1Department of Human Evolutionary Biology, Harvard University, 2Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 3Tomographic Imaging Group, European Synchrotron Radiation Facility, 4Department of Oral Anatomy, Aichi Gakuin University, 5Department of Paleoanthropology and Messel Research, Senckenberg Research Institute Frankfurt a.M., 6MATEIS Lab, INSA Lyon, 7Department of Vertebrate Paleontology, Johann Wolfgang Goethe University, 8Department of Geology, NCB Naturalis
Friday 11:15-11:30, Grand Ballroom II
Scholars frequently debate the taxonomic status of isolated Asian Pleistocene teeth, which is complicated by morphological and metric convergence between fossil orangutan (Pongo sp.) and Homo erectus molars. Moreover, fossil Pongo was widely distributed throughout mainland Asia and Indonesia, showing remarkable dental variation. In order to clarify the occurrence and abundance of Asian hominins, we non-destructively examined 2D relative enamel thickness and distribution, enamel-dentine junction shape, and/or the developmental long-period line periodicity in 30 teeth from the Chinese Apothecary collections (11 “H. erectus,” 19 “Hemanthropus peii”) and 7 teeth from Sangiran Dome (either H. erectus or Pongo). These were compared to 10 definitive H. erectus teeth from Sangiran, Zhoukoudian, and Trinil, and more than 170 fossil Pongo teeth. All teeth were imaged with laboratory grade and/or synchrotron micro-computed tomography. While H. erectus and fossil Pongo show some overlap in relative enamel thickness values, fossil Pongo molars show a more uniform distribution across the enamel cap than H. erectus. Molar enamel-dentine junction shapes are also fairly distinctive, with fossil Pongo showing relatively shorter dentine horns than H. erectus. Long-period line periodicity values are markedly higher in fossil Pongo than in H. erectus, as are postcanine crown formation times. We find that the majority of the teeth assigned to “H. erectus” show greater affinity to orangutans than to H. erectus. Moreover, the “Hemanthropus peii” sample is indistinguishable from fossil Pongo. These results suggest that hominins may have been less common in certain Asian faunas than has been previously appreciated.
Supported by the European Synchrotron Radiation Facility, Harvard University, and the Max Planck Society.