 The order Anura ( from the Ancient Greek a ( n ) - meaning " without " and oura meaning " tail " ) comprises the frogs and toads . They usually have long hind limbs that fold underneath them , shorter forelimbs , webbed toes with no claws , no tails , large eyes and glandular moist skin . Members of this order with smooth skins are commonly referred to as frogs , while those with warty skins are known as toads . The difference is not a formal one taxonomically and there are numerous exceptions to this rule . Members of the family Bufonidae are known as the " true toads " . Frogs range in size from the 30 @-@ centimetre ( 12 in ) Goliath frog ( Conraua goliath ) of West Africa to the 7 @.@ 7 @-@ millimetre ( 0 @.@ 30 in ) Paedophryne amauensis , first described in Papua New Guinea in 2012 , which is also the smallest known vertebrate . Although most species are associated with water and damp habitats , some are specialised to live in trees or in deserts . They are found worldwide except for polar areas . 
