关键词: 许家窑, 人类化石, 中更新世晚期, 东亚, 巨颅人

Abstract:

The Xujiayao hominin remains are key to the study of East Asian human evolution but also the most controversial. The Xujiayao (Houjiayao) site is located west of Liyigou, a tributary on the left bank of the Sanggan River in the northern Nihewan Basin of northern China. The site was first discovered in 1973. Between 1976 and 1979, 21 human fossils were found at the site, including one partial left maxilla, three isolated teeth, two occipital bones, one partial mandible, one left temporal bone and 13 parietal fragments, all representing 16 individuals. Based on the associated fauna, and OSL dating on the middle-lower culture layers, the Xujiayao hominins lived in the late Middle Pleistocene (about 160-200 kaBP). Evaluations of Xujiayao taxonomy have ranged from being representatives of Asian H. erectus, pre-modern Homo sapiens, archaic Homo sapiens, Neandertals, intermediate between H. erectus and modern H. sapiens, unidentified hominin species, or related to Xuchang 1, Penghu 1, Xiahe 1 or Denisovans. Over the past 10 years, there has been renewed attention to these fossils. New results suggest that the Xujiayao hominins have a suite of unusual morphological traits that do not conform to existing patterns of morphology from either the time period or the region. These traits include large and morphologically complex teeth, very large cranial capacity (about 1700 mL), Neanderthal-like traits of bi-level nasal floor and temporal labyrinthine patterns that are common, but not exclusive to that lineage, live slow and die old modern growth and development patterns in the immature maxilla, and several primitive early East Asian traits despite the fossils’ recent age. In addition, the Xujiayao hominins show various pathologies, including a very rare congenital defect of an enlarged parietal foramen associated with cerebral venous and cranial vault anomalies, multiple traumatic lesions of endocranium, and minor temporal auditory porous new bone in external auditory exostoses. In conclusion, the Xujiayao hominins are characterized by a mosaic of archaic morphological features that distinguish them clearly from H. erectus, Neandertals, and modern humans. Given that the Xujiayao and Xuchang crania group closely together in multiple analyses and are quite different from all other comparative Pleistocene hominin crania, we conclude that they represent a new hominin population for the region, Juluren meaning “large head people”. It is quite possible that this population represents gene flow between Asian H. erectus and possibly H. antecessor or early Neandertals, which supports the idea of continuity with hybridization as a major force shaping Chinese populations during the late Middle and early Late Pleistocene.

Key words: Xujiayao, human fossils, Late Middle Pleistocene, East Asia, Juluren