Anurans are amphibians that have tails throughout their lives. There are more than 300 species in 60 genera and 8 families, mainly distributed in the northern hemisphere. There are 3 families, 15 genera and about 35 species known in China. There is little difference in morphology between larvae and adults, mainly including salamanders, small salamanders and giant salamanders. Anurans have fully developed forelimbs and hindlimbs, approximately the same size. There is no eardrum or external ear op