DOI: 10.5061/dryad.b3s4v0g
title: Data from: Convergence and functional evolution of longirostry in crocodylomorphs

description: During the Mesozoic, Crocodylomorpha had a much higher taxonomic and
 morphological diversity than today. Members of one particularly successful
 clade, Thalattosuchia, are well-known for being longirostrine: having
 long, slender snouts. It has generally been assumed that Thalattosuchia
 owed their success in part to the evolution of longirostry, leading to a
 feeding ecology similar to that of the living Indian gharial, Gavialis.
 Here, we compare form and function of the skulls of the thalattosuchian
 Pelagosaurus and Gavialis using digital reconstructions of the skull
 musculoskeletal anatomy and finite element models to show that they had
 different jaw muscle arrangements and biomechanical behaviour.
 Additionally, the relevance of feeding-related mandibular traits linked to
 longirostry in the radiation of crocodylomorph clades was investigated by
 conducting an evolutionary rates analysis under the variable rates model.
 We find that, even though Pelagosaurus and Gavialis share similar patterns
 of stress distribution in their skulls, the former had lower mechanical
 resistance. This suggests that compared to Gavialis, Pelagosaurus was
 unable to process large, mechanically less tractable prey, instead
 operating as a specialised piscivore that fed on softer and smaller prey.
 Secondly, innovation of feeding strategies was achieved by rate
 acceleration of functional characters of the mandible, a key mechanism for
 the diversification of certain clades like thalattosuchians and
 eusuchians. Different rates of functional evolution suggest divergent
 diversification dynamics between teleosaurids and metriorhynchids in the
 Jurassic.
description: Pelagosaurus cranium
 modelSurface model of the
 cranium of Pelagosaurus.pelagosaurus-cranium.stlPelagosaurus mandible modelSurface model of the mandible of Pelagosauruspelagosaurus-mand.stlGavialis cranium modelSurface model of the cranium of Gavialis. (Note: not original size as the model was originally scaled to skull length)gavialis_cranium.stlGavialis mandible modelSurface model of the mandible of Gavialis. (Note: not original size as the model was originally scaled to skull length)gavialis_mand.stlGavialis cranium bilateral anteriorAbaqus input file of Gavialis cranium simulating a bilateral anterior bite.gav_cr_bi_ant.inpGavialis cranium bilateral middleAbaqus input file of Gavialis cranium simulating a bilateral middle bite.gav_cr_bi_mid.inpGavialis cranium bilateral posteriorAbaqus input file of Gavialis cranium simulating a bilateral posterior bite.gav_cr_bi_pos.inpGavialis cranium unilateral anteriorAbaqus input file of Gavialis cranium simulating an unilateral anterior bite.gav_cr_uni_ant.inpGavialis cranium unilateral posteriorAbaqus input file of Gavialis cranium simulating an unilateral posterior bite.gav_cr_uni_pos.inpGavialis mandible bilateral anteriorAbaqus input file of Gavialis mandible simulating a bilateral anterior bite.gav_mand_bi_ant.inpGavialis mandible bilateral middleAbaqus input file of Gavialis mandible simulating a bilateral middle bite.gav_mand_bi_mid.inpGavialis mandible bilateral posteriorAbaqus input file of Gavialis mandible simulating a bilateral posterior bite.gav_mand_bi_pos.inpGavialis mandible unilateral anteriorAbaqus input file of Gavialis mandible simulating an unilateral anterior bite.gav_mand_uni_ant.inpGavialis mandible unilateral posteriorAbaqus input file of Gavialis mandible simulating an unilateral posterior bite.gav_mand_uni_pos.inpPelagosaurus cranium bilateral anteriorAbaqus input file of Pelagosaurus cranium simulating a bilateral anterior bite.pel_cr_bi_ant.inpPelagosaurus cranium bilateral middleAbaqus input file of Pelagosaurus cranium simulating a bilateral middle bite.pel_cr_bi_mid.inpPelagosaurus cranium bilateral posteriorAbaqus input file of Pelagosaurus cranium simulating a bilateral posterior bite.pel_cr_bi_pos.inpPelagosaurus cranium unilateral anteriorAbaqus input file of Pelagosaurus cranium simulating an unilateral anterior bite.pel_cr_uni_ant.inpPelagosaurus cranium unilateral posteriorAbaqus input file of Pelagosaurus cranium simulating an unilateral posterior bite.pel_cr_uni_pos.inpPelagosaurus mandible bilateral anteriorAbaqus input file of Pelagosaurus mandible simulating a bilateral anterior bite.pel_mand_bi_ant.inpPelagosaurus mandible bilateral middleAbaqus input file of Pelagosaurus mandible simulating a bilateral middle bite.pel_mand_bi_mid.inpPelagosaurus mandible bilateral posteriorAbaqus input file of Pelagosaurus mandible simulating a bilateral posterior bite.pel_mand_bi_pos.inpPelagosaurus mandible unilateral anteriorAbaqus input file of Pelagosaurus mandible simulating an unilateral anterior bite.pel_mand_uni_ant.inpPelagosaurus mandible unilateral posteriorAbaqus input file of Pelagosaurus mandible simulating an unilateral posterior bite.pel_mand_uni_pos.inpLower jaws imagesImages of crocodylomorph mandibles that were used to measure the mandibular functional characters. For sources, see Supplementary Information file.Crocodylomorpha lower jaws.zipSupporting InformationIncludes median Von Mises stress values, details of FE models, list of taxa studied in the rates analyses, additional rates trees and randomisation tests resultsPelagosaurus CT dataSpecimen: Pelagosaurus typus BRLSI M1413. Scanned in a Nikon XT H 225ST lCT scanner. Scan parameters: 210 kV, 130 lA, 27.3 W, 0.5 mm copper filter, 1 s exposure time, no binning, ultrafocus reflection target, 3141 projections, 2 frames per projection. Scanned in two parts. Scan data were joined in VGStudio Max v2. The CT data consists of 3419 slices of 0.0956 mm pixel size and 0.0956 mm thickness.BRLSI_M1413.zip