Bufotes taxkorensis and B. zamdaensis are toads endemic to China. Both species inhabit highelevation and saline environments, and so provide a unique opportunity to investigate the adaptive responses of amphibians to ...Bufotes taxkorensis and B. zamdaensis are toads endemic to China. Both species inhabit highelevation and saline environments, and so provide a unique opportunity to investigate the adaptive responses of amphibians to extreme habitats. In the present study, we first observed and measured the histological structures of their skin and kidney in B.taxkorensis and B. zamdaensis. We then compared these results with similar findings for the low-elevation seawater dweller Fejervarya cancrivora and, finally,contrasted them with available data on species living in diverse habitats. Our results revealed the following adaptations:(1) In the Bufotes species, the epidermis and dermis both contain capillary vessels, facilitating blood-gas exchange and promoting adaptation to high-elevation hypoxia. The thick pigment layers present in the ventral skin of B. taxkorensis also help in adaptation to lower temperatures. In addition, the relative epidermis thickness of the dorsal and ventral skin is significantly greater in Bufotes species than in F.cancrivora, indicating adaptation to a terrestrial habitat.Comparing the terrestrial and semiaquatic species, we find that total dorsal and ventral thicknesses are both significantly greater in terrestrial than in semiaquatic species, helping to reduce water evaporation and damage from crawling, and thus promoting adaptation to terrestrial life.(2) The relative kidney filtration area of the Bufotes species is not significantly different from that of F. cancrivora, but accounts for only half that of terrestrial Bufo species. This lower total relative filtration area prevents excessive urea from being filtered out, avoiding excessive loss of body water and promoting adaptation to saline conditions. At the same time, the relative diameter of the proximal segment of Bufotes species is found to be similar to that of the semiaquatic F. cancrivora,facilitating the resorption of water and ions to increase plasma osmolality and promoting adaptation to saline environments. The findings of the present study offer insights into the adaptive mechanisms of amphibians in extreme environments and different habitats.展开更多
The Liaoning clawed salamander(Onychodactylus zhaoermii)is an endemic and critically endangered amphibian species of China.To study the population genetics of natural populations of this species,32 samples were collec...The Liaoning clawed salamander(Onychodactylus zhaoermii)is an endemic and critically endangered amphibian species of China.To study the population genetics of natural populations of this species,32 samples were collected from six different locations,and the mitochondrial genome was sequenced.Population genetic analyses showed that the Liaoning clawed salamander is composed of only one radialized cluster with ultralow nucleotide diversity.Late Pleistocene climate cooling(-100 to-30 kya)may have reduced the effective population size of the Liaoning clawed salamander,and the subsequent temperature increase(~25 kya to present)provided the opportunity for population expansion.Because of heat sensitivity,the maximum temperature of the prebreeding period,especially from March to May,is very important for the surface environment living in the Liaoning clawed salamander.Three suitable regions were predicted by the MaxEnt model,and the largest suitable region(approximately 899 km2)was at the four-county boundary area and was larger than the present’Natural Conservation Community of the Liaoning Clawed Salamander’.To ensure more effective protection of all Liaoning clawed salamanders,we suggest extending the current’Natural Conservation Community of the Liaoning Clawed Salamander’to include the four-county boundary area.展开更多
The impact of the Quaternary glaciation on eastern China’s local fauna and flora is a topic of considerable interest. We use mitochondrial DNA(mtDNA) sequences and coalescent simulations to test two general biogeogra...The impact of the Quaternary glaciation on eastern China’s local fauna and flora is a topic of considerable interest. We use mitochondrial DNA(mtDNA) sequences and coalescent simulations to test two general biogeographic hypotheses related to the effect of the Pleistocene climatic fluctuations on a widespread, eastern Chinese amphibian, Pseudepidalea raddei. Genealogical reconstructions are made and they detect major western and eastern lineages, which overlap in northwestern China, and possibly indicate the secondary contact of the populations that had entered the region from separate glacial refugia. Coalescent tests rejected alternative hypotheses of fragmentation of either a widespread ancestor or panmixia. The tests instead supported the hypothesis of geographic isolation and a remarkable dispersal pattern in one of the lineages. Though the Pleistocene climatic events are known to have affected the historical distributions and intra-specific divergence of Chinese squamates, coalescent and non-coalescent demographic analyses indicated that the toad P. raddei was not adversely affected by glacial cycling. Presumably, an increase in the amount of climatically mild habitats in East Asia is due to the development of monsoons since the Mid-late Pleistocene is responsible for the relatively mild effects.展开更多
基金supported by the National Natural Science Foundation of China (32200378)the Third Xinjiang Scientific Expedition Program (2022xjkk0205-1)+1 种基金the Survey of Wildlife Resources in Key Areas of Xizang (ZL202203601)China Biodiversity Observation Networks (Sino BON-Amphibian & Reptile)。
文摘Bufotes taxkorensis and B. zamdaensis are toads endemic to China. Both species inhabit highelevation and saline environments, and so provide a unique opportunity to investigate the adaptive responses of amphibians to extreme habitats. In the present study, we first observed and measured the histological structures of their skin and kidney in B.taxkorensis and B. zamdaensis. We then compared these results with similar findings for the low-elevation seawater dweller Fejervarya cancrivora and, finally,contrasted them with available data on species living in diverse habitats. Our results revealed the following adaptations:(1) In the Bufotes species, the epidermis and dermis both contain capillary vessels, facilitating blood-gas exchange and promoting adaptation to high-elevation hypoxia. The thick pigment layers present in the ventral skin of B. taxkorensis also help in adaptation to lower temperatures. In addition, the relative epidermis thickness of the dorsal and ventral skin is significantly greater in Bufotes species than in F.cancrivora, indicating adaptation to a terrestrial habitat.Comparing the terrestrial and semiaquatic species, we find that total dorsal and ventral thicknesses are both significantly greater in terrestrial than in semiaquatic species, helping to reduce water evaporation and damage from crawling, and thus promoting adaptation to terrestrial life.(2) The relative kidney filtration area of the Bufotes species is not significantly different from that of F. cancrivora, but accounts for only half that of terrestrial Bufo species. This lower total relative filtration area prevents excessive urea from being filtered out, avoiding excessive loss of body water and promoting adaptation to saline conditions. At the same time, the relative diameter of the proximal segment of Bufotes species is found to be similar to that of the semiaquatic F. cancrivora,facilitating the resorption of water and ions to increase plasma osmolality and promoting adaptation to saline environments. The findings of the present study offer insights into the adaptive mechanisms of amphibians in extreme environments and different habitats.
基金supported financially by the Research Fund for the Educational Commission of Liaoning Province of China(LQN201904 and LJC201901)the Doctoral Program of Shenyang Normal University(Grant No.BS201821)the Natural Science Foundation of Liaoning Province of China(2020-BS-148 and 2021-MS-241)。
文摘The Liaoning clawed salamander(Onychodactylus zhaoermii)is an endemic and critically endangered amphibian species of China.To study the population genetics of natural populations of this species,32 samples were collected from six different locations,and the mitochondrial genome was sequenced.Population genetic analyses showed that the Liaoning clawed salamander is composed of only one radialized cluster with ultralow nucleotide diversity.Late Pleistocene climate cooling(-100 to-30 kya)may have reduced the effective population size of the Liaoning clawed salamander,and the subsequent temperature increase(~25 kya to present)provided the opportunity for population expansion.Because of heat sensitivity,the maximum temperature of the prebreeding period,especially from March to May,is very important for the surface environment living in the Liaoning clawed salamander.Three suitable regions were predicted by the MaxEnt model,and the largest suitable region(approximately 899 km2)was at the four-county boundary area and was larger than the present’Natural Conservation Community of the Liaoning Clawed Salamander’.To ensure more effective protection of all Liaoning clawed salamanders,we suggest extending the current’Natural Conservation Community of the Liaoning Clawed Salamander’to include the four-county boundary area.
基金supported by the Director Foundation of Experimental Centre, Shenyang Normal University (Syzx1104)a Visiting Professorship for Senior International Scientists from the Chinese Academy of Sciences to Robert W. MURPHYsupported by a Discovery Grant of the Natural Sciences and Engineering Research Council of Canada (A3148)
文摘The impact of the Quaternary glaciation on eastern China’s local fauna and flora is a topic of considerable interest. We use mitochondrial DNA(mtDNA) sequences and coalescent simulations to test two general biogeographic hypotheses related to the effect of the Pleistocene climatic fluctuations on a widespread, eastern Chinese amphibian, Pseudepidalea raddei. Genealogical reconstructions are made and they detect major western and eastern lineages, which overlap in northwestern China, and possibly indicate the secondary contact of the populations that had entered the region from separate glacial refugia. Coalescent tests rejected alternative hypotheses of fragmentation of either a widespread ancestor or panmixia. The tests instead supported the hypothesis of geographic isolation and a remarkable dispersal pattern in one of the lineages. Though the Pleistocene climatic events are known to have affected the historical distributions and intra-specific divergence of Chinese squamates, coalescent and non-coalescent demographic analyses indicated that the toad P. raddei was not adversely affected by glacial cycling. Presumably, an increase in the amount of climatically mild habitats in East Asia is due to the development of monsoons since the Mid-late Pleistocene is responsible for the relatively mild effects.
