Ren Bennett, Diana Lopez, Dr. Molly Womack, Dr. Allison Alvarado, Dr. Rudolf von May
Distinct patterns of body size and shape across elevation have been observed in many species, leading to different ecogeographical hypotheses or ‘rules’. According to Bergmann’s rule, organisms living in cooler climates (e.g., high latitude, high elevation) tend to have larger body size than those living in warmer climates. According to Allen’s rule, organisms living in cooler climates tend to have shorter appendages (e.g., shorter limbs, shorter beaks) than those living in warmer climates. However, few studies have tested these hypotheses in amphibians and the observed patterns vary across taxonomic groups. We examined Bergmann’s and Allen’s rules on a diverse group of terrestrial-breeding frogs (Strabomantidae) to understand how species’ body size and body shape vary across elevations. We tested whether (1) species living at high elevations tend to have larger body size than those living at low elevation, and whether (2) the relative size of the appendages (e.g., limb length, head length) in species living at high elevations tend to be shorter than those living a low elevation. We compiled a dataset for ~300 species representing six genera, and used elevation as a proxy for temperature, to assess the relationship between morphological traits and elevational midpoint. Most papers reviewed contained data on one or more species, and we recorded the museum number, coordinates, elevation, and measurements of individual specimens. Bergmann’s rule was supported in one of the six examined genera (Phrynopus) and Allen’s rule was supported in three of the six examined genera (Bryophryne, Phrynopus, Pristimantis). We discuss these findings with respect to microhabitat use and thermal ecology.