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A radiographic study of permanent molar development in wild Virunga mountain gorillas of known chronological age from R wanda
Author(s) -
Kralick Alexandra E.,
Loring Burgess M.,
Glowacka Halszka,
ArbenzSmith Keely,
McGrath Kate,
Ruff Christopher B.,
Chan King Chong,
Cranfield Michael R.,
Stoinski Tara S.,
Bromage Timothy G.,
Mudakikwa Antoine,
McFarlin Shan C.
Publication year - 2017
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.23192
Subject(s) - molar , crown (dentistry) , radiography , mandibular second molar , zoology , biology , orthodontics , dentistry , demography , medicine , surgery , sociology
Objectives While dental development is important to life history investigations, data from wild known‐aged great apes are scarce. We report on the first radiographic examination of dental development in wild Virunga mountain gorillas, using known‐age skeletal samples recovered in Rwanda. Materials and methods In 43 individuals (0.0–14.94 years), we collected radiographs of mandibular molars, and where possible, cone beam CT scans. Molar crown and root calcification status was assessed using two established staging systems, and age prediction equations generated using polynomial regression. Results were compared to available data from known‐age captive and wild chimpanzees. Results Mountain gorillas generally fell within reported captive chimpanzee distributions or exceeded them, exhibiting older ages at equivalent radiographic stages of development. Differences reflect delayed initiation and/or an extended duration of second molar crown development, and extended first and second molar root development, in mountain gorillas compared to captive chimpanzees. However, differences in the duration of molar root development were less evident compared to wild chimpanzees. Discussion Despite sample limitations, our findings extend the known range of variation in radiographic estimates of molar formation timing in great apes, and provide a new age prediction technique based on wild specimens. However, mountain gorillas do not appear accelerated in radiographic assessment of molar formation compared to chimpanzees, as they are for other life history traits. Future studies should aim to resolve the influence of species differences, wild versus captive environments, and/or sampling phenomena on patterns observed here, and more generally, how they relate to variation in tooth size, eruption timing, and developmental life history.