Abstract: The expression of linear enamel hypoplasia (LEH) has been used as a dental indicator of generalized physiological stress during dental development in living and fossil primates. Here, we present the expression of LEH in Late Miocene large-bodied hominoid fossils Lufengpithecus lufengensis from Yunnan, China. Previous studies have shown that Lufengpithecus lufengensis mandibular teeth exhibited high frequencies of LEH and the periodicity of rLEH showed a semi-annual pattern. As an extension, this present study focuses on 261 isolated permanent teeth of Lufengpithecus lufengensis to assess their LEH prevalence and periodicity of rLEH. In the prevalence analysis, 261 isolated permanent teeth were examined with 85.4 % (223 of 261) affected by LEH. For periodicity of rLEH, 12 canines are analyzed by scanning electron microscopy (SEM Hitachi S-3700) and Keyence VHX-600EOS digital microscope. The results showed that LEH defects occurred repeatedly at a range of 4.8-6.6 months (an average of 6 months) in Lufengpithecus lufengensis. Male canines exhibit more LEH than female. Based on the analysis on the palaeoenvironment and diet of Lufengpithecus lufengpithecus, while seasonal cycles can influence both disease and nutritional stress, it is likely that seasonal variation in fruiting cycles results in higher LEH incidence in Lufengpithecus lufengensis.

Key words: Linear enamel hypoplasia; Lufengpithecus lufengensis; Perikymata; Physiological stress