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The Montseny brook newt (Calotriton arnoldi), considered the most endangered amphibian in Europe, is a relict salamandrid species endemic to a small massif located in northeastern Spain. Although conservation efforts should always be guided by genomic studies, those are yet scarce among urodeles, hampered by the extreme sizes of their genomes. Here, we present the third available genome assembly for the order Caudata, and the first genomic study of the species and its sister taxon, the Pyrenean brook newt (Calotriton asper), combining whole-genome and ddRADseq data. Our results reveal significant demographic oscillations which accurately mirrored Europe’s climatic history. Although severe bottlenecks have led to depauperate genomic diversity and long runs of homozygosity along a gigantic genome, inbreeding might have been avoided by assortative mating strategies. Other life history traits, however, seem to have been less advantageous, and the lack of land dispersal has driven to exceptional levels of population fragmentation.

Els rèptils representen el grup de vertebrats terrestres més divers del món i són un element important de la biodiversitat. La guia en recull les més de 50 espècies que habiten als Països Catalans 'tortugues, serps, sargantanes, llangardaixos...' i ens en descriu les característiques principals, l'hàbitat, l'ecologia i les amenaces a les que es veuen sotmeses en un entorn de canvi global. Estructurada en fitxes, amb un text que conté informació clara i rigorosa i amb abundància de fotografies per afavorir-ne la identificació, la guia s'adreça tant als amants del rèptils com a aquells que s'acosten per primera vegada a aquest excepcional grup de vertebrats. Fruit del treball de molts anys i de molts i moltes herpetòlogues, de les quals l'actual autoria n'és només una representació, la guia esdevé una eina no només d'observació i identificació sinó que destaca la importància dels rèptils dins dels ecosistemes i contribueix a esvaïr moltes de les percepcions negatives i dels prejudicis que sovint se'ls atribueixen.

Molecular ecologists often rely on phylogenetic evidence for assessing the species-level systematics of newly discovered lineages. Alternatively, the extent of introgression at phylogeographic transitions can provide a more direct test to assign candidate taxa into subspecies or species categories. Here, we compared phylogenetic versus hybrid zone approaches of species delimitation in two groups of frogs from the Western Mediterranean region (Discoglossus and Pelodytes), by using genomic data (ddRAD). In both genera, coalescent analyses recovered almost all nominal taxa as “species”. However, the least-diverged pairs D. g. galganoi/jeanneae and P. punctatus/hespericus admix over hundreds of kilometers, suggesting that they have not yet developed strong reproductive isolation and should be treated as conspecifics. In contrast, the comparatively older D. scovazzi/pictus and P. atlanticus/ibericus form narrow contact zones, consistent with species distinctiveness. Due to their complementarity, we recommend taxonomists to combine phylogenomics with hybrid zone analyses to scale the gray zone of speciation, i.e., the evolutionary window separating widely admixing lineages versus nascent reproductively isolated species. The radically different transitions documented here conform to the view that genetic incompatibilities accumulating with divergence generate a weak barrier to gene flow for long periods of time, until their effects multiply and the speciation process then advances rapidly. Given the variability of the gray zone among taxonomic groups, at least from our current abilities to measure it, we recommend to customize divergence thresholds within radiations to categorize lineages for which no direct test of speciation is possible.

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.

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.

[EN] The Persian Horned Viper (Pseudocerastes persicus ) is distributed from northeast Iraq through the Iranian Plateau to western Pakistan with isolated populations in the Hajar Mountains of south- eastern Arabia. Like the other members of the genus Pseudocerastes, P. persicus is a sit-and-wait ambush feeder with low vagility, a characteristic that often results in high levels of population differentiation. In order to clarify the level of genetic variability, phylogenetic relationships, and biogeography of the Arabian populations of P. persicus we sequenced 597 base pairs of the mitochondrial cytochrome b of four individuals from the Hajar Mountains in sou th-eastern Arabia and inferred their phylogenetic relationships inclu ding 10 samples of P. persicus from Iran and Pakistan, four P. urarachnoides and one P. fieldi downloaded from GenBank. The four Arabian samples are genetically very similar in the gene fragment analyzed and are phylogenetically very closely related to populations of P. persicus from coastal south Iran. Biogeographically, it appears that colonization of the Hajar Mountains by P. persicus took place from Iran very recently, most probably during the last glaciation, when most of the Persian Gulf was above sea level and did not represent a barrier for dispersal., [ES] La víbora cornuda de Irán (Pseudocerastes persicus) se distribuye desde el noreste de Irak hasta el oeste de Pakistán ocupando gran parte de la meseta iraní, con algunas poblaciones aisladas en las montañas Hajar del sudeste de Arabia. Al igual que los otros miembros del género Pseudocerastes, P. persicus es un depredador pasivo (sit and wait) que posee una baja capacidad de dispersión, característica a menudo relacionada con altos niveles de diferenciación genética entre poblaciones. Con el fin de estudiar el nivel de variabilidad genética, las relaciones filogenéticas y la biogeografía de las poblaciones de P. persicus de las montañas Hajar del sureste de Arabia hemos secuenciado 597 pares de bases del gen mitocondrial citocromo b de cuatro individuos de Arabia y hemos inferido sus relaciones filogenéticas incluyendo 10 muestras de P. persicus de Irán y Pakistán, cuatro P. urarachnoides y una P. fieldi obtenidas de GenBank. Los resultados indican que las cuatro muestras de Arabia son genéticamente muy similares y están filogenéticamente muy relacionadas con las poblaciones de P. persicus de la costa sur de Irán. Biogeográficamente, parece que la colonización de las montañas Hajar por parte de P. persicus tuvo lugar muy recientemente des de Irán, muy probablemente durante la última glaciación, cuando la mayor parte del Golfo Pérsico estaba por encima del nivel del mar y no representaba una barrera geográfica para la dispersión.

The Persian Horned Viper (Pseudocerastes persicus) is distributed from northeast Iraq through the Iranian Plateau to western Pakistan with isolated populations in the Hajar Mountains of south-eastern Arabia. Like the other members of the genus Pseudocerastes, P. persicus is a sit-and-wait ambush feeder with low vagility, a characteristic that often results in high levels of population differentiation. In order to clarify the level of genetic variability, phylogenetic relationships, and biogeography of the Arabian populations of P. persicus we sequenced 597 base pairs of the mitochondrial cytochrome b of four individuals from the Hajar Mountains in south-eastern Arabia and inferred their phylogenetic relationships including 10 samples of P. persicus from Iran and Pakistan, four P. urarachnoides and one P. fieldi downloaded from GenBank. The four Arabian samples are genetically very similar in the gene fragment analysed and are phylogenetically very closely related to populations of P. persicus from coastal south Iran. Biogeographically, it appears that colonisation of the Hajar Mountains by P. persicus took place from Iran very recently, most probably during the last glaciation, when most of the Persian Gulf was above sea level and did not represent a barrier for dispersal.

A comprehensive review of the natural history of the sand lizard Lacerta agilis in Spain.

Patterns of sexual dimorphism and age structure were investigated in two populations of the newt Calotriton arnoldi, endemic of the Montseny Massif (NE of the Iberian Peninsula). In contrast to the Pyrenean newt ( Calotriton asper) sexual dimorphism in the Montseny brook newt is characterized by slightly larger females (60.3 ± 0.3 mm; maximum: 68 mm) than males (59.5 ± 0.2 mm; maximum: 64 mm) and more similar body shape between sexes. Both populations and sexes mature at the same age (3 years), show the same age structure and achieve similar longevity (8-9 years). Comparing our results with the framework of the variation of life-history traits in Calotriton, the Montseny newts exhibit fast sexual maturity and short longevity. Curiously, we have found a lack of covariation between age at sexual maturity, longevity and total body size in the populations of Calotritonspecies. Only in males, age at sexual maturity seems to be affected by altitude, but in an unexpected way: sexual maturation is delayed in populations at low altitudes. Moreover, the age at sexual maturity does not differs between the populations where immatures are terrestrial vs. those where they remain aquatic. Our results suggest that life-history traits in Calotritonnewts could be determined by selective factors that play their role at small geographic scale.

The decline and wealth of amphibian populations is a recurrent centre of interest in the herpetological scientific community since the past eight decades. One of the most worrisome phenomena is the spread of morphological malformations, especially in frogs, but also occasionally in salamanders (Sequeira et al., 1999; Wheeler, McCallum and Trauth, 2002; Ferrer and Lopez, 2003; Miller and Miller, 2005). The Montseny newt (Calotriton arnoldi) is one of the most recent described amphibian species in Europe (Carranza and Amat, 2005). Restricted to a small range within the Montseny massif (north eastern Iberian Peninsula), only seven populations structured into two separated areas by a river (Tordera river), are actually known. Population in these two areas, divided in eastern and western, are genetic and morphologically well differentiated (Valbuena-Ureña, Amat and Carranza, 2013). Calotriton asper is an entirely aquatic species, living in fast flowing steams in forestal areas from 650 m to 1.200 m.a.s.l. In the course of conservation surveys carried out in the Natural Park of Montseny, we detected some individuals affected by limb abnormalities in one population of C. arnoldi . Consequently we performed an especific survey to characterize and quantify the incidence of body abnormalities on C. arnoldi. .

The Pyrenean brook newt (Calotriton asper) is a salamandrid that mostly lives in fast running and cold mountainstreams, although some populations are also found in lakes. In the present work, we report in detail on the occurrence of facultative paedomorphosis traits in a population from a Pyrenean high altitude lake.We compare its morphology, life history traits and mitochondrial DNA variation with a nearby lotic metamorphic population. Our results indicate that the lacustrine newts are smaller and present a less developed sexual dimorphism, smooth skin, and that 53% of the adults retain gills at different degrees of development, but not gill slits. Although both populations and sexes have the same age at sexual maturity (four years), the lacustrine population presents higher longevity (12 and 9 years for males and females, respectively) than the one living in the stream (8 and 9 years). The variation on the climatic conditions at altitudinal scale is probably the main cause of the differences in life history traits found between the two populations. The food availability, which could to be limiting in the lacustrine population, is another factor that can potentially affect body size. These results are congruent with the significant mitochondrial DNA genetic isolation between populations, probably a consequence of the lack of juvenile dispersal.We found low cytochrome b variability and significant genetic structuring in the lake population that is very remarkably considering the short distance to the nearby stream population and the whole species' pattern. We suggest that a bottleneck effect and/or phenotypic plasticity may have resulted in the appearance of a paedomorphic morph in the lake. © 2014 Koninklijke Brill NV, Leiden.

A comprehensive review of the natural history of the Montseny brook newt Calotriton arnoldi in Spain.

Painted frogs (Discoglossus) contain five to six species of Western Palearctic anurans that are mainly distributed in allopatry. We here provide the first comprehensive assessment of the phylogeography of the Moroccan species D. scovazzi and geographically characterize its contact zone with D. pictus in Eastern Morocco. Discoglossus scovazzi shows, in general, a weak phylogeographic structure across Morocco on the basis of mitochondrial DNA sequences of the cytochrome b gene, with only populations centered in the Atlas Mountains characterized by the presence of slightly divergent haplotypes. In eastern Morocco, all populations east of the Moulouya River were clearly assignable to D. pictus. This species was also found along the Mediterranean coast west of the Moulouya, in the cities of Nador and Melilla, suggesting that not the river itself but the wide arid valley extending along much of the river (except close to the estuary) acts as a possible distributional barrier to these frogs. No sympatry of D. scovazzi with D. pictus was observed, and all specimens were concordantly assigned to either species by DNA sequences of cytochrome b and of the nuclear marker RAG1. Species distribution models of the two taxa show largely overlapping areas of suitable habitat, and the two species’ niches are significantly more similar than would be expected given the underlying environmental differences between the regions in which they occur. Comparative data are also presented from the southern Iberian contact zone of D. galganoi galganoi and D. g. jeanneae. These taxa showed less clear-cut distributional borders, extensively shared RAG1 haplotypes, and had instances of sympatric occurrence on the basis of cytochrome b haplotypes, in agreement with the hypothesis of a yet incomplete speciation. In this wide contact zone area we found mitochondrial sequences containing double peaks in electropherograms, suggesting nuclear pseudogenes or (less likely) heteroplasmy, possibly related t

The genus Calotriton includes two species of newts highly adapted to live in cold and fast-flowing mountain springs. The Pyrenean brook newt (Calotriton asper), restricted to the Pyrenean region, and the Montseny brook newt (Calotriton arnoldi), endemic to the Montseny massif and one of the most endangered amphibian species in Europe. In the present manuscript, we use an integrative approach including species distribution modeling (SDM), molecular analyses of mitochondrial and nuclear DNA sequence data and morphology to unravel the historical processes that have contributed to shaping the biogeography and genetic structure of the genus Calotriton, with special emphasis on the conservation of C. arnoldi. The results of the molecular analyses confirm that, despite having originated recently, being ecologically similar and geographically very close, there is no signal of hybridization between C. asper and C. arnoldi. SDM results suggest that tough environmental conditions on mountains tops during glacial periods, together with subsequent warmer periods could have prevented the contact between the two species. Within the critically endangered C. arnoldi, a high genetic structure is revealed despite its extremely small distribution range compared to C. asper. Haplotype networks, AMOVA and SAMOVA analyses suggest that two distinct groups of populations can be clearly differentiated with absence of gene flow. This is in concordance with morphological differentiation and correlates with its geographical distribution, as the two groups are situated on the eastern and western sides of a river valley that acts as a barrier. The genetic and morphological results are highly important for the ongoing conservation program of C. arnoldi and strongly justify the management of this species into at least two independent evolutionary significant units (eastern and western sectors) to guarantee the long-term population viability. © 2013 Valbuena-Ureña et al.

We report the presence of pigmented skin tumors in three populations of the endangered amphibian Montseny brook newt, Calotriton arnoldi, one of the European amphibian species with the smallest distribution range (40 km2 in the Montseny Natural Park, Catalonia, Spain). Examination of one of the tumors by light microscopy was consistent with chromatophoroma and was most suggestive of a melanophoroma. Tumors were not found in juveniles. In adults, only two of three populations were affected. The proportions of males and females affected were not significantly different, but there was a positive correlation between body size and presence of tumors in both sexes. The etiology of chromatophoromas remains unknown but, in our study, they do not appear to have been caused by water quality or Ultraviolet B. © Wildlife Disease Association 2011.