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Paleobiogeography, Paleoecology and Continued Investigation of a Diverse, Terminal Miocene, Primate-Bearing Fauna from Southern China

Tapir

At the heart of the project is the understanding of the composition of an ecosystem which appears poised at the tipping point of a major change based on what is known of terminal Miocene faunas elsewhere in the Old World. The Shuitangba fauna and environment provide an unusually clear and well-preserved picture of a distinctive regional ecosystem that contained long-established species alongside new arrivals.

The period spanning the late Miocene through the early Pliocene, from 8-4 million years ago, witnessed great changes in terrestrial environments throughout the world as the result of changes in continental and oceanic configurations, mountain building and global and local patterns of atmospheric circulation. Landscape heterogeneity and seasonality increased during this time, resulting in great changes in temperature and rainfall regimes, and in food availability for many species. In eastern Asia, this period witnessed a decrease in the areal extent of evergreen tropical and subtropical forests and a concomitant loss in the species dependent on the resources in these environments. The remains of many fossil apes have been retrieved from middle- and late-Miocene-aged sediments in Yunnan Province, but evidence of terminal Miocene and earliest Pliocene apes and monkeys has been scarce. Thus, the timing and nature of the catarrhine “faunal turnover”, which resulted in the near demise of large apes and the rise of gibbons and monkeys in East Asia, is poorly known.

The site of Shuitangba in the Zhatong Basin of northeastern Yunnan Province of China is of great importance because it has yielded the fossil remains of a Miocene fossil ape, Lufengpithecus lufengensis, alongside those of a fossil monkey belonging to the genus Mesopithecus. This is the first unequivocally documented example of hominoid and cercopithecoid co-occurrence in the Miocene of Eurasia. These catarrhine primates are part of a rich water-margin and marsh-associated vertebrate fauna that is preserved in intercalated deposits of lignite and carbon-rich clay. The Shuitangba fauna includes diverse mammalian micro- and mega-fauna, a diverse avifauna, and many reptiles, amphibians and fish. Plant mega-fossil and sporo-pollen remains are also plentiful. The age of the Shuitangba fossils has been estimated at 6.2 million years based on a preliminary magnetostratigraphic study.

The five objectives of this project are:

  1. recovery of more fossils from Shuitangba by excavation and screening by an international team of American and Chinese investigators during field seasons in 2012 and 2013;
  2. detailed analysis of the catarrhine primate remains from the site;
  3. detailed characterization of the depositional environment and taphonomic conditions at the site;
  4. taxonomic, biogeographical, functional anatomical, and ecomorphological study of the site’s vertebrate fauna; and
  5. comparison of the composition of the Shuitangba fauna with other Miocene and Pliocene faunas in eastern Asia for purposes of biostratigraphic correlation and evaluation of endemism.

At the heart of the project is the understanding of the composition of an ecosystem which appears poised at the tipping point of a major change based on what is known of terminal Miocene faunas elsewhere in the Old World. The Shuitangba fauna and environment provide an unusually clear and well-preserved picture of a distinctive regional ecosystem that contained long-established species alongside new arrivals. The site is of signal importance in the context of Eurasian Tertiary paleontology because it uniquely preserves the co-occurrence of a hominoid and a cercopithecoid, the former being an established element of late Miocene Chinese faunas and the latter being a new arrival from the west. A better understanding of the adaptations of species within such transitional ecosystems may shed light on the dynamics of modern unstable environments.

Funding Source:
National Science Foundation

William Kimbel, Arizona State University School of Human Evolution and Social Change
John Kelley, Arizona State University School of Human Evolution and Social Change
Denise Su, Cleveland Museum of Natural History
Nina Jablonski, Pennsylvania State University