Dataset DOI: 10.5061/dryad.4qrfj6qpp

Description of the data and file structure

Files and variables

File: ABAQUS_Input_Files.zip

Description: Abaqus input (.inp) files for the following taxa, under the four loading conditions: caniniform bilateral biting, molariform bilateral biting, unilateral biting, and pull-back loads.

1. Alligator mississippiensis
2. Baurusuchus salgadoensis
3. Caipirasuchus paulistanus
4. Crocodylus niloticus
5. Montealtosuchus arrudacamposi
6. Paleosuchus palpebrosus

All files include the mesh geometries, loads (muscle forces), boundary conditions necessary to run the FEA.

File: ABAQUS_RPTs.zip

Description: Field outputs generated from ABAQUs for all six taxa and under caniniform unilateral and bilateral biting, molariform biting, and pull back loads. All .rpt files were converted to .txt files and formatted for use within R for median value calculations. The files contain values for von Mises stress (SMises), maximum principal stress (SMax), minimum principal stress (SMin), maximum principal strain (EMax), and minimum principal strain (EMin). Stress values in MPa, while strain is dimensionless. 

File: Median.R

Description: An R file containing the code for removing the top 5% of the stress/strain values and then calculating the bottom 95% of the median stress and strain values from the .txt files in the ABAQUS RPTs folder. 

File: Baurusuchus_salgadoensis_(MPMA-62-0001_02).zip

Description: Specimen: Baurusuchus salgadoensis (MPMA-62-0001/02). Scanned using Siemens Somatom Spirit scanner, at Unidade de Radiológica Dr. Fabrício Mallouk, Monte Alto SP, Brazil. The original DICOM dataset and relabeled TIFFs are included as separate folders, with a voxel size of 0.625 x 0.625 x 0.8 mm.

File: Caipirasuchus_paulistanus_(MPMA-67-0001_00).zip

Description: Specimen: Caipirasuchus paulistanus (MPMA-67-0001/00). Scanned using Siemens Somatom Spirit scanner at Hospital das Clínicas da Universidade Federal do Triangulo Mineiro, Brazil. The original DICOM dataset and re-oriented TIFFs are included as separate folders, with a voxel size of 0.429 x 0.429 x 0.3 mm. 

File: Paleosuchus_palpebrosus_(OUNHM_1451).zip

Description: Specimen: Paleosuchus palpebrosus (OUNHM 1451), common name - Cuvier's dwarf caiman. Scanned using Nikon XTH225ST at the University of Bristol. The original uncompressed microCT TIFF stack is included with the scan parameters, with a voxel size of 0.099 x 0.099 x 0.099 mm. 

File: Montealtosuchus_arrudacamposi_(MPMA-16-0007_04).zip

Description: Specimen: Montealtosuchus arrudacamposi (MPMA-16-0007/04). Scanned using Discovery CT750 HD scanner at Instituto de Radiologia – Faculdade de Medicina de São Paulo, USP, Brazil. The complete DICOM dataset is included as separate folders, with a voxel size of 0.63 x 0.63 x 0.63 mm. 

File: Crocodylus_niloticus_(OUNHM_23306).zip

Description: Specimen: Crocodylus niloticus (OUNHM 23306), common name - Nile crocodile. Scanned using Nikon XTH225ST at the University of Bristol. The original uncompressed microCT TIFF stack is included with the scan info and parameters, with a voxel size of 0.12 x 0.12 x 0.25. 

File: Croc_muscle_forces.xlsx

Description: This file contains two spreadsheets including muscle force calculations for Baurusuchus and subsequent calculations and scaling for all other taxa. Models were not scaled to the same size, and forces were scaled to surface area instead.

1. Bauru muscle calculations: This sheet contains the measurements for the left half of the cranial adductor muscles of Baurusuchus, obtained from digital muscle reconstructions. The columns in this sheet represent:
   • Muscle Name – Abbreviation for individual muscles (e.g., mAMEM, mAMES).
   • Volume (mm³) – Measured muscle volumes.
   • Muscle Length (mm) – Estimated total muscle length.
   • Fibre Length (mm) – Estimated muscle fiber length, using the assumption that fiber lengths are 1/3^rd of the muscle length.
   • PCSA (ML = FL) – Estimated physiological cross sectional area (in mm²), obtained by dividing muscle volume by muscle lengths
   • PCSA (ML = FL/3) – Estimated physiological cross sectional area (in mm²), obtained by dividing muscle volume by fiber lengths, fiber lengths are 1/3^rd of the muscle length.
   • Muscle Stress – Assumed muscle stress value.
   • Muscle Force (ML = FL) – Calculated muscle forces derived from multiplying PCSA (ML = FL) and muscle stress.
   • Muscle Force (ML = FL/3) – Calculated muscle forces derived from multiplying PCSA (ML = FL/3) and muscle stress.
2. Muscle Forces: This sheet aggregates and scales muscle force data obtained from Baurusuchus for comparative modeling for all six taxa in the study. The columns in this sheet include:
   • Taxon – Species (e.g., Baurusuchus salgodoensis, Alligator mississippiensis).
   • TSA (mm²) – Total skull surface area
   • Muscle name – Abbreviation for individual muscles (e.g., mAMEM, mAMES).
   • Ratio of Surface Areas – Surface area proportions for each taxon relative to Baurusuchus
   • PCSA (mm²) left side – Calculated PCSA (per side and total skull).
   • % occupied – Proportion of total skull area occupied by the muscle.
   • Muscle Stress – Assumed muscle stress value.
   • Force (N) – Calculated muscle force (per side and total skull).
   • No. of nodes – Number of nodes selected for each muscle group in ABAQUS.
   • Force per node – Calculated forces divided per node for each muscle group by taxa.

File: 3D_FE_Results_USDZ_(iOS_Mac).zip

Description: 3D FEA results for von Mises stress (SMises), maximum principal stress (SMax), minimum principal stress (SMin), and minimum principal strain (EMin), for all four loading conditions. Exported from ABAQUS as .wrl files, and converted to .usdz files which can be viewed without any special software using Quicklook or Preview in 3D/AR on iOS and Mac devices. 

File: 3D_FE_Results_GLTF_(Windows_Android).zip

Description: 3D FEA results for von Mises stress (SMises), maximum principal stress (SMax), minimum principal stress (SMin), and minimum principal strain (EMin) for all four loading conditions. Exported from ABAQUS as .wrl files, and converted to .gtlf files. Can be viewed without any special software using Windows 3D Viewer on Windows or on Android devices, including browsers. iOS/Mac users can use Khronos glTF Viewer.

File: 3D_FE_WRLs_larger_models.zip

Description: 3D FEA results for von Mises stress (SMises), maximum principal stress (SMax), minimum principal stress (SMin), and minimum principal strain (EMin), for all four loading conditions. These files are larger than 100 MB, for Baurusuchus and Crocodylus and were unable to be converted to USDZ/GLTF. Can be viewed using Meshlab, Blender or similar CAD programs. Exported directly from ABAQUS.