Were Neanderthals stoned to death by modern humans?

 
Were Neanderthals stoned to death by modern humans? is the provocative title of a press release reported in New Scientist. The author of the study is interviewed,

Human aerial bombardments might have pushed Neanderthals to extinction, suggests new research. Changes in bone shape left by a life of overhand throwing hint that Stone Age humans regularly threw heavy objects, such as stones or spears, while Neanderthals did not.

"The anatomically modern humans would have this more effective and efficient form of hunting," says Jill Rhodes, a biological anthropologist at Bryn Mawr College in Pennsylvania, who led the new study. A warmer Europe would have opened up forests, enabling longer range hunting, she says.

Rhodes and a colleague studied changes to the arm bone that connects the shoulder to the elbow – the humerus – to determine when humans may have begun using projectile weapons.

"If we're trying to understand whether anatomically modern humans had projectiles, then why not read the signature that it can imprint in the skeleton," Rhodes says.

The paper by Jill Rhodes of the Department of Anthropology, Bryn Mawr College and Steven E. Churchill of the Department of Evolutionary Anthropology, Duke University appears in The Journal of Human Evolution under Article in Press.

Rhodesa, J.A. and Churchill, S.A. (2008) Throwing in the Middle and Upper Paleolithic: inferences from an analysis of humeral retroversion. [doi:10.1016/j.jhevol.2008.08.022M]

Here's the complete text of the conclusiosn from that paper.

Clinical evidence from professional and college-level throwing athletes reveal differences in the humeral retroversion angle both between athletes and comparative (non-throwing) samples and between the dominant (throwing) and non-dominant limbs in the athletes. Comparative analysis of humeral architecture, specifically the humeral retroversion angle, in Pleistocene fossil humans has the ability to contribute new insights into the origins of projectile weaponry by examining the individuals who would have wielded those weapons. While the data is equivocal (in part because of confounding variables that affect humeral retroversion and in part because of small fossil sample sizes), we can reach two conclusions. First, while Neandertals tend to have high amounts of humeral retroversion, the overall pattern between limbs and between sexes strongly suggests that it is not due to habitual throwing behavior. The humeral retroversion data is largely consistent with other lines of evidence pertaining to projectile weaponry; the preponderance of evidence, ranging from fossil spears and Mousterian lithics to the articular and diaphyseal morphology of upper limb bones, suggests that Neandertals did not habitually employ long-range projectile weapons ([Churchill et al., 1996], [Schmitt et al., 2003], [Shea, 2003a], Shea, 2006 J.J. Shea, The origins of lithic projectile point technology: evidence from Africa, the Levant, and Europe, J. Archaeol. Sci. 33 (2006), pp. 823–846. Article | PDF (774 K) | View Record in Scopus | Cited By in Scopus (15)[Shea, 2006] and [Churchill and Rhodes, in press]). It is worth noting that earlier hominins also lack humeral torsion, further demonstrating that the increased retroversion found in Neandertals is unlikely to be linked to throwing. Second, we cannot reject the suggestion of projectile weapon use in the European Upper Paleolithic. The patterns seen in bilateral asymmetry in humeral retroversion angle suggest a variable use of throwing in the middle Upper Paleolithic (and thus great inter-individual variation in asymmetry), perhaps related to regional differences in hunting practices or the importance of projectile-based hunting. The levels of asymmetry seen in late Upper Paleolithic males are consistent with the regular use of projectile technology by this time.

Is it just me, or does there seem to be a disconnect between what's in the paper and what's in the press release? Why would the author allow the press release to say something that cannot be found anywhere in the paper?

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