Unique Dental Morphology of Homo floresiensis and Its Evolutionary Implications

PLoS One. 2015 Nov 18;10(11):e0141614. doi: 10.1371/journal.pone.0141614. eCollection 2015.

Abstract

Homo floresiensis is an extinct, diminutive hominin species discovered in the Late Pleistocene deposits of Liang Bua cave, Flores, eastern Indonesia. The nature and evolutionary origins of H. floresiensis' unique physical characters have been intensively debated. Based on extensive comparisons using linear metric analyses, crown contour analyses, and other trait-by-trait morphological comparisons, we report here that the dental remains from multiple individuals indicate that H. floresiensis had primitive canine-premolar and advanced molar morphologies, a combination of dental traits unknown in any other hominin species. The primitive aspects are comparable to H. erectus from the Early Pleistocene, whereas some of the molar morphologies are more progressive even compared to those of modern humans. This evidence contradicts the earlier claim of an entirely modern human-like dental morphology of H. floresiensis, while at the same time does not support the hypothesis that H. floresiensis originated from a much older H. habilis or Australopithecus-like small-brained hominin species currently unknown in the Asian fossil record. These results are however consistent with the alternative hypothesis that H. floresiensis derived from an earlier Asian Homo erectus population and experienced substantial body and brain size dwarfism in an isolated insular setting. The dentition of H. floresiensis is not a simple, scaled-down version of earlier hominins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Evolution
  • Female
  • Fossils
  • Hominidae / anatomy & histology*
  • Male
  • Tooth / anatomy & histology*

Grants and funding

This work was supported by funding from the Japan Society for the Promotion of Science (https://www.jsps.go.jp/english/), No. 24247044, YK; National Museum of Nature and Science, YK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.