A 3-dimensional assessment of molar enamel thickness and distribution pattern in Gigantopithecus blacki

Reiko T. Kono, Yingqi Zhang, Changzhu Jin, Masanaru Takai, Gen Suwa

In order to investigate molar enamel thickness and distribution in Gigantopithecus blacki, two maxillary and three mandibular molars were micro-CT scanned, and the 3-dimensional (3D) shape of the enamel crown cap was digitally reconstructed. Results show that G. blacki molars have very thick enamel, over 6 mm in places. 3D average thickness of the entire crown relative to crown size was shown to be comparable to that of modern Homo sapiens, and thinner than in the very thick enameled robust Australopithecus condition. Durability of the tooth, calculated as the enamel volume relative to maximum horizontal area of the crown, was shown to be comparable to that of fossil hominids, including Australopithecus robustus. The thick occlusal enamel of G. blacki molars was found to be accompanied by a buccolingual gradient in which thicker enamel occurs on the cusps of the "functional" side. This is associated with higher crown height on the "functional" side of the crown, and implies an adaptation to differential buccolingual wear. These results indicate that G. blacki molars were adapted to heavy wear, but probably in a manner that was different from Pliocene and Pleistocene hominids.

Quaternary International (2014), http://dx.doi.org/10.1016/j.quaint.2014.02.012

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