But the field remains genuinely difficult: skull shape is influenced by many factors, it varies considerably within populations, and the relationship between skull shape and genetic ancestry is not as straightforward as earlier researchers assumed.

The Spirit Cave skull’s apparent morphological distinctiveness was real — researchers were not simply inventing differences that did not exist.

The skull did show features that were statistically different from the typical configuration of later Native American populations.

The Paleoamerican researchers who cited this as evidence of a distinct founding group were not fabricating the morphological data.

What they were getting wrong was the interpretation.

The morphological differences between early and late American populations are real, but they do not require the existence of a separate founding group to explain.