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2022
- handle: 10670/1.29lnrw
- hal: hal-03864564
- doi: 10.1016/j.jhevol.2021.103124
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info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jhevol.2021.103124
info:eu-repo/semantics/OpenAccess
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Biological structure Form in biology Comparative morphology Structure in biology Biological formCiter ce document
Clément Zanolli et al., « Further analyses of the structural organization of Homo luzonensis teeth: Evolutionary implications », HAL-SHS : archéologie, ID : 10.1016/j.jhevol.2021.103124
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The species Homo luzonensis has recently been described based on a set of dental and postcranial elements found at Callao Cave (Northern Luzon, Philippines) and dated to at least 50-67 ka. Seven post-canine maxillary teeth are attributed to this taxon, five of them belonging to the same individual (CCH6) and representing the holotype of H. luzonensis, while the isolated upper 2 premolar CCH8 and the upper third molar CCH9 are paratypes of the species. The teeth are characterized by their small dimensions associated with primitive features, as also found in Homo floresiensis, another hominin having evolved in an insular environment of Southeast Asia. Postcranial bones of the hands and feet of H. luzonensis and H. floresiensis show Homo habilislike or australopith-like features, while cranial and dental morphology are more consistent with the Asian Homo erectus morphology. Due to this mosaic morphology, the origin and phylogenetic relationships of both H. luzonensis and H. floresiensis are still debated. To test the hypotheses that H. luzonensis derives from H. erectus or from an earlier small-brained hominin, we analyzed the microCT scans of the teeth. We investigated both external and internal tooth structure using morphometric methods including: crown outline shape, tooth crown tissue proportions, enamel-dentine junction shape and pulp morphology. Homo luzonensis external crown morphology aligns more with H. erectus than with H. habilis/Homo rudolfensis. The internal structural organization of H. luzonensis exhibits more affinities with that of H. erectus and H. floresiensis than with Neanderthals and modern humans. Our results suggest that both H. floresiensis and H. luzonensis likely evolved from some H. erectus groups that dispersed in the various islands of this region and became isolated until endemic speciation events occurred at least twice during the Pleistocene in insular environments.