| cytophotometric evidence of variation in genome size of desmognathine salamanders. | the amount of dna per haploid genome, the c-value, is often directly correlated with nuclear and cell volume, but inversely correlated with cell replication rate. also, rates of cellular growth sometimes appear to be correlated with organismal developmental rates and life history patterns. among vertebrates, salamanders exhibit the greatest variation in genome size. in the present study we have examined interspecific and intraspecific variation in blood cell dna levels in the genus desmognathus, ... | 1986 | 3744902 |
| variable infection of stream salamanders in the southern appalachians by the trematode metagonimoides oregonensis (family: heterophyidae). | many factors contribute to parasites varying in host specificity and distribution among potential hosts. metagonimoides oregonensis is a digenetic trematode that uses stream-dwelling plethodontid salamanders as second intermediate hosts in the eastern us. we completed a field survey to identify which stream salamander species, at a regional level, are most likely to be important for transmission to raccoon definitive hosts. we surveyed six plethodontid species (n = 289 salamanders) from 23 appal ... | 2015 | 26026670 |
| the influence of ecology and genetics on behavioral variation in salamander populations across the eastern continental divide. | understanding the unique contributions of ecology and history to the distribution of species within communities requires an integrative approach. the eastern continental divide in southwestern virginia separates river drainages that differ in species composition: the more aquatic, predatory desmognathus quadramaculatus is present only in the new river drainage (which drains to the gulf of mexico), while desmognathus monticola is present in both the new river drainage and the james river drainage ... | 2004 | 15278844 |
| time courses of thermal acclimation for critical thermal minima in the salamanders desmognathus quadramaculatus, desmognathus monticola, desmognathus ochrophaeus, and plethodon jordani. | 1. we examined the time courses of thermal acclimation for critical thermal minima (ctmin) in the salamanders desmognathus quadramaculatus, d. monticola, d. ochrophaeus, and plethodon jordani. 2. d. quadramaculatus showed no annual differences in their time courses, but we noted seasonal differences in the ctmin with these salamanders having lower ctmin in the spring. 3. gain in ctmin (25 degrees c to 5 degrees c transfer) was faster than its corresponding loss (5 degrees c to 25 degrees c trans ... | 1987 | 2887388 |
| habitat selection by two streamside plethodontid salamanders. | a series of experiments was conducted to test the hypothesis that habitat selection by the salamanders desmognathus monticola and desmognathus quadramaculatus is influenced differently by interspecific interference than by intraspecific interference. individuals of neither species were influenced differently by the presence of heterospecifics than by the presence of conspecifics in their activity away from cover sites, in selection of different substrate moisture levels, in selection of differen ... | 1985 | 28310876 |
| extreme performance and functional robustness of movement are linked to muscle architecture: comparing elastic and nonelastic feeding movements in salamanders. | muscle-powered movements are limited by the contractile properties of muscles and are sensitive to temperature changes. elastic-recoil mechanisms can both increase performance and mitigate the effects of temperature on performance. here, we compare feeding movements in two species of plethodontid salamanders, bolitoglossa franklini and desmognathus quadramaculatus, across a range of body temperatures (5-25°c) to better understand the mechanism of elastically powered, thermally robust movements. ... | 2016 | 27320361 |
| salamander growth rates increase along an experimental stream phosphorus gradient. | nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. few studies have tested whether nutrient (specifically, nitrogen [n] and phosphorus [p]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether n vs. p is relatively more important in driving effects on food webs. we conducted ... | 2015 | 27070018 |
| metagonimoides oregonensis (heterophyidae: digenea) infection in pleurocerid snails and desmognathus quadramaculatus salamander larvae in southern appalachian streams. | metagonimoides oregonensis (heterophyidae) is a little-known digenetic trematode that uses raccoons and possibly mink as definitive hosts, and stream snails and amphibians as intermediate hosts. some variation in the life cycle and adult morphology in western and eastern populations has been previously noted. in the southern appalachians, pleurocera snails and stream salamanders, e.g., desmognathus spp., are used as intermediate hosts in the life cycle. we completed a series of studies in this s ... | 2012 | 22394058 |
| acute toxicity of acidity in larvae and adults of four stream salamander species (plethodontidae). | high levels of acid deposition have severely affected streamwater chemistry in the southern appalachians. plethodontid stream salamanders living in and around headwater streams rely on cutaneous respiration and are highly susceptible to changes in water quality. we examined the sensitivity to low ph conditions in four stream salamanders by monitoring the response to six ph treatments ranging from ph 2.75 to 6.5. to quantify acid tolerance, we determined median lethal concentrations (lc50) in 96- ... | 2008 | 18522477 |
| the phylogenetics of desmognathine salamander populations across the southern appalachians. | salamanders in the genus desmognathus (caudata: plethodontidae) are distributed along an aquatic to terrestrial habitat gradient in the southern appalachian mountains. the spatial distribution of species is believed to have formed as aquatic ancestors displaced lineages by competition and predatory interactions into less optimal terrestrial habitats. aquatic and terrestrial species may also display different patterns of genetic diversity due to the differing likelihood of gene flow via aquatic c ... | 2003 | 12695085 |
| motor control of tongue movement during prey capture in plethodontid salamanders | four species of salamander of the family plethodontidae were examined using electromyographic (emg) recording during prey-capture behavior to test the hypotheses that the tongue retractor, tongue protractor and jaw depressor muscles are activated simultaneously and in a stereotyped pattern, as was found in other salamanders, and to determine whether species with different tongue morphologies and tongue protraction abilities exhibit different motor control strategies. the results show that sequen ... | 1999 | 10574747 |
| hemoglobin function in a skin-breathing aquatic salamander, desmognathus quadramaculatus. | adult black-bellied salamanders (desmognathus quadramaculatus) were maintained in humidified gas at 12 degrees c. hypoxic salamanders were exposed to 8.1-9.6% o2 for 10-11 days; normoxic animals were maintained in air (20.9% o2). hypoxia acclimation had no effect on blood o2 affinity, o2 equilibrium curve shape or co2 bohr effect. at ph 7.7, p50 values for hypoxic and normoxic salamanders were 28.2 +/- 0.4 and 28.6 +/- 0.8 torr, respectively. hill plots were curvilinear for both treatments; hill ... | 1995 | 7777706 |
| effects of environmental o2 on blood flow and diffusing capacity in amphibian skin. | the effects of local environmental po2 on cutaneous blood flow (q) and the membrane diffusing capacity of the skin (d) were investigated in the leopard frog, rana pipiens, and the lungless salamander, desmognathus quadramaculatus. halothane anesthetized animals were equilibrated with freon-22 (fr) and acetylene (ac) in a box. a gas mixture containing either 0, 20 or 40% o2, respectively, in n2 and initially free of fr and ac was drawn through a small sample chamber on the abdomen. the excretion ... | 1989 | 2787520 |
| elimination kinetics of acetylene and freon 22 in resting and active lungless salamanders. | to quantify diffusion limitation in cutaneous gas exchange, the elimination of two inert gases of different diffusivity, freon 22 (chc1f2) and acetylene (c2h2), was measured simultaneously in exclusively skin-breathing lungless salamanders, desmognathus quadramaculatus. in resting salamanders, elimination of both gases could be described as the sum of three exponential terms. for both the medium and the slow exponential component, the ratio of the respective rate constants (k) for acetylene and ... | 1988 | 3375615 |
| acetylcholinesterase activity in the adrenal chromaffin cells of triturus cristatus, siren lacertina and desmognathus quadramaculatus (amphibia urodela). | | 1986 | 3779752 |
| a peculiar mechanism of bite-force enhancement in lungless salamanders revealed by a new geometric method for modeling muscle moments. | desmognathine salamanders possess unusual morphological features for lungless salamanders that have been proposed to aid in burrowing and biting, including well-ossified jaws and skull and a pair of robust ligaments connecting the atlas to the mandible. we evaluated the function of these and other peculiar desmognathine cranial features in biting by examining the morphology, mechanics and in vivo biting performance of the large desmognathus quadramaculatus we estimated theoretical biting force u ... | 2017 | 28784684 |
| cling performance and surface area of attachment in plethodontid salamanders. | plethodontid salamanders inhabit terrestrial, scansorial, arboreal and troglodytic habitats in which clinging and climbing allow them to access additional food and shelter as well as escape from unfavorable temperature and moisture conditions and ground-dwelling predators. although salamanders lack claws and toe pads found in other taxa, they successfully cling to and climb on inclined, vertical and inverted substrates in nature. maximum cling angle was tested on smooth acrylic, and the relation ... | 2020 | 32675231 |
| genomic data reject the hypothesis of sympatric ecological speciation in a clade of desmognathus salamanders. | closely related taxa with dissimilar morphologies are often considered to have diverged via natural selection favoring different phenotypes. however, some studies have found these scenarios to be paired with limited or no genetic differentiation. desmognathus quadramaculatus and d. marmoratus are sympatric salamander species thought to represent a case of ecological speciation based on distinct morphologies, but the results of previous studies have not resolved corresponding patterns of lineage ... | 2018 | 30246244 |