The only systematic difference of the Dendrobatidae from the ranidae is the absence of teeth, morphologically a very unimportant character, and it is now agreed, on the strength of their distribution, that these little arboreal, conspicuously coloured frogs, Dendrobates in South America, Mantella in Madagascar, do not form a natural group, although a third genus, Cardioglossa in West Africa, seems also to belong to them.
"Darwin and Modern Science"
A.C. Seward and Others