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Batrachuperus yenyuanensis, commonly known as Yenyuan Stream Salamander, is a hynobiid species inhabiting high-altitude (2440–4025 m above sea level) mountain stream and pond environments along the eastern fringe of the Qinghai-Tibetan Plateau in western Sichuan Province, China. Although the species has been known for almost 70 years since its initial discovery in 1950, a thorough osteological description has never been provided. Our study provides a detailed account of the bony anatomy of this species, based on micro computed tomography scanning of multiple specimens collected from the type locality Shuangertang at Bailinshan, Yanyuan County, and several other localities in Sichuan Province. Our revised species diagnosis utilizes both bony and soft anatomical features. Comparative study of the specimens from the type locality in Yanyuan area with those from the nearby Xichang and Mianning areas confirms that they all pertain to Batrachuperus yenyuanensis, thereby removing doubt on the occurrence of the species in the latter areas. With this confirmation, the distribution of the species is extended from the type locality northwards some 180 km to the Mianning area, on both the west and east sides of the Yalong River, which is a major tributary of the upper Yangtze River. This distribution pattern indicates that the biogeographic origin and historical evolution of the species are closely associated with the orogeny of the Hengduan Mountains and formation of the Yalong River. Given the basalmost position of Batrachuperus yenyuanensis in relation to other congeneric species based on molecular studies, however, early expansion of the species distribution by dispersal is expected following the origin of the genus in early–middle Miocene in western Sichuan Province. Thus, the species may well have achieved its current distribution in western Sichuan before the drastic uplift of the Qinghai-Tibetan Plateau in Pliocene. [ABSTRACT FROM AUTHOR]

The Tibet chicken originates from the Qinghai-Tibet Plateau and has adapted well to hypoxia, whereas the Silky chicken is a lowland chicken breed from an area with an altitude of 750 m. The objective of the present study was to investigate whether differences exist in glutathione and related metabolism between the Tibet chicken and the Silky chicken when birds were housed in a normoxic or hypoxic chamber for 20 h. Activities of glutathione peroxidase, glutathione S-transferase, and glutathione reductase and levels of glutathione were determined spectrophotometrically. Under normoxia conditions and moderate hypoxia (14% oxygen concentration) conditions, no differences were found in levels of total glutathione, reduced glutathione (GSH), disulfide-oxidized glutathione (GSSG), the GSH:GSSG ratio, and activities of glutathione peroxidase and glutathione S-transferase between the Tibet chicken and the Silky chicken. Under extreme hypoxia conditions (14% oxygen concentration for 14 h and then 10.5% oxygen concentration for 6 h), values for the GSH content, the GSH:GSSG ratio, and the activity of glutathione reductase in the liver of the Tibet chicken were higher than those of the Silky chicken. The results indicate that the Tibet chicken responded better than the Silky chicken to oxidative stress in extreme hypoxia through glutathione enzymes of detoxification. This work provides reference for future studies on the association of glutathione metabolism with the adaptation to hypoxia. [ABSTRACT FROM AUTHOR]

Early archaeological investigations on the Tibetan Plateau concluded that this harsh, high-elevation environment was successfully colonized around 30,000 years ago. Genetic studies have tended to support this view on the assumption that the uniquely evolved physiological capacities seen among modern Tibetan populations required long-term exposure to high-elevation selective pressures. Archaeological evidence amassed over the last decade suggests, however, that colonization leading to full-time occupation occurred much later. Seasonal foraging forays into high-elevation settings at c . 30 and 15 cal. ka appear to have been limited ‘adaptive radiations’ coincident, respectively, with the appearance of early and late Upper Palaeolithic adaptations in low-elevation source areas around the plateau. More permanent occupation of the plateau probably did not begin before c . 8200 cal. bp and may have been driven by ‘competitive exclusion’ of late Upper Palaeolithic foragers from low-elevation environments by emerging settled agricultural groups. The appearance of specialized epi-Palaeolithic blade and bladelet technologies on the high plateau, after 8200 cal. ka, may indicate ‘directional selection’ impacting on these new full-time residents. An ‘adaptive radiation’ of agriculturalists into the mid-elevations of the plateau, this time leading to year-round occupation, is again seen after 6000 cal. bp. [ABSTRACT FROM AUTHOR]