更新世中期中国古人类演化区域连续性与多样性的化石证据

以往,在东亚大陆发现的更新世中期人类化石被分别归入直立人和古老型智人。这种分类的主要依据是化石形态特征以及年代。魏敦瑞对周口店第一地点人类化石研究描述的一些头骨、下颌骨和牙齿特征通常被作为判定直立人的标准。根据这些化石的年代分布,一般将30万年前的中更新世晚期作为划分直立人与古老型智人的大致年代界限。近20年来,在非洲、欧洲和东亚新发现了一些更新世中期人类化石,目前古人类学界对中国更新世中期人类化石特征及演化有了与以往不同的认识。最近对大荔、许家窑、盘县大洞、许昌、华龙洞等人类化石的研究显示,近30万年以来东亚大陆人类演化呈现复杂的多样性,将这一时期人类全部归入古老型智人难以准确反映更新世中期中国古人类演化模式及规律。本文结合近年中国更新世中期人类演化研究进展,选择部分具有演化及分类价值的形态特征,分析这些特征在更新世中期中国古人类化石的表现特点。在此基础上,对更新世中期中国古人类演化模式做了尝试性探讨。本研究发现,周口店、和县、沂源、南京等中更新世早期人类化石呈现有较多的区域性特征,形态特征表现相对稳定;而大荔、金牛山、许家窑、许昌、华龙洞、马坝、盘县大洞等中更新世晚期人类在化石形态特征表现复杂多样,变异范围大。此外,在这一时期人类化石上发现较多与生存活动、健康、环境适应有关的证据。根据这些发现,作者认为中国中更新世早期组人类演化以形态连续性为主;进入中更新世晚期,中国古人类演化区域性特征减弱,演化模式以多样性为主。一系列新的化石发现和研究证据提示中更新世晚期东亚大陆可能生存有不同的古人类成员。根据目前掌握的化石形态和年代证据,大约30万年前是中国更新世中期演化变化关键时间节点。

The morphological evidence for the regional continuity and diversity of Middle Pleistocene human evolution in China

For decades, the Middle Pleistocene human fossils found in China have been attributed into Homo erectus and archaic Homo sapiens; respectively. This classification was mainly based on morphology and chronology of these fossils. Some cranial, mandibular and dental features identified and described on the human fossils of Zhoukoudian locality 1 by Weidenreich have been used as the standard for Homo erectus. According to the chronology of the Chinese Middle Pleistocene human fossils, later period of Middle Pleistocene around 300 ka are usually regarded as approximate border between Homo erectus and archaic Homo sapiens. For the past two decades, more Middle Pleistocene human fossils have been found in Africa, Europe and East Asia. Currently, the understanding for the fossil morphology and evolution of Middle Pleistocene humans has changed a lot. Recent studies of human fossils from Dali, Xujiayao, Panxian Dadong, Xuchang, Hualongdong indicate that in the past 300 ka, the human evolution in East Asia exhibited complicated diversities. Classifying all the hominins of this time period into archaic Homo sapiens cannot accurately reflect the human evolution patterns in East Asian continent. In the present study, with considering the research progress of Middle Pleistocene human evolution in China, the expressions of some morphological features with evolutionary and taxonomic values were analyzed for the Middle Pleistocene human fossils. Based on these analysis, the evolution pattern of Middle Pleistocene humans in China were tentatively explored. Our study indicates that the human fossils of early period of Middle Pleistocene in China including Zhoukoudian, Hexian, Yiyuan, Nanjing exhibit more features characterizing the region pattern and the expression of these feature are relatively stable. In contrast, the morphology expressions of human fossils from later period of Middle Pleistocene like Dali, Jinniushan, Maba, Panxian Dadong, Xujiayao, Xuchang, Hualongdong are more complicated with wide variation ranges. Besides, a number of evidence showing the living activity, healthy status and adaptation to environment have been found in the human fossils of this period. With these findings, the authors propose that the human evolution of early period of Middle Pleistocene in China mainly follows the pattern of morphological continuity. Entering the later part of Middle Pleistocene, the regional pattern of human evolution in China decreased with diversity taking the main place. A series of new human fossil findings and research progresses indicate that several hominins may co-exist in Middle Pleistocene’s East Asia. With available evidence of human fossil morphology and chronology, approximately 300 ka is the key time point for the evolution changes in Middle Pleistocene in China.