Ureotelism as the prevailing mode of nitrogen excretion in larvae of the marsupial frog Gastrotheca riobambae (Fowler) (Anura, Hylidae)

1. 1. Embryos from the pouch of the marsupial hylid frog Gastrotheca riobambae excrete urea. 2. 2. Free-living tadpoles of G. riobambae excrete mainly urea, in comparison with tadpoles of other hylid frogs. 3. 3. The activity of arginase is high in embryos from the pouch, and in tadpoles of G. riobambae. 4. 4. The ureotelism of G. riobambae larvae is an adaptation for prolonged incubation in the pouch of the mother, and for development in limited amounts of water.