similar results were obtained when comparing the results obtained using primer OPA-3. The lowest similarity was found between populations of the highest altitude (Elrom Pond) and lowest altitude (Fara Pond), relative to the other ponds (Kash Pond, Raihania Pond and Sasa Pond) with a BS of 0.93.

Changes in the blood composition of some anurans

We examined some hematological parameters (red blood cell count, white blood cell count, haemoglobin concentration, hematocrit value, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration and plasma total protein) on five anuran species of terrestrial ( Pseudepidalea viridis , Pelobates syriacus and Hyla arborea ), semi-aquatic ( Rana dalmatina ) and aquatic ( Pelophylax ridibundus ) nature from Canakkale, Turkey. Differences between males and females in terms of haemoglobin, hematocrit and mean cell volume in P. viridis were statistically significant. The RBC count was higher in terrestrial and aquatic species than in semi-aquatic species. Haemoglobin concentration, hematocrit value, MCV and MHC were higher in terrestrial species than in semi-aquatic and aquatic species. The MCHC values were all similar to each other. The plasma total protein was higher in terrestrial species than in aquatic species. To sum up, variations were detected in the some hematological parameters under examination among the anuran species.

Polystoma nacialtuneli n. sp. (Monogenea: Polystomatidae) from the eastern spadefoot, Pelobates syriacus (Pelobatidae) in Turkey

Polystoma nacialtuneli n. sp. is described from the urinary bladder of the eastern spadefoot, Pelobates syriacus from Turkey. This is the fifth polystome species known from Turkey and the third species in Pelobates. We show that this new parasite species can be distinguished from other polystome species in the area by a combination of characteristics, including parasite size and the shape and size of the hamuli. Polystoma pelobatis from Pelobates cultripes has a pair of well-developed hamuli, while P. fuscus from Pe. fuscus characteristically has a pair of underdeveloped hamuli barely larger than the marginal hooklets. Polystoma nacialtuneli n. sp. has well-developed hamuli that vary significantly in shape. Phylogenetic relationships of P. nacialtuneli n. sp. within Polystoma, supplemented with molecular divergences estimated from internal transcribed spacer 1 (ITS1) sequences, indicate that they are well separated from their closest relatives, i.e. P. fuscus and P. pelobatis from Pe. fuscus and Pe. cultripes, respectively.

Morphometrics, distribution and ecology of the amphibians in Jordan

One urodele amphibian species (Ommatotriton vittatus) and four anuran species (Pseudepidalea viridis, Pelophylax bedriagae, Hyla savignyi and Pelobates syriacus) were recorded from Jordan. Alcohol-preserved specimens (n = 340) were examined. Seventeen measurements were taken and are compared between the sexes. The distribution and habitat for each species are discussed. The current status of the amphibians of Jordan is discussed.

Helminth parasites of the eastern spadefoot toad,Pelobates syriacus (Pelobatidae), from Turkey

Ninety-one eastern spadefoot toads, Pelobates syriacus, were collected from 3 localities in Turkey between 1993 and 2003 and examined for helminths. One species of Monogenea (Polystoma sp.) and 3 species of Nematoda (Aplectana brumpti, Oxysomatium brevicaudatum, Skrjabinelazia taurica) were found. Pelobates syriacus represents a new host record for Polystoma sp. and S. taurica.

Effect of habitat drying on the development of the Eastern spadefoot toad (Pelobates syriacus) tadpoles

AbstractAmphibians exhibit plasticity in the timing of metamorphosis, and tadpoles of many species respond to pond drying by accelerating their development. In the present study we investigated the phenotypic plasticity of the developmental response to water volume reduction in tadpoles of Eastern spadefoot toad Pelobates syriacus. The response of tadpoles to the simulated drying conditions was evaluated by gradually reducing the water level in the experimental containers under controlled laboratory conditions. Four water level treatments were used: constant high, slow decrease, fast decrease and constant low level. We tested if (i) tadpoles can speed up their development in a drying aquatic habitat, and (ii) if the accelerated development causes a reduced body size at metamorphosis. Our results showed that P. syriacus tadpoles were able to respond to pond drying by speeding up their metamorphosis and that metamorphosis was not influenced by water level, but by water level decrease rate. The accelerated development caused by the decreasing water level resulted in smaller body size at metamorphosis. The smallest size at metamorphosis was in tadpoles raised in constant low water level treatments and was probably induced by the crowding effect. We compared our results to similar studies which show that the response of the Eastern spadefoot toad tadpoles to pond drying is less impressive, especially if compared to the response of the North American spadefoot toads inhabiting desert environments.

Modelling the range of Syrian spadefoot toad (Pelobates syriacus) with combination of GIS-based approaches

AbstractSyrian spadefoot toads (Pelobates syriacus) are found from Balkan Peninsula throughout the Caucasus, Middle East, and Northern Iran. However, the range of this species is sufficiently mapped only in Balkans. Based on the detailed mapping of the species in Georgia, we analysed the environmental factors influencing species occurrence and produced spatial models for the entire range. Nine models based on the logistic regression, discriminant function analysis, and classification tree analysis, all showed significant influence of the vegetation index and maximum summer temperature on the species distribution. The habitat suitability models based on the presence-only data (Mahalanobis distance estimation and Maximum Entropy approach) had a better performance than the models based on the presence-absence data. The habitat suitability models included two variables only, identified as significant in all preliminary analyses. The area identified as suitable by presence-only models strongly increases when a few environmental variables are included in the analysis. When only two variables are considered, the model predicted large areas north of the actual range. Competition with the related common spadefoot toad (P. fuscus) might have a role on the position of the northern limit of the range of P. syriacus. Within the predicted range, use of breeding sites is negatively associated with presence of fish. Breeding pond preferences of P. syriacus were particularly similar to those of the lake frog (Rana ridibunda), although the latter species uses appropriate habitats more extensively.

Breeding site selection according to suitability for amphibian larval growth under various ecological conditions in the semi-arid zone of northern Israel

A series of field monitoring was conducted over four years on aquatic habitats to test the hypothesis that breeding habitat selection by six different amphibian species, belonging to the Anuran and Urodela orders, was according to the ecological parameters of the water body, and not necessarily according to the type of breeding site. Ecological and biological conditions of 14 different breeding sites inhabited by amphibian larvae in northern Israel, including winter ponds, pits, springs and streams, were investigated in a region where all six species exist. The larval growth period was discovered to vary in different habitats. Most breeding sites studied had Salamandra infraimmaculata larvae, although at different periods of the year. The larvae of Hyla savignyi, Bufo viridis, Rana bedriagae, Pelobates syriacus and Triturus vittatus inhabited mostly the winter ponds and pits. In most cases, the S. infraimmaculata and T. vittatus larvae were not observed during the same time period at the same breeding sites. In other winter ponds, H. savignyi, P. syriacus and T. vittatus were seen at the same time during the spring, and along with R. bedriagae in the summer. Among the various water quality parameters evaluated at the breeding site, namely, temperature, pH, soluble oxygen, electrical conductivity, ammonium (NH 4 ) and invertebrate biomass, the most influential one was the temperature. S. infraimmaculata and B. viridis were detected in ponds with temperatures ranging about 1.5-24 °C, whereas all other larvae were observed at temperatures above this range, up to 34 °C. Based on the results of the investigation, the major factors affecting the habitat selected for breeding are the ecological conditions that allow for survival, growth and metamorphosis completion of the amphibian larvae.

Feeding ecology and behaviour of the last known surviving oriental Northern Bald Ibises, Geronticus eremita (Linnaeus, 1758), at their breeding quarters in Syria

The last handful of individuals from the eastern population of the critically endangered Northern Bald Ibis (Geronticus eremita) have been closely observed and monitored during the breeding seasons 2002–2004 and 2006 in their breeding quarters in the Syrian desert. The home range used by the ibises was estimated to be up to about 450 km², which was already partly included in a specific protected area established by the Syrian authorities in 2004. Their main feeding habitat was a stony and sparsely vegetated open and gently undulating steppe. This feeding habitat is heavily overgrazed by the sheep flocks of the Bedouin nomads, and the native shrub coverage has almost completely disappeared due to uprooting for firewood. Another key feeding habitat are the man-made reservoirs, where ibises fed on larvae of Eastern Spadefoot Toads (Pelobates syriacus), perhaps the most profitable prey occurring at their breeding quarters. The bulk of the diet of Syrian breeding ibises is estimated to be a mixture of beetles (mainly ground beetles, Tenebrionidae), grasshoppers (Acrididae) and young toads – all found to be preyed upon by ibises. A ground mantis and an isopod species, as well as lizards, may possibly be important components of the diet as well. A daily need for drinking water was found. Ibises seemed to hunt their prey both by sight and by probing with the tip of the bill in underground holes and under stones. The foraging behaviour of ibises was highly gregarious and quite conservative during each breeding season and over the years: they tended to use the same feeding areas from year to year, with a similar temporal sequence. Ibises fed at increasingly higher feeding areas throughout the breeding season, starting from about 400 m asl in February and reaching about 950 m asl in June-July.