Dataset to: Páll-Gergely et al. (2024): "Many roads to success: Alternative routes to building an economic shell in land snails"

3D models based on microCT scans of snail shells. This is the dataset to the publication "Many roads to success: Alternative routes to building an economic shell in land snails" (2024) by Páll-Gergely et al.:

Land snails exhibit an extraordinary variety of shell shapes. The way shells are constructed underlie biological and mechanical constraints that vary across gastropod clades. Here, we quantify shell geometry of the two largest groups, Stylommatophora and Cyclophoroidea, to assess the potential causes for variation in shell shape and its relative frequency. Based on μCT scans, we estimate material efficiency through 2D- and 3D-generalisations of the isoperimetric ratio, quantifying the ratios between area and perimeter of whorl cross-sections (2D) and shell volume and surface (3D), respectively. We find that stylommatophorans optimise material usage through whorl overlap, which may have promoted the diversification of flat-shelled species. Cyclophoroids are bound to a circular cross-section because of their operculum; flat shells are comparatively rare. Both groups show similar solutions for tall shells, where local geometry has a smaller effect because of the double overlap between previous and current whorls. Our results suggest that material efficiency is a driving factor in the selection of shell geometry. Essentially, the evolutionary success of Stylommatophora likely roots in their higher flexibility to produce an economic shell.

All shells were imaged using X-ray microcomputed tomography (YXLON FF35 CT, FXE transmission beam, Y.Panel 4343 CT flat panel detector). The image stacks were then processed using ORS Dragonfly (v. 2021.3 for Windows, Object Research Systems Inc., Montreal, Canada). Thresholding was used to separate the shell from the background. Based on this a mesh was calculated and exported. The meshes were then smoothed and decimated in Blender v. 2.81 (The Blender Foundation, Amsterdam, the Netherlands) and exported as STL files.