DOI: 10.5061/dryad.qjq2bvqcg
title: Data from: Biomechanical properties of the jaws of two species of Clevosaurus and a reanalysis of rhynchocephalian dentary morphospace

description: Rhynchocephalians were a successful, globally distributed group of diapsid
 reptiles that thrived in the Mesozoic. Multiple species of Clevosaurus
 existed worldwide in the Upper Triassic and Lower Jurassic, and they are
 characterised by shearing bladelike teeth perhaps functionally analogous
 to the carnassial teeth of mammals. Morphometric analysis shows that the
 dentary morphospace of clevosaurs differs significantly from that of other
 rhynchocephalians. Five Clevosaurus species occupied islands in the
 Bristol Channel archipelago of the UK, but generally not those occupied by
 mammaliaforms, suggesting dietary character displacement. Identifying the
 diet of such ancient, small tetrapods has been difficult. To identify the
 nature of their feeding, we apply finite element analysis to two near
 complete three-dimensional skulls of the species Clevosaurus hudsoni and
 Clevosaurus cambrica to estimate bite force, resistance to bending and
 torsion, and the distribution of stresses during biting. Both species had
 bite forces and tooth pressures sufficient to break apart chitin,
 indicating that like early Mesozoic mammaliaforms, clevosaurs could feed
 on tough-shelled beetles and possibly small vertebrates. In addition, the
 mechanical advantage of the jaws falls within the range of early
 mammaliaforms, so though we cannot demonstrate niche partitioning between
 members of both clades, it raises the prospect that they may have been
 functionally similar.
description: <strong>Supplementary information:</strong>
 README: A PDF summarising and explaining all supplementary
 information and material included in this dataset, as well as including
 supplementary tables and figures. CT-scan
 parameters Homologous points on the mandibular ramus
 of <i>Clevosaurus </i>used for figure 6
 Morphometrics data Description of the
 adductor musculature of <i>Clevosaurus</i> 
 Finite element analyses output (.rpt)
 Surface files for left mandibular ramus of
 <i>Clevosaurus</i> (.stl) Supplementary
 tables Tables S1–S5 
 Figures S1–S5
 <strong>Section C</strong> -
 <strong>Morphometrics data</strong>. An
 excel file containing the list of landmarks used, specimen numbers,
 Procrustes distances results and groupings (e.g. cladistic, period,
 continent). <strong>Section E -
 </strong><b>Finite element analyses output (.rpt)
 </b> Output data for
 <i>Clevosaurus hudsoni </i>(E1-E2) and <i>Clevosaurus
 cambrica </i>(E3-E6). 
 <em>Clevosaurus hudsoni</em>: E1 with a bite position at the
 posterior-most tooth, E2 with a bite position at the anterior-most
 tooth. <em>Clevosaurus cambrica </em>(no
 surface-area to force scaling): E3 with a bite position at the
 posterior-most tooth, E4 with a bite position at the anterior-most
 tooth. <em>Clevosaurus cambrica
 </em>(with surface-area to force scaling): E5 with a bite position
 at the posterior-most tooth, E6 with a bite position at the anterior-most
 tooth. <strong>Section F - Surface
 files for jaws of <i>Clevosaurus</i></strong>
 (.stl): Raw surface files for
 the lower left mandibular ramus of <i>Clevosaurus hudsoni</i>
 (F1) and <i>Clevosaurus cambrica </i>(F2) after reassembly.
 Note that since these jaws are surface files only, they do not retain
 separate label fields for the post-dentary bones and have not yet
 undergone the repairs that were required before pre-processing in FE was
 initiated.
 <strong>Section G - Supplementary
 tables</strong>. Excel spreadsheet summarising
 the following tables (tables S1-S5).