This month in the Journal of Human Evolution, a new study on the teeth of the Dmanisi Homo erectus has been published. A site in the Republic of Georgia, Dmanisi has yielded a vast quantity of hominin fossils dating to approximately 1.8 million years ago—even an elderly individual without teeth. The discovered crania are remarkably well-preserved, and have given scientists the ability to look at our evolutionary history with higher resolution.
Based on the skeletal remains, how can we ascertain specifics about hominin diet? For this particular study, researchers used microwear analysis on two molars from Dmanisi. Microwear analysis observes the patterning left on teeth by components of specific diets. As one example, tough silicates in plants leave identifiable traces, as do other silica-based sands that end up being chewed.
Comparisons in wear patterns were made with Dmanisi H. erectus and African H. erectus as well as the genus Australopithecus and earlier Homo, to get an idea of where the Dmanisi hominins fit in on the spectrum of microwear diagnostic traits. These diagnostic traits include heterogeneity of the tooth surface, as well as complexity in the roughness of the tooth surface. To give you an idea of general evolutionary trends, Australopithecines typically had larger teeth and thicker enamel to break down tougher, lower quality foods. As later Homo emerged, teeth tended to get smaller and enamel thinner.
The results indicated that the molars of Dmanisi Homo erectus were very similar to African Homo erectus in general. However, there were also characteristics found to be consistent with other earlier hominin species. Overall the authors cautioned against drawing conclusions with such a small number of teeth, saying that meaningful statistical results are unattainable based on the sample size.
According to authors, the wear patterns on the Dmanisi teeth are indicative of hominins that exploited a range of foods. It seems then that versatility and not specialization is what defines H. erectus in both Africa and Europe. The ability to take advantage of a larger resource base is no doubt one of the factors that allowed the first hominins to spread out across such an expansive area.
By Matthew Magnani
Pontzer, H., Scott, J.R., Lordkipanidze, D., Ungar, P.S. 2011.“Dental microwear texture analysis and diet in the Dmanisi hominins.” Journal of Human Evolution 61:683-687.