Warts and all: evolutionary and ecological patterns in frog skin texture.

Area of Science:

• Amphibian biology
• Evolutionary biology
• Comparative anatomy

Background:

• Frog skin external appearance exhibits significant variation across species and body regions.
• This diversity is understudied, with evolutionary drivers of skin texture variation remaining unclear due to a lack of quantitative data.
• Previous research has been predominantly qualitative, limiting comprehensive understanding.

Purpose of the Study:

• To quantitatively assess frog skin texture across numerous species and families.
• To investigate how skin texture differences evolve across major frog clades.
• To determine the influence of microhabitat, climate, and body size on skin texture patterns.

Main Methods:

• Standardized gel-based profilometry was employed to quantify skin texture.
• Phylogenetic comparative models were utilized to analyze evolutionary patterns.
• Data were collected from 187 species representing 45 frog families worldwide.

Main Results:

• The ventral posterior skin region, crucial for water uptake, was found to be significantly rougher than other body regions.
• Skin texture evolved at comparable rates across different body regions.
• Microhabitat, especially arboreality, correlated with increased skin texture variation among body regions.
• Body size and local climate had minimal impact on skin texture in terrestrial microhabitats.

Conclusions:

• Skin texture is an informative component of amphibian skin biology, offering insights into diversity.
• Microhabitat is a key factor shaping regional skin texture variation in frogs.
• This study provides a quantitative foundation for understanding the evolution of external skin diversity in frogs.