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There is an increased interest in the evolution and development of newts from the genus Triturus because: (1) morphological differentiation among the nine constituent species largely corresponds to different ecological preferences, (2) hybridization between different species pairs has various evolutionary outcomes in terms of life history traits and morphology, and (3) the genus expresses a balanced lethal system that causes arrested growth and death of half of the embryos. These features provide natural experimental settings for molecular, morphological, and life‐history studies. Therefore, we produce a staging table for the Balkan crested newt (T. ivanbureschi). We provide detailed descriptions of 34 embryonic stages based on easily observable and interpretable external morphological characters, to ensure reproducibility. Compared with previous staging tables for Triturus, we include a vastly increased sample size and provide high‐resolution photographs in lateral, ventral, and dorsal view, complemented by videos of specific developmental periods, and accompanied by detailed explanations on how to delineate the specific stages. Our staging table will serve as a baseline in comparative studies on Triturus newts: an emerging model system in evolutionary and developmental studies. Research highlights: We present a staging table of embryonic development of an emerging model system: the crested newt. Detailed descriptions of external morphology, complemented by photos and videos, make this a valuable resource for evolutionary developmental studies. [ABSTRACT FROM AUTHOR]

The large-bodied newts Triturus cristatus and T. marmoratus possess ranges that overlap in western France where they frequently share breeding ponds. I test the hypothesis that the aquatic phenology differs between them, as associated with a more aquatic and terrestrial life style respectively. Total adult population sizes were determined in spring in 13 experiments by the capture-mark-recapture methodology, followed by equivalent experiments in summer. Population sizes dropped by an order of magnitude on average whereas species frequencies changed in favour of T. cristatus, suggesting that T. marmoratus leaves the breeding site earlier than T. cristatus. Interspecies hybrids behaved like T. marmoratus. Descriptions are provided of other features (in ecology, morphology, demography, and colouration pattern) that support the different, aquatic versus terrestrial life styles of T. cristatus and T. marmoratus. [ABSTRACT FROM AUTHOR]

Amphibians are well-known for their ability to produce and secrete a mixture of bioactive substances in specialized skin glands for the purpose of antibiotic self-protection and defense against predators. Some of these secretions contain various small molecules, such as the highly toxic batrachotoxin, tetrodotoxin, and samandarine. For some time, the presence of peptides in amphibian skin secretions has attracted researchers, consisting of a diverse collection of – to the current state of knowledge – three to 104 amino acid long sequences. From these more than 2000 peptides many are known to exert antimicrobial effects. In addition, there are some reports on amphibian skin peptides that can promote wound healing, regulate immunoreactions, and may serve as antiparasitic and antioxidative substances. So far, the focus has mainly been on skin peptides from frogs and toads (Anura), eclipsing the research on skin peptides of the ca. 700 salamanders and newts (Caudata). Just recently, several novel observations dealing with caudate peptides and their structure-function relationships were reported. This review focuses on the chemistry and bioactivity of caudate amphibian skin peptides and their potential as novel agents for clinical applications. [ABSTRACT FROM AUTHOR]

In this work, the Hypselotriton populations distributed in eastern Guangdong, China are studied in detail to clarify their taxonomic status. Based on morphological comparison and phylogenetic analysis, H. glaucus syn. nov. is synonymised with H. orphicus. Hypselotriton (Cynotriton) oolong sp. nov. from Mt Fenghuang in Chaozhou which used to be misidentified as H. orphicus, is revealed to be an independent lineage of subgenus Cynotriton and can be distinguished from all known congeners in morphology. By contrast, H. orphicus did not cluster within Cynotriton, but gathered with H. jiaoren comb. nov. to form a distinct unnamed clade within the genus. We therefore re-delimitate the intrageneric classification of the genus and a new subgenus Hakkatriton subgen. nov. is erected, corresponding to this unnamed clade. The Chinese Fire-bellied Newt genus Hypselotriton currently contains three subgenera and about ten known species. Identified keys to the subgenera and related congeners of genus Hypselotriton are further provided. [ABSTRACT FROM AUTHOR]

Newts are excellent vertebrate models for investigating tissue regeneration due to their remarkable regenerative capabilities. To investigate the mRNA and microRNAs (miRNAs) profiles within the blastema niche of regenerating newt limbs, we amputated the limbs of Chinese fire belly newts (Cynops orientalis) and conducted comprehensive analyses of the transcriptome and microRNA profiles at five distinct time points post-amputation (0 hours, 1 day, 5 days 10 days and 20 days). We identified 24 significantly differentially expressed (DE) genes and 20 significantly DE miRNAs. Utilizing weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) enrichment analysis, we identified four genes likely to playing crucial roles in the early stages of limb regeneration: Cemip, Rhou, Gpd2 and Pcna. Moreover, mRNA–miRNA integration analysis uncovered seven human miRNAs (miR-19b-1, miR-19b-2, miR-21-5p, miR-127-5p, miR-150-5p, miR-194-5p, and miR-210-5p) may regulate the expression of these four key genes. The temporal expression patterns of these key genes and miRNAs further validated the robustness of the identified mRNA-miRNA landscape. Our study successfully identified candidate key genes and elucidated a portion of the genetic regulatory mechanisms involved in newt limb regeneration. These findings offer valuable insights for further exploration of the intricate processes of tissue regeneration. [ABSTRACT FROM AUTHOR]

This study explores how climate variables influenced the evolution and diversification of Neurergus newts within the Irano‐Anatolian biodiversity hotspot. We use a dated phylogenetic tree and climatic niche models to analyze their evolutionary history and ecological preferences. Using genetic data from nuclear (KIAA) and mitochondrial (16s and 12s) genes, we estimate divergence times and identify four major Neurergus clades. The initial speciation event occurred approximately 11.3 million years ago, coinciding with the uplift of the Zagros and Anatolian mountains. This geological transformation isolated newt populations, likely triggering the first speciation event. By integrating potential geographic distribution with climate variables, we reconstruct ancestral niche occupancy profiles. This highlights the critical roles of temperature and precipitation in shaping Neurergus habitat preferences and distribution. We observe both phylogenetic niche conservatism and divergence, with niche divergence playing a dominant role in diversification. This research emphasizes the complex interplay of geography, climate, and ecology in speciation and the vulnerability of isolated mountain newt populations to environmental changes. [ABSTRACT FROM AUTHOR]

MtDNA barcoding is regularly applied to determine the provenance of invasive species. Variation in spatial genetic structuring across a species' range, typically high within glacial refugia and low in postglacially colonized areas, influences the precision of this approach. The palmate newt (Lissotriton helveticus) has been introduced north of its native range inside the Netherlands. We conduct mtDNA barcoding to try and retrace the origin of the introduced localities. A large increase in sample size, particularly focusing on temperate Europe, emphasizes that the palmate newt shows practically no genetic variation outside the Iberian Peninsula glacial refugium. While we find a haplotype previously only known from the Iberian Peninsula inside the native range in Belgium, the haplotype present in the introduced Dutch populations occurs widely throughout the native range north of the Iberian Peninsula. Although mtDNA barcoding can be a powerful tool in invasion biology, the palmate newt case exposes its limitations. [ABSTRACT FROM AUTHOR]

Morphological diversity within organisms can arise from factors other than genetic diversity alone. Local adaptations and combinations of various factors are also involved in shaping morphology. We investigated the relationship between morphological diversity and ecological niche divergence within two related tropical stream‐dwelling newt species from Indochina: Paramesotriton deloustali and P. guangxiensis. We identified sexual dimorphism within both species and a significantly larger body size in P. deloustali than in P. guangxiensis. Our findings highlighted that climatic variables strongly influence Asian warty newt distribution, indicating the potential effects of climate change on tropical newt populations. Furthermore, we identified significant intra‐ and interspecific morphological and niche differentiation across five populations of the two newt species, suggesting that newt morphology is responsive to environmental factors. A significant negative relationship was observed only between ecological niche similarity and geographic distance among various combinations of factors, indicating that the distinct morphology of the study species mirrors ecological adaptation. [ABSTRACT FROM AUTHOR]

The herpetofauna of the Iberian Peninsula is relatively well-researched, yet detailed studies, at least in part relying on molecular genetic data, continue to reveal taxa new to science, mostly species and subspecies. Newts of the genus Triturus are one such group with undiscovered yet taxonomically relevant variation, as shown by the recent description of new (sub)species of pygmy newts (T. pygmaeus, T. rudolfi). The marbled newt, Triturus marmoratus, shows an equally deep and geographically coherent spatial-genetic diversification. It is here shown that a northern and a southern group are characterized by different mitochondrial dna profiles and are also differentiated in morphometry and colouration pattern. With no firm evidence for selection against intermediate genotypes, the southern group is described at the subspecies level, as T. marmoratus harmannis ssp. nov. The subspecies' contact zone is situated at ca. 41.5 northern latitude and stretches from the Atlantic coast near Porto, Portugal to the northeast of Madrid, Spain. [ABSTRACT FROM AUTHOR]

The modular organization of tetrapod paired limbs and girdles, influenced by the expression of Hox genes is one of the primary driving forces of the evolution of animal locomotion. The increased morphological diversification of the paired limbs is correlated with reduced between‐limb covariation, while correlation within the elements is usually higher than between the elements. The tailed amphibians, such as Lissotriton newts, have a biphasic lifestyle with aquatic and terrestrial environments imposing different constraints on limb skeleton. By employing the methods of computerized microtomography and 3D geometric morphometrics, we explored the pattern of morphological variation, disparity, modularity and morphological integration in the proximal parts of the anterior limbs of six species of Eurasian small bodied newts. Although the species significantly differ in limb shape, there is a great overlap in morphology of scapula and humerus, and there are no differences in morphological disparity. For the scapula, the shape differences related to the duration of the aquatic period are in length, depth and curvature. The shape of the humerus is not affected by the length of aquatic period, and shape differences between the species are related to robustness of the body. The length of aquatic period has statistically supported phylogenetic signal. The scapula and humerus are structures of varying modularity. For the humerus, the strongest support on the phylogenetic level was for the capitulum/shaft hypothesis, which can also be interpreted as functional modularity. For the scapula, the greatest support was for the antero‐posterior hypothesis of modularity in case of Lissotriton vulgaris, which can be explained by different functional roles and muscle insertion patterns, while there was no phylogenetic modularity. The modularity patterns seem to correspond with the general tetrapod pattern, with modularity being more pronounced in the distal structure. The future research should include more salamandrid taxa with different habitat preferences and both adult and larval stages, in order to explore how size, phylogeny and ecology affect the morphology and covariation patterns of limbs. [ABSTRACT FROM AUTHOR]

The Montseny brook newt (Calotriton arnoldi), a glacial relict endemic to a small, isolated massif in northeast Spain, is considered the only Critically Endangered urodele in Europe. Its restricted range is divided by a deep valley that acts as an impassable barrier to dispersal, separating two isolated metapopulations (Western and Eastern) that correspond to independent lineages with different evolutionary trajectories, based on genetic and genomic data. Here, we address the ecological differentiation between lineages and discuss its potential effect on the phenotypic distinctness of each lineage. Based on multiple lines of evidence, we formally describe the Western Montseny brook newt as a new subspecies: Calotriton arnoldi laietanusssp. nov. Finally, our study underscores the importance of considering taxonomic progress in the conservation policies of endangered species, ensuring appropriate management and protection of the newly described taxa. [ABSTRACT FROM AUTHOR]

Background: Previous studies have suggested that macrophages are present during lens regeneration in newts, but their role in the process is yet to be elucidated. Methods: Here we generated a transgenic reporter line using the newt, Pleurodeles waltl, that traces macrophages during lens regeneration. Furthermore, we assessed early changes in gene expression during lens regeneration using two newt species, Notophthalmus viridescens and Pleurodeles waltl. Finally, we used clodronate liposomes to deplete macrophages during lens regeneration in both species and tested the effect of a subsequent secondary injury after macrophage recovery. Results: Macrophage depletion abrogated lens regeneration, induced the formation of scar-like tissue, led to inflammation, decreased iris pigment epithelial cell (iPEC) proliferation, and increased rates of apoptosis in the eye. Some of these phenotypes persisted throughout the last observation period of 100 days and could be attenuated by exogenous FGF2 administration. A distinct transcript profile encoding acute inflammatory effectors was established for the dorsal iris. Reinjury of the newt eye alleviated the effects of macrophage depletion, including the resolution of scar-like tissue, and re-initiated the regeneration process. Conclusions: Together, our findings highlight the importance of macrophages for facilitating a pro-regenerative environment in the newt eye by regulating fibrotic responses, modulating the overall inflammatory landscape, and maintaining the proper balance of early proliferation and late apoptosis of the iPECs. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we investigated how predators and conspecific density impact the growth of Chinhai spiny newt larvae. Using a two-factor experimental design, we manipulated both factors to explore their independent and interactive effects on larval development. Our findings demonstrate that both high and low conspecific densities constrain larval growth, while predators also limit growth. Interestingly, high conspecific density restricts predator-induced growth plasticity without interacting effects. This study provides valuable insights into the complex interplay between environmental factors and larval development in endangered Chinhai spiny newts. Understanding these dynamics is crucial for informing conservation strategies aimed at protecting this vulnerable species. Predators significantly influence amphibian larval development. Predator-induced plasticity is often studied independently from conspecific density effects, but these environmental factors may interact. We conducted two-factor factorial experimental design to manipulate conspecific density and predator cues, aiming to investigate the independently or interactive impacts of these two factors on the development of Chinhai spiny newt larvae (Echinotriton chinhaiensis). Our findings reveal that both high and low conspecific densities constrain spiny newt larval growth and predators also limit growth. Interestingly, high conspecific density restricts predator-induced growth plasticity without interacting effects. Only lower density groups exhibit slower growth responses to predators. Our study investigates how density mediates predator-induced plasticity in the endangered Chinhai spiny newt larvae, providing insights into their intricate life history. These results contribute to the understanding of predator-induced plasticity in amphibians and provide insights into the adaptive strategies of endangered species like Chinhai spiny newt. Such knowledge informs the development of effective conservation strategies for their protection. [ABSTRACT FROM AUTHOR]

Predators significantly impact the development process and subsequently influence the metamorphic decisions of amphibian larvae. Larvae often exhibit induced growth and metamorphic plasticity in response to the presence of predators. However, growth and development rates are not always perfectly correlated, growth responses can vary throughout ontogeny. It is crucial to consider the stage‐specific growth responses induced by predators. Here, we employ a critical windows experimental design and examine development‐related growth and metamorphic responses to predators in the endangered Chinhai spiny newt (Echinotriton chinhaiensis). Our findings reveal that predators constrain the development process of spiny newt larvae and also impact survival to metamorphosis. Inducible plasticity predominantly exhibits in the early and middle stages of larval development. Our results also suggest that diverse developmental plasticity has been adopted by larvae in response to predators. The presence of predators during early stage induces larvae to exhibit a same size at metamorphosis but a prolonged time to metamorphosis, while predators present during middle stage induce larvae to exhibit a large size at metamorphosis but a same time to metamorphosis. The presence of predators at the late developmental stage does not induce any plasticity in larval growth and metamorphosis. Moreover, these results also suggest that several stages of larval development are likely critical developmental windows for spiny newt larvae. This study not only provides basic biological information on predator‐induced developmental plasticity of the endangered Chinhai spiny newt but also likely provides biological insights for the implementation of in situ conservation and preservation efforts for endangered species. [ABSTRACT FROM AUTHOR]

Body size variation is central in the evolution of life‐history traits in amphibians, but the underlying genetic architecture of this complex trait is still largely unknown. Herein, we studied the genetic basis of body size and fecundity of the alternative morphotypes in a wild population of the Greek smooth newt (Lissotriton graecus). By combining a genome‐wide association approach with linkage disequilibrium network analysis, we were able to identify clusters of highly correlated loci thus maximizing sequence data for downstream analysis. The putatively associated variants explained 12.8% to 44.5% of the total phenotypic variation in body size and were mapped to genes with functional roles in the regulation of gene expression and cell cycle processes. Our study is the first to provide insights into the genetic basis of complex traits in newts and provides a useful tool to identify loci potentially involved in fitness‐related traits in small data sets from natural populations in non‐model species. [ABSTRACT FROM AUTHOR]

Ongoing climate change is increasing the frequency and intensity of extreme temperature events. Unlike the gradual increase on average environmental temperatures, these short‐term and unpredictable temperature extremes impact population dynamics of ectotherms through their effect on individual survival. While previous research has predominantly focused on the survival rate of terrestrial embryos under acute heat stress, less attention has been dedicated to the nonlethal effects of ecologically realistic timing and magnitude of temperature extremes on aquatic embryos. In this study, we investigated the influence of the timing and magnitude of current and projected temperature extremes on embryonic life history traits and hatchling behavior in the alpine newt, Ichthyosaura alpestris. Using a factorial experiment under controlled laboratory conditions, we exposed 3‐ or 10‐day‐old embryos to different regimes of extreme temperatures for 3 days. Our results show that exposure to different extreme temperature regimes led to a shortened embryonic development time and an increase in hatchling length, while not significantly affecting embryonic survival. The duration of development was sensitive to the timing of temperature extremes, as early exposure accelerated embryo development. Exposure to temperature extremes during embryonic development heightened the exploratory activity of hatched larvae. We conclude that the timing and magnitude of ecologically realistic temperature extremes during embryogenesis have nonlethal effects on life history and behavioral traits. This suggests that species' vulnerability to climate change might be determined by other ecophysiological traits beyond embryonic thermal tolerance in temperate pond‐breeding amphibians. Research highlights: Embryonic exposure to extreme temperatures affected development time and hatchling length but not survival.Development time was sensitive to the timing of temperature extremes.Temperature extremes increased hatchling exploration. [ABSTRACT FROM AUTHOR]

Invasive species threaten biodiversity globally. Amphibians are one of the most threatened vertebrate taxa and are particularly sensitive to invasive species, including other amphibians. African clawed frogs (Xenopus laevis) are native to Southern Africa but have subsequently become invasive on multiple continents—including multiple parts of North America—due to releases from the pet and biomedical trades. Despite their prevalence as a global invader, the impact of X. laevis remains understudied. This includes the Pacific Northwest of the USA, which now hosts multiple expanding X. laevis populations. For many amphibians, chemical cues communicate important information, including the presence of predators. Here, we tested the role chemical cues may play in mediating interactions between feral X. laevis and native amphibians in the Pacific Northwest. We tested whether native red-legged frog (Rana aurora) tadpoles display an antipredator response to non-native frog (X. laevis) or native newt (rough-skinned newts, Taricha granulosa) predator chemical stimuli. We found that R. aurora tadpoles exhibited pronounced anti-predator responses when exposed to chemical cues from T. granulosa but did not display anti-predator response to invasive X. laevis chemical cues. We also began experimentally testing whether T. granulosa—which produce a powerful neurotoxin tetrodotoxin (TTX)—may elicit an anti-predator response in X. laevis, that could serve to deter co-occupation. However, our short-duration experiments found that X. laevis were attracted to newt chemical stimuli rather than deterred. Our findings show that X. laevis likely poses a threat to native amphibians, and that these native species may also be particularly vulnerable to this invasive predator, compared to native predators, because toxic native newts may not limit X. laevis invasions. Our research provides some of the first indications that native Pacific Northwest species may be threatened by feral X. laevis and provides a foundation for future experiments testing potential management techniques for X. laevis. [ABSTRACT FROM AUTHOR]

To improve monitoring techniques, we investigated the colour vision of the Calabrian Alpine newt (Ichthyosaura alpestris inexpectata). We conducted controlled behavioural experiments on male and female newts to explore their response to artificial coloured light sources in the dark. We used green, blue, and orange glow sticks. Observations indicated that both sexes strongly preferred green glow sticks, which were selected in almost 50% of the trials Additionally, newts exhibited markedly swifter reactions to green light. The attraction to green glow sticks may be due to the biofluorescence within the green wavelength spectrum in this newt. This glowing ability, which resembles the green glow stick's glow, could be beneficial in low-light conditions to locate other newts. Our results show that the behavioural preferences towards a particular light source can significantly enhance the success of capturing newts during population monitoring and conservation efforts for this rare and threatened taxon. [ABSTRACT FROM AUTHOR]

Newts can regenerate functional elbow joints after amputation at the joint level. Previous studies have suggested the potential contribution of cells from residual tendon tissues to joint cartilage regeneration. A serum‐free tissue culture system for tendons was established to explore cell dynamics during joint regeneration. Culturing isolated tendons in this system, stimulated by regeneration‐related factors, such as fibroblast growth factor (FGF) and platelet‐derived growth factor, led to robust cell migration and proliferation. Moreover, cells proliferating in an FGF‐rich environment differentiated into Sox9‐positive chondrocytes upon BMP7 introduction. These findings suggest that FGF‐stimulated cells from tendons may aid in joint cartilage regeneration during functional elbow joint regeneration in newts. [ABSTRACT FROM AUTHOR]

Iberian populations of large-bodied newts, with Triturus marmoratus in the north and T. pygmaeus in the south of the peninsula, were studied for external morphology, mitochondrial dna and for a panel of single nucleotide polymorphisms. This confirmed the species' low level of interspecific hybridization and their parapatric, mosaic-like mutual range border across the peninsula. The genetic data also revealed substantial variation within T. pygmaeus, with narrow (0.43-35.2 km) clinal transitions in the very centre of Portugal. Similar clines were observed for body size and colouration pattern. Pygmy newts in the west of Portugal are larger, with a more striped (less reticulated) green dorso-lateral colouration pattern than those in the east and south of the country. The western group of populations is described as a new species, Triturus rudolfi sp. nov., on account of a long, ca. 2.5 Ma, independent evolutionary history and limited hybridization with its sister-species T. pygmaeus, suggesting selection against hybrid offspring. The range of the newly described species may be restricted to the wider Lisbon Peninsula, stretching northwards along the Atlantic coast to the river Vouga estuary. Inland, the range border may be set by the lower Tejo River, or by the currently wide area of agricultural land at either side of that river, that may accommodate a residual hybrid zone. The close contact between both pygmy newt species is effectively limited to a ca. 20 × 40 km area directly north of the town Entroncamento, where T. rudolfi sp. nov. is sandwiched in between T. marmoratus and the river Tejo. [ABSTRACT FROM AUTHOR]

Morphological and genetic variation of organisms is generally lower in northern than in southern regions of the Palearctic. This ubiquitous geographical pattern has been associated with extinction and recolonization processes in the north versus persistence in the Mediterranean area, as governed by climate change in the Pleistocene. One area of differentiation and complexity is the Iberian Peninsula where two distinct sister-species of marbled newts possess adjoining and geographically sharply delimited ranges over the north (Triturus marmoratus) and the south of the peninsula (T. pygmaeus). Within the latter species two forms are here documented, with different colouration patterns and non-overlapping ranges. The southern form is striped, much as in T. marmoratus, and occurs to the south of the Guadalquivir River. The northern form, here described as a new subspecies, has a reticulated dorsal colouration. It occurs only north of the Guadalquivir and is thus sandwiched in between two striped marbled newt taxa. Both T. pygmaeus subspecies engage inside the Doñana National Park in a ca. 2,500 m narrow contact zone. Although an inferred substantial selection against hybrids goes a long way to support species status, a reanalysis of published genetic data is required to solve this issue, along with the wider investigation of the same type of (microsatelite) data for the southern, nominotypical subspecies. [ABSTRACT FROM AUTHOR]

In amniote limbs, Fibroblast Growth Factor 10 (FGF10) is essential for limb development, but whether this function is broadly conserved in tetrapods and/or involved in adult limb regeneration remains unknown. To tackle this question, we established Fgf10 mutant lines in the newt Pleurodeles waltl which has amazing regenerative ability. While Fgf10 mutant forelimbs develop normally, the hindlimbs fail to develop and downregulate FGF target genes. Despite these developmental defects, Fgf10 mutants were able to regenerate normal hindlimbs rather than recapitulating the embryonic phenotype. Together, our results demonstrate an important role for FGF10 in hindlimb formation, but little or no function in regeneration, suggesting that different mechanisms operate during limb regeneration versus development. [ABSTRACT FROM AUTHOR]

Adult mammals are known for their poor ability to regenerate tissues, including tendons. On the other hand, urodeles have become an important model in regenerative studies for their remarkable ability to regenerate various body parts and organs throughout life, such as limbs, retinas, or even the brain. However, little is known about their capacity to regenerate injured tendons. If newts can also repair tendons without scar formation, they may be a suitable animal model for tendon regeneration studies in other adult vertebrates. Therefore, the present study used Iberian ribbed newts to characterize mechanical and structural regeneration of tendons following transection, using tensile tests and multiphoton microscopy. A digital flexor tendon in a hindlimb was transected either partially or completely, and regenerated tendon was examined 6 and 12 weeks after the operation. Tensile strength of regenerated tendons was significantly less than normal at 6 weeks, but was remarkably recovered at 12 weeks, reaching levels comparable to those of uninjured tendons. On the other hand, mouse tendons demonstrated poor recovery of strength even after 12 weeks. Multiphoton microscopy revealed that tendon‐like collagenous tissue bridges residual tendon stubs in newts, but disorganized scar‐like tissue filled the injured location in mice. These findings highlight the remarkable capacity of newts to recover from tendon injury and confirm the utility of newts as a model to study tendon regeneration. [ABSTRACT FROM AUTHOR]

Vertebrate animals often exhibit sexual dimorphism in body shape. In mammals, decreases in sex hormones caused by testicular castration can affect body shape and occasionally lead to pathologies such as obesity. Post-castration obesity can also be problematic for the health of companion animals, including non-mammals. In order to understand the mechanism of post-castration obesity in vertebrates other than mammals, experimental models are required. We examined whether the Iberian ribbed newt, which has recently become a popular experimental model for amphibian research, could serve as a model for analyzing changes in body shape after castration. In newts, new testes can be regenerated after removal of differentiated testes. We analyzed changes in body shape by removing the testes under conditions in which they could regenerate or conditions in which they could not regenerate. Removal of the testes reduced blood testosterone levels. The body weight and abdominal girth of the newts were increased compared with normal male newts. Transcriptome analysis of the liver showed that a set of genes related to lipid metabolism was continuously up-regulated in castrated newts. Our study suggests that changes in body shape after castration are common in vertebrates. Iberian ribbed newts are thus a suitable model for comparative studies of the long-term physiologic- and endocrine-level effects of castration.

Seasonal activity of the Japanese red-bellied newt, Cynops pyrrhogaster, was monitored in Minami-ohsawa, Hachioji-shi, Tokyo, from 2016 to 2017. The number of newts in the water of a pond was counted immediately after sunset, at least once a week, except in winter. The number of newts counted varied daily, and the time-series data on newt activity were analyzed using state-space modeling to estimate the impact of weather conditions and lunar phase on the activity due to the presence of plausible temporal autocorrelation. We found that some weather conditions, such as water temperature and atmospheric pressure, had significant positive effects on newt activity. Newts became more active during nights with higher temperatures and/or higher pressure. However, we did not detect any significant effect of the lunar phase on newt activity. The most important variable affecting newt activity was water temperature. The active season of newts was estimated to be nine months from March to November. Newt activity showed a sharp decline in the nightly activity of males and an extreme female-biased sex ratio was observed in early April suggesting that the degree of nocturnality differed across seasons and the two genders. This phenomenon may be related to the presence of mating activity during this particular season. [ABSTRACT FROM AUTHOR]

Hybridization between the European smooth and palmate newts has recurrently been mentioned in the literature. The only two studies that attempted to quantify the frequency of hybridization and gene admixture between these two species came to strikingly opposite conclusions. According to Arntzen et al. (1998, 42 allozymes), hybrids are rare in nature and introgression negligible, while according to Johanet et al. (2011, 6 microsatellites), introgressive hybridization is significant and widespread across the shared distribution range. To clarify this question, we implemented high-throughput SNP genotyping with diagnostic biallelic SNPs on 965 specimens sampled across Europe. Our results are in line with Arntzen et al., since only two F1 hybrids were identified in two distinct French localities, and no further hybrid generations or backcrosses. Moreover, reanalysis of 78 of the samples previously studied by Johanet et al. (2011) using our SNPs panel could not reproduce their results, suggesting that microsatellite-based inference overestimated the hybridization frequency between these two species. Since we did not detect methodological issues with the analyses of Johanet et al., our results suggest that SNP approaches outperform microsatellite-based assessments of hybridization frequency, and that conclusions previously published on this topic with a small number of microsatellite loci should be taken with caution, and ideally be repeated with an increased genomic coverage. [ABSTRACT FROM AUTHOR]

The analysis of the parasitic and endosymbiontofauna of the common newt (Lissotriton vulgaris L., 1758) in the natural and urban landscapes of the Middle Urals is presented for the first time. Four species of helminths belonging to the Nematoda type were found, including one taxon indeterminate to the species (Nematoda sp.) and one species of endosymbionts (phylum Chromista). The works devoted to the species composition of L. vulgaris parasites on the territory of Eurasia are analyzed. The fauna of the helminths of the common newt on the eastern slope of the Urals is depleted, which is probably determined by the limited distribution of the species outside Europe, the temperature regime in the north, and the availability of moisture in the south. [ABSTRACT FROM AUTHOR]

Olfaction is an important mechanism of orientation in amphibians toward the breeding site. It is known that anurans can memorize the odor of the native pond during larval development and prefer this odor prior to the beginning of dispersion. However, such a mechanism in urodeles has not been studied yet. We conducted experiments on recognition of the odor of a native water body in juveniles of the smooth newt Lissotriton vulgaris. One group of larvae were reared in pure water (control), the other group in water with morpholine (10–7 mol/L). A few days after metamorphosis, the newts were tested under paired-choice conditions in a T-maze. A total of 73 newts from the experimental group and 47 newts from the control group were tested. The results of the experiment show that the newts in the experimental group preferred the morpholine solution, whereas the individuals of the control group made the choice randomly. We conclude that newts can learn the odor of the environment in which they developed and use this memory for orientation in later stages of life. [ABSTRACT FROM AUTHOR]

The evolutionary causes behind the development of taste discs (TDs), recognized as the only gustatory organs in metamorphosed Batrachia (Caudata and Anura), have yet to be determined. Taste buds (TBs) serve as the gustatory organs in aquatic batrachian larvae, as well as in both larval and adult caecilians (Gymnophiona) inhabiting either aquatic environments or moist terrestrial habitats. We describe the morphology of gustatory organs of adult crocodile newts (Tylototriton cf. verrucosus , Salamandridae, Caudata). Crocodile newts are semi-aquatic and exhibit increased specialization towards an aquatic feeding, distinguishing it from most members of the subfamily Pleurodelinae. Our findings confirm that TDs serve as the gustatory organs in adult T. cf. verrucosus , similarly to many batrachians. We also determined the density and sizes of TDs' sensory zones on the tongue and palate of T. cf. verrucosus , which differs from Batrachia. In terms of micro-morphology, two types of gustatory cells (GCs) were identified in the gustatory epithelium of T. cf. verrucosus. Our literature analysis suggests that TDs were larger in anurans compared to caudate amphibians, but were also larger in aquatic/semi-aquatic than in terrestrial anurans. [ABSTRACT FROM AUTHOR]

Habitat modification and invasive species are considered some of the most impelling causes of the ongoing sixth mass extinction, especially in freshwater ecosystems. Artificial water troughs are, in this regard, particularly vulnerable environments, while being pivotal breeding habitats for many amphibian species. However, despite their well‐known importance and their conservation concern, detailed information on the resilience of such ecosystems is lacking.This note describes the events following the introduction of invasive fish species into a water trough in southern Italy and reconstructs the recolonization times of two newt species (Lissotriton italicus, Triturus carnifex) after disappearance of the fish a few months later.As expected, both newt species were no longer observed in the water as soon as the fish were introduced in the trough. However, in contrast to previous reports, they recolonized it within 2 months of the last observation of fish and, in the case of L. italicus, bred shortly after.Although the short permanence of fish in the trough may have facilitated the recolonization process, this event represents the fastest recolonization by newts of a restored habitat ever reported in the wild and sheds further insights on the resilience of amphibian species. [ABSTRACT FROM AUTHOR]

Updated information on the distribution and studied populations of T. cristatus on the eastern macro-slope of the Urals (Middle and Southern Urals) is provided. Based on tagging with recapture, the number of reproductive individuals of the populations, the sex ratio, and the morphological specificity are estimated for the first time. From the standpoint of assessing the physicochemical features of the habitat environment, possible limiting factors (thermal and moisture availability, geochemical characteristics, climate continentality, and the presence of natural enemies and invasive species) that affect the distribution and abundance of the great crested newt near the northeastern limit of the range are discussed. [ABSTRACT FROM AUTHOR]

In order to observe the habitats of the Anatolian banded newt (Ommatotriton nesterovi), field studies were carried out in a total of 11 different localities in Samsun, Zonguldak, Bartın, and Karabük provinces, and 12 ones in Trabzon and Rize provinces for the Caucasian banded newt (Ommatotriton ophryticus). MaxEnt modeling was performed in order to test the compatibility of the information obtained in field studies with the results obtained as a result of modeling. The coordinate data from of a total of 95 separate localities belonging to the O. nesterovi that exist in the literature and were obtained in this study, and 43 ones belonging to the O. ophryticus were used. When the data obtained from field observations and modeling in this study are evaluated together, it is understood that the Anatolian banded newt endemic to Türkiye chooses places with lower altitude and areas with lower slopes and forest that do not receive much direct sunlight takes an important place in the habitat preference of this species compared to the Caucasian banded newt distributed in Türkiye, Georgia, Russia, and Armenia. [ABSTRACT FROM AUTHOR]

Turbidity represents an obstacle to visual acuity underwater that might entail considerable consequences for multiple faunal traits. Morphology, especially eye size, could be adjusted to cope with reduced visibility in turbid water. Moreover, turbidity could interfere with colour signals or crypsis. Turbid water may simultaneously impair the ability of prey and predators to detect each other, which may cause reduced speed, flight initiation distance, activity time, boldness, and exploratory behaviour by prey.In this work, we compared these traits in larvae of the newt Pleurodeles waltl from transparent and turbid ponds (around 100 and 300 FTU, respectively). Body size did not differ between pond types, but larvae from turbid ponds had smaller eyes, probably because visual acuity is structurally hindered by the environment. Colouration did not differ between transparent and turbid ponds on average, but it was more variable in larvae from transparent than turbid ponds, probably because transparent ponds trigger crypsis towards diverse background colours, whereas turbid ponds promote reduced pigmentation in all cases.In addition, behavioural traits were gauged in larvae from both types of ponds, in tests conducted in either transparent or turbid water. Speed was unaffected by turbidity, but larvae from turbid ponds increased their flight initiation distance when tested in transparent water. In all cases, larvae from transparent ponds were more active, and bolder in transparent water, and all larvae were more exploratory when tested in transparent water (regardless of which pond type they came from).Turbidity could trigger more cautious behaviours, probably because it makes predators harder to track. Alternatively, transparent water could stimulate a more expansive use of space through improved visibility, or it might encourage a more active search for shelter.These results shed light on the role of turbidity as a promotor of morphological and behavioural variability in amphibian larvae. These ecological consequences of water turbidity can be framed in terms of energy allocation and detectability in the context of predator–prey interactions. [ABSTRACT FROM AUTHOR]

Long-time monitoring studies recently indicated that newts are in decline in many regions. Motivated by the above-mentioned, in the year 2019, we started monitoring the newt populations from the Jiu Gorge National Park (JGNP) in the Romanian Carpathians, 10 years after the previous study on the same topic. Compared with other areas where newts are in decline, we identified new distribution locations of the two newt species which are present in the park. Also, the previously known populations have greatly increased. Thus, the Lissotriton vulgaris population increased 2.58 times in 10 years, and the Triturus cristatus increased 1.80 times in 10 years. At the same time, in areas from JGNP affected by human activities in the past (abandoned quarry and areas adjacent to the railway), the newts extended their range in the last years and occupied artificial aquatic habitats. In the case of the populations from the natural habitat, the temporal dynamics and the ratio between sexes and species followed the same evolution as in the case of other populations from Romania. The increase of newt populations from JGNP in the last 10 years was most probably a consequence of the reduced human pressure, corroborated with the large surface occupied by native forests in the park. Thus, in natural areas, probably the best management measures for both newt species are not represented by direct (invasive) human interventions but by the conservation of the natural habitats used by the newts. A protected area should maintain the conservation status at least at the present level, and if the region is natural, this fact will maintain and also increase the newt and probably other amphibian populations. [ABSTRACT FROM AUTHOR]

The southern crested newt Triturus karelinii Strauch, 1870, is widely distributed on the northern Iran plateau, where it is one of the most common newts. Mitochondrial DNA sequences (the genes cyt b and ND4) were used to determine the genetic diversity and phylogenetic position of Iranian Triturus. The results corroborate the monophyly of T. karelinii and confirm that all Iranian and Azerbaijan populations belong to the same species. Genetic distances (K2-p) between Iranian T. karelinii and other Triturus species was relatively high, (7–25% for ND4 and 8–19% for cytb). However, infraspecific genetic diversity among the Iranian populations was very low, which may indicate strong gene flow between populations. [ABSTRACT FROM AUTHOR]

Maintaining habitat connectivity is crucial for maintaining genetic diversity and reducing the risk of inbreeding depression in numerous species. Human-modified habitats pose a threat to population persistence, particularly for amphibians that require both aquatic and terrestrial habitats and often exhibit low dispersal capacity. In this study, we investigated the genetic structure and variation of two sympatric newt species, Triturus cristatus and Lissotriton vulgaris, in an urbanized and agricultural landscape. Using a multiscale resistance modeling approach, we evaluated how landscape features affect gene flow in both species. Our results confirmed that the less abundant T. cristatus exhibited more genetically distinct demes than the more common L. vulgaris, which showed a more subtle structure. Additionally, levels of genetic variation were lower in T. cristatus than in L. vulgaris, but with a similar spatial distribution pattern across shared ponds. We found that the proportion of managed grassland in the study area played a major role in reducing the level of connectivity in both species. Furthermore, considering multiple spatial scales proved to be effective in improving the fit of the landscape resistance models, with the largest scale (900 m) providing the best fit. In T. cristatus, areas with low proportions of trees or high proportions of crop fields negatively affected genetic connectivity. Notably, resistance surfaces optimized for each species were highly correlated. The intensively managed grassland lacked the structural heterogeneity necessary for newts. Therefore, switching to a more traditional management approach in the landscape to increase spatial patchiness at the scale of dispersal would benefit both species. [ABSTRACT FROM AUTHOR]

Plethodon cinereus (Eastern Red-backed Salamander) exhibit multiple color morphs. An uncommon morph of ecological interest is the erythristic morph, where individuals are mostly or entirely red. Populations occasionally obtain high frequencies of erythrism, which may be indicative of an adaptive benefit. Only 5 populations containing erythristic individuals have previously been documented in Maine, and those have occurred in low numbers; denser populations have been mostly limited to southern New England. Here, we report a sixth population; we found 3 erythristic individuals during a survey of a woodlot in Kennebec County, ME, after adjacent landowners submitted photos documenting several erythristic morphs. The sightings indicate a relatively dense population of erythristic morphs for Maine. Notophthalmus viridescens (Eastern Newt), a suspected model for Batesian mimicry by erythristic Red-backed Salamanders, have not yet been documented at this site. [ABSTRACT FROM AUTHOR]

Amphibians are particularly sensitive to habitat loss and fragmentation caused by the intensification and modernization of farming occurring in the second half of the twentieth century in the Mediterranean basin. However, artificial water bodies, associated with traditional husbandry, proved to be important surrogate for amphibian feeding and reproduction. Here, multilocus genotypes were used to investigate the spatial population structure of Lissotriton vulgaris meridionalis and the role of drinking troughs in supporting viable breeding populations within a rural landscape interested by traditional husbandry and agriculture. Our genetic analysis highlighted the conservation value and the potential stepping-stone function of artificial aquatic sites in the dispersal of the species and for the gene flow maintenance. Indeed, populations of drinking troughs show allelic richness and heterozygosity levels comparable to those from natural ponds and there is no great evidence of genetic bottlenecks. A complex system of artificial aquatic sites and few natural wetlands was identified sustaining a well-structured network of demes highly interconnected with themselves and natural aquatic sites. The conservation of the identified genetic clusters may be useful to prevent further population declines and future loss of genetic diversity within the study area characterized by scarce natural wetlands that frequently dried because of agricultural practices and strong seasonality. Site-specific protection measures are needed to contrast the progressive disappearance of drinking troughs observed in the last years in Italy because of the abandonment of traditional farming practices in favour of modern agriculture and intensive farming. [ABSTRACT FROM AUTHOR]

One of the main factors creating intraspecific morphological variation, sexual dimorphism (SD) could be expressed as adult male and female animals having different body sizes or shapes. Female-biased sexual dimorphism has been documented in the vast majority of amphibians and more than half of salamanders. In this study, 18 morphometric characters were used to analyze the size and shape dimorphism of the southern banded newt, Ommatotriton vittatus, a species whose congeners exhibit male-biased dimorphism. In this way, the hypothesis that species within the same genus would have similar sexual dimorphism (for example, male- or female-biased) was tested. Results of the current study confirmed the existence of male-biased sexual size and shape dimorphism in O. vittatus. For instance, snout-vent length and tail length were found to be significantly different between sexes, with males being larger. Moreover, males have larger forelimbs and hindlimbs than females. Data from the present study also indicated significant male-biased differences in five (head length and width, eye diameter, distance between the orbit and naris, and internarial distance) out of eight head characters. This result supports the assumption that species within the same genus will have a similar tendency for sexual dimorphism. [ABSTRACT FROM AUTHOR]

Species with wide‐range distributions usually display high genetic variation. This variation can be partly explained by historical lineages that were temporally isolated from each other and are back into secondary reproductive contact, and partly by local adaptations. The smooth newt (Lissotriton vulgaris) is one of the most widely distributed amphibians species across Eurasia and forms a species complex with a partially overlapping distribution and morphology. In the present study, we explored the population genomic structure of smooth newt lineages in the Carpathian Basin (CB) relying on single‐nucleotide polymorphisms. Our dataset included new and previously published data to study the secondary contact zone between lineages in the CB and also tested for the barrier effect of rivers to gene flow between these lineages. We confirmed the presence of the South L. v. vulgaris Lineage distributed in Transdanubia and we provided new distribution records of L. v. ampelensis inhabiting the eastern territories of the CB. High genetic diversity of smooth newts was observed, especially in the North Hungarian Mountains and at the interfluves of the main rivers in the South with four distinct lineages of L. v. vulgaris and one lineage of L. v. ampelensis showing a low level of admixture with the spatially closest L. v. vulgaris lineage. Moreover, admixture detected at the interfluve of the main rivers (i.e. Danube and Tisza) suggested a secondary contact zone in the area. Finally, we found that the river Danube has a very weak effect on population divergence, while the river Tisza is a geographical barrier limiting gene flow between smooth newt lineages. As the range boundaries of L. v. vulgaris and L. v. ampelensis in the CB coincide with the river Tisza, our study underpins the influence of rivers in lineage diversification. [ABSTRACT FROM AUTHOR]

When two putatively cryptic species meet in nature, hybrid zone analysis can be used to estimate the extent of gene flow between them. Two recently recognized cryptic species of banded newt (genus Ommatotriton) are suspected to meet in parapatry in Anatolia, but a formal hybrid zone analysis has never been conducted. We sample populations throughout the range, with a focus on the supposed contact zone, and genotype them for 31 nuclear DNA SNP markers and mtDNA. We determine the degree of genetic admixture, introgression, and niche overlap. We reveal an extremely narrow hybrid zone, suggesting strong selection against hybrids, in line with species status. The hybrid zone does not appear to be positioned at an ecological barrier, and there is significant niche overlap. Therefore, the hybrid zone is best classified as a tension zone, maintained by intrinsic selection against hybrids. While the two banded newt species can evidently backcross, we see negligible introgression and the pattern is symmetric, which we interpret as supporting the fact that the hybrid zone has been practically stationary since its origin (while extensive hybrid zone movement has been suggested in other newt genera in the region). Our study illustrates the use of hybrid zone analysis to test cryptic species status. [ABSTRACT FROM AUTHOR]

Aim: Current genetic variation and differentiation are expected to reflect the effects of past rather than present landscapes due to time lags, that is, the time necessary for genetic diversity to reach equilibrium and reflect demography. Time lags can affect our ability to infer landscape use and model connectivity and also obscure the genetic consequences of recent landscape changes. In this work, we test whether past forest cover better explains contemporary patterns of genetic differentiation in two closely related but ecologically distinct newt species—Lissotriton montandoni and L. vulgaris. Location: Carpathian Mountains and foothills. Methods: Genetic differentiation between populations was related to landscape resistance optimized with tools from landscape genetics, for multiple timeframes, using forest‐cover data from 1963 to 2015. Analyses were conducted for pairs of populations at distances from 1 to 50 km. Results: We find evidence for a time lag in L. montandoni, with forest cover from 40 years ago (ca. 10 newt generations) better explaining current genetic differentiation. In L. vulgaris, current genetic differentiation was better predicted by present land‐cover models with lower resistance given to open forests. This result may reflect the generalist ecology of L. vulgaris, its lower effective population sizes and exposure to habitat destruction and fragmentation. Main Conclusions: Our study provides evidence for time lags in L. montandoni, showing that the genetic consequences of landscape change for some species are not yet evident. Our findings highlight the interspecific variation in time lag prevalence and demonstrate that current patterns of genetic differentiation should be interpreted in the context of historical landscape changes. [ABSTRACT FROM AUTHOR]

The purpose of this research note was to introduce a novel system of animal health warning labels to (i) contribute to better welfare (health) of animals used at nature-based ecotourism and wildlife (NEWT) attractions and (ii) provide a method to communicate to tourists in a language they are already exposed to daily. Two different frameworks inform the development of the proposed system, both of which are new to the tourism studies domain. The first situates an animal health warning label system within a 'health and social-ecological systems' mode of thinking, while the second focuses on the psychological, social, and philosophical mechanisms that determine participation at NEWT attractions. The research note concludes with policy, practice, implementation and monitoring recommendations. [ABSTRACT FROM AUTHOR]

Serially homologous structures may have complex patterns of regionalization and morphological integration, influenced by developmental Hox gene expression and functional constraints. The vertebral column, consisting of a number of repeated, developmentally constrained, and highly integrated units—vertebrae—is such a complex serially homologous structure. Functional diversification increases regionalization and modularity of the vertebral column, particularly in mammals. For salamanders, three concepts of regionalization of the vertebral column have been proposed, recognizing one, two, or three presacral regions. Using three‐dimensional geometric morphometrics on vertebra models acquired with microcomputerized tomography scanning, we explored the covariation of vertebrae in four closely related taxa of small‐bodied newts in the genus Lissotriton. The data were analyzed by segmented linear regression to explore patterns of vertebral regionalization and by a two‐block partial least squares method to test for morphological integration. All taxa show a morphological shift posterior to the fifth trunk vertebra, which corresponds to the two‐region concept. However, morphological integration is found to be strongest in the mid‐trunk. Taken jointly, these results indicate a highly integrated presacral vertebral column with a subtle two‐region differentiation. The results are discussed in relation to specific functional requirements, developmental and phylogenetic constraints, and specific requirements posed by a biphasic life cycle and different locomotor modes (swimming vs. walking). Further research should be conducted on different ontogenetic stages and closely related but ecologically differentiated species. Research Highlights: •The studied taxa of Lissotriton newts show a common pattern of regionalization, with a morphological transition after the fifth trunk vertebra.•The vertebral column is morphologically integrated, most strongly in the center of the trunk region.•Taken jointly, these results indicate a highly integrated presacral vertebral column with a subtle two‐region differentiation. [ABSTRACT FROM AUTHOR]

The Anatolian banded newt is an endemic amphibian species to the western and northern parts of Türkiye. The present study provides the new locality records of Ommatotriton nesterovi, which constitutes the species' easternmost known locality. With the record of the current study, the known distribution area of the species has been extended about 70 km eastward. Moreover, morphological comparisons were made between individuals from these two new localities and individuals from other regions. [ABSTRACT FROM AUTHOR]

IntroductionUrban areas are challenging environments for wetland species with complex habitat requirements and life cycles. However, even semiaquatic species, representing such complex wetland groups, can be provided with adequate conditions through thorough understanding of their habitat requirements coupled with comprehensive wetland management.MethodsWe studied the occurrence and abundance of the smooth newt (Lissotriton vulgaris), a widely distributed amphibian, in an urban landscape in metropolitan Helsinki, Finland. We classified 50 randomly selected urban wetlands based on their connectivity by applying isolation scores counted using principal component analysis (PCA) and measured the occurrence and abundance of smooth newts in these locations.ResultsOur analyses showed well-connected wetland sites to differ significantly in smooth newt occurrence from both isolated and partially connected sites. Additionally, smooth newt abundance in well-connected wetlands differed from isolated sites. A PCA model with residential buildings (negative effect) and aquatic vegetation (positive effect) best explained smooth newt occurrence and total and male abundance, and female newt occurrence was best explained by a model also incorporating forest and natural open areas. Predation pressure by fish negatively influenced both smooth newt occurrence and abundance.DiscussionTighter networks of constructed wetlands and stricter management guidelines for urban wetland planning and fish community management could increase the suitable habitat for smooth newts in urban landscapes. Managing such areas for the common smooth newt offers potential broad benefits to the conservation of other semiaquatic amphibians and reptiles in urban wetlands and to urban wetland biodiversity in general. Our results show that smooth newt presence may indicate sustained wetland connectivity in an urban landscape and could even be used to signal successful urban planning.

Quaternary climatic cycles strongly affected the genetic diversification and ranges of organisms, shaping current genetic structures and distribution patterns. Urodeles provide ideal examples for exploring these dynamics over time and across space. In this study, we integrated a phylogeographic approach and ensemble species distribution modeling (eSDM) to infer the historical demography and distribution patterns of the Vietnam warty newt, Paramesotriton deloustali. Mitochondrial data revealed two groups, West and East, which diverged approximately 1.92 million years ago (Mya). Diversification was likely driven by change in the climate during early stages of the Pleistocene, with increasing monsoon and drought intensities. Biogeographic analysis indicated that the newt's current distribution formed as a result of vicariance events. In addition, the two groups occupy distinct ecological niches. Demographic reconstruction showed signs of expansion in the effective population sizes of the two major groups beginning around 0.11 and 0.15 Mya, respectively. However, eSDM showed fluctuating predicted distributions during the last interglacial, last glacial maximum, mid-Holocene, and present. Mountain systems in northern Vietnam are likely to have served as climatic refuges and to have played a crucial role in safeguarding species from the effects of climate change. [ABSTRACT FROM AUTHOR]

The Japanese fire-belly newt, Cynops pyrrhogaster, is a near threatened species that is conservation dependent. Here, we examine feeding habits across the year within a genetically divergent intraspecific lineages of this species (the Central Lineage) to provide information to support future insitu and ex-situ conservation activities. Stomach contents from newts were collected in a paddy field habitat, Kyoto City, central Honshu, Japan for two consecutive years. Throughout the year, dipteran aquatic larvae were the most important food source both for males and females, although terrestrial invertebrates were also important prey for the newts. During periods of low prey availability shed skin could also be a relatively valuable source of food. Sympatric frogs and newts appear to target different prey and this may facilitate their co-existence. Our study provides new information on suitable prey items for the Central Lineage of C. pyrrhogaster both in its natural habitat and in captivity. [ABSTRACT FROM AUTHOR]

Studying the relationships between predators and their prey is generally complex but provides valuable knowledge into the process of evolution. The clay model method is a technique that has been widely used to assess prey-predator interaction. In the study, we used clay models of the Vietnam warty newt (Paramesotriton deloustali) to evaluate its predator pressures in Tam Dao National Park (NP), northern Vietnam. We also employed camera traps to detect specific predators of the newt in nature. Our camera trap results showed that northern treeshrew (Tupaia belangeri), rats (Rattus sp.), and greater coucal (Centropus sinensis) are predators of the newt in Tam Dao NP. For the clay model experiment observed attacks on the head of clay models were triple those expected by chance, indicating that predators perceived the clay model as actual prey items. The proportions on the models predated upon differed in three habitat types: broadleaf evergreen forests, mixed broadleaf evergreen and bamboo forests, and bamboo forests. We also detected that the attacks on the models were mainly made by mammals. Attack rates at nighttime were three times higher than during the daytime. [ABSTRACT FROM AUTHOR]

Ecologically distinct species may respond to landscape changes in different ways. In addition to basic ecological data, the extent of the geographic range has been successfully used as an indicator of species sensitivity to anthropogenic landscapes, with widespread species usually found to be less sensitive compared to range‐restricted species. In this study, we investigate connectivity patterns of two closely related but ecologically distinct newt species – the range‐restricted, Lissotriton montandoni and the widespread, L. vulgaris – using genomic data, a highly replicated setting (six geographic regions per species), and tools from landscape genetics. Our results show the importance of forest for connectivity in both species, but at the same time suggest differential use of forested habitat, with L. montandoni and L. vulgaris showing the highest connectivity at forest‐core and forest‐edges, respectively. Anthropogenic landscapes (i.e., higher crop‐ or urban‐cover) increased resistance in both species, but the effect was one to three orders of magnitude stronger in L. montandoni than in L. vulgaris. This result is consistent with a view of L. vulgaris as an ecological generalist. Even so, currently, the negative impact of anthropogenic landscapes is mainly seen in connectivity among L. vulgaris populations, which show significantly stronger isolation and lower effective sizes relative to L. montandoni. Overall, this study emphasizes how habitat destruction is compromising genetic connectivity not only in endemic, range‐restricted species of conservation concern but also in widespread generalist species, despite their comparatively lower sensitivity to anthropogenic landscape changes. see also the Perspective by Kristen N. Finch and Adam D. Leache [ABSTRACT FROM AUTHOR]