1Department of Anthropology, New York University, 2New York Consortium in Evolutionary Primatology, NYCEP, 3Department of Anatomy and Neuroscience, University of Melbourne
March 26, 2015 , Archview Ballroom
Fossil gibbons are known from several sites in China, dating from the early Pliocene onwards. Although gibbons were widely distributed across southern China in the Pleistocene, today they are restricted to Yunnan, Guangxi and Tibet in southwestern China and to Hainan Island. The best-known fossil gibbon from the Chinese Pleistocene is a left mandibular fragment with M2-3 (AMNH-18534) from Yanjinggou, Chongqing Province. Matthew and Granger described this specimen in 1923 as a new genus and species, Bunopithecus sericus. Establishing the age of the specimen has proved difficult because the fossil collections from Yanjinggou represent mixed faunas of different ages, but it probably dates to the early or middle Pleistocene. Subsequent opinions about its taxonomic status have been divided, with different authorities attributing it to extant Nomascus or Hoolock, or retaining it in its own genus, Bunopithecus. We reexamined the dental affinities and relationships of AMNH-18534, comparing it with 289 extant gibbon molars using size and shape variables. The comparative sample included representatives of the four currently recognized hylobatid genera. Our multivariate analyses demonstrate that AMNH-18534 is not attributable to Nomascus, but support for an exclusive affinity with modern hoolocks is equivocal. In most analyses AMNH-18534 does not cluster with any extant taxon and falls outside the range of variation for modern hylobatids, but its distance from the cluster represented by extant hoolocks is relatively small. The evidence indicates that Bunopithecus, retained here as a distinct genus, most likely represents a crown hylobatid that is possibly the sister taxon of Hoolock.
This research was supported by the National Science Foundation (SBR-9815546), Wenner-Gren Foundation, LSB Leakey Foundation, and NYU Center for the Study of Human Origins.