陕西蓝田锡水洞遗址大型哺乳动物保存特征与古人类行为分析

陕西蓝田锡水洞中产出许多中更新世哺乳类化石，这些标本残破者较多。对880件标本作埋藏学分析后发现:其中只有376件较完好，可供分类鉴定;根据身体大小，这些可鉴定的标本可分为较大、中等及较小3类，大个体动物的骨骼保存越破碎;98%的骨骼的风化级别为0—2，只有2%的风化较强，达3—5级;属草食动物的骨骼占97.6%，而食肉类的仅占1.7%;以青羊为例，死亡年龄以中青年为主，为灾变死亡;头骨残破，肢骨近端破碎严重，而远端肢梢几乎完好。种种迹象表明，与古人类活动有关。当时居住在锡水洞中的古人类以草食动物为主要猎取对象，敲骨吸髓，还可用骨作器。

THE LINKS BETWEEN THE PRESERVED LARGE MAMMALS OF THE XISHUIDONG FAUNA,LANTIAN,SHAANXI AND HUMAN BEHAVIOR

About 880 specimens were found in Xishuidong , Lantian, Shaanxi in 1981 in association with stone artifacts, bone tools, charcoal and ash layers. About 42% of them are identifiable, and 58% of them are fragmentary bones. Some of the fragmentary bones can also roughly be classified according to their sizes and their remained character. After studying systematically , it is found that these fossils fall into 13 species, nine of which are large mammals. The preservation of the large mammals shows the following statistical feature:
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From the above table we can see that the number of species and the minimum number of individuals of each species are quite different. The PAS( the Preserved Amount of Specimens∶ the number of specimens of one species of total number of specimens) and the RAS ( the Relative Abundance of Species∶ the minimum number of individuals of one species of the total minimum numbers of the fauna) of the herbivore are much higher than thseo f carnivore. The N SI( the number of specimens per individuals) reflects the relative completeness of an individual animal. From the above table we can also see that the N SI seems to be in proportion to the size of the animal body. The higher the N SI, the larger the animal, and the much more the fragmentation.
According to the standards of Behrensmeyer( 1978) , 80% of the fossils are in weathering stage 0, 18% are in weathering stage 1-2 and only 2% are in weathering stage 3-5. So the exposure time of most bones might not be long . Most fossils show no abrasion. This indicates that the fauna had not been moved by water for along distance.
Almost all skeletal elements of the Naemohedus, Cervus, Dicerorhinus, Bison were preserv ed. However, the preservation of them are not proportioned. The expected number of each element has a great difference with the actual number found. One of the reasons might be that many fragmentary bones can not exactly be determined from which species and which part of the body they are derived.
One obvious character of the broken limb bones can be observed. From humerus and femur to metacarpus and metatarsus, the lower position the bone, the much less the frag- mentation. Most autopodium is complete, while almost all stylopodium and zygopodium are damaged. In addition, the completeness of bones seems to be related to their sizes. This is also reflected by the N SI.
On the character of preservation mentioned above, the authors tried to investigate. What was the cause for the animal bones existing in this cave. Four possible ways are analyzed. In conclusion, it is considered that the large mammals must be carried to Xishuidong by ancient human being , and the main force of the breakage of fossilsis closely related with the chopping of the ancient men. This can best explain the above characters.