Variation in the Lufeng dental remains

Abstract

The dental remains of large-bodied hominoids from Lufeng have been reanalysed using only permanent teeth that can be confidently allocated to a tooth locus. These, and other selection criteria, have meant that the sample available for study ( N=672) is smaller than that used in earlier analyses ( N=936–955). Simple linear crown measurements, observations of twelve non-metrical traits and the areas of the individual cusps of the mandibular postcanine teeth were measured on the fossil collection, and compared with linear measurements from reliably-sexed samples of Gorilla gorilla gorilla ( N=64), Pan troglodytes verus ( N=57) and Pongo pygmaeus pygmaeus ( N=43), and P 3 cusp area measurements from smaller subsets ( N=17) of both Gorilla and Pongo. Variability in the Lufeng and comparative samples were compared using the coefficient of variation and by comparing simple histogram plots. Except for linear dimensions of first and second molar crowns, variation of linear crown measurements within the whole Lufeng sample, and in subsets which eliminated antimeres, was within the observed range of the extant hominoid samples. None of the distributions of the expressions of the discontinuous traits was bimodal, and trait expression was apparently not related to the overall size of the tooth crown. Mandibular molar and posterior premolar crown morphology was monomorphic, dimorphism in the postcanine teeth being restricted to the crown morphology of the P 3, with larger teeth more likely to be unicuspid and smaller teeth bicuspid. However, a comparable, but not identical, dimorphism in P 3 crown morphology was seen within pooled sex samples drawn from Gorilla and Pongo. It is concluded that there is neither strong metrical evidence, nor any morphological basis, to reject the null hypothesis that the Lufeng dental remains sample a single, large-bodied, hominoid taxon.