Neurocranium versus Face: A Morphometric Approach with Classical Anthropometric Variables for Characterizing Patterns of Cranial Integration in Extant Hominoids and Extinct Hominins.

Juan Antonio Pérez-Claros,Juan Manuel Jiménez-Arenas,Paul Palmqvist,Lorenzo Rook

doi:10.1371/journal.pone.0131055

Juan Antonio Pérez-Claros, Juan Manuel Jiménez-Arenas + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0131055

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Journal: PloS one	Publication Date: Jul 15, 2015
Citations: 12	License type: CC BY 4.0

Affiliation: Universidad de Málaga, University of Granada

Abstract

The relative importance of the two main cranial complexes, the neurocranium and the splanchnocranium, has been examined in the five species of extant hominoids and in a huge sample of extinct hominins using six standard craniometric variables that measure the length, width and height of each cranial module. Factor analysis and two-block partial least squares were used for establishing the major patterns of developmental and evolutionary integration between both cranial modules. The results obtained show that all extant hominoids (including the anatomically modern humans) share a conserved pattern of developmental integration, a result that agrees with previous studies. The pattern of evolutionary integration between both cranial modules in australopiths runs in parallel to developmental integration. In contrast, the pattern of evolutionary and developmental integration of the species of the genus Homo is the opposite, which is probably the consequence of distinctive selective regimes for both hominin groups.

Highlights

We are interested in the following two questions: (1) does the modular nature of the cranium reflect the patterns of covariation among the length, width and height of each cranial module? And (2) if this were the case, are there different allometric rules for the relative size of the two main cranial modules? Our results indicate that the relative size of each module is characteristic of each species, there is a common pattern of ontogenetic integration shared by all hominoids that can be detected, to a certain extent, using different methods
Factor loadings of the variables measured in the neurocranium are positive in the first factor and those for the splachnocranium are negative (Table 3)
This factor reflects the basic pattern of morphological integration between the neurocranium and the face in hominoids

Summary

Introduction

Our results indicate that the relative size of each module is characteristic of each species, there is a common pattern of ontogenetic integration shared by all hominoids that can be detected, to a certain extent, using different methods. In order to evaluate the similarities and differences in allometric patterns, the following groups were established: (1) great apes (Pongo, Gorilla and Pan); (2) australopiths (Sahelanthropus, Australopithecus and Paranthropus); (3) extinct Homo (all specimens of Homo except H. sapiens); (4) AMH (anatomically modern humans); (5) early Homo (African and Caucasian Homo dated to the Early Pleistocene); and (6) MPEH (Middle Pleistocene Homo).

Results

Conclusion