TY - JOUR
T1 - Comparative morphometric analyses of the deciduous molars of Homo naledi from the Dinaledi Chamber, South Africa
AU - Brophy, Juliet K.
AU - Moggi-Cecchi, Jacopo
AU - Matthews, Gregory J.
AU - Bailey, Shara E.
N1 - Funding Information:
We would like to thank Lucas Delezene, Lee Berger, John Hawks, Matt Skinner, and Darryl de Ruiter for data and feedback on this paper. We would also like to thank Stephany Potze, Lazarus Kgasi, and Heidi Fourie for access to the collections at the Ditsong Museum and Bernhard Zipfel for access to the University of the Witwatersrand collections. We (SEB) also thank Bill Kimbel and the National Museum of Ethiopia, Addis Ababa for access to A. afarensis fossils, Dr. Fredrick Manthi for fossil access to hominin fossils curated at the National Museum Kenya, and Audax Mabulla, Agness Gidna, and Amandus Kweka at the National Museum of Tanzania for access to the collections. Finally, we thank the Tanzania Commission for Science and Technology for permission to conduct research in Tanzania.
Publisher Copyright:
© 2020 Wiley Periodicals LLC.
PY - 2021/2
Y1 - 2021/2
N2 - Objectives: The purpose of this study is to help elucidate the taxonomic relationship between Homo naledi and other hominins. Materials and Methods: Homo naledi deciduous maxillary and mandibular molars from the Dinaledi Chamber, South Africa were compared to those of Australopithecus africanus, Australopithecus afarensis, Paranthropus robustus, Paranthropus boisei, early Homo sp., Homo erectus, early Homo sapiens, Upper Paleolithic H. sapiens, recent southern African H. sapiens, and Neanderthals by means of morphometric analyses of crown outlines and relative cusp areas. The crown shapes were analyzed using elliptical Fourier analyses followed by principal component analyses (PCA). The absolute and relative cusp areas were obtained in ImageJ and compared using PCA and cluster analyses. Results: PCA suggests that the crown shapes and relative cusp areas of mandibular molars are more diagnostic than the maxillary molars. The H. naledi deciduous mandibular first and second molar (dm1 and dm2) do not have a strong affinity to any taxon in the comparative sample in all analyses. While the H. naledi dm2 plots as an outlier in the relative cusp analysis, the H. naledi specimen fall closest to Australopithecus due to their relatively large metaconid, a primitive trait for the genus Homo. Although useful for differentiating Neanderthals from recent southern African H. sapiens and UP H. sapiens, the PCA of the relative cusp areas suggests that the deciduous maxillary second molars (dm2) do not differentiate other groups. The three H. naledi dm2 cuspal areas are variable and fall within the ranges of other Homo, as well as Australopithecus, and Paranthropus suggesting weak diagnostic utility. Discussion: This research provides another perspective on the morphology of, and variation within, H. naledi. The H. naledi deciduous molars do not consistently align with any genus or species in the comparative sample in either the crown shape or relative cusp analyses. This line of inquiry is consistent with other cranial and postcranial studies suggesting that H. naledi is unique.
AB - Objectives: The purpose of this study is to help elucidate the taxonomic relationship between Homo naledi and other hominins. Materials and Methods: Homo naledi deciduous maxillary and mandibular molars from the Dinaledi Chamber, South Africa were compared to those of Australopithecus africanus, Australopithecus afarensis, Paranthropus robustus, Paranthropus boisei, early Homo sp., Homo erectus, early Homo sapiens, Upper Paleolithic H. sapiens, recent southern African H. sapiens, and Neanderthals by means of morphometric analyses of crown outlines and relative cusp areas. The crown shapes were analyzed using elliptical Fourier analyses followed by principal component analyses (PCA). The absolute and relative cusp areas were obtained in ImageJ and compared using PCA and cluster analyses. Results: PCA suggests that the crown shapes and relative cusp areas of mandibular molars are more diagnostic than the maxillary molars. The H. naledi deciduous mandibular first and second molar (dm1 and dm2) do not have a strong affinity to any taxon in the comparative sample in all analyses. While the H. naledi dm2 plots as an outlier in the relative cusp analysis, the H. naledi specimen fall closest to Australopithecus due to their relatively large metaconid, a primitive trait for the genus Homo. Although useful for differentiating Neanderthals from recent southern African H. sapiens and UP H. sapiens, the PCA of the relative cusp areas suggests that the deciduous maxillary second molars (dm2) do not differentiate other groups. The three H. naledi dm2 cuspal areas are variable and fall within the ranges of other Homo, as well as Australopithecus, and Paranthropus suggesting weak diagnostic utility. Discussion: This research provides another perspective on the morphology of, and variation within, H. naledi. The H. naledi deciduous molars do not consistently align with any genus or species in the comparative sample in either the crown shape or relative cusp analyses. This line of inquiry is consistent with other cranial and postcranial studies suggesting that H. naledi is unique.
KW - Pleistocene Homo
KW - dental morphology
KW - elliptical fourier
KW - intra/interspecific variation
KW - rising star cave
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U2 - 10.1002/ajpa.24190
DO - 10.1002/ajpa.24190
M3 - Article
C2 - 33290582
AN - SCOPUS:85097281678
SN - 0002-9483
VL - 174
SP - 299
EP - 314
JO - American Journal of Physical Anthropology
JF - American Journal of Physical Anthropology
IS - 2
ER -