Dentoalveolar paleopathology of the early modern humans from Zhirendong,South China

The fragmentary early Late Pleistocene, early modern human remains from Zhirendong, south China, present a suite of dentoalveolar pathologies and anomalies. The lesions include lower molar buccal alveolar resorption (Zhiren 1), massive dental caries in a mandibular molar associated with hypercementosis (Zhiren 2), and bilateral mesial premolar (P3) periapical lesions (granulomata with a probable left abscess) (Zhiren 3). The Zhiren 3 periapical lesions, given their bilaterality and the non-pathological incisor and canine alveoli, suggest dens evaginatus, although absence of the Zhiren 3 dentition prevents full evaluation of this diagnosis. These periodontal abnormalities join a number of similar lesions in Pleistocene humans, of varying severity. The carious lesion is noteworthy, given the rarity of them in the Pleistocene human fossil record. In addition, Zhiren 3 exhibits unilateral P3 rotation and bilateral I1 rotation (winging)

Dentoalveolar paleopathology of the early modern humans from Zhirendong,South China

The fragmentary early Late Pleistocene, early modern human remains from Zhirendong, south China, present a suite of dentoalveolar pathologies and anomalies. The lesions include lower molar buccal alveolar resorption (Zhiren 1), massive dental caries in a mandibular molar associated with hypercementosis (Zhiren 2), and bilateral mesial premolar (P3) periapical lesions (granulomata with a probable left abscess) (Zhiren 3). The Zhiren 3 periapical lesions, given their bilaterality and the non-pathological incisor and canine alveoli, suggest dens evaginatus, although absence of the Zhiren 3 dentition prevents full evaluation of this diagnosis. These periodontal abnormalities join a number of similar lesions in Pleistocene humans, of varying severity. The carious lesion is noteworthy, given the rarity of them in the Pleistocene human fossil record. In addition, Zhiren 3 exhibits unilateral P3 rotation and bilateral I1 rotation (winging).</p

Climate significance of speleothem d18O from central China on decadaltimescale

Speleothem-based oxygen isotopic sequences have been widely used to reveal regional climatic changes worldwide. However, the climatic significance of speleothem d18O variations in monsoonal China on decadal- to annual timescales remains in debate, which limits its application to paleoclimate reconstruction in the world&rsquo;s largest country by population. In this study, we analyzed a seasonally resolved d18O record of an annually layered stalagmite, XL21 whose variability covers a period of 98 years (1912&ndash;2009 AD), from Xianglong Cave, central China. The annual d18O trend shows an inverse relationship with local monsoon precipitation, suggesting speleothem d18O variations in this area can reflect monsoon precipitation at least on decadal timescale. Changes in moisture sources and transport pathways have little effect on the d18O variations in speleothems/monsoon precipitation on decadal timescale, which may be ascribed to similar distances from this region to the two main moisture sources, the Bay of Bengal and West Pacific. There is an anti-phase relationship between speleothem d18O records from central China and India during the last 98 years, which indicates the relationship between Indian monsoon intensity and speleothem d18O from central China on short timescales requires further investigation.</p

New 400e320 ka Gigantopithecus blacki remains from Hejiang Cave,Chongzuo City, Guangxi, South China

Gigantopithecus blacki is a typical member of the StegodoneAiluropoda faunal complex (sensu lato) that inhabited southern China or, more broadly, mainland Southeast Asia during the Early and Middle Pleistocene. Current evidence indicates that the giant ape became extinct during the Middle Pleistocene. Recently, new remains of G blacki and associated mammalian fossils have been unearthed from a karst cave site, Hejiang Cave, in Chongzuo City, Guangxi, South China. The age of the Gigantopithecus-bearing depositional unit is estimated to be 400e320 ka using 230The234U disequilibrium U-series dating of flowstone samples bracketing the deposits. These finds document the latest occurrence of Gigantopithecus and provide potential insights regarding its extinction. Comparisons of dental dimensions between the Hejiang G. blacki remains, more than four hundred isolated teeth from Early Pleistocene localities, and over ninety isolated teeth from local drugstores show that the Hejiang teeth are slightly larger in their buccolingual dimensions. In addition, the crowns of the three unerupted upper premolars differ from those of all of the other Gigantopithecus material in having more complex crenulations. The differences in dental dimensions and morphology are possibly reflective of dietary responses to environmental changes that eventually led to the extinction of Gigantopithecus.</p

The Holocene Indian monsoon variability over the southern Tibetan Plateau and its teleconnections

A high-resolution stalagmite oxygen isotope record from Tianmen Cave, located in the south central Tibetan Plateau, characterizes detailed climatic variations between 8.7 and 4.3 ka BP on centennial and decadal time scales, with a temporal resolution of 3 to 7 years. The Tianmen record is in good agreement with speleothem records from Asian monsoon regions (i.e., Dongge Cave, Dykoski et al., 2005; Wang et al., 2005; Qunf Cave, Fleitmann et al., 2003), upwelling records from the Arabian Sea (Gupta et al., 2003, 2005) and peat bog records from southeast Tibetan Plateau (Hong et al., 2003), indicating that the Indian summer monsoon (ISM) gradually weakened as Northern Hemisphere summer insolation declined during the early-mid Holocene and that ISM intensity, rather than temperature, dominates the precipitation delta O-18 on centennial to decadal time scales in the southern TP. On centennial to decadal time scales, the detrended Tianmen record correlates well with the Greenland ice core record, further confirming the mechanistic connection between the ISM and high northern latitude temperature changes. Meanwhile, the Tianmen record bears significant solar activity cycles, suggesting that the solar output changes may affect the variability of the ISM and likely the position of the Intertropical Convergence Zone (ITCZ) as well. Moreover, due to joint effects of changes in monsoon precipitation, moisture source and temperature, the Tianmen delta O-18 record shows much larger amplitude changes than speleothem delta O-18 records from low-elevation Asian Monsoon regions, which is similar to the previously reported Marine Isotope Stage (MIS) 5 record (Cai et al., 20W), suggesting heightened sensitivity of precipitation isotope composition to climate changes over the high-elevation regions and further demonstrating that the stable isotope lapse rate may change under different climatic conditions.</p

Role of seasonal transitions and westerly jets in East Asianpaleoclimate

The summer rainfall climate of East Asia underwent large and abrupt changes during past climates, in response to precessional forcing, glacialeinterglacial cycles as well as abrupt changes to the North Atlantic during the Last Glacial. However, current interpretations of said changes are typically formulated in terms of modulation of summer monsoon intensity, and do not account for the known complexity in the seasonal evolution of East Asian rainfall, which exhibits sharp transition from the Spring regime to the Meiyu, and then again from the Meiyu to the Summer regime. We explore the interpretation that East Asian rainfall climate undergoes a modulation of its seasonality during said paleoclimate changes. Following previous suggestions we focus on role of the westerly jet over Asia, namely that its latitude relative to Tibet is critical in determining the stepwise transitions in East Asian rainfall seasons. In support of this linkage, we show from observational data that the interannual co-variation of June (JulyeAugust) rainfall and upper tropospheric zonal winds show properties consistent with an altered timing of the transition to the Meiyu (Summer), and with more northwardshifted westerlies for earlier transitions. We similarly suggest that East Asian paleoclimate changes resulted from an altered timing in the northward evolution of the jet and hence the seasonal transitions, in particular the transition of the jet from south of the Plateau to the north that determines the seasonal transition from Spring rains to the Meiyu. In an extreme scenario e which we speculate the climate system tended towards during stadial (cold) phases of D/O stadials and periods of low Northern Hemisphere summer insolation e the jet does not jump north of the Plateau, essentially keeping East Asia in prolonged Spring conditions. We argue that this hypothesis provides a viable explanation for a key paleoproxy signature of D/O stadials over East Asia, namely the heavier mean d18O of precipitation as recorded in speleothem records. The southward jet position prevents the low-level monsoonal flow e which is isotopically light e from penetrating into the interior of East Asia; as such, precipitation there will be heavier, consistent with speleothem records. This hypothesis can also explain other key evidences of East Asian paleoclimate changes, in particular the occurrence of dusty conditions during North Atlantic stadials, and the southward migration of the Holocene optimal rainfall

A Chinese cave links climatechange, social impacts, and humanadaptation over the last 500 years

The collapse of some pre-historical and historical cultures, including Chinese dynasties were presumably linked to widespread droughts, on the basis of synchronicities of societal crises and proxy-based climate events. Here, we present a comparison of ancient inscriptions in Dayu Cave from Qinling Mountains, central China, which described accurate times and detailed impacts of seven drought events during the period of 1520&ndash;1920 CE, with high-resolution speleothem records from the same cave. The comparable results provide unique and robust tests on relationships among speleothem &delta;18O changes, drought events, and societal unrest. With direct historical evidences, our results suggest that droughts and even modest events interrupting otherwise wet intervals can cause serious social crises. Modeling results of speleothem &delta;18O series suggest that future precipitation in central China may be below the average of the past 500 years. As Qinling Mountain is the main recharge area of two large water transfer projects and habitats of many endangered species, it is imperative to explore an adaptive strategy for the decline in precipitation and/or drought events.</p