Origins and evolution of plant diversity in the Hengduan Mountains, China

1.Introduction The Hengduan Mountains region(HDM)in southwest China,one of the earth's 34 biodiversity hotspots,is characterized by its unique geology,dramatic topography,a climate where snow and below freezing temperatures can occur on any day of the year,by its location at elevations averaging between(1400e)2000 and4500(e5300)meters above sea level(m a.s.l.),and by one of

Discussion on Rb-Sr Isochron Ages of Granitoids in the Hengduan Mountains

Based on the Rb-Sr isotopic study of the granitoids in the Hengduan Mountains, the classification andgeologic significance of whole-rock Rb-Sr isochrons as well as the factors influencing homogenization of theisotopic systems are discussed. Usually. there is no good linear correlation of isochrons for diorites andalkali-rich intrusive rocks (including alkaline rock and alkalic granite). But by means of the external isochron ofmonominerals from the rocks. isochrons with good linear correlation as well as ages and Sr initial ratios with ahigh confidence can be obtained. In order to obtain a satisfactory isochron, the discriminant parameters shouldbe calculated from the Rb/Sr ratios and estimated ages of samples. Only those that meet the requirements canbe used as the Rb-Sr isochrons. The quality of an isochron should be judged from three factors, i.e. correlationcoefficient. MSWD and homogenization degree.

A New Species of the Genus Scincella Mittleman,1950(Squamata:Scincidae)from Sichuan Province,Southwest China

The genus Scincella Mittleman,1950,within the family Scincidae,is a diverse group comprising 39 described species.The taxonomy of the genus is complex due to morphological similarities among species,which often obscures the true extent of biodiversity,resulting in several undescribed species requiring further exploration.In China,particularly within the unique ecosystems of the Hengduan Mountains,the diversity of Scincella is notably underestimated,with only 12 species currently recognized.In the present study,we describe a new species of the genus Scincella,Scincella liangshanensis sp.nov.,from Sichuan Province,Southwest China.Morphological characteristics and phylogenetic analyses revealed that the putative new species is distinct from all other known congeners.This discovery not only expands the known diversity of Scincella but also emphasizes the inadequacies in our current understanding of herpetological diversity in China.The addition of this species to the scientific record highlights the necessity for ongoing biodiversity assessments to uncover hidden species and enhance our understanding of the intricate web of life in one of the world’s biodiversity hotspots.