title: Palate anatomy and morphofunctional aspects of interpterygoid vacuities in temnospondyl cranial evolution.
abstract: Temnospondyls were the morphologically and taxonomically most diverse group of early tetrapods with a near-global distribution during the Palaeozoic and Mesozoic. Members of this group occupied a range of different habitats (aquatic, amphibious, terrestrial), reflected by large morphological disparity of the cranium throughout their evolutionary history. A diagnostic feature of temnospondyls is the presence of an open palate with large interpterygoid vacuities, in contrast to the closed palate of most other early tetrapods and their fish-like relatives. Although the function of the interpterygoid vacuities has been discussed in the past, no quantitative studies have been performed to assess their biomechanical significance. Here, we applied finite element analysis, to test the possibility that the interpterygoid vacuities served for stress distribution during contraction of the jaw closing musculature. Different original and theoretical skull models, in which the vacuities differed in size or were completely absent, were compared for their mechanical performance. Our results demonstrate that palatal morphology played a considerable role in cranial biomechanics of temnospondyls. The presence of large cranial vacuities were found to offer the dual benefit of providing additional muscle attachment areas and allowing for more effective force transmission and thus an increase in bite force without compromising cranial stability.
authors.affiliation: School of Earth Sciences, University of Bristol, Bristol, BS8 1TQ, UK. glzsl@bristol.ac.uk.
authors.forename: Stephan
authors.identifier: http://orcid.org/0000-0003-3472-814X
authors.initials: S
authors.lastname: Lautenschlager
authors.affiliation: Department of Ecology and Evolutionary Biology, Brown University, G-B204, Providence, RI, 02912, USA. florian.witzmann@mfn-berlin.de.|Museum für Naturkunde, Leibniz-Institut für Evolutions- and Biodiversitätsforschung, Invalidenstraße 43, 10115, Berlin, Germany. florian.witzmann@mfn-berlin.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Witzmann
authors.affiliation: Museum für Naturkunde, Leibniz-Institut für Evolutions- and Biodiversitätsforschung, Invalidenstraße 43, 10115, Berlin, Germany.|Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at Eberhard Karls Universität, Sigwartstraße 10, 72076, Tübingen, Germany.|Fachbereich Geowissenschaften der Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Werneburg
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001696:Biomechanical Phenomena; D005247:Feeding Behavior / Q000502:physiology; D020342:Finite Element Analysis; D005580:Fossils; D010159:Palate / Q000033:anatomy & histology* / Q000502:physiology*; D012886:Skull / Q000033:anatomy & histology; D014714:Vertebrates / Q000033:anatomy & histology* / Q000502:physiology*
keywords: Biomechanics; Finite element analysis; Interpterygoid vacuities; Parotosuchus helgolandicus; Temnospondyli