A normal table of developmental stages of the Indian bull frog, Rana tigrina Daud (Ranidae, Anura, Amphibia)

Abstract

In Meerut 'Western Uttar Pradesh) the Indian bull"frog, Rana tigrina (Daud) breeds mainly during early part (June-July) of the monsoon season. The spawn consisting of about 3000 eggs is a flat sheet floating over water. At 26-30°C hatching occurs in about 18 hours when embryos are approximately 4,5 mm, long. The tadpoles preferring to stay at the bottom of the pond metamorphose in 7f to 8 weeks after hatching. In the normal table the entire development of R. tigrina beginning from the freshly spawned unfertilized egg and ending with metamorphosis into frog-let is divided into; 55 discrete stages on the basis of external morphological features. Stages 1 to 26 describe the development during embryogenesis upto hatching. Stages 27 to 32 include the short post-hatching period until the operculum is formed and the definitive tadpole begins feeding. From stage 32 to 46 the hindlimbs develop and the tadpoles grow to attain the maximum length. Stages 47 and 4S are those of mature tadpoles during which there is no increase in length of the body or tail but hindlimbs grow rapidly and become functional, ihe metamorphic changes ending with transformation of the aquatic tadpole to froglet are described under stages 49 to 55.