Data from: Salamander ecomorphology reveals a unique suite of climbing adaptations
Data files
Jul 30, 2025 version files 144.32 KB
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AllometryData.csv
2.76 KB
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MainScript.R
40.29 KB
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PhalangesData.csv
6.28 KB
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RawMorphometrics.csv
45.16 KB
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README.md
4.09 KB
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Stewart_Wien_2025_S3_fulltree.nex
45.74 KB
Abstract
Many salamanders climb extensively but lack morphological adaptations, such as claws or adhesive toe pads, found in other climbing tetrapods. Here, we compared climbers and non-climbers from the salamander genera Aneides and Plethodon to evaluate potential morphological adaptations for climbing across multiple levels of biological organization. We integrated body shape morphometrics, allometry of the autopods (manus and pes), mechanical advantage of the digits, and comparisons of epithelial microstructures. Compared to non-climbers, climbers have longer limbs that likely facilitate faster climbing and have larger and positively allometric autopods that likely yield superior clinging performance. Longer digits increase climbing reach at the expense of grip force, but climbers circumvent this trade-off with phalangeal morphologies that increase the mechanical advantage of their digits. A few species also have pes epithelia that may increase adhesion or friction but epithelial morphology was largely uncorrelated with habitat use. While scansorial species of Aneides and Plethodon share some characteristics with other genera of climbing salamanders, our results reveal subtle differences between rock-climbing and tree-climbing salamanders that reflect different selective pressures imposed by their microhabitats. Many-to-one mapping enables alternate strategies to address the challenges of climbing and helps to explain the abundance and diversity of climbing tetrapods.
Dataset DOI: 10.5061/dryad.n02v6wx96
Description of the data and file structure
Files and variables
File: AllometryData.csv
Description: Static allometry coefficients for the pes (cm^2) relative to body mass (g) for 30 species of plethodontids.
Variables
- species: Genus species name.
- n: Number of individuals used to infer the scaling coefficients.
- slope: Static slope of the allometric relationship.
- int: Static intercept of the allometric relationship.
- svl_max: Maximum snout-vent length reported in the literature (mm).
- Locomotion: Climbing preference of the species (Scansorial or Non-Climber).
- Habitat: Habitat preference of the species (Arboreal, Saxicolous, or Terrestrial).
- Allometry Citation: The source of the scaling coefficients or the original data.
- SVL Citation: The source of the maximum snout-vent length.
File: RawMorphometrics.csv
Description: Body shape measurements for 411 specimens across 13 species of Aneides and Plethodon. See Figure 2 of the manuscript for a visual representation of measurements.
Variables
- Species: Genus species name.
- Genus: Genus name.
- ID: Natural history collection catalogue code and number.
- Mass: Body mass (g).
- SVL: Snout-vent length (mm).
- TL: Tail length (mm).
- Humerus: Upper arm length (mm).
- Radius: Lower arm length (mm).
- Hand: Manus length (mm).
- Finger: Longest finger length (mm).
- Femur: Upper leg length (mm).
- Tibia: Lower leg length (mm).
- Foot: Pes length (mm).
- Toe: Longest toe length (mm).
- HandArea: Manus area (mm^2)
- FootArea: Pes area (mm^2)
File: Stewart_Wien_2025_S3_fulltree.nex
Description: Salamander phylogeny from Stewart and Wiens (2025).
File: PhalangesData.csv
Description: Measurements taken from the phalanges for 13 species of Aneides and Plethodon. See Figure 2 of the manuscript for a visual representation of measurements.
Variables
- Species: Genus species name.
- Habitat: Habitat preference of the species (Arboreal, Saxicolous, or Terrestrial).
- ID: Natural history collection catalogue code and number.
- Digit: Indicator of which digit was sampled (Finger or Toe).
- Side: Which side of the body the digit was sampled from (Left or Right).
- SVL: Snout-vent length (mm).
- Met_L: Metacarpal (finger) or metatarsal (toe) length (mm).
- PP_L: Proximal phalanx length (mm).
- PP_PW: Proximal phalanx proximal width (mm).
- PP_DW: Proximal phalanx distal width (mm).
- PP_PH: Proximal phalanx proximal height (mm).
- PP_MH: Proximal phalanx medial height (mm).
- PP_DH: Proximal phalanx distal height (mm).
- MP_L: Penultimate phalanx length (mm).
- MP_PW: Penultimate phalanx proximal width (mm).
- MP_DW: Penultimate phalanx distal width (mm).
- MP_PH: Penultimate phalanx proximal height (mm).
- MP_MH: Penultimate phalanx length (mm).
- MP_DH: Penultimate phalanx distal height (mm).
- DP_L: Terminal phalanx length (mm).
- DP_PW: Terminal phalanx proximal width (mm).
- DP_DW: Terminal phalanx distal width (mm).
- DP_PH: Terminal phalanx proximal height (mm).
- X: Measurement "X" used to calculate terminal phalanx curvature (mm).
- Y: Measurement "Y" used to calculate terminal phalanx curvature (mm).
- Z: Measurement "Z" used to calculate terminal phalanx curvature (mm).
- DP_C: Terminal phalanx curvature (mm).
- PIP_M: Proximal interphalangeal joint moment arm (mm).
- PIP_L: Proximal interphalangeal joint load arm (mm).
- DIP_M: Distal interphalangeal joint moment arm (mm).
- DIP_L: Distal interphalangeal joint load arm (mm).
- TIP_M: Tip of the digit moment arm (mm).
- TIP_L: Tip of the digit load arm (mm).
File: MainScript.R
Description: R script containing all of the main analyses.
Code/software
MainScript.R was written with R Programming Language version 4.3.2 in RStudios. It requires the following packages: ggplot2, tidyverse, plyr, phytools, geomorph, RRPP, patchwork, and smatr.