Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12136/227
Item metadata
Title: Cranial shape variation in adult howler monkeys (Alouatta seniculus)
Authors: Fiorenza, Luca
Bruner, Emiliano
Keywords: Airorhynchy;Allometry;Atelidae;Geometric morphometrics;Pterion sutural pattern
Issue Date: Jan-2018
Publisher: Wiley
Citation: American Journal of Primatology, 2018, 80 (1): e22729
Abstract: Howler monkeys (genus Alouatta) display a distinctive cranial architecture characterized by airorhynchy (or retroflexion of the facial skeleton on the cranial base), a small braincase, and a posteriorly oriented foramen magnum. This configuration has been associated with distinct factors including a high folivory diet, locomotion, and the presence of a specialized vocal tract characterized by large hyoid bone. However, the morphological relationships between the facial and neurocranial blocks in Alouatta have been scarcely investigated. In this study we quantitatively analyzed the cranial shape variation in Alouatta seniculus, to evaluate possible influences and constraints in face and braincase associated with airorhynchy. We also considered the structural role of the pteric area within the cranial functional matrix. We applied landmark‐based analysis and multivariate statistics to 31 adult crania, computing shape analyses based on 3D coordinates registration as well as the analysis of the Euclidean distance matrix to investigate patterns of intraspecific morphological variability. Our results suggest that allometry is the main source of variation involved in shaping cranial morphology in howlers, influencing the degree of facial proportions and braincase flattening, and generating the main sexual differences. Larger individuals are characterized by a higher degree of airorhynchy, neurocranial flattening, and expansion of the zygomatic arch. Allometric variations influence the skull as a whole, without distinct patterns for face and braincase, which behave as an integrated morphological unit. A preliminary survey on the pteric pattern suggests that the morphology of this area may be the result of variations in the vertical growth rates between face and braincase. Future studies should be dedicated to the ontogenetic series and focus on airorhynchy in terms of differential growth among distinct cranial districts.
URI: http://hdl.handle.net/20.500.12136/227
ISSN: 1098-2345
0275-2565
DOI: 10.1002/ajp.22729
metadata.dc.relation.publisherversion: https://doi.org/10.1002/ajp.22729
Type: Article
Appears in Collections:Paleobiología



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.