- 辻川 寛（京都大学）
- Geologic age and palaeoenvironments of Samburu Hills, yielding Miocene large hominoids, were studied on the basis of mammalian faunas. The mammalian faunas of the two strata show that the environment became more arid from the Middle Miocene to the Late Miocene as well as other sites in Africa. The analysis of herbivores' hypsodonty and brachyodonty reveals that a Late Miocene hominoid, Samburupithecus kiptalami (ca. 9.5 Ma) seems to have lived in woodland surrounded by savanna whereas a Middle Miocene hominoid, Nacholapithecus kerioi (ca. 15.5 Ma) are thought to have inhabited in forest. The former environment, in fact, is seen in other hominid-bearing sites during the Late Miocene.