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Shell shape and environmental data for five North American land snail species

Citation

Minton, Russell; Fagan, Nicholas; Meyer, Ashley (2021), Shell shape and environmental data for five North American land snail species, Dryad, Dataset, https://doi.org/10.5061/dryad.ffbg79ct5

Abstract

The morphological distinctness of land snail shells is almost certainly related to the unique environments in which they live. Even with the development of genetic and epigenetic tools for understanding factors contributing to phenotype, much research is focused on understanding environmental effects on land snail shell form. Most studies focus on single taxa, with review articles summarizing shared patterns and correlations of shell response to the environment. Herein we provide a dataset of shell shapes and environmental data for five species of partially sympatric North American land snail. Data are sourced from museum specimens, invaluable resources for biological and biodiversity information. We imaged, landmarked, georeferenced, and extracted environmental parameters for 3,701 land snail specimens representing five North American land snail species: Anguispira alternataEuglandina rosea, Haplotrema concavum, Mesodon thyroidus, and Mesomphix globosus. These specimens represent most of the primary dry holdings for the five species at the Florida Museum of Natural History, Gainesville, Florida, USA. The landmark and environmental data are provided in formats (TPS and CSV respectively) compatible with modern methods of analyzing and interpreting geometric morphometric data.

Methods

We utilized shell material from the Florida Museum of Natural History, Gainesville, Florida, USA mollusk collection. Specimen identifications and locality data on museum labels were assumed to be correct. Each shell was digitally photographed in apertural view. A set of landmarks was digitized on each shell using tpsDig2 and a slider file was generated for each species using tpsUtil. The positions of type III landmarks (=semi-landmarks) can be allowed to "slide" in order to minimize either Procrustes distance or bending energy during generalized Procrustes alignment. A set of landmark "links" for each species was also produced in tpsUtil to aid in visualizing differences between individuals and taxa.

Locality information from the museum label accompanying each shell was captured and used to georeference the specimen using GEOLocate 3.22. We accepted the GEOLocate-generated latitude and longitude coordinates for each specimen without correction except in the case where a single locality string produced multiple possible matches. In those instances, we chose the locality we felt was most consistent with what was known about where the collector collected from and the uncertainty radius generated by GEOLocate. With the latitude and longitude coordinates generated by GEOLocate, we extracted 13 environmental values for each specimen using ArcGIS 10 and multiple, publicly available geographical information system (GIS) files.

Usage Notes

Images are provided for Haplotrema concavumMesodon thyroidus, and Mesomphix globosus.