Bronzed frog

Appearance

Its vomerine teeth are present in two oblique series that extend beyond the level of the hind edge of the choanae. Its head is depressed and triangular; the snout is subacuminate and prominent. The canthus rostralis is angular and the loreal region is nearly vertical and strongly concave. The interorbital space is as broad as the upper eyelid or rather broader in some cases. The tympanum is very distinct and is as large as the eye, but sometimes a little smaller.

The digits are moderate wherein the first extends beyond the second. The toes are almost entirely webbed. The tips of the fingers and toes are dilated into well-developed disks. Its subarticular tubercles are well developed, while the inner metatarsal tubercle is oval and blunt with a small, round, outer metatarsal tubercle and no tarsal fold. The tibiotarsal articulation reaches from the nostril to the tip of the snout and sometimes a little beyond it.

The skin of these frogs is smooth or finely granulate above, with a narrow glandular lateral fold. While the dorsal regions are brown coloured, the loreal and temporal regions, and sometimes also the sides of the body are dark brown in colour. A white labial band can also be seen. Its limbs have dark cross bands. The ventral parts are typically white, with the throat and breast more or less speckled with brown spots. Males have internal vocal sacs and oval flat glands on the inner side of their arms. Males also have a strong pad on the inner side of the first finger, covered during the breeding season with a greyish brown velvet-like horny layer.

Naming

The frogs' common name is derived from the small bronze-coloured strips that appear on either side of the lower jaw, between the snout and the posterior point of the forelimbs, within a week after metamorphosis. The species has been referred to by several names, including ''Hylarana malabarica'' , ''Rana flavascens'', ''Rana malabarica'', ''Hylorana malabarica'', ''Hylorana temporalis'', ''Hylorana flavescens'', ''Rana temporalis'', and ''Sylvirana temporalis''.

Distribution

The bronzed frog is found only in Sri Lanka. They are chiefly found on edges of rocky streams at low altitude. They sit exposed on flat rocks and stones, and leap, often to a considerable distance, into the water when disturbed.

Behavior

Tadpoles of bronzed frogs show a social aggregation phenomenon. However, the nature and significance of this behaviour is yet to be understood.

Habitat

The bronzed frog is found only in Sri Lanka. They are chiefly found on edges of rocky streams at low altitude. They sit exposed on flat rocks and stones, and leap, often to a considerable distance, into the water when disturbed.Following the south-west monsoon rains that lash the Indian west coast from the first week of June, innumerable anuran species breed in ephemeral ponds and puddles. This incidentally puts the individuals in severe intra- and interspecific competition for food and space, and also to predation pressures. Microhabitat selection is, therefore, an important strategy employed by the anuran species including the bronzed frog. Tadpoles of bronzed frogs, which possess ventral mouths, predominantly occupy the substrate zone, and in greater numbers at the night than in daytime.

Reproduction

The bronzed frog typically breeds along the edges of gently flowing and/or in pockets of still water along the streams. The muddy colour of the tadpoles matches well with the substratum of the stream. The oral armature is well-suited for grazing at the bottom. In near permanent water, the tadpoles may have longer metamorphic duration to enable body growth and emergence of larger/stronger froglets.

Breeding season begins from August to May, and males will begin their mating call from 9:00 to 11:00 PM. Eggs are slightly green in color and can be found in clutches of 800 to 1200. These are usually deposited at the edges of rocky pools.

Food

Tadpoles of bronzed frogs detect food based on chemical cues and not visually, indicating that chemical perception predominates visual senses in ''R. temporalis'' tadpoles.