TY - JOUR
T1 - Evolutionary trend in dental size in fossil orangutans from the Pleistocene of Chongzuo, Guangxi, southern China
AU - Harrison, Terry
AU - Zhang, Yingqi
AU - Yang, Liyun
AU - Yuan, Zengjian
N1 - Funding Information:
This work was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB26000000). We thank Song Xing for inviting us to contribute to this special issue. The authors are grateful to Russell L. Ciochon, Eric Delson, Changzhu Jin, Yuan Wang, and Wei Wang for support, advice, and discussion. The clarity of the manuscript has benefitted from the critical comments and editorial suggestions of Andrea Taylor (Co-Editor-in-Chief), Jay Kelley, Eric Delson, an anonymous reviewer, and the Guest Editor. We thank colleagues at the following institutions for access to collections: American Museum of Natural History, New York; Institute of Vertebrate Paleontology and Paleoanthropology, Beijing; Zoological Reference Collection, Singapore.
Funding Information:
This work was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB26000000 ). We thank Song Xing for inviting us to contribute to this special issue. The authors are grateful to Russell L. Ciochon, Eric Delson, Changzhu Jin, Yuan Wang, and Wei Wang for support, advice, and discussion. The clarity of the manuscript has benefitted from the critical comments and editorial suggestions of Andrea Taylor (Co-Editor-in-Chief), Jay Kelley, Eric Delson, an anonymous reviewer, and the Guest Editor. We thank colleagues at the following institutions for access to collections: American Museum of Natural History, New York; Institute of Vertebrate Paleontology and Paleoanthropology, Beijing; Zoological Reference Collection, Singapore.
Publisher Copyright:
© 2021
PY - 2021/12
Y1 - 2021/12
N2 - More than 800 isolated teeth of fossil Pongo have been recovered from cave sites in the vicinity of Chongzuo in Guangxi, southern China, ranging from the Early to Late Pleistocene (2.0–0.1 Ma). These collections provide a unique regional window into the evolutionary history of orangutans over a two-million-year period at the northernmost extent of their former geographic range. Here we investigate the nature and timing of the evolutionary change in the dental size of fossil orangutans from Chongzuo. Fossil tooth size (mesiodistal length∗buccolingual breadth) was compared against an extant Pongo pygmaeus standard (n = 106 individuals). During the course of the Pleistocene, orangutans from southern China exhibited a progressive reduction in overall dental size. Early Pleistocene Pongo has cheek teeth with occlusal areas that are 38.1% larger than those of extant P. pygmaeus. Those from the Middle and Late Pleistocene are 25.2% and 18.9% larger, respectively. Previously, the size difference in dentition between the Early to Middle Pleistocene and Middle to Late Pleistocene samples was used to differentiate time-successive species of Pongo, namely Pongo weidenreichi and Pongo devosi. However, with access to larger samples and better representation of populations through time, the evidence in support of this taxonomic arrangement requires reconsideration. Diminution of the teeth now appears to be a gradual evolutionary transformation rather than a punctuated event. Moreover, the morphological features that distinguish the Chongzuo fossil orangutans from extant Pongo spp. remain uniform throughout the Pleistocene. Retaining P. weidenreichi and P. devosi as anagenetic species remains an option, but, given the current evidence, we consider it preferable to assign all of the fossil orangutans from Chongzuo to P. weidenreichi. Beyond resolving questions of alpha taxonomy, the study of fossil orangutan dental size provides a basis for estimating body mass, which has implications for interpreting the paleobiology of Pleistocene Pongo in southern China.
AB - More than 800 isolated teeth of fossil Pongo have been recovered from cave sites in the vicinity of Chongzuo in Guangxi, southern China, ranging from the Early to Late Pleistocene (2.0–0.1 Ma). These collections provide a unique regional window into the evolutionary history of orangutans over a two-million-year period at the northernmost extent of their former geographic range. Here we investigate the nature and timing of the evolutionary change in the dental size of fossil orangutans from Chongzuo. Fossil tooth size (mesiodistal length∗buccolingual breadth) was compared against an extant Pongo pygmaeus standard (n = 106 individuals). During the course of the Pleistocene, orangutans from southern China exhibited a progressive reduction in overall dental size. Early Pleistocene Pongo has cheek teeth with occlusal areas that are 38.1% larger than those of extant P. pygmaeus. Those from the Middle and Late Pleistocene are 25.2% and 18.9% larger, respectively. Previously, the size difference in dentition between the Early to Middle Pleistocene and Middle to Late Pleistocene samples was used to differentiate time-successive species of Pongo, namely Pongo weidenreichi and Pongo devosi. However, with access to larger samples and better representation of populations through time, the evidence in support of this taxonomic arrangement requires reconsideration. Diminution of the teeth now appears to be a gradual evolutionary transformation rather than a punctuated event. Moreover, the morphological features that distinguish the Chongzuo fossil orangutans from extant Pongo spp. remain uniform throughout the Pleistocene. Retaining P. weidenreichi and P. devosi as anagenetic species remains an option, but, given the current evidence, we consider it preferable to assign all of the fossil orangutans from Chongzuo to P. weidenreichi. Beyond resolving questions of alpha taxonomy, the study of fossil orangutan dental size provides a basis for estimating body mass, which has implications for interpreting the paleobiology of Pleistocene Pongo in southern China.
KW - Dentition
KW - Paleobiology
KW - Pongo
KW - Primate community
KW - Taxonomy
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U2 - 10.1016/j.jhevol.2021.103090
DO - 10.1016/j.jhevol.2021.103090
M3 - Article
C2 - 34781087
AN - SCOPUS:85118934646
SN - 0047-2484
VL - 161
JO - Journal of Human Evolution
JF - Journal of Human Evolution
M1 - 103090
ER -