Frogs

Frogs 🐸 are members of a diverse and mostly carnivorous group of short-bodied, tailless amphibians composing the order Anura (Ancient Greek ἀν-, without + οὐρά, tail). 

Magnificent tree frog (Litoria splendida) Australian Green Tree Frog. image:LiquidGhoul/wikipedia 

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. 

Range of frogs

Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is 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.

Range of frog habitats. image:wikipedia

Layout of frogs

The body plan of adult frogs are 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. 

Skins of frogs and the difference between toads

The skins of frogs are glandular, with secretions ranging from distasteful to toxic. Warty species of frog tend to be called toads but the distinction between frogs and toads is based on informal naming conventions concentrating on the warts rather than taxonomy or evolutionary history.

An adult can toad, note more warts than the ‘smoother’ frog. image:brian.gratwicke /wikimedia

 Frogs' skins vary in colour from well-camouflaged dappled brown, grey and green to vivid patterns of bright red or yellow and black to advertise toxicity and warn off predators.

Taxonomy of frogs and toads

Frogs and toads are broadly classified into three suborders: 

• Archaeobatrachia, which includes four families of primitive frogs; 
• Mesobatrachia, which includes five families of more evolutionary intermediate frogs; and 
• Neobatrachia, by far the largest group, which contains the remaining 24 families of modern frogs, including most common species throughout the world. 

Source adapted from: Wikipedia contributors. (2018, June 23). Frog. In Wikipedia, The Free Encyclopedia. Retrieved 07:28, July 17, 2018, from https://en.wikipedia.org/w/index.php?title=Frog&oldid=847194180