Franck Guy

Publications (33) View all

• Article: Tchad : un nouveau site à Hominidés Pliocène

  Michel Brunet, Alain Beauvilain, Denis Geraads, Franck Guy, Mahamat Kasser, Hassane T. Mackaye, Laura M. MacLatchy, Guy Mouchelin, Jean sudre, Patrick Vignaud
  Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie 02/2013; 324:341-345.
• Source

  Available from: Dimitri Neaux

  Article: Covariation Between Midline Cranial Base, Lateral Basicranium, and Face in Modern Humans and Chimpanzees: A 3D Geometric Morphometric Analysis.

  Dimitri Neaux, Franck Guy, Emmanuel Gilissen, Walter Coudyzer, Stéphane Ducrocq
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  ABSTRACT: Previous studies showed that in modern humans the basicranium is formed of two modules: the midline cranial base and the lateral basicranium which are integrated with the face in very different ways. The study of the relationship between these structures is of prime interest in the context of hominids craniofacial evolutionary history. In this study, we aim to test if the relationship between the midline cranial base and the face on one hand and the lateral basicranium and the face on the other hand are qualitatively and quantitatively different in modern humans and chimpanzees: two phylogenetically close but morphologically different hominids. This work is performed using three-dimensional (3D) landmarks to take into account the face and basicranium 3D shape. Modern humans and chimpanzees both exhibit a significant relationship between lateral basicranium and face, and a nonsignificant relationship between midline cranial base and face. However, the patterns of integration are different for the two species. These results underscore the essential role of the lateral basicranial shape in the setting of the facial morphology in modern humans and chimpanzees. The important differences in the patterns of integration may be related to the genetic, developmental, and functional requirements of each taxon, acquired along their respective evolution. From a common, tight, relationship between lateral basicranium, and face, each taxon may develop different patterns of integration in order to adapt to particular functions and morphologies. Anat Rec, 2013. © 2013 Wiley Periodicals, Inc.
  The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 02/2013; · 1.47 Impact Factor
• Source

  Available from: Dimitri Neaux

  Article: Facial orientation and facial shape in extant great apes: a geometric morphometric analysis of covariation.

  Dimitri Neaux, Franck Guy, Emmanuel Gilissen, Walter Coudyzer, Patrick Vignaud, Stéphane Ducrocq
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  ABSTRACT: The organization of the bony face is complex, its morphology being influenced in part by the rest of the cranium. Characterizing the facial morphological variation and craniofacial covariation patterns in extant hominids is fundamental to the understanding of their evolutionary history. Numerous studies on hominid facial shape have proposed hypotheses concerning the relationship between the anterior facial shape, facial block orientation and basicranial flexion. In this study we test these hypotheses in a sample of adult specimens belonging to three extant hominid genera (Homo, Pan and Gorilla). Intraspecific variation and covariation patterns are analyzed using geometric morphometric methods and multivariate statistics, such as partial least squared on three-dimensional landmarks coordinates. Our results indicate significant intraspecific covariation between facial shape, facial block orientation and basicranial flexion. Hominids share similar characteristics in the relationship between anterior facial shape and facial block orientation. Modern humans exhibit a specific pattern in the covariation between anterior facial shape and basicranial flexion. This peculiar feature underscores the role of modern humans' highly-flexed basicranium in the overall integration of the cranium. Furthermore, our results are consistent with the hypothesis of a relationship between the reduction of the value of the cranial base angle and a downward rotation of the facial block in modern humans, and to a lesser extent in chimpanzees.
  PLoS ONE 01/2013; 8(2):e57026. · 4.09 Impact Factor
• Conference Proceeding: Covariation entre morphologie et orientation de la face chez les grands singes actuels : une analyse de morphométrie géométrique

  Dimitri Neaux, Franck Guy, Emmanuel Gilissen, Walter Coudyzer, Patrick Vignaud, Stéphane Ducrocq
  7ème Symposium de Morphométrie et Evolution des Formes, Lyon, France; 05/2012
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  Available from: Franck Guy

  Article: Analysis of dental root apical morphology: a new method for dietary reconstructions in primates.

  NoÉmie Hamon, Edouard-Georges Emonet, Yaowalak Chaimanee, Franck Guy, Paul Tafforeau, Jean-Jacques Jaeger
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  ABSTRACT: The reconstruction of paleo-diets is an important task in the study of fossil primates. Previously, paleo-diet reconstructions were performed using different methods based on extant primate models. In particular, dental microwear or isotopic analyses provided accurate reconstructions for some fossil primates. However, there is sometimes difficult or impossible to apply these methods to fossil material. Therefore, the development of new, independent methods of diet reconstructions is crucial to improve our knowledge of primates paleobiology and paleoecology. This study aims to investigate the correlation between tooth root apical morphology and diet in primates, and its potential for paleo-diet reconstructions. Dental roots are composed of two portions: the eruptive portion with a smooth and regular surface, and the apical penetrative portion which displays an irregular and corrugated surface. Here, the angle formed by these two portions (aPE), and the ratio of penetrative portion over total root length (PPI), are calculated for each mandibular tooth root. A strong correlation between these two variables and the proportion of some food types (fruits, leaves, seeds, animal matter, and vertebrates) in diet is found, allowing the use of tooth root apical morphology as a tool for dietary reconstructions in primates. The method was then applied to the fossil hominoid Khoratpithecus piriyai, from the Late Miocene of Thailand. The paleo-diet deduced from aPE and PPI is dominated by fruits (>50%), associated with animal matter (1-25%). Leaves, vertebrates and most probably seeds were excluded from the diet of Khoratpithecus, which is consistent with previous studies.
  The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 05/2012; 295(6):1017-26. · 1.47 Impact Factor