This folder contains the supplementary information for the paper "A revision of Praearcturus gigas: a giant scorpion from the Lower Devonian (Lochkovian) of Britain." Microtomography data and models When unzipped, the folder Microtomography contains the following: Praearcturus_4light_packed.zip - this is a zip of the Blender file used to create images and animations for publication. It can be unzipped and then opened in the open source software Blender (). PraearcturusI534\_(RG_10-07-2009_10.42.51).zip - this is a zip of the SPIERS dataset used to create the meshes rendered in Blender. When unzipped it contains the following: A folder called Info, which has all the scanning metadata within A folder called BMP which includes the BMP stack of slices, and all the files required by SPIERS to output a model within SPIERSview. An animation video Howard_et_al_2026_Praearcturus.mp4 which shows a rendering of the digital visualisation created for this paper. PBDB data and Plots When unzipped, in the folder PBDB there is an R script called Howard_et_al_arachnids_plot.R. In any system with bash, you can run this script using the command: Rscript Howard_et_al_arachnids_plot.R It will then load PBDB data from the file included in that folder (pbdb_data_arachnids_palaeozoic_21_may_2025.csv), do the required processing, and output into that folder the three graphs presented in the paper within two PDFs. For publication these were combined by hand using Inkscape. It can also be run from within R - if so you might be required to set the working directory where indicated in the script. The script is fully commented.