The Experts below are selected from a list of 63 Experts worldwide ranked by ideXlab platform
Glenn J Tattersall - One of the best experts on this subject based on the ideXlab platform.
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the effect of graded hypoxia on the metabolic rate and buccal activity of a Lungless Salamander desmognathus fuscus
2000Co-Authors: Elizabeth A Sheafor, Stephen C Wood, Glenn J TattersallAbstract:The hypothesis that the Lungless Salamander Desmognathus fuscus responds actively to hypoxia was tested. Patterns of buccal movements [apneic period duration, the duration (min h(−)(1)) of buccal pumping and buccal pumping frequency], heart rate and metabolic rate (rates of oxygen uptake and carbon dioxide output) were determined during a control period (21 % oxygen), a hypoxic period (2, 5, 6.5, 8 or 10 % oxygen) and a recovery period (21 % oxygen). Hypoxic Salamanders maintained their rate of oxygen uptake at control levels until a critical oxygen level between 10 and 8 % oxygen was reached. The rate of carbon dioxide output remained constant across all oxygen levels, except for a significant increase during exposure to 5 % oxygen. The buccal activity of Lungless Salamanders was responsive to environmental hypoxia, with a significant stimulation during exposure to 6.5 % and 5 % oxygen. Buccal pumping frequency was inhibited at 2 % oxygen. Heart rate was stimulated at all hypoxic levels except 2 % O(2). During recovery, metabolic rate and heart rate returned to control levels within 20 min after all hypoxic exposures. The durations of apneic periods increased significantly compared with the hypoxic value during recovery from exposure to 10 %, 6.5 % and 5 % oxygen. Overall, the animals responded actively to hypoxia by increasing the duration of buccal activity as oxygen levels decreased. The ability of these changes to facilitate oxygen uptake is not known. However, the response of the dusky Salamander to low levels of oxygen is analogous to the hypoxic ventilatory response observed in lunged vertebrates.
David B Wake - One of the best experts on this subject based on the ideXlab platform.
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a new genus and species of Lungless Salamander family plethodontidae from the appalachian highlands of the south eastern united states
2009Co-Authors: Carlos D Camp, William E Peterman, Joseph R Milanovich, Trip Lamb, John C Maerz, David B WakeAbstract:We describe a striking new species of the Lungless Salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25–26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6–5.3%). This new form appears to be rare and is of immediate conservation concern.
Elizabeth A Sheafor - One of the best experts on this subject based on the ideXlab platform.
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the effect of graded hypoxia on the metabolic rate and buccal activity of a Lungless Salamander desmognathus fuscus
2000Co-Authors: Elizabeth A Sheafor, Stephen C Wood, Glenn J TattersallAbstract:The hypothesis that the Lungless Salamander Desmognathus fuscus responds actively to hypoxia was tested. Patterns of buccal movements [apneic period duration, the duration (min h(−)(1)) of buccal pumping and buccal pumping frequency], heart rate and metabolic rate (rates of oxygen uptake and carbon dioxide output) were determined during a control period (21 % oxygen), a hypoxic period (2, 5, 6.5, 8 or 10 % oxygen) and a recovery period (21 % oxygen). Hypoxic Salamanders maintained their rate of oxygen uptake at control levels until a critical oxygen level between 10 and 8 % oxygen was reached. The rate of carbon dioxide output remained constant across all oxygen levels, except for a significant increase during exposure to 5 % oxygen. The buccal activity of Lungless Salamanders was responsive to environmental hypoxia, with a significant stimulation during exposure to 6.5 % and 5 % oxygen. Buccal pumping frequency was inhibited at 2 % oxygen. Heart rate was stimulated at all hypoxic levels except 2 % O(2). During recovery, metabolic rate and heart rate returned to control levels within 20 min after all hypoxic exposures. The durations of apneic periods increased significantly compared with the hypoxic value during recovery from exposure to 10 %, 6.5 % and 5 % oxygen. Overall, the animals responded actively to hypoxia by increasing the duration of buccal activity as oxygen levels decreased. The ability of these changes to facilitate oxygen uptake is not known. However, the response of the dusky Salamander to low levels of oxygen is analogous to the hypoxic ventilatory response observed in lunged vertebrates.
Carlos D Camp - One of the best experts on this subject based on the ideXlab platform.
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a new genus and species of Lungless Salamander family plethodontidae from the appalachian highlands of the south eastern united states
2009Co-Authors: Carlos D Camp, William E Peterman, Joseph R Milanovich, Trip Lamb, John C Maerz, David B WakeAbstract:We describe a striking new species of the Lungless Salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25–26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6–5.3%). This new form appears to be rare and is of immediate conservation concern.
William E Peterman - One of the best experts on this subject based on the ideXlab platform.
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the effects of temperature and activity on intraspecific scaling of metabolic rates in a Lungless Salamander
2013Co-Authors: Matthew E Gifford, Timothy A Clay, William E PetermanAbstract:The scaling of metabolic rate with body mass holds substantial predictive power as many biological processes depend on energy. A significant body of theory has been developed based on the assumption that metabolic rate scales with body mass as a power function with an exponent of 0.75, and that this scaling relationship is independent of temperature. Here we test this hypothesis at the intraspecific level in a Lungless Salamander using data on both standard and maximal metabolic rates (SMR and MMR, respectively). We also address a recently proposed alternative explanation that predicts systematic variation in this mass-scaling exponent, the metabolic level boundaries hypothesis (MLB). Consistent with predictions of the metabolic theory of ecology the mass scaling of SMR and MMR were independent of temperature, however, we find evidence that the mass-scaling exponent for SMR and MMR differ significantly from 0.75. Further, our data do not provide strong support for MLB. Mass-scaling exponents for MMR generally exceed those for SMR, although these differences are rarely statistically significant.J. Exp. Zool. 9999A:1-7,2013. © 2013 Wiley Periodicals, Inc. How to cite this article: Gifford ME, Clay TA, Peterman WE. 2013. The effects of temperature and activity on intraspecific scaling of metabolic rates in a Lungless Salamander. J. Exp. Zool.
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a new genus and species of Lungless Salamander family plethodontidae from the appalachian highlands of the south eastern united states
2009Co-Authors: Carlos D Camp, William E Peterman, Joseph R Milanovich, Trip Lamb, John C Maerz, David B WakeAbstract:We describe a striking new species of the Lungless Salamander family Plethodontidae from the Appalachian foothills of northern Georgia, USA. This miniature species, c. 25–26 mm (adult standard length), is so distinctive genetically and morphologically that we erect a new genus, the first new genus of amphibian described from the US in nearly 50 years. It is unique among plethodontids from eastern North America in displaying sexual colour dimorphism. Although certain miniaturized plethodontids exhibit a reduced number (four) of digits on the pes, this species possesses a full complement of five toes. A plethodontid phylogeny derived from mitochondrial and nuclear DNA sequences places it in the tribe Spelerpini as the sister taxon to Eurycea. Genetic divergence between the new species and Eurycea for the nuclear gene Rag-1 (4.7%) is among the higher levels observed between long-established spelerpine genera (2.6–5.3%). This new form appears to be rare and is of immediate conservation concern.
