The nasal complex of Neanderthals: an entry portal to their place in human ancestry.
Neanderthals are one of the most intensely studied groups of extinct humans, as aspects of their phylogeny and functional morphology remain controversial. They have long been described as cold adapted but recent analyses of their nasal anatomy suggest that traits formerly considered adaptations may be the result of genetic drift. This study performs quantitative and qualitative analysis of aspects of the nasal complex (NC) in Neanderthals and other later Pleistocene fossils from Europe and Africa. A geographically diverse sample of modern human crania was used to establish an anatomical baseline for populations inhabiting cold and tropical climates. Nasofrontal angle, piriform aperture dimensions, and relative maxillary sinus volume were analyzed along with qualitative features of the piriform aperture rim. Results indicate that Neanderthals and other later Pleistocene Homo possessed NC's that align them with tropical modern humans. Thus comparison of Neanderthal nasal morphology with that of modern humans from cold climates may not be appropriate as differences in overall craniofacial architecture may constrain the narrowing of the piriform apertures in Neanderthals. They retain primitively long, low crania, large maxillary sinuses, and large piriform aperture area similar to mid-Pleistocene Homo specimens such as Petralona 1 and Kabwe 1. Adaptation to cold climate may have necessitated other adaptations such as bony medial projections at the piriform aperture rim and, potentially, midfacial prognathism. Nasal complex components of the upper respiratory tract remain a critical but poorly understood area that may yet offer novel insight into one of the greatest continuing controversies in paleoanthropology.