LATE EOCENE SIVALADAPID PRIMATE FROM GUANGXI-ZHUANG AUTONOMOUS REGION, PEOPLES-REPUBLIC-OF-CHINA

A new genus and species of Sivaladapidae is described from the late Eo cene Gongkang Formation, Yongle Basin, western Guangxi Zhuang Autonomo us Region, southern China. Guangxilemur tongi, new genus and species, shows a combination of traits that occur separately in earlier and mor e primitive Asian adapiforms (Hoanghonius and Rencunius) and in Miocen e sivaladapines (Sivaladapis and Sinoadapis). Phylogenetic analysis of dental characters suggests that Guangxilemur is closely related to th e Miocene sivaladapine clade. Miocene sivaladapines were the latest su rviving members of a broad radiation of Eocene adapiforms in Asia that included Hoanghonius, Rencunius, and Wailekia in addition to Guangxil emur. European Periconodon may also be specially related to this prima rily Asian clade, but current anatomical data are insufficient to test this possibility adequately. Sivaladapine adapiforms and tarsiid tars iiforms maintained relictual distributions in southern and/or southeas tern Asia far beyond the extirpation of their closest relatives on oth er Holarctic continents near the Eocene-Oligocene boundary. This tempo ral persistence was mediated by Asian paleogeography, which allowed vi rtually continuous access to tropical refugia during a middle Cenozoic interval of climatic deterioration that coincided with the extinction of adapiforms and tarsiiforms in Europe and North America. (C) 1998 A cademic Press.