Bronzed Frog
Encyclopedia
The bronzed frog is a species of true frog
found in the riparian evergreen
forests of the Western Ghats
, India
and the highlands of Southwestern Sri Lanka
. They are found abundantly on or close to the ground near water. Individuals are not shy and react by jumping only when provoked. They are important prey of many species of snakes including the Malabar Pit Viper
and the Vine Snake
.
Vomer
ine teeth are present in two oblique series that extend beyond the level of the hinder edge of the choana
e. Head is depressed and triangular, snout subacuminate and prominent. The canthus
rostralis is angular and lore
al region nearly vertical and strongly concave. The Inter-orbital space is broad as the upper eyelid or rather broader in some cases. The tympanum
is very distinct which is as large as the eye but sometimes a little smaller.
Fingers are moderate wherein the first extends beyond the second. Toes are almost entirely webbed. Tips of fingers and toes are dilated into well- developed disks. 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 tibio-tarsal articulation reaches the nostril to the tip of the snout and sometimes a little beyond it.
The skin of the individuals are smooth or finely granulate above with a narrow glandular lateral fold. While the dorsal
regions are brown coloured, 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. 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 an oval flat gland
on the inner side of the arm. 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.
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 (incorrectly), Rana flavascens, Rana malabarica, Hylorana malabarica, Hylorana temporalis, Hylorana flavescens, Rana temporalis, Sylvirana temporalis etc.
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 (3–4 months)to enable body growth and emergence of larger/stronger froglets.
. Tail fin is transparent and pointed with moderately developed musculature. Slight pigmentation is visible on the skin of tail muscles and tail fins. The height of the dorsal fin is greater than the ventral fin. The teeth are blunt with the dental formula 2(2)/3(1). A characteristic yellowish brown strip is formed on the dorsal side between the snout and the posterior tip. On the lateral side, a black strip runs from the anterior to the posterior side of the body. Within a week of metamorphosis, small bronzed coloured strips appear on either sides of the lower jaw, between the snout and the posterior point of the forelimbs. The bronzed strips are interrupted below the forelimbs.
, including the bronzed frog. Studies show that generally growth rates, measured in terms of body mass, vary inversely with population density, and slowly growing individuals metamorphose at smaller sizes than their larger conspecifics. Growth and size at metamorphic climax were therefore inversely correlated with density of rearing.
Interestingly, presence of kin
and non-kin also affects larval growth and metamorphosis. Larval growth where significantly greater when reared with siblings (crowded or uncrowded) compared to those reared with non-kin. Also variation in size was also lower in individuals reared in pure groups compared to those reared in mixed groups. In mixed groups, the spectrum of developmental stages were broader vis-a-vis pure groups.
True frog
The true frogs, family Ranidae, have the widest distribution of any frog family. They are abundant throughout most of the world, occurring on most continents except Antarctica...
found in the riparian evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
forests of the Western Ghats
Western Ghats
The Western Ghats, Western Ghauts or the Sahyādri is a mountain range along the western side of India. It runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The Western Ghats block rainfall to the Deccan...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and the highlands of Southwestern Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
. They are found abundantly on or close to the ground near water. Individuals are not shy and react by jumping only when provoked. They are important prey of many species of snakes including the Malabar Pit Viper
Trimeresurus malabaricus
Trimeresurus malabaricus is a venomous pitviper species found in southwestern India. No subspecies are currently recognized.-Description:...
and the Vine Snake
Ahaetulla nasuta
The Green vine snake , is a slender green tree snake found in India, Sri Lanka, Bangladesh, Myanmar, Thailand, Cambodia and Vietnam.-Description:...
.
Physical Characteristics
Vomer
The vomer is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones.-Biology:...
ine teeth are present in two oblique series that extend beyond the level of the hinder edge of the choana
Choana
Choana is the posterior nasal aperture.The choanae are separated by the vomer.- Boundaries :It is the opening between the nasal cavity and the nasopharynx....
e. Head is depressed and triangular, snout subacuminate and prominent. The canthus
Canthus
The Canthus is either corner of the eye where the upper and lower eyelids meet.Canthus may also refer to:* Canthus of the eye, also called the orbital canthus* Canthus , the sides of the snout in reptiles in amphibians...
rostralis is angular and lore
Lore
Lore may refer to:* Loré , a city and subdistrict in Lautém District* Lore , the region on each side of a birds face between eye and bill* Lore , a fictional android* Lore Sjöberg, an internet humourist...
al region nearly vertical and strongly concave. The Inter-orbital space is broad as the upper eyelid or rather broader in some cases. The tympanum
Tympanum (zoology)
The tympanum is an external hearing structure in animals such as frogs, toads, insects, and mammals, to name a few.-Anurans:In frogs and toads, it is located just behind the eye. It does not actually process sound waves; it simply transmits them to the amphibian's inner ear, which is protected...
is very distinct which is as large as the eye but sometimes a little smaller.
Fingers are moderate wherein the first extends beyond the second. Toes are almost entirely webbed. Tips of fingers and toes are dilated into well- developed disks. 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 tibio-tarsal articulation reaches the nostril to the tip of the snout and sometimes a little beyond it.
The skin of the individuals are smooth or finely granulate above with a narrow glandular lateral fold. While the dorsal
Dorsum (anatomy)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
regions are brown coloured, 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. 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 an oval flat gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
on the inner side of the arm. 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.
Etymology
The frogs' common nameCommon name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
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 (incorrectly), Rana flavascens, Rana malabarica, Hylorana malabarica, Hylorana temporalis, Hylorana flavescens, Rana temporalis, Sylvirana temporalis etc.
Distribution and habitat
The bronzed frog is distributed throughout the Western ghat mountains of South India, along Kerala, Tamil Nadu, Karnataka and Maharashtra at an elevation of 200–1800 m and the wet forests of southwestern Srilanka at an elevation of 60–1830m. The individuals are chiefly found on edges of rocky streams at low altitude. It sits exposed on flat rocks and stones and leaps, often to a considerable distance, into the water when disturbed.Breeding
Growth and Development
The tadpoles of bronzed frogs start appearing in the streams by October till March. They are at least 11–14 mm long at metamorphosis and weigh about 100–170 mg. The larval duration varies from 90–120 days. The dorsal side of the tadpoles bear a muddy green/white/yellowish or olive brown colour while their lateral side is usually muddy. They carry a triangular snout with a single, sinistral and lateral spiracleSpiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
. Tail fin is transparent and pointed with moderately developed musculature. Slight pigmentation is visible on the skin of tail muscles and tail fins. The height of the dorsal fin is greater than the ventral fin. The teeth are blunt with the dental formula 2(2)/3(1). A characteristic yellowish brown strip is formed on the dorsal side between the snout and the posterior tip. On the lateral side, a black strip runs from the anterior to the posterior side of the body. Within a week of metamorphosis, small bronzed coloured strips appear on either sides of the lower jaw, between the snout and the posterior point of the forelimbs. The bronzed strips are interrupted below the forelimbs.
Effects of Density and Kinship on Growth and Metamorphosis
Density can significantly influence growth and metamorphosis in many species of anurans like the Indian bull frog (Rana tigrina) and the toad Bufo melanostictusBufo melanostictus
The Common Indian Toad or Common Asiatic/Asian Toad or Black-spined Toad Duttaphrynus melanostictus is a species of toad that is common in South Asia. The species grows to almost 20 cm long. The species breeds during the monsoons and the tadpoles are black...
, including the bronzed frog. Studies show that generally growth rates, measured in terms of body mass, vary inversely with population density, and slowly growing individuals metamorphose at smaller sizes than their larger conspecifics. Growth and size at metamorphic climax were therefore inversely correlated with density of rearing.
Interestingly, presence of kin
Kin
-Places:* Kin, Okinawa, a town in Okinawa, Japan* Kin, Pakistan, a village along the Indus in Pakistan* Kin, Mogok, a village in Mogok Township, Burma * Kin, Ye, a village in Ye Township, Burma...
and non-kin also affects larval growth and metamorphosis. Larval growth where significantly greater when reared with siblings (crowded or uncrowded) compared to those reared with non-kin. Also variation in size was also lower in individuals reared in pure groups compared to those reared in mixed groups. In mixed groups, the spectrum of developmental stages were broader vis-a-vis pure groups.
Microhabitat Choice
Following the south-west monsoon rains that lashes the Indian west coast from the first week of June, innumerable anuran species co-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. Experiments show that tadpoles of bronzed frogs which possesses a ventral mouth, predominantly prefers to occupy the substrate zone and that the number of individuals that exercise this preference is greater in the night than in daytime.Social Aggregation
Tadpoles of bronzed frogs show social aggregation phenomenon. However, the nature and significance of this behaviour is yet to be understood.Kin Recognition
Kin recognition is a phenomenon widespread in organisms as diverse as social insects, fishes, amphibians, birds, and mammals and even plants. Kin recognition behaviour in bronzed frog seems to be associated with growth regulation as their growth and metamorphosis is enhanced when reared with siblings than with non-siblings.Foraging Strategy
Ideal Free Distribution (IFD) refers to the idea that individuals of a species will distribute themselves amongst areas or patches in such a way that the average gain to all individuals is equal. Studies have shown that tadpoles of bronzed frog exhibit IFD behaviour while foraging regardless of whether they are siblings of non-siblings in a group, which correlates well with their group-living strategy in nature.Food Perception
Studies on individual test tadpoles of bronzed frog suggest that food is detected based on chemical cues and not visually indicating that chemical perception predominates visual senses in R. temporalis tadpoles.External links
- IUCN Red List page on H. temporalis.
- CalPhotos image and details on H. temporalis
- Breeding call audio from You tube [Contributed by Western Ghat Regional Centre, Calicut]
- Amphibian Species of the World 5.3, an Online Reference page on H.temporalis