Adult males of this species carry around the tadpoles on their backs until they turn into little froglets. The second photo here shows an adult male with a few little tadpoles on its back.
I had originally identified these frogs as Silverstoneia nubicola (aka Colestethus nubicola), but I changed my mind after looking again at the photos with more references available.
- Chacón, F. M., Johnston, R. D. 2013. Amphibians and Reptiles of Costa Rica: A Pocket Guide
- Köhler, G. 2011. Amphibians of Central America
- Leenders, T. 2001. A Guide to Amphibians and Reptiles of Costa Rica
- Savage, J. M. 2002. The Amphibians and Reptiles of Costa Rica