A closer look at Neanderthal postcanine dental morphology: the mandibular dentition.

Neanderthals are known to exhibit unique incisor morphology as well as enlarged pulp chambers in postcanine teeth (taurodontism). Recent studies suggest that their overall dental pattern (i.e., in morphologic trait frequencies) is also unique. However, what this means in a phylogenetic sense is not known. Although exploring the polarity of dental morphologic characters is essential to understanding the phylogenetic implications of unique patterns of variation, few have undertaken this task. This study moves beyond standard scoring methods, which are based on modern humans, to include several postcanine traits that have not been considered previously. In addition, Homo erectus is used as an outgroup to Neanderthals and modern humans to explore the polarity of these traits. The findings of this study suggest that Neanderthals are not only unique in their pattern of dental trait frequencies (as found in previous studies) but that they present several dental autapomorphies, as well. These include a high frequency of the mid-trigonid crest in lower molars and unique morphology of the lower premolars. Interestingly, these characters are not observed in the Mauer mandible, which some have claimed to be a member of a chronospecies that is a unique ancestor to Neanderthals.