Dismantling Argument No. 1: Shovel‑Shaped Incisors Are Not a Legacy

The Out‑of‑Africa model rests on an untested assumption: that a regionally frequent morphological trait (e.g., shovel‑shaped incisors in East Asia) represents a phylogenetic signal from a single ancestral population – i.e., “morphology equals kinship”. This paper dismantles that morphological pillar. We integrate three lines of evidence. First, morphological data from East Asian archaic hominins show that shovel‑shaped incisors occur persistently in Hexian (~412 ka), Jinniushan (~260‑280 ka), Xujiayao (~100‑125 ka) and Liujiang (~33‑23 ka²), spanning nearly 400,000 years. The Hexian upper medial incisor (specimen PA835) is explicitly described in the original report as “distinctly shovel‑shaped” or having a “pronounced shovel shape”, with thickened and in‑rolled lingual margins, a well‑developed tuberculum dentale and a central lingual fossa – features of extreme shoveling. Second, ancient DNA data show that the EDAR V370A allele, which is significantly associated with shovel‑shaped incisors, is first detected in East Asian ancient DNA at about 19 ka – far later than the first appearance of shovel‑shaped incisors in the fossil record. Third, modern population genetic studies demonstrate a significant association between this allele and shovel‑shaped incisors (Kimura et al., 2009). Based on this evidence, we propose the homoplasy hypothesis of shovel‑shaped incisors: they are not a retained African ancestral trait, but an “ecological imprint” independently evolved by East Asian hominins through multiple molecular pathways under specific ecological niches. EDAR V370A is one efficient pathway – driven to high frequency by positive selection – but not the only one. Currently, public databases contain no dental enamel palaeoproteomic data from East Asian archaic hominins. We call for systematic proteomic analyses of key sites (Hualongdong, Hexian, Jinniushan) to directly test the homoplasy hypothesis.