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The Chicken Turtle, Deirochelys reticularia, is an understudied species despite the fact that it is distributed across much of the southeastern United States. In addition, no previous study has been conducted on the western subspecies, D. r. miaria, even though it is considered rare and possibly in decline within portions of its range. A capture–recapture study was conducted over 3 yr on a population of D. r. miaria in central Arkansas to determine demographic and reproductive characteristics. The population approached a male bias (1.9:1) and consisted of few total individuals (N = 42). Reproductive traits, including clutch, egg, and hatchling size, appear to be similar between D. r. miaria and eastern populations. Annual survival estimates were similar among males, females, and juveniles (0.70, 0.70, and 0.69, respectively) and did not change over the course of the study. Although low compared with most turtles, similar results have been reported for other populations of D. reticularia, which suggests that the species may have a different life-history strategy than that of most other chelonians. Due to this difference, management practices are likely to affect D. r. miaria differently from other turtle species.
The Japanese Pond Turtle, Mauremys japonica, and the Reeves' Pond Turtle, Mauremys reevesii, are common aquatic geoemydid species in Japan. The former is endemic to Japan, whereas the latter is distributed widely throughout East Asia, China, Korea, Taiwan, and Japan. Although the Japanese populations of M. reevesii were generally considered to be indigenous, it was suggested recently that Japanese M. reevesii is derived from multiple artificial introductions from elsewhere in Asia. Putative hybrid individuals, with intermediate morphological characters, have been observed in the wild. Furthermore, captive congeneric individuals have produced viable offspring that attained sexual maturity. To clarify the extent of hybridization between these species, we examined nuclear DNA and mitochondrial DNA genetic markers of putative hybrids collected in the field. We found that most of the animals assayed had nuclear DNA derived from both species. In addition, several individuals originated from hybrid mothers implying that hybridization is indeed occurring in the wild and that female hybrids are fertile and reproduce. Our results indicate an ongoing process of introgression of introduced M. reevesii alleles into the gene pool of native populations of M. japonica.
Bog Turtles (Glyptemys muhlenbergii) are imperiled by habitat loss and degradation; yet, population responses to habitat management and restoration efforts have not been well documented because of the difficulties of studying this long-lived species. We compared Bog Turtle population demography and habitat use from 1994 to 2009 at two sites in Massachusetts, USA: one site was managed for nonnative invasive species and natural succession (Site 1), and the other site was flooded from American Beaver (Castor canadensis) activity resulting in an expansion of nonnative invasive plants (Site 2). A mark–recapture study involving 90 individual turtles indicated that survival rates and population sizes remained stable before and after habitat management at Site 1 where the extent of high suitable habitat remained the same, whereas population size and survival rates declined at Site 2 where the extent of low suitable habitat increased. Together, these results suggest that habitat management and restoration efforts can improve or maintain the status of Bog Turtle populations. This study supports the value of properly planned and enacted habitat management actions for this federally threatened and state endangered species.
We describe a Paleocene–Eocene pelomedusoid turtle from tropical South America in a new fossiliferous locality, from Los Cuervos Formation, at the Calenturitas Coal Mine, Colombia. Although no further systematic precision beyond Pelomedusoides incertae sedis can be supported, the presence of an ischial scar positioned far anteriorly to the anal notch, and a strongly decorated ventral surface of the plastron, indicate that this specimen is potentially related to the bothremydid clade formed by Puentemys–Foxemys. We also demonstrate the potential organic preservation of osteocytes and blood vessels for this specimen, indicating that preservation of soft tissue such as vessels and bone cells in the fossil record is independent of bone type, fossil site, or locality; occurring in different lineages of vertebrates; and that it is even possible to occur in tropical depositional environments during a period of maximum global warming such as the Paleocene–Eocene.
Aqui describimos la primera ocurencia de tortugas pelomedusoid del Paleoceno–Eoceno en la parte tropical de Suramérica, en una nueva localidad fósilifera, de la Formación Los Cuervos, en la mina de carbón Calenturitas, Colombia. Aunque, no mayor precisión sistemática puede ser soportada más que Pelomedusoides incertae sedis, la presencia de una cicatriz isquial posicionada muy anteriormente a la escotadura anal y una fuertemente decorada superficie ventral del plastron, indican que el especimen esta relacionado con el clado bothremydido formado por Puentemys–Foxemys. También demostramos la posible preservación orgánica de osteocitos y vasos sanguineos para este especimen; indicando que la preservación de tejidos blandos como vasos y celulas oseas en el registro fósil es independiente del tipo de hueso, sitio fósil o localidad, ocurriendo en diferentes linajes de vertebrados, y que es possible que ocurra en ambientes deposicionales tropicales, durante periodos de maximo calentamiento global como el Paleoceno–Eoceno.
Most Emydidae, including Diamond-backed Terrapins (Malaclemys terrapin), have temperature-dependent sex determination. However, the full relationship between incubation temperature and offspring sex in the Diamond-backed Terrapin has not been reported, and the pivotal temperature, range of transitional temperatures, and the temperature-sensitive period have not been investigated fully. Here we report on these parameters, comparing our data with data from other emydid turtles, and also comparing our laboratory data to field data collected previously for this population.
La mayoría de Emydidae, incluyendo a las Diamond-backed Terrapins (Malaclemys terrapin), tienen determinación de sexo por temperatura. Sin embargo, la relación entre temperatura de incubacion y sexo de crías en el Diamond-backed Terrapin no ha sido reportada, ni el umbral de temperatura ni el período sensible a la temperatura han sido investigados. Aquí reportamos ambos fenómenos y los compararmos con otras Emydidae, asi como con datos de campo de ésta población previamente colectados.
The Jackson's Chameleon (Trioceros jacksonii xantholophus) is a predatory, arboreal east African lizard that has become established in the forests of several Hawaiian Islands where they have been shown to prey upon rare endemic invertebrate taxa. In this study, we used radiotelemetry to assess movement behavior of T. j. xantholophus in three different habitats that varied in suitability for sustained persistence of chameleons. Landscape ecology theory holds that movement behavior tends to be relatively rapid and linear in unsuitable habitat, minimizing time spent in suboptimal areas, but more circuitous and less rapid in suitable habitat to optimize resource use. Therefore, we predicted that in Hawaii, chameleons released in unsuitable habitat will 1) move longer distances each day; 2) follow straighter paths; 3) move away from point of release continuously; and 4) cover larger areas, relative to those released in suitable habitat. Our results indicated that mean daily distance, total cumulative distance, total net displacement, and home range did not vary significantly among the three habitats. However, daily distances decreased and path tortuosity increased over time under suitable conditions, whereas the opposite pattern was seen under unsuitable conditions. Notably, daily net displacement did not increase over time, regardless of habitat type or suitability, and home range overlap was inversely correlated with habitat suitability. In general, Jackson's Chameleons traveled short distances with nonlinear paths, reflecting a sedentary life history. We propose that localized control and potential eradication in critical areas may be possible via manual removal.
We review the species of the Brachymeles bonitae Complex (B. bonitae and B. tridactylus) and describe an additional two new species in this highly specialized, limb-reduced, endemic Philippine clade of fossorial lizards. For more than 4 decades, B. bonitae has been recognized as a single “widespread” species, a perception that has persisted as a result of limited sampling and similar overall morphology (body sizes, scale pigmentation) among populations. However, on the basis of new collections we note consistent morphological differences between populations, and our new data build on previous observations, allowing us to utilize newly defined character state differences for the purpose of delimiting unambiguous boundaries between species. Here, we use morphological and molecular data to define species limits in B. bonitae and its close relatives. Our data indicate that the “widespread” species B. bonitae is actually a complex of four distinct evolutionary lineages, several of which are not each others' closest relatives. The taxa we define possess allopatric geographic ranges (biogeographically supporting our taxonomic conclusions) and differ from their congeners by several diagnostic characters of external morphology. We conclude that each, therefore, should be recognized as full species in accordance with lineage-based species concepts. Species diversity in the genus has doubled in the last 4 yr, with newly described taxa increasing the total number of species of Brachymeles to 38.
Seasonal abundance is known to fluctuate in many reptile species, but comparative studies of proximal macrohabitats across seasons are rare. We surveyed for differences in abundance in a common lowland Central American forest anole, Anolis polylepis, across proximal forest and riparian habitats during the wet and dry seasons in southwest Costa Rica. We found that dry-season decreases in population abundance of A. polylepis in a forest habitat are mirrored by simultaneous increases in abundance in an adjacent riparian area. This result is compatible with seasonal movements between forest and riparian macrohabitats in A. polylepis. Likely causal factors for this macrohabitat shift include increased risk of desiccation and decreased prey abundance in the forest habitat during dry periods. We briefly discuss potential conservation implications of habitat shifts to suitable microhabitats on this tropical lizard.
Roads have significant impacts on the dispersal of wildlife. Although this poses a threat to the abundance and diversity of desirable flora and fauna, it also affords some opportunity for enhancing control of invasive species. Roads are the most common terrain features that may affect the rate of landscape-scale movements of invasive Brown Treesnakes (Boiga irregularis) throughout Guam. We radio tracked 45 free-ranging Brown Treesnakes in close proximity to two roads in Guam and recorded instances where daily relocations of snakes spanned roads. Then we reconstructed observed movement histories with randomized turning angles, which served as a useful null hypothesis for assessing the effect of roads or road edge habitat on Brown Treesnake movement patterns. Random walk simulations demonstrated that Brown Treesnakes crossed these roads at a rate far lower than would be expected if snake movement was random with respect to roads and road edge habitat. We discuss two alternative hypotheses for these results: 1) habitat gaps posed by roads physically or behaviorally restrict snake movement; or 2) road edges provide preferred foraging habitat from which snakes are reluctant to depart. Because roads often form the boundaries of jurisdictional and management units, the effects of roads on the movement of invasive Brown Treesnakes will influence the prospects for success of future landscape-level suppression efforts.
Ichthyophis bannanicus is a terrestrial caecilian, and little is known about many aspects of the ecology of this species. We investigated the correlation between diet and body size, spatiotemporal variation in dietary composition, diversity index of prey, and size dimorphism among populations for this species. Specimens (N = 135) were collected from May 2010 to April 2011 in the Mekong Delta, Vietnam. We found 178 prey items representing 11 unique families and discovered that the diet of I. bannanicus is composed mainly of small prey; the most important were Achatinidae, Lumbricidae, and Formicidae, with a combined importance index of 77%. Diet composition, prey size, and total prey volume in I. bannanicus changed between dry and rainy seasons and among regions (P < 0.001). Mean prey volume increased with body size and showed positive correlations (P < 0.001) between total length and mouth width and prey size consumed. The total dietary breadth of I. bannanicus was 4.52, and all six populations of the Bannan Caecilian were found to consume snails, earthworms, ants, and termites. Results indicated that precipitation, but not temperature, was associated positively with prey volume. All collected I. bannanicus were adult females; we did not find male individuals of this species in the study area.
Foraging underground poses a number of important challenges for fossorial animals, such as amphisbaenians. For instance, visual detection and identification of prey is often hampered by low light conditions and poor eye sight. In response, many fossorial animals have switched to other sensory systems, such as chemoreception. We tested the ability of the amphisbaenian Trogonophis wiegmanni to detect and discriminate between different prey types based on chemical cues alone. Results of a laboratory experiment showed that amphisbaenians were able to detect prey using chemoreception, as indicated by an increase in chemosensory tongue-flick responses to swabs bearing chemicals from prey in comparison with blank controls. Also, differential tongue-flick rates to chemicals from different prey types indicated that at least some prey types may be discriminated from others based on chemosensory cues. These results suggest that T. wiegmanni amphisbaenians use chemoreception when foraging.
We describe a new species of large black Bolitoglossa from the Sierra de las Minas and adjacent regions of Guatemala based on both morphological and molecular data. The new species, specimens of which were formerly assigned to Bolitoglossa meliana (Melanistic Salamander), is distinguished by its dark coloration, numerous teeth, and large size. We present molecular data to support the distinctiveness of this species and estimate its phylogenetic placement within the subgenus Magnadigita. Molecular data do not support a sister taxon relationship between the new species and B. meliana, despite their outward morphological similarity. This species adds to the already high salamander species diversity of the Sierra de las Minas, much of which has been described recently.
Describimos una nueva especie de Bolitoglossa grande y negra de la Sierra de la Minas y regiones cercanas en Guatemala, basados en datos morfológicos y moleculares. La nueva especie, anteriormente asignada a Bolitoglossa meliana, se distingue por su coloración obscura, dientes numerosos y gran tamaño. Presentamos datos moleculares para apoyar el reconocimiento de esta especie y para estimar su posición filogenética dentro del subgénero Magnadigita. Los datos moleculares no apoyan una relación de grupo hermano entre la especie nueva y B. meliana, a pesar de su similitud morfológica externa. Esta especie aumenta la alta diversidad de especies de salamandras de la Sierra de las Minas, mucha de la cual se ha descrito recientemente.
We describe and compare the fatty acid composition of three different adipose tissue types, namely, abdominal, tail, and steatotheca (an abdominal fat body) tissues of healthy wild Nile Crocodiles (Crocodylus niloticus). No significant differences were observed in the fatty acid composition among the three fat tissues, apart from eicosapentaenoic acid, which occurs in small amounts of less than 1% in all the types of tissue. In individual animals, limited variation in the steatotheca may occur compared with the other two adipose fats. The total fat of the male crocodile is more saturated, with 44.4% ± 3.2% saturated fatty acids compared with the 42.0% ± 3.2% of the female. The greatest differences between the sexes were observed for pentadecylic, margaric, stearic, palmitoleic, vaccenic, and oleic acids. No interaction between gender and anatomical position of fatty acids was observed. This is a first comparative study of fat composition of different adipose tissues in a reptile. When the data are compared with similar data of fish, birds, and mammals, it may be concluded that differentiation of the composition of adipose fat is an evolutionary development of mammals.
One of the main aspects of natural history is trophic ecology, which affects survival and population size. In the present study, we registered the contribution of prey types to the diet of Physalaemus ephippifer and tested for differences in diet according to sex and season (rainy and dry) of three populations of P. ephippifer in eastern Amazonia. We analyzed frequency of occurrence, trophic amplitude, feeding overlap, and food importance index for each prey category. We analyzed 102 specimens (69 males and 33 females) and observed that the most important prey categories were termites and ants. The most important prey category for females during rainy season included coleopteran larvae, whereas during dry season the most important prey category was termites. In both seasons, the most important prey category for males was ants. We did not observe any seasonal or sexual variation in the diet of P. ephippifer. On the other hand, during the rainy season, coleopteran larvae and termites were the most important prey categories for females, which have a more nutritious diet than males. Increase in nutritional value of the diet of females coincided with the reproductive period, when females would require a greater amount of energy for gamete production.
Age and size at sexual maturity are major life-history traits that affect growth rate and reproductive output. The differences in these life-history traits can be better assessed in syntopic populations of related species, where environmental variability in time and space is removed. The Spadefoot Toads (Pelobates spp.) are highly specialized burrowing and nocturnal species with a narrow ecological niche. We tested if age-related parameters are responsible for sexual size dimorphism and size differences in two syntopic populations from the Danube Delta Biosphere Reserve (Romania). The two populations differed significantly in size and body mass, and showed distinct sexual dimorphism, with females significantly larger in P. fuscus, and males slightly larger in P. syriacus. We also found differences in age structure: P. fuscus was on average 5.0 yr old, whereas P. syriacus was on average 7.4 yr old. Both species reached sexual maturity at a similar age. Different growth rates before sexual maturity and differences in energy allocation between growth and reproduction after sexual maturity are responsible for the differences in adult size between these syntopic populations. Our results suggest that growth allocation between species and sexes cannot be explained solely on the basis of age-related parameters.
We report direct observation of seasonal movements of adult Plethodon cinereus uphill to a rocky hilltop in the fall and downhill into a wet area in the spring. Counts from arrays of cover boards in both areas showed occupancy patterns that were consistent with seasonal changes in spatial distribution. Soil moisture was markedly higher and pH was slightly lower in the downhill area. Soil temperature did not differ between the two areas. Young age classes do not migrate but apparently stay in the wet area where they hatch. Differences in body size and egg diameter between fall and spring samples suggest that migratory adult salamanders grow and yolk eggs during the winter. The most likely explanation for this behavior is that the rocky hillside provides crevices that allow salamanders to get far enough underground to remain active in winter.
European vipers are typical capital breeders and most studies have revealed that females usually reproduce once every two or three years and that, in some cases, females reproduce once during their lifetime. This paper presents evidence, based on monitoring marked snakes in consecutive years, that several female adders (Vipera berus) from a montane environment from the Northern Romanian Carpathians reproduced annually (2007–2008), and also gives preliminary data on other female reproductive traits. Reproductive females and their offspring were smaller and lighter than V. berus individuals from most previously studied populations. Maternal traits were not significantly correlated with litter and offspring characteristics.
The pure-diploid Blue-spotted Salamander (Ambystoma laterale) is among the rarest amphibians in northeastern North America, and data on its ecology are sparse. We assessed the movement ecology and terrestrial habitat use of A. laterale using radio- and passive integrated transponder (PIT) tag- telemetry. We radio-tracked 22 A. laterale for a median of 54 days (range 6–126 days) in the spring and summer of 2009 and 2010. Using a modified PIT tag reader, we conducted 34 in situ surveys during the spring and summer of 2009 through 2011, resulting in 42 relocations. We detected salamanders at a median straight-line distance of 67 m (range 7–281 m) from their breeding wetland. The life zone (i.e., critical terrestrial habitat), encompassing 95% of observed salamander movements, extended 152 m from the edge of the breeding wetland. Eighteen radio-tracked salamanders migrated to upland forest, three to a wet meadow, and one to a red maple (Acer rubrum) swamp. Salamanders used upland forest and wet meadow more often than the availabilities of those habitats would predict. We recorded habitat data at 10-m and 1-m-diameter circular plots centered on animal locations. At the 10-m scale, salamander presence was correlated positively with percent cover of slash and correlated negatively with percent cover of grass, total basal area of trees, and relative humidity. At the 1-m scale, salamander locations had deeper leaf litter and moister soil than did random locations. Our results suggest existing, published recommendations for the conservation of vernal pool species are applicable to A. laterale.
Free-living vertebrates tend to respond to environmental challenges by increasing circulating glucocorticoid levels. Changes in glucocorticoids can modulate various aspects of physiology and behavior, which can have fitness benefits in the short term but may be detrimental to fitness if elevated levels are frequent, prolonged, or both. The transfer of glucocorticoids from females to offspring might also have fitness consequences, but there is less known about the potential effects of transgenerational glucocorticoid transfer. Our study examined corticosterone levels in female Red-eared Sliders (Trachemys scripta) during the nesting season because of the potential fitness consequences for both females and offspring. Whether caught in aquatic traps or caught during the nesting process, females had similar circulating corticosterone levels that were relatively low. However, when females were subjected to a restraint protocol, corticosterone rose. Therefore, corticosterone levels may be elevated during the nesting process, but the nesting process itself does not result in elevated corticosterone levels. Understanding how natural processes such as nesting influence corticosterone levels has important consequences for interpreting corticosterone levels as an index of fitness.
Sertraline (“Zoloft”) is a selective serotonin reuptake inhibitor (SSRI) suspected of causing developmental abnormalities in some aquatic organisms at environmentally relevant concentrations. SSRIs have been detected downstream from wastewater treatment plants, but the risks associated with environmental exposure have not been well documented. We tested the effects of sertraline on development of Wood Frog (Lithobates sylvaticus) larvae. Tadpoles hatched from wild-collected egg masses were exposed to concentrations of 0, 0.1, 1.0, or 10.0 μg/L of sertraline through metamorphosis. We tracked tadpole development using image analysis (452 digital images) to estimate mass periodically during the tadpole stage, and we also recorded mass at metamorphosis. Time to metamorphosis did not differ between treatments, but sertraline-exposed tadpoles grew less when raised among conspecifics. However, this effect was not detected when the study was repeated with tadpoles raised individually. This indicates that the effects of sertraline and other SSRIs may be enhanced when tadpoles are raised under more stressful conditions.
We examined comparative skin permeability by measuring cutaneous water loss and epidermal lipid content of two sympatric snake congeners, the Southern Copperhead (Agkistrodon contortrix) and the Western Cottonmouth (A. piscivorus). Samples of shed epidermis from each snake species were taken to first investigate species-specific differences. Shed samples from multiple regions along the dorsal and ventral integument were then used to examine potential variation in skin permeability and lipid content among different regions along the body for each species. Rates of cutaneous water loss were significantly higher for A. piscivorus. In addition, cutaneous water loss rates of A. piscivorus differed among region (i.e., anterior, mid, and posterior) and surface (i.e., dorsal and ventral) with the highest rates of cutaneous water loss from the mid-dorsum. Lipid content did not differ between species. However, lipid content varied between the dorsal and ventral surfaces of both species, with greater lipid content on the dorsal surface. Our results support a species-specific difference in cutaneous water loss between A. contortrix and A. piscivorus and may reflect species-specific adaptations to their differences in microhabitat preference.