DOI: 10.5061/dryad.6t1g1jx46
title: Data from: Severe enamel defects in wild Japanese macaques

description: Plane-form enamel hypoplasia (PFEH) is a severe dental defect in which
 large areas of the crown are devoid of enamel. This condition is rare in
 humans and even rarer in wild primates. The etiology of PFEH has been
 linked to exposure to severe disease, malnutrition, environmental toxins,
 and associated with systemic conditions. In this study, we examined the
 prevalence of enamel hypoplasia in several populations of wild Japanese
 macaques (Macaca fuscata) with the aim of providing context for severe
 defects observed in macaques from Yakushima Island. We found that 10 of 21
 individuals (48%) from Yakushima Island displayed uniform and significant
 PFEH; all 10 specimens were from two adjacent locations in the south of
 the island. In contrast, macaques from other islands and from mainland
 Japan have low prevalence of the more common types of enamel hypoplasia
 and none exhibit PFEH. In Yakushima macaques, every tooth type was
 affected to varying degrees except for first molars and primary teeth, and
 the mineral content of the remaining enamel in teeth with PFEH was normal
 (i.e., no hypo- or hyper mineralization). The aetiology of PFEH might be
 linked to extreme weather events or high rates of environmental fluoride
 causing enamel breakdown. However, given that the affected individuals
 underwent dental development during a period of substantial human-related
 habitat change, an anthropogenic related etiology seems most likely.
 Further research on living primate populations is needed to better
 understand the causes of PFEH in wild primates.
description: Specimens studied originate from three Japanese islands and
 mainland (Yakushima: 21 individuals; Honshu: 10 individuals; Koshima: 19
 individuals). All specimens are curated at the Primate Research Institute
 (PRI) (now the Center for the Evolutionary Origins of Human Behavior),
 Kyoto University, Japan. All 48 individuals studied lived in the wild,
 with those on Koshima (Kojima) Island provisioned regularly as part of a
 primatological study. Enamel hypoplasia data was
 collected following Towle and Irish (2019). Teeth were held under a lamp
 and rotated allowing light to hit the surface at different angles. The
 smallest discernible macroscopic defect was recorded, with a hand lens
 used to rule out postmortem damage. Postmortem damage was distinguished
 from enamel hypoplasia by distinct characteristics, including sharp edges
 and contrasting coloration between the fractured enamel and the rest of
 the crown. These features seldom resemble common forms of enamel
 hypoplasia, such as pitting, linear, or plane form defects. Under a hand
 lens, postmortem damage also lacks evidence of wear during the
 individual's life. Methods for recording LEH follow Goodman and Rose
 (1990) and Miszkiewicz (2015). Localized hypoplasia was recorded following
 Skinner et al. (2016). PEH was recorded if there were multiple
 circular/oval enamel defects on a tooth crown (Towle and Irish, 2019). If
 pitting was present within a LEH band, then it was recorded as LEH not
 PEH, but the pitting was noted. Plane-form enamel hypoplasia was recorded
 following Towle et al. (2017). Data are presented by tooth count rather
 than individual, with the number of hypoplastic teeth displayed as a
 percentage of the total number of observable permanent teeth.
 The data analyzed includes the location, year of inclusion into
 the PRI collection and sex of each individual studied when it was
 available. Sex assignment was taken from the PRI database, and in the
 present study we did not attempt to assign sex to remaining specimens.
 Further details on the samples, as well as other information on tooth wear
 and pathologies for these populations can be found in Towle et al. (2022)
 and Towle and Loch (2021).
 <strong>References</strong> Towle,
 I., & Irish, J. D. (2019). A probable genetic origin for pitting
 enamel hypoplasia on the molars of <em>Paranthropus
 robustus</em>. <em>Journal of Human Evolution</em>, 129,
 54-61. Goodman, A. H., & Rose, J. C. (1990).
 Assessment of systemic physiological perturbations from dental enamel
 hypoplasias and associated histological structures. <em>American
 Journal of Physical Anthropology</em>, 33(S11), 59‐110.
 Miszkiewicz, J. J. (2015). Linear enamel hypoplasia and
 age‐at‐death at medieval (11th–16th Centuries) St. Gregory's Priory
 and Cemetery, Canterbury, UK. <em>International Journal of
 Osteoarchaeology</em>, 25(1), 79-87. Skinner, M.
 F., Skinner, M. M., Pilbrow, V. C., & Hannibal, D. L. (2016). An
 enigmatic hypoplastic defect of the maxillary lateral incisor in recent
 and fossil orangutans from Sumatra (<em>Pongo abelii</em>) and
 Borneo (<em>Pongo pygmaeus</em>). <em>International
 Journal of Primatology</em>, 37(4), 548-567.
 Towle, I., Dove, E. R., Irish, J. D., & De Groote, I.
 (2017). Severe plane-form enamel hypoplasia in a dentition from Roman
 Britain. <em>Dental Anthropology</em>, 30(1).
 Towle, I., & Loch, C. (2021). Tooth chipping prevalence
 and patterns in extant primates. <em>American Journal of Physical
 Anthropology</em>, 175(1), 292-299. Towle, I.,
 MacIntosh, A. J., Hirata, K., Kubo, M. O., & Loch, C. (2022).
 Atypical tooth wear found in fossil hominins also present in a Japanese
 macaque population. <em>American Journal of Biological
 Anthropology</em>, 178(1), 171-181. https://doi.org/10.1002/ajpa.24500
description: # Severe enamel defects in wild Japanese macaques
 Specimens studied
 originate from three Japanese islands and mainland (Yakushima: 21
 individuals; Honshu: 10 individuals; Koshima: 19 individuals). All
 specimens are curated at the Primate Research Institute (PRI) (now the
 Center for the Evolutionary Origins of Human Behavior), Kyoto University,
 Japan. All 48 individuals studied lived in the wild, with those on Koshima
 (Kojima) Island provisioned regularly as part of a primatological study.
 Enamel hypoplasia data was collected following Towle and Irish (2019).
 Teeth were held under a lamp and rotated allowing light to hit the surface
 at different angles. The smallest discernible macroscopic defect was
 recorded, with a hand lens used to rule out postmortem damage. Postmortem
 damage was distinguished from enamel hypoplasia by distinct
 characteristics, including sharp edges and contrasting coloration between
 the fractured enamel and the rest of the crown. These features seldom
 resemble common forms of enamel hypoplasia, such as pitting, linear, or
 plane form defects. Under a hand lens, postmortem damage also lacks
 evidence of wear during the individual's life. Methods for recording
 LEH follow Goodman and Rose (1990) and Miszkiewicz (2015). Localized
 hypoplasia was recorded following Skinner et al. (2016). PEH was recorded
 if there were multiple circular/oval enamel defects on a tooth crown
 (Towle and Irish, 2019). If pitting was present within a LEH band, then it
 was recorded as LEH not PEH, but the pitting was noted. Plane-form enamel
 hypoplasia was recorded following Towle et al. (2017). Data are presented
 by tooth count rather than individual, with the number of hypoplastic
 teeth displayed as a percentage of the total number of observable
 permanent teeth. The data analyzed includes the location, year of
 inclusion into the PRI collection and sex of each individual studied when
 it was available. Sex assignment was taken from the PRI database, and in
 the present study we did not attempt to assign sex to remaining specimens.
 Further details on the samples, as well as other information on tooth wear
 and pathologies for these populations can be found in Towle et al. (2022)
 and Towle and Loch (2021). ## Description of the data and file structure
 **Teeth** First letter: Right (R) or Left (L) Second letter: Upper (U) or
 Lower (L) M: Molar P: Premolar C: Canine I: Incisor **Recording criteria**
 0: Tooth observable but no enamel hypoplasia present 1: Linear enamel
 hypoplasia 2: Localized enamel hypoplasia 3: Pitting enamel hypoplasia 4:
 Plane-form enamel hypoplasia 8: Not recordable due to postmortem damage
 n/a: Not applicable due to no associated tooth (e.g., unerupted or lost
 ante-or-postmortem)