~FROG~

There are around 3,900 species of tailless amphibians, or Anura, also called Salientia, including the frog and toad.

Amphibians

Frogs are members of the zoological class called Amphibia.
Amphibians are cold-blooded (or poikilothermic) vertebrate animals. They differ from reptiles in that they lack scales and generally return to water to breed. 
They are one of three types of Amphibians. Anura, also called Salientia, (frogs and toads), caudate (salamanders and newts) and caecilians (worm-like amphibians).

Difference between frogs and toads.

Frogs

Generally speaking, though, when we think of frogs, we generally picture what are called "True Frogs"....
members of the family Ranidae, containing more than 400 species.
These frogs have the characteristics of:

• two bulging eyes
• strong, long, webbed hind feet that are adapted for leaping and swimming
• smooth or slimy skin (generally, frogs tend to like moister environments)
• Frogs tend to lay eggs in clusters.

Frogs from this family can be found on every continent except Antarctica. They are referred to as the "true frogs" because of their generalized body form and life history: the so-called generic frog.
Members of this family include the bullfrog, common frog, green frog, leopard frog, marsh frog, pickerel frog, and wood frog.

Toads

The term toads tends to refer to "True Toads"....
members of the family Bufonidae, containing more than 300 species.
These types of frogs have are characterized by:

• stubby bodies with short hind legs (for walking instead of hopping)
• warty and dry skin (usually preferring dryer climates)
• paratoid (or poison) glands behind the eyes
• The chest cartilage of toads is different also.
• Toads tend to lay eggs in long chains. (There are some toads (genera Nectophrynoides), however, that are the only types of anurans to bear live young!)

True Toads can be found worldwide except in Australasia, polar regions, Madagascar, and Polynesia, though Bufo marinus has been artificially introduced into Australia and some South Pacific islands.
Besides Bufo, the family includes 25 genera, all of which, like the frogs, are anura!