Infrared reflection: A taxonomic tool for neotropical tree frogs

Many Neotropical hylid species have been shown to exhibit an optical reflection profile characterised by a distinct increase in reflectance in the near infrared part of the spectrum, described as the red edge [1]. Although first identified in 1977 this property has not been extensively studied and is considered to be an isolated novelty to potentially aid in thermoregulation in a select group of leaf sitting hylids. Here, 18 additional species have been identified as possessing this reflectance, bringing the total number of identified species to 26 from a genetically and geographically diverse range. We propose that the paradigm relating to near infrared reflectance in leaf sitting hylids needs to be reassessed, and the existence of the red edge considered as a key taxonomic metric in the classification of hylid species - with the suggested primary benefit of cryptic thermoregulation.