This model held that the first people to arrive in the Americas came from northeastern Asia via the Bering land bridge during the late Pleistocene, spread southward through the interior of the continent, and left behind the characteristic fluted projectile points — Clovis points — that defined their archaeological signature.

The oldest well-accepted Clovis sites were dated to approximately 13,000 to 13,200 calibrated years before the present.

Under the dominant model, no human presence in the Americas predated these sites, and claims of earlier human occupation were viewed with deep suspicion.

The Manis site, with its apparent radiocarbon dates in the range of 13,000 to 14,000 years, was right at the edge of the Clovis horizon — potentially just outside it.

If Gustafson’s interpretation was correct, the embedded object in the mastodon rib was either contemporaneous with Clovis people, or — more provocatively — it predated them.