Indus Valley Bullfrog
© 2008 Miguel Vences and Frank Glaw (1 of 8)
Color: Dorsum olive green, olive or gray, with dark blotches, a light yellow vertebral streak, rarely absent; a dark canthal and a lighter labial streak often present; limbs with dark bars, which may break in dark blotches; thighs posteriorly marbled with black and yellow; a fine yellow line along upper surface of thigh, another on the inner side of calf. Ventrum white, sometimes feeble pigmentation on throat (Khan and Tasnim 1987b).
The tadpole of Holobatrachus tigerinus has a cylindrical body, which does not bulge out; tail is muscular, almost as broad as body, fins are narrow, parallel, tail tip is acutely pointed. Anterior oral disc, with nonpapillated rim. Posterior labium extensible into an additional postdisc sucker. Beak strong, prebuccal half of it is strongly serrated, medially produced into a long serrated tooth, while postbuccal half is sharp, nonserrated with a median recess to receive the median tooth of the prebuccal half. The labial tooth row formula is 5(4)/5(3), teeth are biserial in arrangement (Figure 6C). A tooth is a 0.3-0.4 mm long cylindrical body, with a gradual taper toward acute tip (Khan 1991a, 1996b).
The tadpole is predominantly carnivorous and feeds primarily on sympatric tadpoles and bodies of drowned animals (Khan 1996b). It is benthic in habits, eyes and nostrils are dorsally placed. It stalks its prey, while lying at the bottom of water, darting to catch it in its powerful jaws. Melanophores are concentrated just below eyes, and along dorsolateral sides of body; tail and fins are speckled with black, tail tip heavily pigmented. Total length of the tadpole 40-43 mm, tail 23-26 mm.
A very large semiaquatic frog, measuring up to 170 mm. One male from Madagascar measured 120 mm. Dorsally greenish or brown with dark spots and often a light vertebral line. Ventrally whitish. Males become yellow in the breeding season. Skin with longitudinal rows of tubercles. Hands without webbing, feet more or less fully webbed. Males with nuptial pads on first finger and paired lateral vocal sacs.
Similar species: Ptychadena mascareniensis is smaller and has more longitudinal, continuous ridges on dorsum rather than rows of tubercles.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Afghanistan, Bangladesh, India, Myanmar, Nepal, Pakistan, Sri Lanka. Introduced: Madagascar, Maldives.
Life History, Abundance, Activity, and Special Behaviors
Breeding activity is primarily confined to monsoons. The breeding males are lemon yellow in color, hence locally called "Basanti Dadoo", while females remain dull and drab-colored. The deep blue vocal sacs of male are prominent against the yellowishwhite color of the throat of the male. The call is a powerfull nasal " Cronk, cronk, cronk", which sometimes sounds like "oong wang, oong wang, oong wang" repeated several times. Calling males sit close to each other in shallow water, now and then jumping over each other. Females lurch around. One falling within the range of a male is grabbed by the male in an amplectic hold, with neighbors soon jumping on the pair and trying to dislodge them which starts much fighting, pushing, and tugging. The pair somehow moves to a quieter place where large eggs (2.5-2.8 mm diameter) are laid in several groups, each egg enclosed in a double coat of jelly. Eggs are soon attached to grass blades and often sink into the water (Khan 1969, 1996b).
Holobatrachus tigerinus is a voracious feeder; anything that is moving is bounced upon and swallowed. If needed it uses its anterior limbs to thrust larger food into its mouth. In addition to a great variety of insects, it feeds on a variety of items: mice, shrew, young frogs, earthworms, roundworms, juvenile snakes, and small birds. Vegetable matter and several odd objects are recorded from its stomach (Khan 1973). Lizards like Uromastyx (Daniel 1975), snakes: Lycodon aulicus, Ramphotyphlops braminus, Leptotyphlops sp., and young Ptyas mucosus (pers. obs.) have also been recorded from its diet.
The frog does not stay in water for a long time; it spends most of its time hiding and feeding in surrounding vegetation. On approach of danger, it plunges into deep water, stays underwater for 2-3 minutes, then returns quietly to the marginal vegetation undetected. In clear pools of water it hides under bottom gravel.
Karyotype number recorded for this species is 26 (Natarajan 1958).
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
Glaw, F., and Vences, M. (2007). Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Vences and Glaw Verlag, Köln.
Khan, M.S (1969). ''A normal table of Rana tigrina Daudin. 1. Early development (Stages 1-27).'' Pakistan Journal of Science, 21, 36-50.
Khan, M.S. (1996). ''The oropharngeal morphology and feeding habits of tadpole of Tiger Frog Rana tigerina Daudin.'' Russian Journal of Herpetology, 2, 163-171.
Natarajan, R. (1958). ''Contribution to the cytology of Indian Anura: II. On the number and morphology of the chromosomes of three species of Rana (Ranidae).'' Journal of the Zoological Society of India, 9, 114-119.
Padhye, A., Manamendra-Arachchi, K., Dutta, S., Kumar, T., Bordoloi, S., Papenfuss, T., Anderson, S., Kuzmin, S., Sharif Khan, M., and Nussbaum, R. (2008). Hoplobatrachus tigerinus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 14 April 2009.
Written by M. S. Khan (typhlops99 AT hotmail.com), Herp Lab, Rabwah, Pakistan.
First submitted 2002-03-19
Edited by Henry Zhu (2010-10-14)
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