DOI: 10.5061/dryad.pnvx0k6v0
title: Evolution of large eyes in stromboidea (Gastropoda): Impact of photic environment and life history traits

description: Eyes within the marine gastropod superfamily Stromboidea range widely in
 size, from 0.2 to 2.3 mm - the largest eyes known in any gastropod.
 Despite this interesting variation, the underlying evolutionary pressures
 remain unknown. Here, we use the wealth of material available in museum
 collections to explore the evolution of stromboid eye size and structure.
 Our results suggest that depth is a key light-limiting factor in stromboid
 eye evolution; here, increasing water depth is correlated with increasing
 aperture width relative to lens diameter, and therefore an increasing
 investment in sensitivity in dim light environments. In the major clade
 containing all large-eyed stromboid families, species observed active
 during the day and the night had wider eye apertures relative to lens
 sizes than species observed active during the day only, thereby
 prioritising sensitivity over resolution. Species with no consistent diel
 activity pattern also had smaller body sizes than exclusively day-active
 species, which may suggest that smaller animals are more vulnerable to
 shell-crushing predators, and avoid the higher predation pressure
 experienced by animals active during the day. Within the same major clade,
 ancestral state reconstruction suggests that absolute eye size increased
 above 1 mm twice. The unresolved position of Varicospira, however, weakens
 this hypothesis and further work with additional markers is needed to
 confirm this result.
description: # Evolution of Large Eyes in Stromboidea (Gastropoda): Impact of Photic
 Environment and Life History Traits --- ## Description of the data and
 file structure Data files (uploaded to Dryad, can be viewed with a
 standard text editor): * Alignment 1: Concatenated four-gene nexus
 alignment of stromboid sequences obtained via Sanger sequencing (COI, 12S,
 16S and 28S). * Alignment 1: Concatenated four-gene fasta alignment of
 stromboid sequences obtained via Sanger sequencing (COI, 12S, 16S and
 28S). * Alignment 2: Concatenated alignment of stromboid mitogenome and
 nuclear data in nexus format. See partitions file. * Alignment 2:
 Concatenated alignment of stromboid mitogenome and nuclear data in fasta
 format. See partitions file. * Partitions for Alignment 2 * COI alignment
 of stromboid sequences in nexus format.  * 12S alignment of stromboid
 sequences in nexus format.  * 16S alignment of stromboid sequences in
 nexus format.  * 28S alignment of stromboid sequences in nexus format. 
 Supplementary files (uploaded to Zenodo): * Figure S1: Diagram of
 measurements taken for morphological trait data * Figure S2: Phylogenetic
 analyses of mitochondrial + nuclear, mitochondrial-only and nuclear-only
 data. Results are summarised in Figure 2. * Figure S3: LIPA analysis *
 Figure S4: CT scan videos: examples of a large- and a small-eyed stromboid
 * Table S1: Depth range of each stromboid family, and locomotion behaviour
 as described in the literature * Table S2: Specimen collection data *
 Table S3: Model selection and sequence analysis * Table S4: Morphological
 trait data used in analyses * Table S5: Left and right eye measurements *
 Table S6: Diel activity justifications * Table S7: Predators of
 stromboids, as described in the literature