Sir's I agree with the author's basic premise in "Surprising rapid growth in Neanderthals (Nature 428,936; 2004) that, "Life history traits correlate closely with dental growth" However, there is a serious problem in their method
of determining dental growth. The authors claim to have counted all the
perikymata on the buccal surfaces of the permanent anterior teeth from 146 H.
neanderthalensis, 100 H. sapiens, 106 H. Heidelbergensis, and 8 H. antecessor,
have estimated the number of perikymata on teeth with worn crowns. They
wrote: "Teeth with heavy wear or without perikymata were not included." But paradoxically, they justify the utilization of some worn anterior teeth by stating:
"But wear concerns principally or exclusively the occlusal plane; that is to say that even in worn teeth, the counting of perikymata can easily be done in the rest of the crown."
The buccal or labial surface of an incisor that is worn down to half or a quarter of its original height is not in such pristine condition so that counting this periodicity is "easily done". Strangely, they never reveal the criteria for the measure of wear that is used to eliminate or include a tooth in the study. This is a flaw in the research.
Stringer and Gamble state: "The Neanderthals must have had special uses for their front teeth, for these are very large and often heavily worn compared with those of their probable ancestors." They also commented on unidirectional scratches, made by stone cutting tools on numerous Atapuerca anterior teeth. (1)
I have seen many Neanderthal anterior teeth worn occlusally as well as labially and must take serious issue with this claim. La Ferrassie 1 is a case in point. It is among the list of Neanderthals included by the authors. I have studied the original in detail, with x-rays; there are no dental crowns at all on the anterior teeth of this Neanderthal. In addition, I have observed and photographed perikymata in Le Moustier 1, in Germany, and they are closely packed at the cervical margin, contrary to the author's claims. The authors provide no photomicrographs to document their data, no counts per decile, only charts are shown where one is forced to measure small lines to obtain numerical quantities. Therefore, how can anyone be sure of their conclusions? This seems to be a peer review problem by allowing some flimsy arguments to slide through.
1. Stringer, C, Gamble C In Search of Neanderthals, Thames & Hudson Inc. NY, NY. 1993 p. 76-77.
Jack Cuozzo DDS, MS
Lebanon, NJ 08833
May 25, 2004