The new fossil skull from Dmanisi published this week on Science adds again more questions than answers. The specimens from this site, dated to 1.8 My, display a considerable degree of variation, at the same time showing some resemblance with Homo ergaster, H. erectus, H. habilis, and even with the genus Australopithecus. This last individual has massive facial structures, with a very small cranial capacity which even clashes with the common ranges associated with the human genus. Assuming that all the skulls from Dmanisi are members of the same species, and assuming that morphology is a good indicator for the specie level, the variation at Dmanisi is such that we could lump most of those cited taxa into a single and heterogeneous group. But, of course, there is no reason to think they represent a single species. Most of all, we already know that morphology can be a very bad source of information on species identity. So, why do we paleontologists insist to define species if we know that it is but a meagre speculation? We can put it in nice colours, appealing statistics, and pretty doll-like nicknames. But it is still a personal opinion, not an analytical solution. Of course, we have to call the attention of the media, that’s a good point. But this way paleoanthropology will never be a robust scientific field. If every descriptive study will be associated with firm, striking, and unverifiable statements, we will keep on swinging from one breaking announcement to another, without a solid development of the field. Maybe we have to change a bit the perspective, or even the aims. And maybe we have to focus more on biology and anatomy, their functions, meaning, and evolution, more than keeping on naming rocks.
Posts Tagged 'species concept'
Tags: Dmanisi, human genus, species concept
Tags: American Journal of Primatology, species concept
Taxonomy must ensure a fine balance between changing information and stable communication. The main uncertainties and debates surrounding taxonomic nomenclature are associated with too severe applications of species concepts, differences in scopes and needs, and also confounding factors related to ethics or personal targets. Primatology is particularly sensitive to “taxonomic inflation”, and many interesting theoretical issues have not managed to supply effective practical solutions to numerous outstanding questions. Recently, Colin Groves and Alfred Rosenberger have discussed these topics in the American Journal of Primatology. A third paper written by me gives a further perspective in evolutionary anthropology, for which most of these problems are amplified because of the scarce information associated with incompleteness of the fossil record, limits in assessing taxonomic levels from morphology alone, and narrow diversity in hominid evolutionary radiation. Analytical outputs are often directly presented as phylogenies and automatically transformed into compulsive taxonomic changes. This forces subsequent interpretations of natural processes and diversity into rigid and probably unrealistic perspectives, biased by our mental necessity to focus on discrete objects rather than on their dynamic relationships.