and Rhinophrynus are known to remain active underground, and at least juvenile Glyphoglossus forage above ground (A. Lathrop and G. Zug, personal communications) during the rainy season. Various other burrowers aestivate while encased in epidermal cocoons. Other than Otophryne (Otophryninae, South America) and Scaphiophryne (Scaphiophryninae, Madagascar), each of which have different keratinized structures on the jaw cartilages, microhylid tadpoles lack keratinized mouthparts, and except in one case (i.e., Otophryne), have a midventral spiracle.