Frogs are a diverse and largely carnivorous group of short-
bodied, tailless amphibians composing the order Anura (Ancient
Greek an-, without + oura, tail). The oldest fossil "proto-frog"
appeared in the early Triassic of Madagascar, but molecular
clock dating suggests their origins may extend further back to
the Permian, 265 million years ago. Frogs are widely
distributed, ranging from the tropics to subarctic regions, but
the greatest concentration of species diversity is found in
tropical rainforests. There are approximately 4,800 recorded
species, accounting for over 85% of extant amphibian species.
They are also one of the five most diverse vertebrate orders.
The body plan of an adult frog is generally characterized by a
stout body, protruding eyes, cleft tongue, limbs folded
underneath and the absence of a tail. Besides living in fresh
water and on dry land, the adults of some species are adapted
for living underground or in trees. The skin of the frog is
glandular, with secretions ranging from distastef