首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Dung from a mammoth was preserved under frozen conditions in Alaska. The mammoth lived during the early part of the Late Glacial interstadial (ca 12,300 BP). Microfossils, macroremains and ancient DNA from the dung were studied and the chemical composition was determined to reconstruct both the paleoenvironment and paleobiology of this mammoth. Pollen spectra are dominated by Poaceae, Artemisia and other light-demanding taxa, indicating an open, treeless landscape (‘mammoth steppe’). Fruits and seeds support this conclusion. The dung consists mainly of cyperaceous stems and leaves, with a minor component of vegetative remains of Poaceae. Analyses of fragments of the plastid rbcL gene and trnL intron and nrITS1 region, amplified from DNA extracted from the dung, supplemented the microscopic identifications. Many fruit bodies with ascospores of the coprophilous fungus Podospora conica were found inside the dung ball, indicating that the mammoth had eaten dung. The absence of bile acids points to mammoth dung. This is the second time that evidence for coprophagy of mammoths has been derived from the presence of fruit bodies of coprophilous fungi in frozen dung. Coprophagy might well have been a common habit of mammoths. Therefore, we strongly recommend that particular attention should be given to fungal remains in future fossil dung studies.  相似文献   

2.
Patterns in the spatial or temporal distribution of genotypes may be indicative of natural selection. Previous work on the woolly mammoth melanocortin-1 receptor (Mc1r) gene identified three polymorphic positions that suggest Pleistocene populations may have harboured both light- and dark-haired mammoths (Rompler et al., 2006, 313: 62). Here, we extend this work and present the first population-level analysis of a functional gene in an extinct species. We genotyped the Mc1r gene in 47 woolly mammoth samples excavated from sites across the central portion of the woolly mammoths’ former range to examine the extent of variation of this polymorphism through time and across space. Only one individual was found to be heterozygous, indicating that the frequency of the ‘light’ mutant allele was very low. We conclude that light-coloured woolly mammoths would have been very rare, and may even have been non-existent if the ‘light’ mutant allele was strongly selected against in its homozygotic form. With the increasing availability of large-scale sequencing technologies, population-level datasets capable of identifying local adaptation will become increasingly attainable.  相似文献   

3.
The ecological implications of a Yakutian mammoth's last meal   总被引:1,自引:0,他引:1  
Part of a large male woolly mammoth (Mammuthus primigenius) was preserved in permafrost in northern Yakutia. It was radiocarbon dated to ca. 18,500 14C yr BP (ca. 22,500 cal yr BP). Dung from the lower intestine was subjected to a multiproxy array of microscopic, chemical, and molecular techniques to reconstruct the diet, the season of death, and the paleoenvironment. Pollen and plant macro-remains showed that grasses and sedges were the main food, with considerable amounts of dwarf willow twigs and a variety of herbs and mosses. Analyses of 110-bp fragments of the plastid rbcL gene amplified from DNA and of organic compounds supplemented the microscopic identifications. Fruit-bodies of dung-inhabiting Ascomycete fungi which develop after at least one week of exposure to air were found inside the intestine. Therefore the mammoth had eaten dung. It was probably mammoth dung as no bile acids were detected among the fecal biomarkers analysed. The plant assemblage and the presence of the first spring vessels of terminal tree-rings of dwarf willows indicated that the animal died in early spring. The mammoth lived in extensive cold treeless grassland vegetation interspersed with wetter, more productive meadows. The study demonstrated the paleoecological potential of several biochemical analytical techniques.  相似文献   

4.
Woolly mammoths were large, herbivorous, cold-adapted mammals of the Late Pleistocene. The diet and habitat requirements of the species set certain constraints on the palaeoenvironments it could occupy. The relationship between the mammoth’s shifting range and changing environments can be explored using independent data on ice sheet configuration, temperature, and vegetation, provided the locality and age of the fossil remains can be validated. Here we present a comprehensive record of occurrence of the woolly mammoth in the circum-Baltic region of northern Europe during the last glaciation, based on a compilation of radiocarbon-dated remains. The record shows that the mammoth was widespread in northern and north-eastern Europe during Marine Isotope Stage 3 (MIS 3), at 50,000–30,000 calibrated years ago (50–30 ka). The presence of the species up to 65°N latitude supports the restriction of the Scandinavian Ice Sheet (SIS) during MIS 3. The widest distribution range round 30 ka was followed by a decline that led to the disappearance of mammoths from the area during the maximum extent of the SIS, from 22 to 18 ka. The woolly mammoth re-colonized the Baltic region and southern Scandinavia after the onset of the late-glacial deglaciation at 17 ka. The late-glacial record suggests a markedly fluctuating population changing its range in tune with the rapid environmental changes. The last appearance of mammoth in our study region was in Estonia during the Younger Dryas (Greenland Stadial 1; GS1) at about 12 ka. The two major periods of occurrence during MIS 3 and the late-glacial stadial suggest that mammoth had a wide tolerance of open to semi-open tundra and steppe-tundra habitats with intermediately cold climate, whereas the 22–18 ka disappearance suggests a major southward and/or eastward retreat in response to extremely cold, glacial conditions near the SIS margin. The final regional extinction correlates with the re-forestation during the rapid warming at the Younger Dryas–Holocene boundary.  相似文献   

5.
Excavations at Sevsk, Bryansk Region, Russia, by the Paleontological Institute of the Russian Academy of Sciences in 1988–1991 recovered 3800 bones of woolly mammoth (Mammuthus primigenius Blum.) representing a minimum of 33 individuals. The locality is one of the largest naturally occurring deposits of mammoth remains in Europe and is inferred to be a catastrophic death assemblage. The material includes five skeletons of juvenile mammoths, from 1 month to 6 or 7 years of age, as well as partial skeletons and isolated bones of adult individuals. A femur and humerus of an approximately 10–12-month-old fetus are also among the finds. Morphological features suggest that the Sevsk mammoths belonged to one family group; the age structure and sexual composition of the assemblage do not differ significantly from that of a family group of Modern African elephants. In contrast to other localities in Siberia and central Russia, relatively more (about 45% of individuals) prepubertal animals are preserved at Sevsk. Radiocarbon dates indicate that the mammoths died about 14,000 years ago. Data from diatoms, pollen and rodents, as well as archeological evidence, corroborate this age, and provide the basis for a paleoenvironmental reconstruction at the end of the Valdaian Glaciation in western Russia.  相似文献   

6.
The causes of large animal extinctions at the end of the Pleistocene remain a hotly debated topic focused primarily on the effects of human over hunting and climate change. Here we examine multiple, large radiocarbon data sets for humans and extinct proboscideans and explore how variation in their temporal and geographic distributions were related prior to proboscidean extinction. These data include 4532 archaeological determinations from Europe and Siberia and 1177 mammoth and mastodont determinations from Europe, Siberia, and North America. All span the period from 45,000 to 12,000 calendar years BP. We show that while the geographic ranges of dated human occupations and proboscidean remains overlap across the terminal Pleistocene of the Old World, the two groups remain largely segregated and increases in the frequency of human occupations do not coincide with declines in proboscidean remains. Prior to the Last Glacial Maximum (LGM; ca 21,000 years BP), archaeological 14C determinations increase slightly in frequency worldwide while the frequency of dated proboscidean remains varies depending on taxon and location. After the LGM, both sympatric and allopatric groups of humans and proboscideans increase sharply as climatic conditions ameliorate. Post-LGM radiocarbon frequencies among proboscideans peak at different times, also depending upon taxon and location. Woolly mammoths in Beringia reach a maximum and then decline beginning between 16,000 and 15,500 years BP, woolly mammoths in Europe and Siberia ca 14,500 and 13,500 BP, and Columbian mammoth and American mastodont only after 13,000 BP. Declines among woolly mammoths appear to coincide with the restructuring of biotic communities following the Pleistocene–Holocene transition.  相似文献   

7.
Qagnaxˆ Cave, a lava tube cave on St. Paul Island in the Pribilofs, has recently produced a mid-Holocene vertebrate faunal assemblage including woolly mammoth, polar bear, caribou, and Arctic fox. Several dates on the mammoth remains converge on 5700 14C yr BP. These dates, ~ 2300 yr younger than mammoth dates previously published from the Pribilof Islands, make these the youngest remains of proboscideans, and of non-extinct Quaternary megafauna, recovered from North America. Persistence of mammoths on the Pribilofs is most parsimoniously explained by the isolation of the Pribilofs and the lack of human presence in pre-Russian contact times, but an additional factor may have been the local existence of high-quality forage in the form of grasses enriched by nutrients derived from local Holocene tephras. This interpretation is reinforced by stable carbon and nitrogen isotope values obtained from the mammoth remains. The endpoint of mammoth survival in the Pribilofs is unknown, but maybe coterminous with the arrival of polar bears whose remains in the cave date to the Neoglacial cold period of ~ 4500 to 3500 14C yr BP. The polar bear record corroborates a widespread cooling of the Bering Sea region at that time.  相似文献   

8.
A set of radiocarbon dates on woolly mammoth were obtained from several regions of Arctic Siberia: the New Siberian Islands (n = 68), north of the Yana-Indigirka Lowland (n = 43), and the Taimyr Peninsula (n = 18). Based on these and earlier published dates (n = 201) from the East Arctic, a comparative analysis of the time-related density distribution of 14C dates was conducted. It was shown that the frequencies of 14C dates under certain conditions reflect temporal fluctuations in mammoth numbers. At the end of the Pleistocene the number of mammoths in the East Arctic changed in a cyclic manner in keeping with a general “Milankovitch-like” trend. The fluctuations in numbers at the end of the Pleistocene occurred synchronously with paleoenvironmental changes controlled by global climatic change. There were three minima of relative mammoth numbers during the last 50 000 years: 22 000, 14 500–19 000, and 9500 radiocarbon years ago, or around 26 000, 16–20 000, and 10 500 calendar years respectively. The last mammoths lived on the New Siberian Islands, which were connected to the continent at that time, 9470 ± 40 radiocarbon years ago (10 700 ± 70 calendar years BP). This new youngest date approximates the extinction time of mammoths in the last continental refugium of the Holarctic. The adverse combination of environmental parameters was apparently a major factor in the critical reduction in mammoth numbers. The dispersal of humans into the Arctic areas of Siberia no later than 28 000 radiocarbon years ago did not overtly influence animal numbers. Humans were not responsible for the destruction of a sustainable mammoth population. The expanding human population could have become fatal to mammoths during strong the minima of their numbers, one of which occurred at the very beginning of the Holocene.  相似文献   

9.
Andrei Sher (1939–2008) was a key individual in Beringian studies who made substantial and original contributions, but also, importantly, built bridges between western and eastern Beringian scientists spanning some five decades of research. He is perhaps best known as a Quaternary palaeontologist, specializing in large mammals, and mammoths in particular, but his field of his scientific research was much broader, encompassing Quaternary geology, stratigraphy, geocryology, and paleoenvironmental reconstructions. He worked mainly in Siberia, in the Kolyma and Indigirka lowlands, and Chukotka, but also completed fieldwork in Alaska and Yukon through joint projects with American and Canadian scientists. Andrei was an active scientist until the last days of his life. He was involved in many different research projects ranging from mammoth evolution, fossil insects and environmental changes and ancient DNA. Without Andrei’s connections between researchers, many unique discoveries would likely be unknown.  相似文献   

10.
We present and discuss a full list of radiocarbon dates for woolly mammoth and other species of the Mammoth fauna available from Wrangel Island, northeast Siberia, Russia. Most of the radiocarbon dates are published here for the first time. Of the124 radiocarbon dates on mammoth bone, 106 fall between 3700 and 9000 yr ago. We believe these dates bracket the period of mammoth isolation on Wrangel Island and their ultimate extinction, which we attribute to natural causes. The absence of dates between 9–12 ka probably indicates a period when mammoths were absent from Wrangel Island. Long bone dimensions of Holocene mammoths from Wrangel Island indicate that these animals were comparable in size to those on the mainland; although they were not large animals, neither can they be classified as dwarfs. Occurrence of mammoth Holocene refugia on the mainland is suggested. Based on other species of the Mammoth fauna that have also been radiocarbon on Wrangel Island, including horse, bison, musk ox and woolly rhinoceros, it appears that the mammoth was the only species of that fauna that inhabited Wrangel Island in the mid-Holocene.  相似文献   

11.
寒区环境中的古DNA分子   总被引:1,自引:0,他引:1  
林清  程国栋 《冰川冻土》2002,24(6):812-818
寒区埋藏环境常年处于负温条件下,土壤冻结或冰的形成过程产生封闭作用,可以隔离造成埋藏生物遗体同DNA氧化分解的氧气之间的接触.由于液态水含量极大地减少和冰胶结作用,使得主要依赖于液态水而发生的生物大分子的化学分解以及生物降解反应作用减慢,有机体没有成岩过程中降解以及水解作用,从而使古DNA分子可以得到较好的保存.目前绝大多数关于古DNA研究的重要成果所使用生物材料均来自寒区环境,最为引人注目的有关猛犸象、棕熊和企鹅化石古DNA的研究.这些研究分别从个体、种群和同一种群在不同时间尺度上描绘了它们与现代生物种之间的亲缘关系、过去发生的生物迁移和空间隔离以及特定生物分子水平上的时间演化.从目前来看,大量的生物标本很好地保存在那里,以至于单一考贝基因都可以获得,因此是获取古DNA并获得相应遗传信息的理想地区.  相似文献   

12.
A summary of previous and new research on the Schaefer mammoth site is presented. The Schaefer site in extreme southeastern Wisconsin, USA was excavated in 1992 and 1993. Seventy-five percent of a mammoth ?Mammuthus primigenius, the woolly mammoth (but comparable as well with M. jeffersonii, the Jefferson mammoth) was recovered. Drifted wood specimens and plant macro fossils were also recovered from the site.Twenty-five specimens of wood have been identified as Picea sp., Picea/Larix sp., or unidentified hardwood. Macro fossils in the form of cones have been identified as black spruce (Picea mariana). These preliminary data do not appear to support the traditional environment inferred for the woolly mammoth and points to a need for study of the animal's attribution to species. The animal was a male, 36 years of age at death.Thirteen AMS 14C assays on bone cluster between 12,290 and 12,570 BP. Sixteen dates on wood specimens intimately associated with bone yield a range of dates from 11,980 to 12,940 BP.The remains exhibit multiple cut and wedge marks interpreted as cultural. Non-diagnostic cultural lithics were recovered. A disarticulated bone pile deposited in a low energy environment is consistent with human interaction.  相似文献   

13.
近20年来, 古DNA研究技术和方法已迅猛发展.目前从古人类残骸中获取DNA序列, 进而讨论人类的演化、亲缘关系和迁移成为分子人类学的一个重要方向.本研究对采自陕西临潼仰韶文化6 000多年前的姜寨遗址第一期和第二期文化层中的古人类残骸进行古DNA提取、扩增和测序, 获得了169 bp的线粒体高变控制区Ⅰ的古DNA片段, 与现代西安人同源性序列有2个位点的突变.另外, 通过在不同实验室进行重复性实验和系统发育分析等方法详细地论证了所获得的DNA序列的可靠性.在所研究的6个姜寨遗址样品中有3个样品获得古DNA序列, 古DNA的提取成功率为50%, 高于一般的古DNA研究材料的提取率, 说明姜寨遗址的人类残骸是研究古DNA的理想材料, 为今后从分子水平上研究姜寨遗址及其他同地区仰韶文化遗址的古人类墓葬及中国古人类分子演化关系奠定了基础.   相似文献   

14.
《Quaternary Science Reviews》2007,26(7-8):954-957
The world's definite southernmost woolly mammoth record is a molar from Ji’nan (around 36°N), Shandong Province, China. AMS 14C dating of the specimen, gave a conventional 14C age of 33,150±250 BP. The period of 40–30 ka BP corresponds to the later phase of the Marine Oxygen Isotope Stage 3 (MIS 3a), recognized as the global interstadial of the last glacial period. However, it is known that the winter monsoon strengthened in Asia during the period 35–33 ka BP, and the age of the woolly mammoth specimen from Ji’nan corresponds to that age. The specimen suggests that this area became cold and dry in 33 ka BP, and grassland or open forest, suitable habitat for woolly mammoths, developed during this short time span. This age is similar to the age of the southernmost woolly mammoth record in Europe, therefore supporting a hypothesis by Porter and An [1995. Correlation between climate events in the North Atlantic and China during the last glaciation. Nature 375, 305–308] that an important component of Chinese palaeoclimates may be linked to changes in North Atlantic oceanic conditions.  相似文献   

15.
Chlachula, J. & Serikov, Y. B. 2010: Last glacial ecology and geoarchaeology of the Central Trans‐Ural area: the Sosva River Upper Palaeolithic Complex, western Siberia. Boreas, 10.1111/j.1502‐3885.2010.00166.x. ISSN 0300‐9483. Quaternary and geoarchaeology studies from the eastern limits of the Ural Mountains provide multiple lines of evidence of the Palaeolithic peopling of this geographically marginal and still poorly explored territory of western Siberia following the mid‐last glacial (MIS 3) warming. A complex of investigated open‐air localities in the Sosva River basin (the north‐central Trans‐Ural area) at the periphery of the western Siberian Plain, distinguished by very high concentrations of Pleistocene megafaunal remains previously regarded as ‘mammoth cemeteries’, indicate, in conjunction with the associated diagnostic ivory/bone and stone industry, open occupation sites during the Last Glacial (MIS 2). Fossil faunal remains, dominated by mammoth (98%) together with bird and fish species, indicate various methods of exploitation of the Late Pleistocene natural resources and successful behavioural adaptation to the last glacial sub‐polar tundra‐steppe environment. The taphonomy and composition of the well‐preserved skeletal remains from the main occupation sites suggest both active hunting and anthropogenic ‘scavenging’ practices. The contextual geology and the cultural and biotic multi‐proxy records from the Trans‐Ural Upper Palaeolithic Complex provide new insights into the timing and palaeoecological conditions of the Pleistocene human occupation of north‐central Asia.  相似文献   

16.
Skeletal remains of the extinct American mastodon have often been found with deposits of short, decorticated twigs intermixed with plant fragments presumed to be gastrointestinal or fecal material. If such deposits are digesta, paleobotanical evidence may be used to analyze mastodon foraging strategy, with implications for assessing habitat selection, ecological roles, and response to environmental change. To identify components of mastodon diet in mid-latitude late-Pleistocene boreall forests of eastern North America, plant macrofossils and pollen from a molar socket (Hyde Park site, New York) were compared with dispersed deposits associated with skeletal remains (Hiscock and Chemung sites, New York). Similar macrofossil condition and twig morphology among samples, but difference from a modern boreal fen analog, confirmed the deposits were digesta. Comparison of twigs with material from other paleontological sites and modern elephants suggested dimensions generally indicative of digesta. Picea formed the bulk of each sample but Pinus may have been locally important. Wintertime browsing of Salix and Populus, and springtime consumption of Alnus, were indicated. Evidence for Cyperaceae, Gramineae, and Compositae was ambiguous. If conifers, broadleaf trees, shrubs, and herbs were necessary to fulfill dietary requirements, mastodons would have been nutritionally stressed by rapid late-Pleistocene decrease in vegetational diversity.  相似文献   

17.
Twelve new AMS (Accelerator Mass Spectrometry) dates of large Quaternary mammal remains were reported: mammoth (Mammuthus primigenius, bison (Bison priscus), and musk ox (Ovibos pallantis) found in the Archangelsk Region. The absolute age of the identified samples varies from 46 000 to 22 000 calibrated years ago. These data suggest that a substantial part of the Archangelsk Region was not covered by ice during the indicated time interval.  相似文献   

18.
An isotopic investigation of upper Pleistocene mammal bones and teeth from Scladina cave (Sclayn, Belgium) demonstrated the very good quality of collagen preservation. A preliminary screening of the samples used the amount of nitrogen in whole bone and dentine in order to estimate the preserved amount of collagen before starting the extraction process. The isotopic abundances of fossil specimens from still-extant species are consistent with their trophic position. Moreover, the15N isotopic abundance is higher in dentine than in bone in bears and hyenas, a phenomenon already observed in modern specimens. These results demonstrate that the isotopic compositions of samples from Scladina cave can be interpreted in ecological terms. Mammoths exhibit a high15N isotopic abundance relative to other herbivores, as was the case in Siberian and Alaskan samples. These results suggest distinctive dietary adaptations in herbivores living in the mammoth steppe. Cave bears are clearly isotopically different from coeval brown bears, suggesting an ecological separation between species, with a pure vegetarian diet for cave bear and an omnivorous diet for brown bear.  相似文献   

19.
Global climate change at the end of Pleistocene led to extinction in the huge territories of Northern Eurasia of the typical representatives of the Mammoth fauna: mammoth, woolly rhinoceros, wild horse, bison, musk-ox, and cave lion. Undoubtedly the Mammoth fauna underwent pressure from Upper Paleolithic humans, whose hunting activity could also have played a role in decreasing the number of mammoths and other representatives of megafauna. Formerly it was supposed that the megafauna of the “Mammoth complex” had become extinct by the beginning of the Holocene. Nevertheless the latest data indicate that extinction of the Mammoth fauna was significantly delayed in the north of Eastern Siberia. In the 1990s some radiocarbon dates established that mammoths existed in the Holocene on Wrangel Island—from 7700 until 3700 yBP. Radiocarbon data show that wild horses inhabited the north of Eastern Siberia 4600–2000 yBP. Muskoxen lived here about 3000 yBP. Some bison remains from Eastern Siberia belong to the Holocene. The following circumstances could promote the survival of representatives of Mammoth fauna. Cool and dry climate in this region promotes the maintenance of steppe associations—the habitats of those mammals. Late Paleolithic and Mesolithic settlements are not found in the Arctic zone of Eastern Siberia from Taimyr Peninsula to the lower Yana River; they are very rare in basins of the Indigirka and Kolyma Rivers. The small number of Stone Age hunting tribes in the northern part of Eastern Siberia was probably another factor that contributed to the survival of some Mammoth fauna representatives.  相似文献   

20.
古代生物分子与分子考古学   总被引:14,自引:0,他引:14  
分别论述了从古DNA,古蛋白质,类脂化合物等古代生物分子的尺度去研究人类的起源和迁移,动,植物的家养和驯化过程及早期农业的发展,考古点动植物骸的精确鉴定,新的定年技术以及古气候的变化等与考古学相关的许多重要问题,对分子考古学及其应用进行综述,并就在我国开展分子考古学研究提出了展望。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号