TY - JOUR
T1 - Comparative description and taxonomic affinity of 3.7-million-year-old hominin mandibles from Woranso-Mille (Ethiopia)
AU - Haile-Selassie, Yohannes
AU - Saylor, Beverly Z.
AU - Alene, Mulugeta
AU - Deino, Alan
AU - Gibert, Luis
AU - Schwartz, Gary T.
N1 - Funding Information:
This research was supported by the Cleveland Museum of Natural History , earlier grants from the US National Science Foundation ( BCS-1124705 , BCS-1124713 , BCS-1124716 , BCS-1125157 , and BCS-1125345 ), the National Geographic Society , and The Leakey Foundation . We thank the Authority for Research and Conservation of Cultural Heritage (ARCCH) of the Ethiopian Ministry of Culture and Tourism for permission to conduct field research at Woranso-Mille and laboratory work in the National Museum of Ethiopia in Addis Ababa; the government of the Afar Regional State for administrative support; the Afar people of the Woranso-Mille area and the Mille District administration for their hospitality and support; and field crew members of the Woranso-Mille Paleontological Research Project. For access to original fossil specimens in their care we also thank D. Dagne, Y. Assefa, M. Endalamaw, T. Getachew, G. Tekle, S. Melaku, and the National Museum of Ethiopia; F.K. Manthi and the National Museums of Kenya; and B. Zipfel and the Evolutionary Studies Institute at the University of the Witwatersrand. We are also grateful to the Casting Lab technicians in the Paleoanthropology Laboratory of ARCCH. We thank T.M. Ryan and T. Stecko at the Center for Quantitative Imaging, Pennsylvania State University, for CT scanning and image processing, A. Jaeger for surface scanning, and A. Ragni for help with R Statistics. We are grateful to B. Asfaw, the late W.H. Kimbel, G. Suwa, and T. White, for sharing unpublished data, and to W.H. Kimbel for constructive comments, edits, and discussions, C. Dean for discussions about dental development, and D. Su and S. Melillo for edits and assistance with some figures. We are grateful to Andrea Taylor, the Associate Editor, and four anonymous reviewers for constructive comments and edits that considerably improved this manuscript.
Funding Information:
This research was supported by the Cleveland Museum of Natural History, earlier grants from the US National Science Foundation (BCS-1124705, BCS-1124713, BCS-1124716, BCS-1125157, and BCS-1125345), the National Geographic Society, and The Leakey Foundation. We thank the Authority for Research and Conservation of Cultural Heritage (ARCCH) of the Ethiopian Ministry of Culture and Tourism for permission to conduct field research at Woranso-Mille and laboratory work in the National Museum of Ethiopia in Addis Ababa; the government of the Afar Regional State for administrative support; the Afar people of the Woranso-Mille area and the Mille District administration for their hospitality and support; and field crew members of the Woranso-Mille Paleontological Research Project. For access to original fossil specimens in their care we also thank D. Dagne, Y. Assefa, M. Endalamaw, T. Getachew, G. Tekle, S. Melaku, and the National Museum of Ethiopia; F.K. Manthi and the National Museums of Kenya; and B. Zipfel and the Evolutionary Studies Institute at the University of the Witwatersrand. We are also grateful to the Casting Lab technicians in the Paleoanthropology Laboratory of ARCCH. We thank T.M. Ryan and T. Stecko at the Center for Quantitative Imaging, Pennsylvania State University, for CT scanning and image processing, A. Jaeger for surface scanning, and A. Ragni for help with R Statistics. We are grateful to B. Asfaw, the late W.H. Kimbel, G. Suwa, and T. White, for sharing unpublished data, and to W.H. Kimbel for constructive comments, edits, and discussions, C. Dean for discussions about dental development, and D. Su and S. Melillo for edits and assistance with some figures. We are grateful to Andrea Taylor, the Associate Editor, and four anonymous reviewers for constructive comments and edits that considerably improved this manuscript.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/12
Y1 - 2022/12
N2 - Fossil discoveries of early Australopithecus species from Woranso-Mille have played a significant role in improving our understanding of mid-Pliocene hominin evolution and diversity. Here, we describe two mandibles with dentitions, recovered from sediments immediately above a tuff radiometrically dated to 3.76 ± 0.02 Ma, and assess their taxonomic affinity. The two mandibles (MSD-VP-5/16 and MSD-VP-5/50) show morphological similarities with both Australopithecus anamensis and Australopithecus afarensis. Some of the unique features that distinguish Au. anamensis from Au. afarensis are present in the mandibles, which also share a few derived features with Au. afarensis. Their retention of more Kanapoi Au. anamensis-like traits, compared to the fewer derived features they share with Au. afarensis, and the presence of Au. anamensis at Woranso-Mille in 3.8-million-year-old deposits, lends support to their assignment to Au. anamensis. However, it is equally arguable that the few derived dentognathic features they share with Au. afarensis could be taxonomically more significant, making it difficult to conclusively assign these specimens to either species. Regardless of which species they are assigned to, the mosaic nature of the dentognathic morphology and geological age of the two mandibles lends further support to the hypothesized ancestor–descendant relationship between Au. anamensis and Au. afarensis. However, there is now limited fossil evidence indicating that these two species may have overlapped in time. Hence, the last appearance of Au. anamensis and first appearance of Au. afarensis are currently unknown. Recovery of Australopithecus fossils from 4.1 to 3.8 Ma is critical to further address the timing of these events.
AB - Fossil discoveries of early Australopithecus species from Woranso-Mille have played a significant role in improving our understanding of mid-Pliocene hominin evolution and diversity. Here, we describe two mandibles with dentitions, recovered from sediments immediately above a tuff radiometrically dated to 3.76 ± 0.02 Ma, and assess their taxonomic affinity. The two mandibles (MSD-VP-5/16 and MSD-VP-5/50) show morphological similarities with both Australopithecus anamensis and Australopithecus afarensis. Some of the unique features that distinguish Au. anamensis from Au. afarensis are present in the mandibles, which also share a few derived features with Au. afarensis. Their retention of more Kanapoi Au. anamensis-like traits, compared to the fewer derived features they share with Au. afarensis, and the presence of Au. anamensis at Woranso-Mille in 3.8-million-year-old deposits, lends support to their assignment to Au. anamensis. However, it is equally arguable that the few derived dentognathic features they share with Au. afarensis could be taxonomically more significant, making it difficult to conclusively assign these specimens to either species. Regardless of which species they are assigned to, the mosaic nature of the dentognathic morphology and geological age of the two mandibles lends further support to the hypothesized ancestor–descendant relationship between Au. anamensis and Au. afarensis. However, there is now limited fossil evidence indicating that these two species may have overlapped in time. Hence, the last appearance of Au. anamensis and first appearance of Au. afarensis are currently unknown. Recovery of Australopithecus fossils from 4.1 to 3.8 Ma is critical to further address the timing of these events.
KW - Australopithecus afarensis
KW - Australopithecus anamensis
KW - Hadar
KW - Kanapoi
KW - Laetoli
KW - Taxonomy
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U2 - 10.1016/j.jhevol.2022.103265
DO - 10.1016/j.jhevol.2022.103265
M3 - Article
C2 - 36306541
AN - SCOPUS:85140300935
SN - 0047-2484
VL - 173
JO - Journal of human evolution
JF - Journal of human evolution
M1 - 103265
ER -