On the Invalidity of the Hypothesis Using the Inca Bone as a Marker of Biological Continuity

The Inca bone, a Wormian bone located in the occipital region, has been used by some researchers as a morphological marker to infer hominin population continuity or late African modern human migration. This paper systematically evaluates the validity of the Inca bone as a marker of biological affinity from four dimensions: developmental biology, paleoanthropology, genetics, and philosophy of science. Our analysis demonstrates that: (1) the genetic-causal basis of the Inca bone lacks any positive experimental validation; (2) the genotype of individuals exhibiting the Inca bone in early East Asian hominin fossils is completely unknown; (3) the temporal occurrence of the Inca bone predates the putative “late African gene” by hundreds of thousands of years, constituting a temporal paradox; (4) systematic frequency data from African fossil hominins are absent; (5) a proof of exclusivity is logically impossible to achieve; (6) raw data accessibility is severely insufficient; (7) a systematic taxonomic confusion exists between the Inca bone and the pre-interparietal bone; (8) the modern population frequency distribution does not support any unidirectional migration hypothesis. Based on these eight constraints, the Inca bone is fundamentally a stochastic byproduct of failed ossification center fusion, lacking the stability, specificity, and verifiability required of a biological affinity marker. Until the relevant empirical standards are met, this hypothesis should be regarded as evidentially invalid.