Michelle Glantz

Oligocene mammals from Ethiopia and faunal exchange between Afro-Arabia and Eurasia

Afro-Arabian mammalian communities underwent a marked transition near the Oligocene/Miocene boundary at approximately 24 million years (Myr) ago. Although it is well documented that the endemic paenungulate taxa were replaced by migrants from the Northern Hemisphere, the timing and evolutionary dynamics of this transition have long been a mystery because faunas from about 32 to 24 Myr ago are largely unknown. Here we report a late Oligocene fossil assemblage from Ethiopia, which constrains the migration to postdate 27 Myr ago, and yields new insight into the indigenous faunal dynamics that preceded this event. The fauna is composed of large paenungulate herbivores and reveals not only which earlier taxa persisted into the late Oligocene epoch but also demonstrates that one group, the Proboscidea, underwent a marked diversification. When Eurasian immigrants entered Afro-Arabia, a pattern of winners and losers among the endemics emerged: less diverse taxa such as arsinoitheres became extinct, moderately species-rich groups such as hyracoids continued into the Miocene with reduced diversity, whereas the proboscideans successfully carried their adaptive radiation out of Afro-Arabia and across the world.

New hominin remains from Uzbekistan

Although the Paleolithic occupations of Uzbekistan and the neighboring foothill regions of Tajikistan and Kazakhstan are well-documented, almost no hominin fossil material has been discovered in the area since Teshik-Tash 1 in 1938. Here we describe and offer a preliminary comparative framework for hominin remains that were recovered in 2003 from two Middle Paleolithic sites in Uzbekistan, Obi-Rakhmat Grotto and Anghilak Cave. The description of Teshik-Tash as a Neandertal and the preponderance of lithic assemblages identified as Mousterian in character has supported the interpretation of the region as the eastern-most extent of the Neandertal range. The material from Obi-Rakhmat (OR-1), a subadult represented by part of a permanent maxillary dentition and a fragmentary cranium, expresses a relatively Neandertal-like dentition coupled with more ambiguous cranial anatomy. The remains from Anghilak Cave include a non-diagnostic, diminutive right fifth metatarsal (AH-1). These findings are important additions to the Central Asia hominin fossil record.

The affinity of the dental remains from Obi-Rakhmat Grotto, Uzbekistan

A human partial maxillary dentition and a fragmentary cranium were recovered from Obi-Rakhmat Grotto in northeastern Uzbekistan in 2003. Initial descriptions of this single juvenile (OR-1) from a Middle Paleolithic archaeological context have emphasized its mosaic morphological pattern; the dentition appears archaic, while certain morphological aspects of the cranial fragments may be more ambiguous. The present study provides a systematic and comparative analysis of the dental morphology and morphometrics of OR-1 to provide a more refined appraisal of its phenetic affinity vis á vis Neandertals and modern humans. Two analyses were performed. The first uses 28 non-metric dental traits scored from Neandertals, Upper Paleolithic, and Middle Paleolithic modern humans to assess the posterior probability of group membership for the Obi-Rakhmat individual. The second is a morphometric analysis of the first upper molar of OR-1. The results of both analyses suggest the dentition of OR-1 is essentially Neandertal.

Is Central Asia the Eastern Outpost of the Neandertal Range? A Reassessment of the Teshik-Tash Child

Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered a Neandertal. Its affinity is important to studies of Late Pleistocene hominin growth and development as well as interpretations of the Central Asian Middle Paleolithic and the geographic distribution of Neandertals. A close examination of the original Russian monograph reveals the incompleteness of key morphologies associated with the cranial base and face and problems with the reconstruction of the Teshik-Tash cranium, making its Neandertal attribution less certain than previously assumed. This study reassesses the Neandertal status of Teshik-Tash 1 by comparing it to a sample of Neandertal, Middle and Upper Paleolithic modern humans, and recent human sub-adults. Separate examinations of the cranium and mandible are conducted using multinomial logistic regression and discriminant function analysis to assess group membership. Results of the cranial analysis group Teshik-Tash with Upper Paleolithic modern humans when variables are not size-standardized, while results of the mandibular analysis place the specimen with recent modern humans for both raw and size-standardized data. Although these results are influenced by limitations related to the incomplete nature of the comparative sample, they suggest that the morphology of Teshik-Tash 1 as expressed in craniometrics is equivocal. Although, further quantitative studies as well as additional sub-adult fossil finds from this region are needed to ascertain the morphological pattern of this specimen specifically, and Central Asian Middle Paleolithic hominins in general, these results challenge current characterizations of this territory as the eastern boundary of the Neandertal range during the Late Pleistocene.

The History of Hominin Occupation of Central Asia in Review

The timing of hominin dispersals during the early Pleistocene, specifically into East Asia, is well established. The pattern of migration across inner Asia and the subsequent duration/intensity of hominin colonization of these areas, however, are still poorly resolved. The large territory of Central Asia defines a clear path within Eurasia through which hominin dispersals farther east may have occurred. The purpose of the present study is to examine the degree to which an autochthonous evolutionary trajectory is supported in Central Asia and how the potential connections between this and neighboring regions may be characterized during the Pleistocene. Archaeological and human paleontological evidence from the region is reviewed and compared to that from the Near East, the Altai, and China. This review informs a more detailed analysis of the Central Asian Middle Paleolithic record. Prevailing theoretical models suggest that Central Asia was inhabited by Neandertals migrating from the west to seek refuge from expanding modern human populations during the Middle Paleolithic. Morphological analyses of the newly discovered Obi-Rakhmat hominin and a re-evaluation of the Teshik-Tash child, both from sites in Uzbekistan, provide a test of this model. Results indicate that evidence of the morphological pattern that typically describes European Neandertals is equivocal in Central Asia. Although both Obi-Rakhmat and Teshik-Tash express some Neandertal features, their morphologies also suggest some admixture with local populations and/or those migrating into Central Asia from the North and East.

Dental Development and Age at Death of a Middle Paleolithic Juvenile Hominin from Obi-Rakhmat Grotto, Uzbekistan

Studies of dental development have reported conflicting results regarding whether Neanderthal growth and development was similar to that of modern humans. The discovery of a partial permanent maxillary juvenile dentition (OR-1) from the Obi-Rakhmat Grotto, Uzbekistan, provides the opportunity to assess dental development and age at death in a Paleolithic hominin with strong Neanderthal similarities using incremental dental features. Long-period lines on tooth crowns (perikymata) and roots (periradicular bands) were quantified, and crown formation, root development, and age at death were estimated. An anomalous upper molar was determined to be a left M2 with a rare developmental condition (gemination). Perikymata numbers for OR-1 were similar to modern southern African population means, but were less than modern northern European and Neanderthal means. Root extension rates were estimated to be similar to (or slightly higher than) modern human values, although few modern comparative data are available. Assuming the long-period line periodicity of this individual fell within a Neanderthal distribution (6–9 days), the maximum age at death of OR-1 is estimated at 8.1 years, but is more likely to have been 6.7–7.4 years (7 or 8 day periodicity). Modern European human developmental standards would suggest an age at death of approximately 8–9 years. These results are consistent with other studies suggesting that Neanderthal dental development overlaps with the low end of modern human populations, and demonstrates a greater range of variation in Middle Paleolithic hominins than previously reported. It is clear that perikymata number alone does not distinguish these taxa; data on long-period line periodicity and molar eruption would yield additional insight into Neanderthal life history.

A chronological framework connecting the early Upper Palaeolithic across the Central Asian piedmont

Central Asia has delivered significant paleoanthropological discoveries in the past few years. New genetic data indicate that at least two archaic human species met and interbred with anatomically modern humans as they arrived into northern Central Asia. However, data are limited: known archaeological sites with lithic assemblages generally lack human fossils, and consequently identifying the archaeological signatures of different human groups, and the timing of their occupation, remains elusive. Reliable chronologic data from sites in the region, crucial to our understanding of the timing and duration of interactions between different human species, are rare. Here we present chronologies for two open air Middle to Upper Palaeolithic (UP) sequences from the Tien Shan piedmont in southeast Kazakhstan, Maibulak and Valikhanova, which bridge southern and northern Central Asia. The chronologies, based on both quartz optically stimulated luminescence (OSL) and polymineral post-infrared infrared luminescence (pIR-IRSL) protocols, demonstrate that technological developments at the two sites differ substantially over the ∼47-19 ka time span. Some of the innovations typically associated with the earliest UP in the Altai or other parts of northeast Asia are also present in the Tien Shan piedmont. We caution against making assumptions about the directionality of spread of these technologies until a larger, better defined database of transitional sites in the region is available. Connections between the timing of occupation of regions, living area setting and paleoenvironmental conditions, while providing hypotheses worth exploring, remain inconclusive. We cautiously suggest a trend towards increasing occupation of open air sites across the Central Asian piedmont after ∼40 ka, corresponding to more humid climatic conditions which nevertheless included pulses of dust deposition. Human occupation persisted into the Last Glacial Maximum, despite cooler, and possibly drier, conditions. Our results thus provide additional data to substantiate arguments for occupation of Central Asia.

Study on dynamic change of the oasis-desert ecotone using fractal theory

The research is based on data derived from fieldwork that is interpreted using fractal theory. The present study relied on multi-time satellite remote sensing data for the main sources of information. With the aide of image analysis techniques, desertification of Qira county and changes in the oasis-desert ecotone are analyzed.. In addition, the function of fractal theory in highly quantitative research of oasis-desert ecotones is discussed.. We suggest that the model derived from the present study should serve as a reference in decision-making concerning regional development and construction in order to simplify existing research processes.

Stability study of oasis ecosystems in arid land areas of western China

An oasis is a type of landscape that is only present in arid regions due to the arid climate, landform, and hydrological pattern. It is important to study the stability of oasis to keep sustainable development of regional economy. The stability of oasis is affected by many factors. Human activity is one of major factors. Those non-human factors like salinization in the oasis and desertification in surrounding areas are also critical. Both salinization and desertification are related to water, energy transformations and interactions among different ecosystems. The stability of oasis is influenced by the distribution and utilization of water resources, interactions between ecosystems and climate. Adjustment in the groundwater table may help to prevent the secondary land salinization. It is important to limit salinization and desertification for the stability of oasis.