Frogs and toads (Amphibia: Anura) display diverse ecologies and behaviours, which are often correlated with visual capacity in other vertebrates. Additionally, anurans exhibit a broad range of relative eye sizes, which have not previously been linked to ecological factors in this group. We measured relative investment in eye size and corneal size for 220 species of anurans representing all 55 currently recognized families and tested whether they were correlated with six natural history traits hypothesized to be associated with the evolution of eye size. Anuran eye size was significantly correlated with habitat, with notable decreases in eye investment among fossorial, subfossorial and aquatic species. Relative eye size was also associated with mating habitat and activity pattern. Compared to other vertebrates, anurans have relatively large eyes for their body size, indicating that vision is probably of high importance. Our study reveals the role that ecology and behaviour may have played in the evolution of anuran visual systems and highlights the usefulness of museum specimens, and importance of broad taxonomic sampling, for interpreting macroecological patterns.

Here we include three anuran datasets and one vertebrate dataset in support of the above work investigating eye-body allometry and relative eye size across anurans: 1) a set of morphological data gathered from preserved anuran museum specimens, 2) a set of morphological data collected from fresh anuran specimens, 3) a set of ecological traits and source references for the anuran species in our study, and 4) a set of morphological data compiled from published work on vertebrate eye size. The latter two datasets were supported by published materials, and references for each are posted in an associated pdf file. 

Details on the collection of these data can be found in the associated manuscript (DOI: 10.1098/rspb.2020.1393), and all code for analyzing these datasets and producing figures from the manuscript is available on GitHub: https://github.com/knthomas/anuran-eye-size. Explanations of each data file follow.

Thomas_museum_specimens.csv

This file includes taxonomic and morphological data for 640 museum specimens of frogs and toads (anurans). Measurements were made by Kate Thomas and David Gower and taxonomic identifications were confirmed by Jeffrey Streicher. Below is a guide to columns; in all columns, “NA” indicates a blank cell/no data.

Order: Taxonomic order according to Frost (2020); this dataset is all anurans

Suborder: Taxonomic suborder according to Feng et al. (2017a)

Family: Taxonomic family according to Frost (2020)

Subfamily: Taxonomic subfamily according to Frost (2020)

Genus: Taxonomic genus according to Frost (2020)

Species: Taxonomic species according to Frost (2020)

genus_species: Binomial generated from the previous two columns (Genus_Species)

Feng_tiplabel: Phylogeny tip label name for matching species data exactly to the Feng et al. (2017b) phylogeny

mod_tiplabel: Phylogeny tip label names for matching species data to exact matches and to close relatives (see associated manuscript for details) in the Feng et al. (2017b) phylogeny

Museum: Collection housing each specimen measured here. NHM = the Natural History Museum (London, UK); NCSM = North Carolina Museum of Natural Sciences (Raleigh, NC, USA); BNHS = the Bombay Natural History Society (Mumbai, India).

SpecimenNumber = Catalog identification number for each specimen

Sex = Sex of specimen, if identified

Stage = Life stage of specimen; this dataset includes only adult anurans

SVL_mm = Snout-vent length of specimen in mm

Mass_g = Wet mass of specimen in g

ED_right_mm = Transverse right eye diameter of specimen in mm

ED_left_mm = Transverse left eye diameter of specimen in mm

CD_right_mm = Transverse right cornea diameter in mm

CD_left_mm = Transverse left cornea diameter in mm

Measured_by = Collector of morphological measurements (4 specimens of Nasikabatrachus sahyadrensis measured by David Gower, all other specimens measured by Kate Thomas)

Thomas_fresh_specimens.csv

This file includes taxonomic and morphological data for 67 fresh (unpreserved) specimens of frogs and toads (anurans). Live anurans were obtained through fieldwork in French Guiana (permit RAA: R03-2018-06-12-006) and via collection in the UK or the pet trade (NHM license NE: WML-OR04). Measurements were made by Jeffrey Streicher, David Gower, and Kate Thomas. Taxonomic identifications were made by Jeffrey Streicher and David Gower. All specimens were preserved after eye dissection and added to museum collections. Note that for these specimens, eye measurements were taken from only one eye (left or right, not tracked), as the other eye was destructively sampled for other research. Below is a guide to columns; in all columns, “NA” indicates a blank cell/no data.

Source: Source of live specimens and date of collection

Field_number: Field number assigned to each specimen prior to museum accession

Museum: Museum collection now housing each specimen (note that these specimens have not yet been given catalog numbers, but can still be traced by their field numbers). NHM = Natural History Museum (London, UK)

Order: Taxonomic order according to Frost (2020); this dataset is all anurans

Family: Taxonomic family according to Frost (2020)

Subfamily: Taxonomic subfamily according to Frost (2020)

Genus: Taxonomic genus according to Frost (2020)

Species: Taxonomic species according to Frost (2020)

Stage = Life stage of specimen; this dataset includes only adult anurans

SVL_mm = Snout-vent length of specimen in mm

Mass_g = Wet mass of specimen in g

ED_mm_insitu = Transverse eye diameter measured externally (prior to dissection) in mm

CD_mm_insitu = Transverse cornea diameter measured externally (prior to dissection) in mm

ED_mm_dissected = Transverse eye diameter measured after removal of whole eye from specimen (in mm)

CD_mm_dissected = Transverse corneal diameter measured after removal of whole eye from specimen (in mm)

AD_mm_dissected = Axial length of eye measured after removal of whole eye from specimen (in mm)

LD_mm_dissected = Maximum diameter of lens measured after dissection out of eye in mm (note that these data were not included in the associated study, but are included here in case useful to other researchers)

Thomas_species_traits.csv

This file includes ecological trait data for 220 anuran species and references that categorizations were based on. See associated manuscript for details of ecological categorizations. Full citations for references supporting this dataset are available in the "Species_traits_references.pdf" file; in-text citations are indicated for each trait in an associated reference column. All coauthors participated in the assignment of ecological traits. Below is a guide to columns; in all columns, “NA” indicates a blank cell/no information found. 

Order: Taxonomic order according to Frost (2020); this dataset is all anurans

Family: Taxonomic family according to Frost (2020)

Subfamily: Taxonomic subfamily according to Frost (2020)

Genus: Taxonomic genus according to Frost (2020)

Species: Taxonomic species according to Frost (2020)

Feng_tiplabel: tip label name for matching species data exactly to the Feng et al. (2017b) phylogeny

Common_name: One or more common names linked to each species (not comprehensive)

Adult_habitat: Habitat where adult activity primarily occurs (semiaquatic, aquatic, scansorial, ground-dwelling, subfossorial, or fossorial)

AH_source: Reference for adult habitat

Activity_period: Period when adult activity primarily occurs (diurnal, nocturnal, or both)

AP_source: Reference for activity period

Mating_habitat: Habitat where mating behaviors primarily occur (lotic water, lentic water, plants, or ground)

MH_source: Reference for mating habitat

Life_history: Presence or absence of a free-living larval stage (free-living larvae or no free-living larvae)

LH_source: Reference for life history

Larval_habitat: Habitat where larvae are primarily active (no larvae, lotic water, lentic water, on land, or obscured)

LHab_source: Reference for larval habitat

Sex_dichromatism: Whether males and females exhibit differences in colors or patterns (present or absent)

SD_source: Reference for sexual dichromatism

Thomas_vertebrates.csv

This file includes data on eye size and body size from 1285 species or specimens complied from 9 published studies (Howland et al. 2004; Werner and Seifan 2006; Lisney and Collin 2007; Hall 2008; Hall and Heesy 2011; Schmitz and Wainwright 2011; Liu et al. 2012; Schmitz et al. 2013; Veilleux and Kirk 2014). These data were then matched to phylogenies retrieved from VertLife.org (mammals: Upham et al. 2019; birds: Jetz et al. 2012; squamates: Tonini et al. 2016; sharks: Stein et al. 2018) and TimeTree.org (fishes: Kumar et al. 2017) (see our associated manuscript for details), and this dataset includes columns for name matching between morphological datasets and phylogenies. Full citations for both data and phylogenies are listed in "Vertebrates_references.pdf". Please see our associated manuscript for full details. Below is a guide to columns; in all columns, “NA” indicates a lack of data.

Dataset_name: Genus and species names as in original datasets extracted from published papers

Common_name: Common name from original datasets extracted from published papers (if included originally)

Group: Broad clade descriptions of vertebrates included in analyses (birds, fishes, mammals, reptiles, sharks/rays) along with more specific high-level taxonomic ranks

Subgroup: Common names for the taxonomic rank divisions we grouped by in analyses given the distribution of taxa we had available (ranks are not the same among clades)

Subclade: Taxonomic names for the taxonomic rank divisions we grouped by in analyses given the distribution of taxa we had available (ranks are not the same among clades)

Body_mass_kg: Body mass in kg. If original dataset was in a different unit of mass, it has been converted to kg here.

Axial_diameter_mm: Axial length of the eye in mm

SVL_mm: Snout-vent length in mm (applies only to reptiles and amphibians)

Trans_diameter_mm: Transverse diameter of the eye in mm

Cornea_diameter_mm: Transverse diameter of the cornea in mm

Reference: Citation for source of morphological data (see full citations in "Vertebrates_references.pdf")

VertLife_name: Phylogeny tip labels from VertLife trees that match each species from the morphology dataset (if names are different, this is due to species synonyms or changes in taxonomy). See full citations for phylogeny sources in "Vertebrates_references.pdf"

VertLife_basetree: Phylogeny from VertLife that applies to each row of the dataset (matches tree names on VertLife)

TimeTree_tiplabel: Phylogeny tip labels from TimeTree (used only for Actinopterygii) that match each species from the morphology dataset (if names are different, this is due to species synonyms or changes in taxonomy). “NA” indicates that the morphology dataset species was not available in a TimeTree phylogeny. For full reference for TimeTree, see "Vertebrates_references.pdf"

TimeTree_genus_sub: Tip labels from TimeTree (used only for Actinopterygii) that match each species from the morphology dataset at the genus level (but not the species level). These genus-level substitutions were used to approximate the phylogenetic position of species that were not available as direct matches in the phylogeny for analyses.