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Differences in environmental conditions such as those between lakes and streams can produce phenotypic variation and ultimately promote evolutionary diversification. Some species of newts and salamanders can occupy these habitats and express alternative phenotypes: metamorphs that lose gills at metamorphosis and paedomorphs that retain them at the adult stage. Whereas this process is facultative in some species, it is obligatory in others, thus suggesting that isolation and environmental pressures may have canalized developmental pathways. In this study, we focused our research on the Pyrenean brook newt, Calotriton asper, which is present in both lakes and streams, but whose fully aquatic paedomorphic individuals are only present in lakes. We aimed to determine the genetic structure and differentiation of two paedomorphic populations, including their surrounding stream and lake metamorphic populations, to test whether populations of paedomorphs can constitute evolutionary significant units. Although gene flow was identified between lakes and nearby stream populations, there was a low percentage of dispersers, and the paedomorphic populations were genetically differentiated from the populations of metamorphs. It is likely that the studied lakes have offered peculiar conditions that have allowed the development of a paedomorphic phenotype. These populations and phenotypes therefore constitute good models to understand local adaptations. As each of these populations of paedomorphs can be considered evolutionary significant units that cannot be replaced by other nearby populations in case of a population crash, conservation actions should be focused directly on them. The rare lake populations of the Pyrenean brook newt Calotriton asper with individuals exhibiting paedomorphosis (retention of larval traits at the adult stage) constitute evolutionary significant units. Because of their genetic differentiation with surrounding stream and lake populations, they can be considered at a high risk of extinction due to the introduction of invasive species such as fish and chytrids that have already been found in some of them. Conservation measures should therefore target in priority these peculiar populations. Photograph: M. Denoël. [ABSTRACT FROM AUTHOR]

Abstract: Thoropa miliaris is a frog species endemic to the Brazilian Atlantic Rainforest, inhabiting wet rocky habitats. Males of this species present nuptial excrescences, which are keratinized spines on the surface of some fingers and internal metacarpal tubercles. Although these spines are usually associated with male adulthood, no details of their development are available. To investigate the sequence of spines' appearance, we correlated the number of spines with size and age, which was estimated by skeletochronology. We studied individuals collected from Rio de Janeiro, Brazil. There was significant correlation between size of individuals and number of spines and between age and number of spines in the callosities. The first spines appeared in metacarpal–phalangeal articulation of finger II, when specimens were 1 year old. The estimated growth curve did not show stabilization at any age. We considered the degree of development of the nuptial excrescences as a proxy for sexual maturity and so individuals may already be sexually active by 1 year of age. Estimated longevity of T. miliaris is similar to that estimated for other tropical species of frogs. Although growth in anuran species is considered to be undetermined, in T. miliaris, it seems to fit either undetermined or determined models. [ABSTRACT FROM AUTHOR]

Skeletochronology was used to estimate age and several life history traits of the Iberian spadefoot toad (Pelobates cultripes) from a semiarid zone of the Ebro Valley (in the northeastern Iberian Peninsula). The lines of arrested growth (LAGs) were clearly visible in all cross sections of the adult phalanges, showing fast growth in the first year of life, with large adult sizes. The growth, size (SVL) and age structure varied between sexes, suggesting that the larger size of females (mean±SE=76.14±0.95 mm; males: 71.76±0.90 mm) is related to a delay in age at maturity (3 years) compared to males (2 years). In addition, females were more long-lived (6 years) than males (5 years), resulting in a similar potential reproductive life span (PRLS=3 years). A data set including life history traits from several P. cultripes populations was used to analyse demographic variation. We suggest multiple factors such as altitude, latitude, predation, and soil characteristics can explain life history trait variation in this species. [ABSTRACT FROM AUTHOR]

In the last decade, taxonomic studies have drastically increased the number of species known to inhabit the Arabian deserts. While ongoing phylogenetic studies continue to identify new species and high levels of intraspecific genetic diversity, few studies have yet explored the biogeographic patterns in this arid region using an integrative approach. In the present work, we apply different phylogenetic methods to infer relationships within the Palearctic naked-toed geckos. We specifically address for the first time the taxonomy and biogeography of Bunopus spatalurus Anderson, 1901, from Arabia using multilocus concatenated and species tree phylogenies, haplotype networks and morphology. We also use species distribution modelling and phylogeographic interpolation to explore the phylogeographic structure of Bunopus spatalurus hajarensis in the Hajar Mountains and the roles of climatic stability and possible biogeographic barriers on lineage occurrence and contact zones in this arid mountain endemism hot spot. According to the inferred topology recovered using concatenated and species tree methods, the genus ' Bunopus' is polyphyletic. Bunopus tuberculatus and B. blanfordii form a highly supported clade closely related to Crossobamon orientalis, while the two subspecies of ' Bunopus' spatalurus branch together as an independent highly supported clade that diverged during the Miocene according to our estimations. Within B. s. hajarensis, three geographically structured clades can be recognized that according to our estimations diverged during the Late Miocene to Pliocene. The paleodistribution models indicate climatic stability during the Late Pleistocene and the lineage occurrence, and predicted contact zones obtained from phylogeographic interpolation therefore probably result from the older splits of the groups when these lineages originated in allopatry. As demonstrated by the results of the multilocus molecular phylogenetic analyses and the topological test carried out in this study, the genus ' Bunopus' is not monophyletic. To resolve this, we resurrect the genus Trachydactylus Haas and Battersby, 1959; for the species formerly referred to as Bunopus spatalurus. Considering the morphological differences, the high level of genetic differentiation in the 12S mitochondrial gene and the results of the phylogenetic and the cmos haplotype network analysis, we elevate Trachydactylus spatalurus hajarensis to the species level Trachydactylus hajarensis (Arnold, 1980). [ABSTRACT FROM AUTHOR]

The article discusses research on the use of mtDNA analyses and ecological niche modelling to infer the evolutionary history of the midwife toad found in Morocco. The researchers studied the effects of past climatic conditions on the toad's contemporary intraspecific genetic structuring which could have been caused by homogenization due to gene flow. It advises the use of additional genetic markers to study the effects of population fragmentation on this species.

Whereas many amphibians use olfactory cues to detect aquatic habitats, less attention has been paid to the specificity of the information carried by these cues with respect to breeding habitat quality. In the present work, we address this question by taking advantage of the selectivity for specific breeding habitats exhibited by the natterjack toad (temporary waters, gravel pits). Toads were sampled from two populations located in semi-arid regions of the Iberic peninsula experiencing Mediterranean climate, and one population in a temperate region of France experiencing oceanic-continental climate. The choice was given in a maze between waters coming either from habitats known to be suitable for the species (temporary waters on an inorganic-dominated substratum) or from unsuitable habitats (ponds with eutrophic water or permanent water on organic-rich substratum). The toads from the temperate region exhibited a clear selection for water from the suitable habitat. In contrast, toads from the Mediterranean region did not show any preference, either when the waters came from their original region or when they came from the other region. These results show that toads can use chemical cues to discriminate specific habitats, allowing them to quickly find suitable habitat patches that are temporary and often spatially unpredictable. Variation between the two populations in the ability to select water quality is likely to be connected with habitat availability at the regional scale. [ABSTRACT FROM AUTHOR]

Demographic life history traits were investigated in three Bufo calamita populations in Germany (Rhineland-Palatinate: Urmitz, 50°N; 1998-2000) and Spain (Catalonia: Balaguer, Mas de Melons, 41°N; 2004). We used skeletochronology to estimate the age as number of lines of arrested growth in breeding adults collected during the spring breeding period (all localities) and during the summer breeding period (only Urmitz). A data set including the variables sex, age and size of 185 males and of 87 females was analyzed with respect to seven life history traits (age and size at maturity of the youngest first breeders, age variation in first breeders, longevity, potential reproductive lifespan, median lifespan, age-size relationship). Spring and summer cohorts at the German locality differed with respect to longevity and potential reproductive lifespan by one year in favour of the early breeders. The potential consequences on fitness and stability of cohorts are discussed. Latitudinal variation of life history traits was mainly limited to female natterjacks in which along a south-north gradient longevity and potential reproductive lifespan increased while size decreased. These results and a review of published information on natterjack demography suggest that lifetime number of offspring seem to be optimized by locally different trade-offs: large female size at the cost of longevity in southern populations and increased longevity at the cost of size in northern ones. [ABSTRACT FROM AUTHOR]

The movements of 19 natterjack toads (Bufo calamita) were monitored by telemetry in a semi-arid agricultural landscape in NE Spain. Toads reproduced in two water pools in fields of barley and an ancient clayquarrying zone filled by rainfall. Thirteen toads were followed during the breeding season (weeks 5-17 of 1997) and 11 toads were followed after reproduction (weeks 18 to 46). During the breeding season four toads moved distances of up to 500 m between breeding sites. No significant differences in movement patterns were found between the sexes, but a tendency was observed for males to show higher terrestrial site fidelity than females. Distances moved after the breeding season were substantial. The distance between the furthest positions recorded was from 164 to 1201 m, the maximum distance observed between daily recordings ranged from 125 to 353 m and the maximum overall distances ranged from 567 to 4411 m. No significant differences were observed between males and females or between small and large toads. The movements of these toads in a semi-arid agricultural landscape in Spain are compared with those observed in England and Germany. [ABSTRACT FROM AUTHOR]

Several experiments have shown that ambient ultraviolet-B radiation (UV-B) has negative effects on the development of amphibians' embryos. We studied the effects of UV-B radiation on development, survival and frequency of deformity during egg development in the Natterjack toad (Bufo calamita) from a semiarid region of Lleida (Catalonia, Spain). Eggs exposed to ambient levels of UV-B and those protected from UV-B with a filter exhibited similar developmental rate, mortality rate and frequency of developmental anomalies. These experiments show that eggs of Bufo calamita of the studied population are able to develop normally during embryonic period when exposed to current high levels of UV-B observed in Catalonia. These results will be used as reference for future studies on geographic variation in UV-B tolerance in this species.