Curator and Mary R. Dawson Chair of Vertebrate Paleontology K. Christopher Beard
Figure 1: Life restoration of Eosimias centennicus, an early anthropoid primate from the middle Eocene Heti Formation, Shanxi Province, PRC. Eosimias was a tiny (91–179 g), tree-dwelling primate that probably ate fruits and insects.
Illustration by Nancy Perkins
The evolutionary origin of anthropoid or “higher” primates remains one of the most hotly contested issues in primate and human evolution. Pertinent questions include: (1) What is the phylogenetic position of Anthropoidea with respect to other living and fossil primates? (2) Where and when did the anthropoid clade originate? (3) Did the large number of (derived) morphological and molecular characters that distinguish living anthropoids from all other primates evolve all at once or in mosaic fashion? (4) If anthropoids acquired their unique features through mosaic evolution, by what sequence did this occur?
Expeditions by Carnegie Museum of Natural History and the Institute of Vertebrate Paleontology & Paleoanthropology (Academia Sinica, Beijing, PRC) have greatly advanced our knowledge of early fossil anthropoids in China. For example, our team discovered the complete lower dentition of the 40-million-year-old anthropoid Eosimias centennicus along the Yellow River in southern Shanxi Province in May 1995. These and other specimens show that primitive anthropoids inhabited eastern Asia millions of years before they are represented by such nearly complete fossils in the African fossil record. Because the nearest living relative of anthropoid primates (the primate Tarsius) occurs only in Southeast Asia and because some of the earliest and most primitive fossil anthropoids are known from Asia, it seems likely that the anthropoid clade actually originated on the Asian landmass.
Additional fossil evidence is necessary to understand more fully the diversity, anatomy, and evolutionary position of Eosimias and other early Asian anthropoids. Our ongoing field and laboratory research has been funded by the National Science Foundation, the National Geographic Society, the L. S. B. Leakey Foundation, and Carnegie Museum of Natural History.
For further information about Eosimias, please see "Searching for Our Primate Ancestors in China," available online at the Center for the Study of Chinese Prehistory website (article originally published in Volume LXIII, Number 2, Carnegie magazine online).
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