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Geometric variation of the frontal squama in the genus homo : Frontal bulging and the origin of modern human morphology
Author(s) -
Bruner Emiliano,
Athreya Sheela,
de la Cuétara José Manuel,
Marks Tarah
Publication year - 2013
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.22202
Subject(s) - paleoanthropology , homo sapiens , morphology (biology) , homo erectus , evolutionary biology , biology , trait , human evolution , morphometrics , frontal bone , brain size , frontal lobe , hominidae , zoology , skull , anatomy , paleontology , pleistocene , biological evolution , geography , archaeology , neuroscience , computer science , medicine , genetics , radiology , magnetic resonance imaging , programming language
The majority of studies of frontal bone morphology in paleoanthropology have analyzed the frontal squama and the browridge as a single unit, mixing information from different functional elements. Taking into account that the bulging of the frontal bone is often described as a species‐specific trait of Homo sapiens , in this article we analyze variation in the midsagittal profile of the genus Homo , focusing on the frontal squama alone, using landmark‐based superimpositions and principal components analysis. Our results demonstrate that anatomically modern humans are definitely separated from extinct human taxa on the basis of frontal bulging. However, there is minor overlap among these groups, indicating that it is necessary to exercise caution when using this trait alone to make taxonomic inferences on individual specimens. Early modern humans do not show differences with recent modern humans, and “transitional” individuals such as Jebel Irhoud 1, Maba, and Florisbad, show modern‐like frontal squama morphology. The bulging of the frontal squama in modern humans may represent a structural consequence of more general cranial changes, or it could be a response to changes in the morphology of the underlying prefrontal brain elements. A subtle difference between Neandertals and the Afro‐European Middle Pleistocene Homo sample is associated with flattening at bregma in the former group, a result that merits further investigation. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc