TY - JOUR
T1 - Sexual dimorphism of body size in an African fossil ape, Nacholapithecus kerioi
AU - Kikuchi, Yasuhiro
AU - Nakatsukasa, Masato
AU - Tsujikawa, Hiroshi
AU - Nakano, Yoshihiko
AU - Kunimatsu, Yutaka
AU - Ogihara, Naomichi
AU - Shimizu, Daisuke
AU - Takano, Tomo
AU - Nakaya, Hideo
AU - Sawada, Yoshihiro
AU - Ishida, Hidemi
N1 - Funding Information:
We thank J. M. Plavcan (Editor), associate editor, N. Roach (referee), and two anonymous referees for reviewing our paper, using their precious time and giving us helpful comments. We thank F. Manthi, E. Mbua, M. Kibunja and the other staff of the National Museums of Kenya for their support of our study and the NACOSTI for permission to carry out this research. We thank the curators of the Division of Osteology of the National Museums of Kenya; C. Zollikofer, and M. Ponce de León of the Anthropological Institute and Museum, Universität Zürich-Irchel (Switzerland); C. Funk of the Museum für Naturkunde Berlin (Germany); and E. Gilissen and W. Wendelen of the Department of African Zoology at the Royal Museum for Central Africa (Belgium) for access to collections under their care. The Japan Society for Promotion of Science, Nairobi Research Station helped us to conduct research in Kenya. This study was supported by JSPS KAKENHI Grant Numbers 20247033 , and 15K14621 , and by a fiscal 2017 Grant-in-Aid for Scientific Research and a Grant for Basic Science Research Projects from the Sumitomo Foundation Grant Number 170071 .
Funding Information:
We thank J. M. Plavcan (Editor), associate editor, N. Roach (referee), and two anonymous referees for reviewing our paper, using their precious time and giving us helpful comments. We thank F. Manthi, E. Mbua, M. Kibunja and the other staff of the National Museums of Kenya for their support of our study and the NACOSTI for permission to carry out this research. We thank the curators of the Division of Osteology of the National Museums of Kenya; C. Zollikofer, and M. Ponce de Le?n of the Anthropological Institute and Museum, Universit?t Z?rich-Irchel (Switzerland); C. Funk of the Museum f?r Naturkunde Berlin (Germany); and E. Gilissen and W. Wendelen of the Department of African Zoology at the Royal Museum for Central Africa (Belgium) for access to collections under their care. The Japan Society for Promotion of Science, Nairobi Research Station helped us to conduct research in Kenya. This study was supported by JSPS KAKENHI Grant Numbers 20247033, and 15K14621, and by a fiscal 2017 Grant-in-Aid for Scientific Research and a Grant for Basic Science Research Projects from the Sumitomo Foundation Grant Number 170071.
Publisher Copyright:
© 2018 Elsevier Ltd
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2018/10
Y1 - 2018/10
N2 - Sexual size dimorphism in the African fossil ape Proconsul nyanzae (18 million years ago, 18 Ma) has been previously documented. However, additional evidence for sexual dimorphism in Miocene hominoids can provide great insight into the history of extant hominoid mating systems. The present study focused on body mass (BM) sexual dimorphism in Nacholapithecus kerioi from the Middle Miocene (16–15 Ma) in Africa. Bootstrap analysis revealed that P. nyanzae BM sexual dimorphism was lower than that in Pan troglodytes, which exhibits moderate sexual dimorphism, as reported previously. The same simulation revealed that BM sexual dimorphism of N. kerioi was comparable with that in Gorilla spp.; i.e., the males were approximately twice as large as the females. High sexual dimorphism in extant apes is usually indicative of a polygynous social structure (gorilla) or solitary/fission-fusion social system (orangutan). However, because of the high proportion of adult males in this fossil assemblage, the magnitude of dimorphism inferred here cannot be associated with a gorilla-like polygynous or oranguran-like solitary/fission-fusion social structure, and may reflect either taphonomic bias, or some other social structure. Extant hominoids have a long evolutionary history owing to their deep branching, comprising only a few existing members of the original highly successful group. Therefore, it is not surprising that the mating systems of extant hominoids fail to provide fossil apes with a perfect “model”. The mating systems of extinct hominoids may have been more diverse than those of extant apes.
AB - Sexual size dimorphism in the African fossil ape Proconsul nyanzae (18 million years ago, 18 Ma) has been previously documented. However, additional evidence for sexual dimorphism in Miocene hominoids can provide great insight into the history of extant hominoid mating systems. The present study focused on body mass (BM) sexual dimorphism in Nacholapithecus kerioi from the Middle Miocene (16–15 Ma) in Africa. Bootstrap analysis revealed that P. nyanzae BM sexual dimorphism was lower than that in Pan troglodytes, which exhibits moderate sexual dimorphism, as reported previously. The same simulation revealed that BM sexual dimorphism of N. kerioi was comparable with that in Gorilla spp.; i.e., the males were approximately twice as large as the females. High sexual dimorphism in extant apes is usually indicative of a polygynous social structure (gorilla) or solitary/fission-fusion social system (orangutan). However, because of the high proportion of adult males in this fossil assemblage, the magnitude of dimorphism inferred here cannot be associated with a gorilla-like polygynous or oranguran-like solitary/fission-fusion social structure, and may reflect either taphonomic bias, or some other social structure. Extant hominoids have a long evolutionary history owing to their deep branching, comprising only a few existing members of the original highly successful group. Therefore, it is not surprising that the mating systems of extant hominoids fail to provide fossil apes with a perfect “model”. The mating systems of extinct hominoids may have been more diverse than those of extant apes.
KW - Africa
KW - Fossil hominoid
KW - Miocene
KW - Sexual dimorphism
KW - Social structure
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U2 - 10.1016/j.jhevol.2018.07.003
DO - 10.1016/j.jhevol.2018.07.003
M3 - Article
AN - SCOPUS:85051537873
VL - 123
SP - 129
EP - 140
JO - Journal of Human Evolution
JF - Journal of Human Evolution
SN - 0047-2484
ER -