人类从哪里来?——(5)北京直立人真的是东亚人的直系祖先吗?

Where are our humans from?--(5)Is Homo erectus pekinensis really the direct ancestor of East Asians?

简要介绍了北京周口店北京直立人发现的过程、已发现的化石材料、现存的化石材料及首批复制的头盖骨模型。描述了北京直立人的主要形态特征,讨论了直立人与现代人在形态特征上的差异,认为包括北京直立人在内的东亚地区直立人是一个灭绝的支系,没有留下后代,不是现代东亚人或中国人的直系祖先。大约在2.0 Ma前,直立人起源于非洲的匠人或能人,而后走出非洲扩散到欧洲和亚洲。非洲的直立人约在90万a前演化为先驱人,约在60万a前演化为海德堡人,约在30万a前演化为尼安德特人、丹尼索瓦人和包括现代人在内的智人。推测从非洲向欧洲扩散的海德堡人后来有可能演化为尼安德特人,而向亚洲扩散的海德堡人后来可能演化为丹尼索瓦人和智人。讨论了北京直立人的分类位置和名称有效性问题,认为亚种不可能单独存在,必须有2个或2个以上的亚种才有效。当前需进一步深化研究北京直立人,探讨周口店的直立人与爪哇岛的直立人究竟有无差别。如果二者没有差别,那么周口店发现的直立人北京亚种(Homo erectus pekinensis)就不是有效名称,应直接归于直立人(Homo erectus),称为“发现于北京的直立人”(Homo erectus unearthed from Beijing)。如果二者差异明显,有2种处理方法:一是直接提升为种,称为“北京人”(Homo pekinensis);二是保持现状,仍然称为“直立人北京亚种”(Homo erectus pe⁃kinensis),但印尼爪哇岛发现的直立人学名需作变动,应称为“直立人直立人亚种”(Homo erectus erectus)。

This paper makes a brief introduction to the discovery history of Homo erectus pekinensis from Zhoukoudian of Beijing,China,the information of all the fossils unearthed from there,the extant fossil materials and the first batch of human skull models.This paper also introduces the important morphological features of Homo erectus pekinensis,discusses the main differences between Homo erectus and modern humans and considers that Homo erectus in East Asia,including Homo erectus pekinensis,might be an extinct group with no descendants and could not be the direct ancestor of modern East Asians and Chinese.About 2 Ma ago,Homo erectus derived from Homo habilis or Homo ergaster in Africa and then spread out of Africa into Europe and Asia.Homo erectus in Africa gave rise to Homo antecessor about 0.9 Ma ago,to H.heidelbergensis about 0.6 Ma ago and to Homo sapiens,H.neanderthalensis and Denisovans(or H.denisovaensis)about 0.3 Ma ago.The authors also speculate that H.heidelbergensis in Europe might evolve to H.neanderthalensis later,and that H.heidelbergensis in Asia might evolve to both Homo sapiens and Denisovans later.This paper also discusses the classification position and the name validity of Homo erectus pekinensis.Homo erectus pekinensis is only a single subspecies of Homo erectus at present.As is known,subspecies are mainly formed by long-term geographic isolation,so it is impossible that a species has only one subspecies.If a species has two or more subspecies,the names of its subspecies are valid.Presently,the task is mainly to deepen the study of Homo erectus pekinensis to make a comparison of characteristic similarities and differences between Homo erectus from Java of Indonesia and Homo erectus from Zhoukoudian of Beijing.If there would be no difference between them,the subspecies name of Homo erectus pekinensis should not be a valid name,and it should be called as"Homo erectus unearthed from Beijing".If there would be some obvious differences between them,there could be 2 ways to deal with it.It might be directly upgraded to be a species:"Homo pekinensis",or,Homo erectus from Zhoukoudian of Beijing is still called as"Homo erectus pekinensis",but the name of Homo erectus from Java of Indonesia should be changed to be"Homo erectus erectus".