Xujiayao sits on the west bank of the Liyi River, a tributary of the Sanggan River, within the Nihewan Basin -- one of the most important paleoanthropological regions in East Asia. The basin straddles the border between Shanxi and Hebei provinces, and Xujiayao itself consists of two localities: one near Xujiayao village in Yanggao County, Shanxi, and the other near Houjiayao village in Yangyuan County, Hebei. Most fossils and artifacts came from the Hebei site. The geological layers date to the early Late Pleistocene, between roughly 130,000 and 71,000 years ago, placing the Xujiayao hominins in a period when multiple human species coexisted across Eurasia.

The twenty fossil fragments -- twelve parietal bones, two occipital bones, one temporal bone, a mandibular fragment, a juvenile maxilla, and three isolated teeth -- present a taxonomic puzzle. Dental analysis shows features shared with earlier East Asian hominins from the Early and Middle Pleistocene, while the maxilla looks surprisingly modern. One specimen, Xujiayao 15, appeared non-Neanderthal by every external measure until a CT scan revealed its inner ear was arranged in a distinctly Neanderthal configuration. Another specimen, Xujiayao 11, exhibited an enlarged parietal foramen -- a hole in the skull found in fewer than 1 in 25,000 modern humans. It is the oldest hominin fossil known to display this condition. The reconstructed cranial capacity reached an estimated 1,700 cubic centimeters, at the upper extreme of the modern human range.

The Xujiayao hominins were skilled horse hunters. Among the roughly 5,000 animal specimens recovered from the site, the vast majority belong to Przewalski's horse and the Asiatic wild ass, Equus hemionus. Woolly rhinoceros, antelopes, gazelles, red deer, sika deer, and pigs round out the faunal picture of a steppe-grassland environment. Nearly 30,000 stone, bone, and antler artifacts were also unearthed, with finished tools accounting for over half the assemblage. Scrapers dominate, comprising more than 40 percent of all artifacts, but the site's most distinctive find is the collection of over 1,000 stone spheroids -- the largest cache from any Paleolithic site in China. Their exact purpose remains debated.

The 2024 designation of Homo juluensis proposes grouping the Xujiayao hominins with fossils from several other enigmatic East Asian sites, including the Lingjing site at Xuchang, the Xiahe mandible from Tibet, and the Penghu jaw from the Taiwan Strait, as well as with the Denisovans -- the mysterious population known primarily from DNA extracted at Siberia's Denisova Cave. If the classification holds, it would reshape understanding of human diversity in Asia during the Late Pleistocene, suggesting that a distinct lineage thrived for tens of thousands of years alongside both Homo erectus and early Homo sapiens. From the air, the Nihewan Basin reveals nothing of these secrets -- just the quiet, eroded landscape of a river valley where the sediments run deeper than memory.