The Herpetological Journal

Authors: Maletzky, Andreas; Mikulíček, Peter; Franzen, Michael; Goldschmid, Alfred; Gruber, Hans-Jürgen; Horák, Ales & Kyek, Martin

Abstract: In the area between south-eastern Bavaria (Germany) and Upper Austria the distribution ranges of northern (Triturus cristatus) and Italian crested newts (T. carnifex) are narrowly sympatric and a hybrid zone has been suggested on the basis of morphological data. In our study of 35 autochthonous populations in this region, we compared distribution patterns and hybridization on the basis of one morphological (Wolterstorff index, WI) and two molecular (cytochrome b, microsatellites) markers. Furthermore, we studied the status of an introduced T. carnifex population, originating from Croatia and thriving in a locality near Munich for more than 15 years. Tissue samples from Bavarian populations (preserved phalanges) were already available from a previous study. Austrian samples were gained non-destructively, by collecting buccal cells with sterile cotton buds. Results showed good concordance for all markers in most populations. Average WI values per population were within the range of the species T. cristatus and T. carnifex. Six populations from Salzburg and Upper Austria showed intermediate index values in males and females. Applying standard measures of genetic diversity within populations as well as Bayesian analysis of population structure, we detected admixed populations and individuals in three regions of Salzburg and Upper Austria. No autochthonous population of T. carnifex could be detected in Bavaria. The hybrid zone is probably unimodal, with hybrid individuals predominating in the centre. As the present-day distribution ranges of both species in the surveyed area are fragmented and populations are heavily reduced in numbers, we only can observe their remains. The analysis of molecular markers revealed considerable genetic uniformity. The studied area has been colonized by a limited number of individuals and probably less often than areas with slightly higher diversity. Hybrid zones in the study region were most probably formed by one genetically different T. carnifex population and two different T. cristatus populations. The allochthonous T. carnifex population in Isen (Bavaria) showed no signs of interbreeding with native T. cristatus. The assumption that this population was based on offspring from one pair is highly questionable according to our data.

Keywords: MICROSATELLITES, HYBRID ZONE, MTDNA, SALAMANDRIDAE, ADMIXTURE, TRITURUS CRISTATUS SUPERSPECIES, BAYESIAN ANALYSIS, WOLTERSTORFF INDEX

pp. 16-22
Authors: Santos, Xavier; Pleguezuelos, Juan M.; Brito, José C.; Llorente, Gustavo A.; Parellada, Xavier & Fahd, Soumia

Abstract: Species that inhabit regions with highly contrasting environmental conditions often exhibit geographic variation in diet as a consequence of differences in prey availability among populations. The Lataste's viper Vipera latastei is an ambush predator that lives in regions of the Iberian Peninsula varying from extremely dry (170 mm annual rainfall) to very rainy (3000 mm). Given this high adaptability, we expect interpopulational differences in its diet. We examined the gut content of 347 preserved adult specimens from the entire Iberian range deposited in museum collections. There were geographic differences in the consumption of the two main prey types, small mammals and reptiles. Logistic regression results indicate that three climatic variables (annual rainfall, average temperature and average radiation) explain the consumption of reptiles or small mammals by adult vipers: vipers preferentially forage on small mammals in wet, cold and cloudy areas, but combine the consumption of reptiles and small mammals in dry, hot and sunny ones. As small mammal species diversity and abundance in the Iberian Peninsula increase with rainfall, our results suggest that the consumption of small mammals versus reptiles is driven by prey availability.

Keywords: FEEDING ECOLOGY, VIPERIDAE, IBERIAN PENINSULA

pp. 23-31
Authors: García-París, Mario; Parra-Olea, Gabriela & Wake, David B.

Abstract: The Costa Rican plethodontid salamander long known as Bolitoglossa subpalmata is a species complex that includes B. subpalmata of the Cordillera Central and adjoining areas, B. pesrubra of the Cordillera de Talamanca, B. bramei and B. gomezi from the Pacific slopes of the Panama–Costa Rica border region and a species from the extreme northern portions of the Cordillera de Talamanca and the Cerros de Escazú described here as Bolitoglossa tica. The new species is a gracile, semi-arboreal species that has a prominent head well delimited from the neck. It differs from the parapatrically distributed B. pesrubra in coloration, and it occupies lower elevations. Allozymes and mitochondrial DNA sequences distinguish it from other species in the complex.

Keywords: BIOGEOGRAPHY, SALAMANDER, TAXONOMY, CENTRAL AMERICA

pp. 32-39
Authors: Jones, Rhys; Cable, Joanne & Bruford, Michael W.

Abstract: Genetic studies of native herpetofauna populations are important for the conservation of European biodiversity, but previous studies have been largely dependent on invasive sample collection. Here we explore the efficiency of noninvasive sampling (NIS) for molecular studies and review the various potential sources of such samples. Snakes produce a multitude of by-products, such as sloughed skin, faeces and eggs or embryos, that, along with road kills, predated specimens and museum samples, could potentially be used in molecular studies. We describe a new method for obtaining snake faeces in the field and, using mitochondrial cytochrome b primers, we successfully amplified 500 and 758 bp sequences from a variety of tissues collected by NIS. The availability and degradation of such material differed greatly, and both DNA extraction and PCR success appeared dependent upon sample origin and storage. Nevertheless, for the first time we demonstrate that faecal, egg and foetal tissues, as well as sloughed skin and carcasses, represent valuable NIS source material permitting genetic studies with minimal disturbance to the individual and its population.

Keywords: MITOCHONDRIAL DNA, SNAKES, CORONELLA AUSTRIACA, NATRIX NATRIX, VIPERA BERUS

pp. 40-44
Authors: Hartel, Tibor

Abstract: As ectotherm vertebrates, amphibians are sensitive to weather conditions, which may influence the start of the breeding season, body condition and survival during the winter. If climatic conditions change at large spatial and temporal scales, this can have adverse effects on amphibians, including susceptibility to disease. In this study, I recorded the start of the breeding season (males and females separately) and monitored population size in a Rana dalmatina population over an 11-year period. I found no indication of an early extension of the breeding season or a significant population trend. Initiation of breeding and the size of the population were significantly negatively correlated with temperature and precipitation in February. The growth rate of the population is significantly related to density. This result suggests that if the climate change results in drier springs, this population of R. dalmatina may be adversely affected.

Keywords: TÂRNAVA MARE BASIN, BREEDING, CLIMATIC CONDITIONS

pp. 45-48
Authors: Costa, Gabriel C.; Mesquita, Daniel O. & Colli, Guarino R.

Abstract: Pitfall trapping is a widely used sampling method in amphibian and reptile studies. Despite their broad use and numerous advantages, the question of whether diets of trapped animals differ from those under natural conditions remains uninvestigated. We use data on eight lizard species to test the hypotheses that lizards captured in pitfall traps differ in diet composition and/or have higher stomach content volumes when compared to lizards collected using other methods. The basis for these hypotheses is that many common lizard prey items fall into the traps and are thus available to trapped lizards. Testing these hypotheses is critical to validate the results of diet studies that use animals taken from pitfall traps. Our results showed that lizards collected from pitfall traps did not differ significantly from lizards collected outside the traps in diet composition or volume of prey consumed. However, two species (among eight) had different stomach content volumes inside the traps; one (Anolis chrysolepis) had a higher volume and the other (Tropidurus oreadicus) had a lower volume. For the species we studied, we found that lizards collected with pitfall traps can be used in diet studies. Nevertheless, we recommend checking traps at least once a day to avoid prolonged exposure to different prey items, collecting large sample sizes, and also collecting animals outside the traps.

Keywords: NICHE OVERLAP, TEIIDS, FORAGING BEHAVIOR, IGUANIDS, FOOD SELECTION

pp. 49-58
Authors: Macale, Daniele; Vignoli, Leonardo & Maria Carpaneto, Giuseppe

Abstract: Dendropsophus nanus, D. sanborni and Lysapsus limellum are three hylid species, similar in body size and frequently coexisting at the same reproductive sites. To determine whether food partitioning occurred during the reproductive phase, both numerical and volumetric analyses of stomach contents were performed on syntopic populations inhabiting a wetland system in Corrientes Province, north-east Argentina. The analyses showed a marked specialization towards Diptera prey in Dendropsophus species, particularly in D. sanborni, and a more generalist habit in L. limellum. The three study species exhibited different foraging modes, with L. limellum belonging to the sit-and-wait predator type, D. sanborni to the forager predator type, and D. nanus exhibiting a mixed foraging mode. The comparison of the feeding strategies adopted by the various species in different habitat types and condition of syntopy showed a noteworthy plasticity. According to Schoener's food size selection strategy model for a syntopic predator species system, the larger species (L. limellum) selected prey bigger in size and the smaller (D. sanborni) ate a larger number of prey specimens, whereas D. nanus showed an intermediate trophic strategy. Although the degree of trophic niche overlap was higher than expected, the study species did not show a clear segregation in terms of use of space, hence the coexistence mechanism during the reproductive period should not be related to competition processes for food resources.

Keywords: DIET, DENDROPSOPHUS, AMPHIBIA, LYSAPSUS, RESOURCE PARTITIONING

pp. 59-62
Authors: Brown, Richard P. & Roberts, Neil

Abstract: Lizards may select higher body temperatures after feeding, but rigorous experimental evidence of this is confined to a small number of lineages. Here it was examined in an anguid lizard, namely the slow-worm Anguis fragilis, which is a semi-fossorial cool temperate species that exhibits relatively low field body temperatures. Body temperatures selected by slow-worms in a thermal gradient were low compared with many other lizards (means ranged from 25.3 to 26.4 °C). This indicates that low field body temperatures described previously are not due to thermoconformity in a cool environment. More significantly, selected body temperatures differed between fed and three-day fasted treatments, with an increase of 0.4–1.2 °C being observed after feeding. The magnitude of this increase is similar to that reported for two iguanid lizards, and shows that a postprandial response is also present in this ecologically and phylogenetically distant species.

Keywords: TEMPERATURE SELECTION, THERMOREGULATION, FASTING, ANGUIDAE, FOOD

pp. 63-65
Authors: Narayan, E.; Christi, K.; Morley, C. & Trevenen, P.

Abstract: A study was conducted to determine whether simple morphological characteristics could be used to rapidly determine the sex of cane toads. We found that four characteristics reliably allowed rapid assessment of sex: skin texture on the dorsal surface, skin colour on the dorsal surface, the presence of a creamy-coloured stripe along the dorsal margin and the presence of vocal sac openings. These criteria were tested by an assessment of use by both experienced and novice operators and were shown to be reliable for sexing cane toads that were large enough to assess morphological characteristics reliably (individuals with a snout–vent length exceeding 50 mm). Of the four techniques, the presence of vocal sac openings proved to be the most reliable. Such techniques may be used for a number of purposes, and are particularly useful during conservation projects that attempt to eradicate or reduce the effects of this invasive alien species on local ecosystems.

Keywords: VOCAL SAC, MORPHOLOGICAL CHARACTERISTICS, SEXING, FIJI ISLANDS

pp. 66-68
Authors: Salvidio, Sebastiano

Abstract: The adult sex ratio of a population of Speleomantes strinatii living in an underground habitat was studied for 12 consecutive years by temporal removal sampling. Capture probabilities of males (0.72) and females (0.69) were similar and yielded highly reliable sex ratio values. The adult sex ratio, expressed as the proportion of males, was significantly male-biased (mean 0.57, bootstrap 95% confidence intervals 0.53–0.65) and remained relatively constant during the study. A negative relationship was observed between adult sex ratio in one year and the abundance of juveniles in the following one (P=0.02), suggesting that an excess of males limited juvenile recruitment and therefore influenced population dynamics.

Keywords: CAVE HABITAT, POPULATION DYNAMICS, PLETHODONTIDAE, CAPTURE PROBABILITIES, RECRUITMENT