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Morphometric analysis of molars in a M iddle P leistocene population shows a mosaic of ‘modern’ and N eanderthal features
Author(s) -
MartinónTorres María,
Spěváčková Petra,
GraciaTéllez Ana,
Martínez Ignacio,
Bruner Emiliano,
Arsuaga Juan Luis,
Bermúdez de Castro José María
Publication year - 2013
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/joa.12090
Subject(s) - homo sapiens , population , crown (dentistry) , cusp (singularity) , combinatorics , molar , polygon (computer graphics) , biology , anatomy , evolutionary biology , mathematics , geography , orthodontics , geometry , paleontology , computer science , demography , medicine , archaeology , sociology , telecommunications , frame (networking)
Previous studies of upper first molar ( M 1 ) crown shape have shown significant differences between H omo sapiens and H omo neanderthalensis that were already present in the E uropean M iddle P leistocene populations, including the large dental sample from A tapuerca‐ S ima de los H uesos ( SH ). Analysis of other M 1 features such as the total crown base area, cusp proportions, cusp angles and occlusal polygon have confirmed the differences between both lineages, becoming a useful tool for the taxonomic assignment of isolated teeth from L ate P leistocene sites. However, until now the pattern of expression of these variables has not been known for the SH sample. This fossil sample, the largest collection from the E uropean M iddle P leistocene, is generally interpreted as being from the direct ancestors of N eanderthals, and thus is a reference sample for assessing the origin of the N eanderthal morphologies. Surprisingly, our study reveals that SH M 1 s present a unique mosaic of H . neanderthalensis and H . sapiens features. Regarding the cusp angles and the relative occlusal polygon area, SH matches the H . neanderthalensis pattern. However, regarding the total crown base area and relative cusps size, SH M 1 s are similar to H . sapiens , with a small crown area, a strong hypocone reduction and a protocone enlargement, although the protocone expansion in SH is significantly larger than in any other group studied. The SH dental sample calls into question the uniqueness of some so‐called modern traits. Our study also sounds a note of caution on the use of M 1 occlusal morphology for the alpha taxonomy of isolated M 1 s.