Why ruminating ungulates chew sloppily : biomechanics discern a phylogenetic pattern
Zhou, Zupeng (Guilin University of Electronic Technology. School of Mechanical and Electrical Engineering)
Winkler, Daniela E. (Johannes Gutenberg University Mainz. Institute of Geosciences)
Fortuny, Josep (Institut Català de Paleontologia Miquel Crusafont)
Kaiser, Thomas (University of Hamburg)
Marcé Nogué, Jordi (Institut Català de Paleontologia Miquel Crusafont)
Universitat Autònoma de Barcelona

Date:	2019
Abstract:	There is considerable debate regarding whether mandibular morphology in ungulates primarily reflects phylogenetic affinities or adaptation to specific diet. In an effort to help resolve this debate, we use three-dimensional finite element analysis (FEA) to assess the biomechanical performance of mandibles in eleven ungulate taxa with well-established but distinct dietary preferences. We found notable differences in the magnitude and the distribution of von Mises stress between Artiodactyla and Perissodactyla, with the latter displaying lower overall stress values. Additionally, within the order Artiodactyla the suborders Ruminantia and Tylopoda showed further distinctive stress patterns. Our data suggest that a strong phylogenetic signal can be detected in biomechanical performance of the ungulate mandible. In general, Perissodactyla have stiffer mandibles than Artiodactyla. This difference is more evident between Perissodactyla and ruminant species. Perissodactyla likely rely more heavily on thoroughly chewing their food upon initial ingestion, which demands higher bite forces and greater stress resistance, while ruminants shift comminution to a later state (rumination) where less mechanical effort is required by the jaw to obtain sufficient disintegration. We therefore suggest that ruminants can afford to chew sloppily regardless of ingesta, while hindgut fermenters cannot. Additionally, our data support a secondary degree of adaptation towards specific diet. We find that mandibular morphologies reflect the masticatory demands of specific ingesta within the orders Artiodactyla and Perissodactyla. Of particular note, stress patterns in the white rhinoceros (C. simum) look more like those of a general grazer than like other rhinoceros' taxa. Similarly, the camelids (Tylopoda) appear to occupy an intermediate position in the stress patterns, which reflects the more ancestral ruminating system of the Tylopoda.
Grants:	Agencia Estatal de Investigación CGL2017-82654-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-86 European Commission 681450
Note:	Altres ajuts: "Beatriu de Pinos" 2014 - BP-A 00048
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	PloS one, Vol. 14, Núm. 4 (April 2019) , art. e0214510, ISSN 1932-6203

DOI: 10.1371/journal.pone.0214510
PMID: 30995252

21 p, 2.9 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut Català de Paleontologia Miquel Crusafont (ICP)
Articles > Research articles
Articles > Published articles