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24 f R o G S A n d T o A d S

Convergent evolution Convergent evolution is the result of unrelated species finding similar solutions to similar problems so that they look and behave like each other. Arboreal frogs with expanded toe pads are one example, and the digging spade on the hind feet of many unrelated burrowing frogs is another, but perhaps the best example is the case of the so-called flying frogs, of which there are two distinct groups. In new World rainforests, tree frogs of the genera Agalychnis and Phyllomedusa, have huge, heavily webbed feet that they use to glide from the forest canopy to lower levels. In Southeast Asian rainforests, an unrelated group of frogs, belonging to the genus Rhacophorus, do exactly the same thing and have evolved along similar lines. differences between, say, Spurrell’s flying frog, Agalychnis spurrelli, from Central America and Reinwardt’s flying frog, Rhacophorus reinwardtii, from malaysia and Indonesia, are so slight that they could easily be mistaken for each other at first glance, even though they belong to two different families: the hylidae and the Rhacophoridae. Incidentally, none of these frogs breed in open water but

instead lay egg-masses on leaves overhanging pools. They above Spurrell’s flying frog, Agalychnis spurrelli, a member of the rarely if ever enter the water – ironically, the extensive hylidae from Costa Rica.

webbing that allows them to parachute to the ground is below Reinwardt’s flying frog, Rhacophorus reinwardtii, a not suitable for swimming. member of the Rhacophoridae from Borneo.