Spatial Distribution Pattern For Salamander(Paramesotriton)species In The Mountains Of Southern China

The Amphibia salamander family Salamandridae has 14 species in the genus Paramesotriton,which is distributed worldwide only in southern China and northern Vietnam.Previous studies have largely clarified the species group of the genus based on morphological characters and single segment molecular markers,namely,the P.caudopunctatus species group and the P.chinensis species group.These species have narrow ranges and are less mobile,making them good models for studying how relevant geographic and environmental factors affect the dispersal of animal origins.Continuous historical mountain building movements and surface uplift and regional climatic changes have created different habitats in the mountains of southern China,providing opportunities to study species formation,evolution and spatial distribution patterns in this region.However,there is a lack of research on how historical orogeny and climate change drive species formation,historical population dynamics and spatial distribution patterns of Paramesotriton.in the mountains of southern China.Therefore,this study explored the evolutionary processes and spatial distribution patterns of species of the genus Paramesotriton in southern China by combining biogeography,MaxEnt model and geographic information technology.The main findings are as follows:1.In this study,the mitochondrial genome and 32 nuclear genes of14 species(27 samples)of the genus Paramesotriton were sequenced to determine the timing of species group divergence and reconstruct the evolutionary history of the genus.Molecular dating and tectonic history suggest that the genus Paramesotriton originated in the Late Oligocene(ca.25.42 Ma),when the second uplift of the Himalayan/Tibetan Plateau occurred in southern China,driving the origin of the genus Paramesotriton,and that ancestral regional reconstructions indicate that the most recent common ancestor of the species was likely distributed in the Yunnan-Guizhou Plateau;Early Miocene(ca.22.86 Ma)with the gradual development of karst landscapes in southern China,the Driven-P.caudopunctatus species group and the P.chinensis species group began to differentiate;During the middle Miocene(15-10 Ma),the Hengduan Mountains and the Wuyi-Nanling Mountains uplift significantly altered the geomorphic landscape and river erosion patterns in southern China,and orogenic movements in a small area of Guizhou led to interstitial uplift of the landscape,further development of karst(the mountain-basin karst stage),and the first peak of intraspecific differentiation of the genus Paramesotriton;The Pliocene(5.3-1.8 Ma)genus Paramesotriton diverged into P.wulingensis,P.caudopunctatus,P.longliensis(Hubei clade),P.zhijinensis,and P.longliensis(Huishui clade);During the early Pleistocene(1.8-0.12 Ma),the Wuluo movement in Guizhou pushed the Miaoling Mountains westward,accelerated karst development,and basically formed the water system pattern in Guizhou,resulting in geographic isolation that pushed the formation of P.maulanensis and P.longliensis(Longli and Dafang clade).2.In this study,the MaxEnt model and geoinformation technology were used to simulate paleoclimatic changes since the Late Pleistocene to investigate whether the ice age affected the distribution of the genus Paramesotriton.The results of the study show that the habitat of the P.caudopunctatus species group contracted during the last ice age and migrated to the vicinity of the Miaoling Mountains in Guizhou,presumably because Guizhou was less affected by the Quaternary glaciation at that time,and the Miaoling Mountains acted as a "microclimatic refuge" for the population;The P.chinensis species group(eastern)shrank to the Tianmu Mountains and nearby ranges in Zhejiang during the last bloom ice age,demonstrating that the eastern group was also affected by the Quaternary ice age at that time;The regional habitat range of the P.chinensis species group(southern)was generally unchanged,and it is assumed that the southern group was not affected by the Quaternary ice age at that time.3.The distribution of Paramesotriton species in current and future periods is influenced by both human activities and climate change.The MaxEnt model and remote sensing images showed that the three geographic groups of the genus Paramesotriton show fragmentation of suitable habitat in the current period compared to the paleoclimate period,which is related to the current human disturbance of surface activities;the habitat range of P.caudopunctatus species group shrinks and moves to higher latitudes under the future climate warming model.In situ expansion of the suitable habitat range of the P.chinensis species group(eastern)occurs.The area change of the P.chinensis species group species group(southern)is minimal.This study explores the origin and population history dynamics of the genus Paramesotriton in the mountains of southern China by combining molecular techniques and geological and tectonic events,and further investigates the role of geological and tectonic movements and paleoclimate on the formation,evolution and distribution of species diversity.In the context of increasing anthropogenic disturbance and global warming,the response and distribution mechanisms of different geographic groups of this genus to environmental changes were studied.This study contributes to the conservation of the habitat of this taxon and provides a scientific basis for the establishment of national parks in Guizhou Province,and provides key information for the conservation and assessment of regional species diversity.