Extant apes (except small gibbons) have laryngeal air sacs, Selam and Lucy also had them (based on the hyoid bone). Humans don’t, though 2% of humans develop laryngocoels in the same position as air sacs (Fitsch).

I believe one neandertal hyoid indicated no air sac. Has any other apith or early Homo fossils given indication of possessing air sacs?

AFAICT, laryngeal air sacs developed in early apes as a result of natural selection for flotation in wetland (perhaps tidal) forests, with vocalization becoming more important with time. The vertical flotation resulting from inflated air sacs (during which the individual could exhale and inhale independently) eventually produced a more vertical posture and loss of the tail in hominoids.

That the Dmanisi fossils were found near a river/lake and in the vicinity of flint quarries later used by Sumerians for trade is intriguing.
Hope they find a hyoid or two!

The oldest H. erectus fossils, to date, have come from Africa. Fossils like, KNM ER 3733, KNM ER 992, KNM ER 3883, and KNM WT 15000.

The Dmanisi hominids show there are differences between populations of H. erectus in Africa, and the populations of Europe, Africa and Asia around 1.8-1.5 million years ago. But by 1 million years ago, fossils like Daka calvaria show that there are a lot of similarities in features that people were formerly using to separate early African erectus from late Asian ones. From the abstract,

“Here we report that the ‘Daka’ calvaria’s metric and morphological attributes centre it firmly within H. erectus. Daka’s resemblance to Asian counterparts indicates that the early African and Eurasian fossil hominids represent demes of a widespread palaeospecies. Daka’s anatomical intermediacy between earlier and later African fossils provides evidence of evolutionary change. Its temporal and geographic position indicates that African H. erectus was the ancestor of Homo sapiens.”

Here are the links to the two papers which show by 1 million years ago, erectus was pretty uniform. “Homo erectus, Homo ergaster, Homo “cepranensis,” and the Daka cranium,” and “Remains of Homo erectus from Bouri, Middle Awash, Ethiopia.”

Kambiz

“Does this mean once the African H. erectus figured it out and moved out of Africa, that these primitive Homo were replaced?”

To me it, along with the recent discovery of possible overlap of H. erectus and H. habilis in Africa, suggests African H. erectus evolved from something like this Dmanisi population who had moved back into Africa. This link from John Hawks’ Four Stone Hearth suggests this sort of movement has had a hand in human evolution over the last 10,000 years. Why not longer ago too?