Showing papers in "Amphibia-reptilia in 2008"
TL;DR: No single independent variable can explain density differences among populations under study, and neither degree of island accessibility nor presence/absence of seagull breeding colonies, were able to explain lizard densities.
Abstract: The Balearic lizard, Podarcis lilfordi , is present in 43 insular populations in the Cabrera archipelago and around the coasts of Mallorca and Menorca islands (Spain). We studied lizard densities over the entire range of distribution, analyzing observed differences of density in relation to island area, habitat diversity, availability of resources, presence of predators, competitors and human disturbances. The density of the Balearic lizard varies from less than 35 to almost 8000 lizards ha –1 , with an average of around 1500 lizards ha –1 . In some very small islets we detected no more than 10 individuals. Using a subsample of nine coastal islets (Menorca) we did not find any significant correlation between ground arthropod biomass and lizard density. The combination of island area and its maximal altitude, its so-called biotic capacity, was also uncorrelated with lizard density. In addition, neither degree of island accessibility nor presence/absence of seagull breeding colonies, were able to explain lizard densities. Islands without ship rats ( Rattus rattus ) showed a significantly higher lizard density, but islands in which rat eradication programs were launched during the study period, showed lower densities than those with rats but no eradication actions. Genetic variability was significantly higher on bigger lizard populations, lacking a correlation with lizard densities. No single independent variable can explain density differences among populations under study. Our results are discussed in the light of available hypotheses on factors affecting population densities.
74 citations
TL;DR: Females had higher incidence of road-kills than males, due to the differential activity patterns of both sexes during the reproductive period, and most of the road-killed and live specimens were located on migration routes crossing suitable habitats.
Abstract: Road-kills are the greatest source of direct human-induced wildlife mortality, especially in amphibians. Country roads could act as the most important source of mortality when main roads act as strong barriers hampering the migration movements of some species. Mortality patterns of amphibians on country roads (1380 km) were studied in Salamanca (Spain) in order to quantify the mortality levels, to test the effects of sex and age factors on road-kills, to determine the spatial distribution patterns of road-kills, and to identify routes of migration through a friction map and hotspots of road-kills. From a total of 819 records of amphibians, 38.1% were road-killed and 61.9% were live. Fourteen amphibian species were recorded during the surveys (10 anurans and four urodeles). The species more affected by road-kills were the anurans Bufo calamita, Pelobates cultripes and B. bufo (38.5, 23.4 and 11.9%, respectively). Females had higher incidence of road-kills than males, due to the differential activity patterns of both sexes during the reproductive period. Adults were the most common age period and also the most road-killed. The spatial distribution patterns of live and road-killed records were clustered. On the sampled roads, there were 0.23 road-kills per kilometre and 52 hotspots of road-kills. The friction map showed that most of the road-killed and live specimens were located on migration routes crossing suitable habitats. Conservation measures should be implemented in these areas, as these mortality patterns may be causing significant negative impacts at the population level.
64 citations
TL;DR: Results suggest that anuran tadpoles may be living near their physiological limit for salinity in the studied wetland, as salt water intrusion and urban encroaching inland may result in anuran population replacement, from native species to introduced species in this wetland.
Abstract: Many amphibians depend on wetland ecosystems for reproduction and survival, and coastal wetlands are not the exception. Recent advances on climate change research predict a reduction in land cover of coastal wetlands due to sea-level rise in response to global warming. Although this scenario will contribute to further amphibian population declines worldwide the impacts of sea-level rise and its related salt water intrusion on anuran assemblages in coastal wetlands remain largely unknown. I documented patterns of abundance of the native Caribbean white-lipped frog ( Leptodactylus albilabris ) and the introduced marine toad ( Bufo marinus ) along an inland-to-coastal salinity gradient in Puerto Rico. In addition, I investigated the effects of increasing salinity on larval growth and survival to metamorphosis in L. albilabris and B. marinus in laboratory experiments. In the field, relative abundance of adults of L. albilabris decreased with increasing salinity, while B. marinus showed the opposite pattern. Laboratory experiments with L. albilabris and B. marinus revealed that percentage of larvae surviving to metamorphosis in both species was greatly reduced in 22-25% seawater (8 ppt), which is within salinity levels found in their natural distribution. In this salinity level, the native L. albilabris showed ∼100% metamorphosis failure while the introduced B. marinus showed ∼60% metamorphosis failure. The reduction in metamorphosis was due to high mortality in L. albilabris and was accompanied with morphological abnormalities in B. marinus . Tadpoles of only L. albilabris reared for four weeks showed significant weight loss at 8 ppt, but showed no difference in length. These results suggest that anuran tadpoles may be living near their physiological limit for salinity in the studied wetland. Conservation implications are profound, however, as salt water intrusion and urban encroaching inland may result in anuran population replacement, from native species to introduced species in this wetland.
51 citations
TL;DR: The African Clawed Frog, Xenopus laevis, shows a strong ability to establish populations and invade various geographic regions and the analysis of their diet shows that the aquatic larvae of nektonic insects comprise the major portion of mass while small planktonic crustaceans are the most numerous component.
Abstract: The worldwide spread of invasive species is considered to be one of the main causes of global amphibian declines and the loss of biodiversity in general. The African Clawed Frog, Xenopus laevis, shows a strong ability to establish populations and invade various geographic regions. In 2004 X. laevis was found in Sicily for the first time. The Sicilian population is probably the largest in Europe with a range of about 225 km 2 in an area characterized by numerous agricultural ponds. This high density of ponds has potentially facilitated the dispersal of X. laevis. The frogs can move far from rivers or watercourses by utilizing the ponds as suitable "islands". The analysis of their diet shows that the aquatic larvae of nektonic insects comprise the major portion in terms of mass while small planktonic crustaceans are the most numerous component. There is a significant difference between the diet of adults and juveniles.
46 citations
TL;DR: Tortoises showed a marked preference for the open-canopy swampy forest, where long term recruitment was not favorable for seedlings of the species examined, however, the high solar radiation in this forest type promoted survival of pioneer seedlings in the short term.
Abstract: The Amazonian tortoise Geochelone denticulata may play an important role in forest dynamics due to its highly frugivorous diet, ability to disperse viable seeds, and predilection for resting in forest gaps for thermoregulation. The purpose of our study was to evaluate the species' effectiveness as a seed disperser. We measured dispersal quantity (abundance of seeds in feces, frequency of droppings, and population density of the disperser) and dispersal quality (movement patterns, habitat use, germination rates of dispersed seeds, and recruitment probabilities of seedlings) in a SW Amazonian forest, in Peru. Population density was calculated by mark-recapture and line-transect methods. Eight individuals were radio-tracked to monitor habitat use. Diet was described from fecal samples, which were washed to count seeds and for germination experiments. Seedling survival in different environmental conditions was monitored for three plant species. Population densities with mark-recapture estimates (0.15-0.31 individuals/ha) were much higher than with line transects estimates (0.0025 individuals/ha). Diet included fruit of 55 different plant species. Dispersed seeds had high germination rates (average 76%). In spite of their low activity, we documented long seed dispersal distances (average 89.6 m). Tortoises showed a marked preference for the open-canopy swampy forest, where long term recruitment was not favorable for seedlings of the species examined. However, the high solar radiation in this forest type promoted survival of pioneer seedlings in the short term. In conclusion, while G. denticulata did not perform a very efficient role in terms of the quantity of seed dispersal, the species can be considered efficient in many aspects of dispersal quality.
41 citations
TL;DR: The long-term monitoring has showed an increasing birth rate of triploid hybrids in this mixed population of rock lizard species Darevskia, and the frequency of captured males with fully developed reproductive systems and presumably fertile females also increased significantly.
Abstract: A unique hybridization zone of rock lizard species of genus Darevskia, with diploid (2n), triploid (3n )a nd tetraploid (4n) individuals, occurs in the mountain steppe of central Armenia. Our long-term monitoring has showed an increasing birth rate of triploid hybrids in this mixed population. Among these hybrids, the frequency of captured males with fully developed reproductive systems and presumably fertile females also increased significantly. Consequently, intensive microevolution has taken place in this sympatric population. The morphological, ecological, cytological, histological, and parasitological characteristics of the hybrid Darevskia are presented here and compared with parental species.
41 citations
TL;DR: The results indicate that Coronella austriaca presents at least three mtDNA lineages in Iberia that may have originated during the Messinian Salinity Crisis, 5.3-5.9 Ma, and support the more recent view that the accentuated environmental instability occurred during the Pleistocene did not lead to speciation in many animal groups.
Abstract: The European Smooth snake, Coronella austriaca Laurenti, 1768, presents a continuous distribution range across central and northern Europe, with isolated fragmented populations in the southern European peninsulas. Up to 814 bp of mitochondrial DNA from 34 specimens were used to determine the phylogeny and biogeography of this species within the Iberian Peninsula. The results indicate that Coronella austriaca presents at least three mtDNA lineages in Iberia that may have originated during the Messinian Salinity Crisis, 5.3-5.9 Ma. Posterior range shifts within the independent clades were facilitated by climatic fluctuations that occurred during the Pleistocene Ice Ages and, in the Iberian Peninsula, created a complex scenario of refugia-within-refugia. The formation of old allopatric lineages during the Messinian followed by shifts in the distribution range during the Pleistocene coincide with what has been reported for other Iberian reptiles and amphibians and highlights the importance of the Southern European Peninsulas as "old" hotspots of biodiversity. Our results also support the more recent view that the accentuated environmental instability occurred during the Pleistocene did not lead to speciation in many animal groups. The subspecific status of C. a. acutirostris is confirmed by the mtDNA analyses.
38 citations
TL;DR: It is suggested that Saurodactylus will need to be partitioned into two genera, pending further investigations, because of the extremely high mtDNA variability almost universally reported from within gecko species.
Abstract: Phylogenetic relationships of the three morphological forms within the gecko genus Saurodactylus were estimated using mtDNA (12S rRNA and ND4) sequences. High between morphological forms variation (up to 25% with ND4), confirms that all three deserve specific status. Saurodactylus mauritanicus and Saurodactylus brosseti are strongly supported as sister taxa. Our results again highlight the extremely high mtDNA variability almost universally reported from within gecko species. The position of Saurodactylus within the Gekkonoidea was also investigated. Although considered as a member of the sphaerodactyl geckos, its taxonomic position is still highly uncertain. Evaluation of C- mos nuclear DNA sequences supports many of the recent taxonomic rearrangements within the Gekkonoidea. Using this marker, Saurodactylus is paraphyletic, with S. mauritanicus and S. brosseti sister taxa to Teratoscincus przewalskii rather than Saurodactylus fasciatus . This is supported by a further nuclear marker, RAG1 , although for this gene region sampling is more limited. Based on this paraphyly, supported by two independent nuclear markers, we suggest it likely that Saurodactylus will need to be partitioned into two genera, pending further investigations.
27 citations
TL;DR: Whether strong chemosensory response evolves to match current diet has not been established for snakes using the comparative method, and the basis for observed relationships is innate rather than experiential.
Abstract: Adaptations to foraging requirements have molded sensory capacities of animals in intriguing and sometimes spectacular ways, including evolution of echolocation by bats and infrared detection by pitvipers, as well as of location of prey using lingually sampled chemical cues by actively foraging lizards. Among snakes, specialized diets and geographic differences in diets have evolved many times. Because snakes identify prey by vomerolfactory analysis of chemicals sampled by tongue-flicking, it may be predicted that responsiveness to lingually sampled chemical cues corresponds to diet: It should be much stronger to prey included in than excluded from specialized diets and should covary with geographic dietary differences in prey generalists. Breeding studies in Thamnophis elegans showed that greater responsiveness to local prey in populations having geographically variable diets has a heritable component. Whether strong chemosensory response evolves to match current diet has not been established for snakes using the comparative method. For all paired comparisons of dietary change now available, chemosensory behavior changed so that strongest responses were limited to cues from the current prey. Because diets were specialized and snakes were ingestively naive hatchlings in almost all comparisons, the basis for observed relationships is innate rather than experiential. Snake chemosensory responses have evolved to match current diets.
TL;DR: Homalopsid Snakes: Evolution in the Mud is the only available book on these aquatic reptiles and the first comprehensive review of the group in 35 years.
Abstract: Cerberus rynchops (Schneider, 1799) Enhydris Sonnini and Latreille, 1802 Enhydris albomaculata (Duméril, Bibron, and Duméril, 1854) Enhydris alternans (Reuss, 1834) Enhydris bennettii (Gray, 1842) Enhydris bocourti (Jan, 1865) Enhydris chanardi Murphy and Voris, 2005 Enhydris chinensis (Gray, 1842) Enhydris doriae (Peters, 1871) Enhydris dussumieri (Duméril, Bibron, and Duméril, 1854) Enhydris enhydris (Schneider, 1799) Enhydris gyii Murphy, Voris and Auliya, 2005 Enhydris indica (Gray, 1842) Enhydris innominata (Morice, 1875) Enhydris jagorii (Peters, 1863) Enhydris longicauda (Bourret, 1934) Enhydris maculosa (Blanford, 1879) Enhydris matannensis (Boulenger, 1897) Enhydris pahangensis Tweedie, 1946 Enhydris pakistanica Mertens, 1959 Enhydris plumbea (Boie, 1827) Enhydris polylepis (Fischer, 1886) Enhydris punctata (Gray, 1849) Enhydris sieboldii (Schlegel, 1837) Enhydris subtaeniata (Bourret, 1934) Enhydris vorisi Murphy 2006 Erpeton Lácèpéde, 1800 H omalopsid snakes are aquatic rear-fanged snakes that inhabit freshwater, brackish water, and marine environments from Pakistan’s Indus River east ward to Queensland, Australia. While a few live in flowing streams with clear water and rocky bottoms, most live in the muddy habitats created by Himalayan silt flowing to the seas of Southeast Asia. Many feed on fish, but a few have adapted to feeding on crustaceans and some are commensal with crustaceans living in their burrows. The Indochinese Peninsula and Sunda Shelf contain the greatest species diversity, and the history of these snakes is closely tied to the changing landscape of Southeast Asia. Homalopsid Snakes: Evolution in the Mud is the only available book on these aquatic reptiles and the first comprehensive review of the group in 35 years. It contains species accounts, summaries of the field work, and photographs of the snakes and their morphology which can only be found in this book.
TL;DR: The morphometry and diet of two sympatric species of Chironius from Brazilian Cerrado are described, and these two snake species showed a brownish colour pattern and exhibited no ontogenetic variation, suggesting that juveniles and adults use similar substrates.
Abstract: The morphometry and diet of two sympatric species of Chironius (C. flavolineatus and C. quadricarinatus) from Brazilian Cerrado are described. The two snake species differ in external morphology, as Chironius flavolineatus was the largest species (body, tail and eyes) whereas C. quadricarinatus the heaviest. Each species also showed marked sexual size dimorphism. In terms of dietary ecology, both species feed exclusively on frogs with a heavy preference for hylids and may have tendency to eat small items, as noticed in other colubrine species. These two snake species showed a brownish colour pattern and exhibited no ontogenetic variation, suggesting that juveniles and adults use similar substrates. Chironius flavolineatus and C. quadricarinatus present a semi-arboreal habit, with active foraging behaviour, feeding in the ground most of time. Chironius flavolineatus uses higher vegetation for resting and, based on morphological results, seems to be more arboreal than C. quadricarinatus.
TL;DR: The first complete molecular species-level phylogeny for Oplurinae based on DNA sequences of the mitochondrial 16S rRNA gene and the nuclear c-mos gene is presented, confirming that, within the genus Oplurus, the largely arboreal O. cuvieri and O. cyclurus form the sister clade to the remaining, more rock-dwelling species.
Abstract: The iguanid subfamily Oplurinae consists of seven species of small to medium-sized, arboreal, sand-dwelling or rock-dwelling lizards endemic to Madagascar and the Comoros, belonging to the genera Oplurus and Chalarodon. We here present the first complete molecular species-level phylogeny for Oplurinae based on DNA sequences (865 bp) of the mitochondrial 16S rRNA gene and the nuclear c-mos gene. Our study is based on 52 specimens sampled from different populations in Madagascar and includes the geographically isolated population from Grande Comore, hitherto considered as subspecies Oplurus cuvieri comorensis or even as a separate species O. comorensis. Our results confirm that, within the genus Oplurus, the largely arboreal O. cuvieri and O. cyclurus form the sister clade to the remaining, more rock-dwelling species. Within the latter lineage, Oplurus quadrimaculatus is placed most basal, O. fierinensis and O. grandidieri are closely related sister species with high support, and O. saxicola is sister to the fierinensis/grandidieri lineage. Within the arboreal Oplurus, the Comoran sample shows no genetic differentiation relative to O. cuvieri populations from the North West and Sambirano regions of Madagascar, indicating that this population should not be considered as a separate species. In the monotypic genus Chalarodon, we discovered deep genetic divergences among populations of C. madagascariensis indicating the presence of a previously unrecognized cryptic species and the need for taxonomic revision.
TL;DR: The discovery of D. haasi as well as the recent described D. kopsteini Vogel and Van Rooijen, 2007, demonstrate that the systematics of Dendrelaphis are still poorly explored and thus need further investigation, an updated key to the DendRelaphis-species of the Sunda Region is provided.
Abstract: A new species of the colubrid genus Dendrelaphis Boulenger, 1890 is described. Dendrelaphis haasi sp. nov. ranges from the Malaysian Peninsula to Sumatra, Java and Borneo. Within this range it also inhabits the islands of Pulau Tioman, Nias, Billiton and the Mentawei Archipelago. D. haasi is similar to Dendrelaphis pictus (Gmelin, 1789) with which it occurs sympatrically. However, univariate and multivariate analyses demonstrate that D. haasi differs from D. pictus in several aspects of its coloration and morphology. D. haasi differs from D. pictus in possessing a faint, instead of bright, ventrolateral line, a narrow, instead of broad, postocular stripe, broader vertebral scales, a lower number of temporal scales, a higher number of subcaudals, a smaller eye, a longer tail and a parietal scale that extends further down the side of the head. The discovery of D. haasi as well as the recent description of D. kopsteini Vogel and Van Rooijen, 2007, both fairly common species, demonstrate that the systematics of Dendrelaphis are still poorly explored and thus need further investigation. An updated key to the Dendrelaphis-species of the Sunda Region is provided.
TL;DR: The goal of the study was to assess the ability of P. sicula to recognize insect preys provided with chemical repellents and aposematic colorations under laboratory conditions, and the importance of chemical signals used by the prey model as antipredatory strategy.
Abstract: Food preferences and the effects of prey chemical repellents in the dietary behaviour of Podarcis sicula were tested using four species of Carabid beetles as prey models. The goal of the study was to assess (i) the ability of P. sicula to recognize insect preys provided with chemical repellents and aposematic colorations under laboratory conditions, and (ii) the importance of chemical signals used by the prey model as antipredatory strategy. Preys used in this study were Brachinus sclopeta and Anchomenus dorsalis (aposematic species) and Amara anthobia and A. aenea (non-aposematic species). Aposematic species are characterized by warning color pattern and by production of chemical repellents, while non-aposematic ones do not. Amara anthobia and A. aenea were attacked with high frequency by P. sicula, Brachinus sclopeta and Anchomenus dorsalis with low frequency. Non-aposematic species were preyed more often than the aposematic ones. Brachinus sclopeta was preyed after low latency, while Amara anthobia and A. aenea after long latency. Non-aposematic species were captured and eaten without difficulty, while when B. sclopeta or A. dorsalis were captured, lizards always tossed their head and then rub the snout on the soil, probably because of the unpalatability of aposematic preys.
TL;DR: Of the two populations, it is found that the temperate population experiences lower adult mortality and the relative importance (estimated as the relative contribution to population growth rate) of permanence and of the adult/reproductive size classes is higher in the temperates than in the tropical populations.
Abstract: There appears to be variation in life-history strategies even between populations of the same species. For ectothermic organisms such as lizards, it has been predicted that demographic and life-history traits should differ consistently between temperate and tropical populations. This study compares the demographic strategies of a temperate and a tropical population of the lizard Xenosaurus platyceps . Population growth rates in both types of environments indicated populations in numerical equilibrium. Of the two populations, we found that the temperate population experiences lower adult mortality. The relative importance (estimated as the relative contribution to population growth rate) of permanence and of the adult/reproductive size classes is higher in the temperate population. In contrast, the relative importance for average fitness of fecundity and growth is higher in the tropical population. These results are consistent with the theoretical frameworks about life-historical differences among tropical and temperate lizard populations.
TL;DR: The genetic variability found within the Iberian haplogroup and the existence of a single haplotype within the European lineage suggests a complex pattern of rapid radiations and anthropogenic introductions in T. mauritanica.
Abstract: The Mediterranean gecko Tarentola mauritanica is one of the most abundant reptile species in the western Mediterranean Basin. We use mitochondrial DNA sequences, 12sRNA and 16sRNA, to analyse the patterns of distribution in the Iberian Peninsula. The results show three well defined lineages. The first one, already known to be widespread throughout Europe, is distributed along the eastern coast and southern areas of the Iberian Peninsula. The second one, endemic to the Iberian Peninsula, is widely found in central regions; and the third lineage, found so far only in two southern localities is unrelated to the other Iberian lineages, but rather to a Northern Moroccan clade. The genetic variability found within the Iberian haplogroup and the existence of a single haplotype within the European lineage suggests a complex pattern of rapid radiations and anthropogenic introductions. The third clade seems to be the result of a natural colonization from North Africa. All the data indicate that T. mauritanica is a species complex. The Iberian Peninsula, due to its geological complex history, appears to be both a hotspot and a melting pot of biodiversity, with several studies of diverse herpetofauna indicating that cryptic species occur there. More studies of additional species will be needed to develop a comparative phylogeographic framework for the region.
TL;DR: Different color patterns in European Whip snake, range from normal ("viridiflavus" pattern), to abundistic (dark pattern) to melanic-melanotic (black) patterns as discussed by the authors.
Abstract: Different colour patterns in European Whip snake, range from normal ("viridiflavus" pattern), to abundistic (dark pattern), to melanic-melanotic (black) patterns. Sexes are highly dimorphic, with more abundistic and melanotic-melanic males, than females. Colour patterns are also distributed in well defined areas of the species' distribution range. Normal colour is distributed in N Europe, N, NW and C Italy, while abundistic snakes are typical of Corsica and Sardinia, and melanic-melanotic snakes are very common or exclusive of NE, S Italy and Sicily. Proximal causes that may have driven the distribution of present colour patterns are linked to palaeogeographic events, even if fossil reconstruction of past colonization or a suitable phylogeographic hypothesis are not available.
TL;DR: None of three adaptive hypotheses respectively linked to thermoregulation, predation, or protection against sun radiations, provided a satisfactory account for the occurrence of melanism in study populations, and it is suggested that melanism was a fortuitous phenomenon.
Abstract: Ontogenic melanism (progressive darkening of the skin) has been documented in snakes. Black coloration of the skin often compromises the cryptic effects associated with other patterns (e.g. zigzags) and exposes individuals to predation; however, the mortality risk can be balanced, for example by a thermoregulatory advantage during sun basking. Such adaptive context has been proposed to explain the appearance and the maintenance of melanism within snake populations. Based on a very large captures and re-captures sample (>8000 observations) gathered on two species of sea-kraits (Laticauda saintgironsi and L. laticaudata in New Caledonia), we observed that melanism occurred in only one species (L. laticaudata), was infrequent and concerned adult snakes solely. None of three adaptive hypotheses respectively linked to thermoregulation, predation, or protection against sun radiations, provided a satisfactory account for the occurrence of melanism in our study populations. Therefore, we suggest that melanism was a fortuitous phenomenon.
TL;DR: It is found that P. unifilis females exhibited a promiscuous mating system (polyandry) with all nests being fathered by at least two males.
Abstract: We used eight microsatellite loci to investigate the mating system in P. unifilis. DNA samples were collected from 66 hatchlings sampled from six nests on a central Amazon River beach near Barreirinha, Amazonas, Brazil. We found that P. unifilis females exhibited a promiscuous mating system (polyandry) with all nests being fathered by at least two males. The presence of multiple males contributing to each clutch was ascertained by the presence of at least two extra alleles in multilocus genotypes in each nest. Our data demonstrate that polyandry seems to be the prevalent system of mating in this endangered species.
TL;DR: Individuals were captured all year round, but showed activity peaks in spring and summer, which suggested a seasonal difference in activity patterns between sexes.
Abstract: The Snake-necked Turtle ( Hydromedusa tectifera ) is mainly distributed in the northeastern provinces of Argentina; however, some isolated populations occur in central Cordoba. This is the first report on some ecological aspects of one of these populations. Population density and annual activity pattern were characterized at Toro Muerto Stream in the Sierras region of the Cordoba province, central Argentina. Turtles were hand-captured and sex and carapace length were determined for each individual. Mark-recapture data were used to estimate population density, variation in monthly capture rates, and sex ratios throughout the sampling months. A total of 96 turtles were captured and density was estimated at 218 individuals ha −1 . Individuals were captured all year round, but showed activity peaks in spring and summer. This seasonal pattern has also been observed in other freshwater turtles. During the mating season a higher number of males were captured, which suggested a seasonal difference in activity patterns between sexes.
TL;DR: The sequence of β-fibint7 in Discoglossus is the shortest described for amphibians so far, 378 base pairs, and low levels of variability are found, with no alternatively fixed haplotypes in samples attributed to D. galganoi or D. jeanneae.
Abstract: The generalized use of nuclear introns in combination with mitochondrial DNA data in molecular systematic and intraspecific phylogeographical studies is providing new insights into the complex evolutionary histories of taxa surviving the Quaternary glaciations. Previous studies have highlighted the suitability of the beta-fibrinogen intron 7 (β-fibint7 )f or phylogenetic and phylogeographic studies in a wide variety of taxa, including amphibians. Here we use sequences of this marker to assess inter- and intraspecific variation in Discoglossus (Discoglossidae), with special emphasis on geographic patterns of genetic structure in the Iberian Peninsula, where recent studies have questioned the taxonomic status of D. jeanneae. We obtained 81 sequences of β-fibint7 from samples including all currently recognized species except D. montalentii and 37 populations in the Iberian Peninsula and compared levels of genetic variation with those observed in a fragment of similar length of the mtDNA gene cytochrome b. The sequence of β-fibint7 in Discoglossus is the shortest described for amphibians so far, 378 base pairs. In general, we found low levels of variability (only 26 parsimony-informative sites in the dataset), with no alternatively fixed haplotypes in samples attributed to D. galganoi or D. jeanneae based on their mtDNA. Values of pairwise sequence divergence between non-Iberian species ranged from 1.1% to 4.5% (13.3% to 20.9% in mtDNA). The patterns observed in samples from the Iberian Peninsula are consistent with either incomplete lineage sorting or ongoing gene flow between D. galganoi and D. jeanneae. We conclude by reviewing the genetic evidence available to address the taxonomic status of Iberian species of Discoglossus.
TL;DR: It is suggested that in the volcanic mountains of Central Mexico body growth, and therefore age and size at maturity, are relatively more limited during the whole year in comparison with populations inhabiting northern or lower-altitude localities.
Abstract: We conducted an analysis of the body growth pattern of the viviparous lizard Sceloporus grammicus in one of its montane populations in Central Mexico. We calculated 177 individual growth rates for the period comprised between June 1991 and June 1997. Von Bertalanffy growth model provided the best fit to our data in comparison with logistic models. No intersexual differences were found in the growth pattern. The constructed growth curve estimated an age at maturity of 12 and a half months for females and 14 months for males. In spite of marked seasonality in the region, growth rates were not significantly different between seasons. Our results, together with previous studies on the growth ecology of other populations of S. grammicus , suggest that in the volcanic mountains of Central Mexico body growth, and therefore age and size at maturity, are relatively more limited during the whole year in comparison with populations inhabiting northern or lower-altitude localities.
TL;DR: It is revealed that vertebrae number might present higher intraspecific variation than previously thought inPodarcis bocagei and P. carbonelli, and that sexual variation existed, females presenting higher counts than males for both trunk and total presacral vertebraes, while males showed higher values of cervical vertebraE.
Abstract: Podarcis bocagei and P. carbonelli are two closely related lizard species, endemic to the western Iberian Peninsula. Although genetic and morphological distinction between them is now well established, information on anatomical features is still very restricted. We studied presacral vertebrae number in both species, separately examining cervical and trunk vertebrae counts, in order to assess the interspecific and intersexual variation in these characters. There was no significant interspecific variation among lizards of the same sex for any of the vertebrae counts studied. However, important sexual variation existed, females presenting higher counts than males for both trunk and total presacral vertebrae, while males showed higher values of cervical vertebrae. Although our results lie within the known limits for other closely related species, they reveal that vertebrae number might present higher intraspecific variation than previously thought.
TL;DR: A steep variation in body size and reproductive traits in two anuran species in southwestern Spain, associated with changes in the geological substrate is described, suggesting the existence of a reproductive trade-off that could explain the differences in reproductive allocation between populations and species.
Abstract: Geographic variation in body size and reproductive traits has been reported in a wide range of organisms, including amphibians. Most studies have focused on latitudinal and/or altitudinal variation where differences in temperature and duration of the growing season are the main causes for population divergence. We describe a steep variation in body size and reproductive traits in two anuran species in southwestern Spain, associated with changes in the geological substrate. Pelobates cultripes and Bufo calamita (= Epidalea calamita ) drastically reduced their size (a 71.6% and 76.1% reduction in body mass for P. cultripes and B. calamita , respectively) in just about 60 km. This extreme size reduction was more pronounced at the boundary between two different geological substrates (hercinic and sandy soil). Mean clutch mass, egg size, and clutch size were all smaller in B. calamita populations in the sandy environment. Likewise, clutch mass and egg size were both smaller in sandy P. cultripes populations. We observed a negative correlation between size-adjusted fecundity and egg size for both species, suggesting the existence of a reproductive trade-off that could explain the differences in reproductive allocation between populations and species. In P. cultripes , small-bodied populations had relatively higher fecundities and smaller eggs than large-bodied ones, whereas in B. calamita populations from the sandy area we found both populations with high fecundity and small eggs, and populations with low fecundity and large eggs. Common environmental effects associated with the sandy substrate produce a similar reduction in size in both toad species.
TL;DR: The longitudinal movements and abiotic factors that determine the distribution of Pyrenean mountain newts were examined in a 1500 meters segment of a Pre-Pyrenean stream and indicate that the number of refugia (wood debris, stones and fissures) determines the Distribution of newts.
Abstract: The longitudinal movements and abiotic factors that determine the distribution of Pyrenean mountain newts (males, females, amplexus and metamorphic newts) were examined in a 1500 meters segment of a Pre-Pyrenean stream. Migration of adult newts was studied by means of capture-recapture techniques in the course of one year. Our results indicate that the mean distance the newts migrated per year was less than 50 meters and the population could be considered sedentary. No significant differences in longitudinal movement patterns between the sexes were observed, and movement patterns were more or less constant over time. Habitat variables determining newt abundance was estimated by means of a GLM. Our results indicate that the number of refugia (wood debris, stones and fissures) determines the distribution of newts. Larval abundance was correlated with stream-bed structure.
TL;DR: A tendency of positive correlation of foraging measures (PTM, percentage of time moving; MPM, number of movements per minute) with laboratory measured endurance capacity is found, however, the relationship of foraged measures with maximal sprint speed remains less clear.
Abstract: Foraging strategy is often considered to play a central role in moulding diverse aspects of an animal's general biology. Active foragers should have greater locomotor endurance, allowing high movement activity rates, while sit-and- waiting foragers may be better adapted to sprinting, allowing catching prey by a quick attack from an ambush site, and going with specific predator escape tactics. In this study we investigate these predicted patterns in a set of lacertid lizard species. There is considerable variation in foraging activity within Lacertidae, which allows the close investigation of the co-evolution of the traits considered. We found a tendency of positive correlation of foraging measures (PTM, percentage of time moving; MPM, number of movements per minute) with laboratory measured endurance capacity. However, the relationship of foraging measures with maximal sprint speed remains less clear. MPM correlates negatively with maximal sprint speed, but PTM does not. When sprint speed was corrected for body size, no correlations were found at all.
TL;DR: The results do not support the previous predictions that gravid C. flavomarginata may select higher environmental temperatures prior to nesting season and there were significantly intersexual differences in mean weekly shell surface temperature during nesting season.
Abstract: Thermal preference of free-living yellow-margined box turtle, Cuora flavomarginata , was studied in a mesic forested habitat using a combination of radiotransmitters and temperature dataloggers attached to individual turtles. Patterns of mean weekly shell surface temperature variation of selected individuals were highly related to seasonal change of environmental temperature, with a peak temperature of 24.5-25.1°C in males and 26.0-27.0°C in females during June and July. Minimum shell surface temperature occurred in late January (4.5-7.6°C). Despite a small sample size, there were significantly intersexual differences in mean weekly shell surface temperature during nesting season. Individual females of C. flavomarginata tended to maintain higher shell surface temperature during nesting season (May-July). This difference was mostly pronounced during the day. There were no obviously intersexual differences prior to and after nesting season. Our results do not support the previous predictions that gravid C. flavomarginata may select higher environmental temperatures prior to nesting season.
TL;DR: Results might support that femoral secretions of males convey different messages for male or female I. cyreni lizards.
Abstract: The effects of intrasexual selection (i.e., male-male competition) and intersexual selection (i.e., mate choice) may result on the evolution of different secondary sexual traits. We tested whether chemosensory responses of male and female Iberolacerta cyreni lizards to femoral secretion of conspecific males (a chemical sexual trait used in social behavior) were eliciting by different chemical traits. Tongue-flick essays showed that males and females had similar chemosensory responses to the femoral secretions of males, but males and females differed in the magnitude of their chemosensory responses to the different chemicals found in secretions. Moreover, responses to chemicals related to body size depended on the own body size of the responding male, but did not in females. These results might support that femoral secretions of males convey different messages for male or female I. cyreni lizards.