@article{f8115b03c0e2462cb19704bf4852f5fe,
title = "Growth and development of the third permanent molar in Paranthropus robustus from Swartkrans, South Africa",
abstract = "Third permanent molars (M3s) are the last tooth to form but have not been used to estimate age at dental maturation in early fossil hominins because direct histological evidence for the timing of their growth has been lacking. We investigated an isolated maxillary M3 (SK 835) from the 1.5 to 1.8-million-year-old (Mya) site of Swartkrans, South Africa, attributed to Paranthropus robustus. Tissue proportions of this specimen were assessed using 3D X-ray micro-tomography. Thin ground sections were used to image daily growth increments in enamel and dentine. Transmitted light microscopy and synchrotron X-ray fluorescence imaging revealed fluctuations in Ca concentration that coincide with daily growth increments. We used regional daily secretion rates and Sr marker-lines to reconstruct tooth growth along the enamel/dentine and then cementum/dentine boundaries. Cumulative growth curves for increasing enamel thickness and tooth height and age-of-attainment estimates for fractional stages of tooth formation differed from those in modern humans. These now provide additional means for assessing late maturation in early hominins. M3 formation took ≥ 7 years in SK 835 and completion of the roots would have occurred between 11 and 14 years of age. Estimated age at dental maturation in this fossil hominin compares well with what is known for living great apes.",
author = "Christopher Dean and Cl{\'e}ment Zanolli and {Le Cabec}, Adeline and Mirriam Tawane and Jan Garrevoet and Arnaud Mazurier and Roberto Macchiarelli",
note = "Funding Information: The SXRF work presented in this study was supported by DESY Project proposal I‐20180047 and by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. We thank the DESY User Office, Dr. Gerald Falkenberg, Dr. Kathryn Spiers and those who have developed techniques employed in this study. We acknowledge the support to C.D. from the Calleva Foundation and to A.L.C. from The Max Planck Society. C.Z. and R.M. received support from the AESOP and AESOP+ consortia coordinated by Jos{\'e} Braga. We sincerely acknowledge Stephany Potze for her help in 2015 at the Ditsong Nat. Museum Nat. History (DNMNH), Pretoria. We thank William Kimbel, Helen Liversidge, Ann Margyelashvili, Philip Rightmire, Friedemann Schrenk, Fred Spoor and Francis Thackeray for their help and support. For access to comparative µCT data of extant hominids, we thank Marie-Dominique Wandhammer (Mus. Zool. Strasbourg), Salvador Moy{\`a}-Sol{\`a}, David M. Alba, Josep Fortuny and Alessandro Urciuoli (Inst. Catal{\`a} Paleontol. Miquel Crusafont), Deborah Arbulla (Mus. Storia Nat. Trieste) and the Morphosource Database (https ://www.morphosource.org). We extend our sincere thanks to the referees for their comments and suggestions. Publisher Copyright: {\textcopyright} 2020, The Author(s).",
year = "2020",
month = dec,
day = "1",
doi = "10.1038/s41598-020-76032-2",
language = "English",
volume = "10",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Nature Publishing Group",
number = "1",
}