Amphignathodon guentheri Boulenger, 1882
Gastrotheca guentheri is the only known frog with true teeth in its lower jaw. Its teeth have re-evolved after being absent for over 200 million years, challenging Dollo's law. Re-evolution of teeth in the lower jaw may have been made easier because the frogs have teeth in their upper jaw so there was already a biochemical pathway for developing teeth after 200 million years, unlike, say, birds.
This species is declining in abundance. One cause of the declines is habitat loss, but the species has also declined within suitable habitat in Ecuador, possibly because of climate change or chytridiomycosis.
- Bolívar, W., Luis A. Coloma, Santiago Ron, Diego Cisneros-Heredia, Juan Manuel Renjifo (2004). "Gastrotheca guentheri". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 5 April 2014.
- Frost, Darrel R. (2014). "Gastrotheca guentheri (Boulenger, 1882)". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 5 April 2014.
- Wiens, J. J. (2011). "Re-evolution of lost mandibular teeth in frogs after more than 200 million years, and re-evaluating Dollo's law". Evolution 65 (5): 1283–1296. doi:10.1111/j.1558-5646.2011.01221.x. PMID 21521189.
- Sindya N. Bhanoo (8 February 2011). "A Frog Evolved to Regain the Teeth Its Ancestors Jettisoned". NYTimes.com. Retrieved 13 February 2011.