Head with distinct rostral, preorbital, supraorbital, postorbital and a short orbito-tympanic, cranial crests; no temporal ridge; interorbital space much broader than upper eyelid; tympanum very distinct, at least two third the diameter of the eye; first finger generally but not always extends beyond second; double subarticular tubercles only under third finger. Toes with single subarticular tubercle; parotid elipticle, with dark brown scattered branching concretions; skin heavily tuberculated on flanks, tubercles usually tipped with dark brown spines; a lateral dorsal staggered row of 8-9 enlarged tubercles; cranial crests, lips, digit tips, metacarpal and metatarsal tubercles are cornified with dark brown, which tend to peal off in preserved specimens; head is almost smooth.
Recently Khan (2001) has distinguished Pakistani population of this toad as a new subspecies Bufo melanostictus hazarensis, on the basis of kidney shaped parotid glands; double subarticular tubercles under penultimate phalanx of all fingers; rostral ridge absent from head; temporal ridge present; light brown dorsum.
It is the largest toad in Pakistan, female exceeds 150 mm in snout-vent length.
Color: Dorsum uniform gray of various shades, brown or reddish with dark spots, ventrum uniform dirty white, speckled with light brown on chin and throat.
The throat of breeding male is light orange or yellow. It develops cornified pads on inner side of first and second fingers.
In Pakistan this toad is a highland form, does not extend in the Indus Valley.
Asian common toads (Duttaphrynus melanostictus) have a wide distribution across Asia. The native distribution extends north from Pakistan through Nepal, Bangladesh, India, Sri Lanka, Southern China, Myanmar, Lao, Vietnam, Thailand, Cambodia, Malaysia, Singapore, and Indonesia (Sumatra, Java, Borneo and Natuna Islands).
Asian common toads have been naturalized in Indonesia (Bali, Sulawi, Ambon, Manokwari and Maluku), New Guinea (West Papua and New Guinea), and the Andaman Nicobar Islands. B. melanostictus has also been recently found in East Timor.
Biogeographic Regions: oriental (Native ); australian (Introduced , Native ); oceanic islands (Introduced , Native )
Distribution and Habitat
Until recently Bufo melanostictus was reported to as the common toad of Indo-Pakistan subcontinent (Günther, 1864; Murray, 1884; Boulenger, 1890; Annandale and Rao, 1918). However, in Pakistan, this toad is confined to District Hazara, Northwestern Frontier Province, Alpine Punjab and Azad Kashmir (Mertens, 1969a; Khan, 1972a).
Asian common toads are stout, mid to large sized toads with a modestly sized head and short limbs. They have thick dry skin with prominent cranial ridges and protruding parotid gland. The tympana are oval or circular in shape, stand out well and are about 2/3rds the size of the eyes (Mercy 1999). Snout-vent length of males ranges from 57 to 83 mm and females range between 65 and 85 mm. Elevated ridges appear on head, and eyelids have a long dark crest around the boarder. Colors are extremely variable throughout this species and can range from plain brick red to almost fully black. The most common color pattern is pale yellow-brown marked boldly with dark or reddish brown streaks and spots. Their backs are covered with a series of warts varying in sizes; warts are encircled with black or dark pigments and have spines protruding. Males have a subgular vocal sac; breeding males have a throat region that is bright yellow orange and the inner side of the first and second fingers have nuptial pads. Juveniles possess a black band around the throat that runs between the chin and the breast. Juveniles do not have warts and have a very small Tympanum. Tadpoles are back, small around 15 mm in size and are found in groups (Khan 2000, Mercy 1999, The State of Queensland 2010, van Dijk et al 2011).
Range length: 57 to 83 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; poisonous
Sexual Dimorphism: male larger
Asian common toads are nocturnal terrestrial toads that are found throughout, subtropical, and tropical habitats up to 2000 meters above sea level. Asian common toads are generalists when it comes to choosing a habitat, but they prefer lowland areas such as lowland disturbed forests, forest margins, riparian areas, dense evergreen forests, gardens, and human dominated agricultural and urban areas. (Khan 2000, Mercy 1999, The State of Queensland 2010)
Range elevation: 0 to 2000 m.
Habitat Regions: temperate ; tropical ; terrestrial ; freshwater
Terrestrial Biomes: forest ; rainforest
Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools
Wetlands: marsh ; swamp ; bog
Other Habitat Features: urban ; suburban ; agricultural ; riparian
Habitat and Ecology
Asian common toads are insectivorous although these toads are also know to be an opportunist and will feed on a variety of arthropods and even mollusks. An analysis of the stomach contents of multiple specimens of Asian common toads yielded arthropod orders such as earwigs, grasshoppers, crickets, weta, and locusts, true bugs, moths and butterflies, beetles, typical bugs, sawflies, wasps, bees and ants, termites, cockroaches, and mantids, true flies, centipedes, and millipedes. Though these toads are opportunistic feeders the insects that showed the greatest abundance in the stomach were sawflies, wasps, bees and ants, beetles and termites. This toad is feeds on insects that are known pests to human such mosquitoes and various crop pests (Mercy 1999, The State of Queensland 2010).
Animal Foods: amphibians; eggs; insects; terrestrial non-insect arthropods; mollusks; terrestrial worms
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods, Vermivore)
Asian common toads are an important insectivore, because they feeds on many insect pests known to humans. These toads have few natural predators; although they have been known to be preyed upon by snakes and birds. The possible introduction of these toads could be detrimental to a new ecosystem. Consuming anurans as a food source in Southeast and Southern Asia is a common practice; Asian common toads are fairly toxic and they have caused many deaths and illnesses in Lao and Taiwan (Keomany 2007, Khan 2000, Mercy 1999, The State of Queensland 2010, van Dijk et al 2011).
Predation on Asian common toads are variable because of their extremely large range; throughout their range snakes and birds are common predators. These toads are toxic and can cause illness and death in humans. This could be a possible reason why Asian common toads do not have many predators (Keomany 2007, Mercy 1999, The State of Queensland, 2010).
Life History and Behavior
Male Asian common toads will call during the breeding season to attract females; the call that is used is can be described as melodic “creo-o,o; cro-ro-ro-ro-ro-ro-ro” or “curr, curr, curr”. Beyond calling during mating Asian common toads are not known to make any other vocalizations (Mercy 1999, The State of Queensland 2010).
Communication Channels: acoustic
Other Communication Modes: vibrations
Perception Channels: visual ; tactile ; acoustic ; vibrations
Asian common toads have typical anuran development which is indirect with an aquatic tadpole stage. Eggs become larva within 24 and 28 hours. Saidapur and Girish (2001) showed that Asian common toad tadpoles reared with sibling groups grow at a higher rate and develop faster compared to larvae reared in mixed groups. Because females produce so many eggs, intraspecific competition among tadpoles is likely intense in the ephemeral pools in which this species breeds. Therefore, Saidapur and Girish (2001) suggested that the rapid growth and development of tadpoles in the presence of siblings helps increase reproductive success. A study done by Mogali et al (2011) illustrates that tadpoles of Asian common toads will emerge at different times and sizes with the presents of predators. When predators are present tadpoles will decrease in body mass up to 46% and metamorphosis will also occur earlier (Mogali et al 2011,The State of Queensland 2010, Saidapur and Girish 2001).
Development - Life Cycle: metamorphosis ; indeterminate growth
Asian common toads live an average of 4 years in the wild and up to 10 years in captivity.
Status: wild: 4 years.
Status: captivity: 10 (high) years.
Breeding is water dependent. In areas with a clear wet and dry season breeding will typically happen at the beginning of the wet season. In areas with no lack of moisture breeding will persist year round. The lunar cycle dictates ovulation, which occurs just before or after a full moon. The ovaries can make up 30% of the total body weight at this time. The female will lay a long string of black eggs, which are externally fertilized by the male. Eggs are enclosed in a thick mucus membrane and deposited on submerged vegetation. Eggs are usually laid in a temporary pond or vernal pool. Huang et al (1997) suggested male Asian common toads have a continuous spermatogenic cycle; in other words, sperm cells are produced year round. Thus, mating for males is not seasonally dependent in areas that are continuously moist. Although in more temperate regions with a clear wet and dry season, Asian common toads have been shown to favor specific seasons, a study done in Taiwan showed that there was a larger concentration of spermatophores in the male toad during a specific time of the year (Kahn 2000, Mercy 1999, The State of Queensland 2010, Saidapur and Girish 2001).
Mating System: polygynandrous (promiscuous)
Asian common toads breed opportunistically in small lentic bodies of natural and man-made fresh water. Males congregate at breeding sites and call females. The call can be noted as sounding like “creo-o,o; cro-ro-ro-ro-ro-ro-ro”. There intense competition amongst males for females; many males are often found clinging to a single female (Kahn 2000, Mercy 1999, The State of Queensland 2010, Saidapur and Girish 2001).
Breeding interval: Asian common toads breed twice per year.
Breeding season: Asian common toads breed during the wet season in seasonal areas.
Average number of offspring: 40,000 eggs per clutch .
Range time to hatching: 24 to 48 hours.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
There is no parental care in Asian common toads (Kahn 2000, Mercy 1999, The State of Queensland 2010, Saidapur and Girish 2001)
Parental Investment: no parental involvement
Molecular Biology and Genetics
Barcode data: Duttaphrynus melanostictus
No available public DNA sequences.
Download FASTA File
Statistics of barcoding coverage: Duttaphrynus melanostictus
Public Records: 1
Specimens with Barcodes: 23
Species With Barcodes: 1
Barcode data: Bufo melanostictus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Bufo melanostictus
Public Records: 5
Specimens with Barcodes: 8
Species With Barcodes: 1
Asian common toads are listed on the International Union for Conservation of Nature (IUCN) Red list as “Least Concern”. In the regions of the world that these toads have become naturalized, populations are on the rise. These toads are becoming increasingly common, although pesticide run off can become a detriment to them if it is not monitored. Sumanadasa et al’s (2007) study showed that exposure to small levels of an insecticide called diaznon resulted in almost 100% death of Asian common toads. This chemical is highly regulated by the United States and European Union, yet it is still used widely throughout the developing counties of Asia (Church 1960, Harper et al 2009, Lever 2003, Mercy 1999, Sumanadasa et al 2007, The State of Queensland 2010).
IUCN Red List Assessment
Red List Category
Red List Criteria
Life History, Abundance, Activity, and Special Behaviors
Life history notes: A rare toad in Pakistan mostly confined to the low northern hilly ranges and Azad Kashmir. Nocturnal, appears soon after sunset; during day hides under stones, logs, piles of vegetation, holes and crevices among stones and in ground. Once a suitable place is selected, it is permanently shared with several toads.
The toad is lethargic timid animal. It moves about with deliberate hops from place to place in search of insects on which it feeds. In tropical southeast Asia it is most common amphibian, comes out after sunset in large numbers and frequents mostly the human habitations, where it congregate under street lamps to feed on photophilic insects (Church, 1960).
In temperate environs of western Himalayas, the breeding is initiated by the monsoon rains, from July to August. Males, gather in shallow side-pools along torrents and ponds. The call in low melodious "curr, curr, curr" repeated several times ending in a whistling note. The calling males become quite aggressive, tugging and jumping over each other, males for exceed female in numbers. It breeds in every available space containing some water from first showers of monsoon rains in the southern India (McCann, 1938). Males are much smaller than females. However, in tropical southeast Asia, the toad is known to breed throughout the year (Church, 1960).
Calling males occasionally jump over each other and try to secure a nuptial hold on each other, however, kicks and zestful wriggling dislodge them from each other and soon they resume calling. The females lurch round, as soon one comes close, a male jumps over it and quickly tightens it nuptial clasp, the other suitors are shaken off as the nuptial pair moves to a quitter place away from the site.
The eggs are laid in a double jelly string, generally in deep quieter water, where the egg-string is entangled in the vegetation or female moves round the submerged vegetation to wound the egg string round it. An egg is enclosed in a double gelatinous capsule (Khan, 1982b).
Tadpole: The tadpoles are uniform dark, inhabits side pools along hilly torrents, schools of them swarm along the marginal waters of ponds and puddles feeding on any type of algal material. The body is typically bufonid, globular with weak tail, dorsal fin is broad while ventral is narrow. The oral disc is typically bufonid, with 2(2)/3 labial tooth row formula, the oral papillae are lateral. The beak is finely serrated and sharp (Khan, 1991a).
Total length of tadpole 26-27 mm, tail 19-20 mm.
The swarms of recently metamorphosed toadlets from synchronised pairings leave water, many fall pray to several kind of predators, while several are crushed under feet and passing traffic. Karyotype number recorded for this species is 22 (Nataranjan, 1953).
Life History, Abundance, Activity, and Special Behaviors
Species of rugged mountains. Breeds in paddy fields, where pollution by chemicals affect its eggs and larvae.
Relevance to Humans and Ecosystems
Asian common toads have been introduced to the islands of Bali, Papua New Guinea, Sulawesi, Andaman and Nicobar. The ways in which these toads have been introduced is not fully known in most areas, although in some areas it is assumed that Asian common toads first occurred on these islands when they were fist settled. In other cases, such as in Papua New Guinea, it is rumored that the Department of Health released these toads as means to control mosquito populations These toads are understood to be reproducing rapidly in these areas; there is a possibility that Asian common toads are displacing a smaller species of toads such as crested toads. Asian common toads are suspected to cause intense ecological damage. On the islands where Asian common toads have become naturalized it is competing heavily for similar resources of native anurans. These toads are also known to feed on the eggs, larva and juveniles of other native amphibians, which further exasperates the added competition. This competition may in the future resemble the ecological crisis of cane toads in Australia (Church 1960, Lever 2003, The State of Queensland 2010).
Negative Impacts: injures humans (poisonous )
Asian common toads have a wide diet throughout their range. In Mercy (1999) found evidence that these toads eat insects that are known to be a problem to farmers in India.
Positive Impacts: controls pest population
Relation to Humans
Exterminates crop pests and other insects.
Duttaphrynus melanostictus is commonly called Asian common toad, Asian toad, black-spectacled toad, common Sunda toad and Javanese toad. It is probably a complex of more than one toad species that is widely distributed in South and Southeast Asia.
The species grows to about 20 cm (8 in) long. The species breeds during the monsoons and the tadpoles are black. Young toads may be seen in large numbers after the monsoons.
The top of the head has several bony ridges, along the edge of the snout (canthal ridge), in front of the eye (pre-orbital), above the eye (supra-orbital), behind the eye (post-orbital), and a short one between the eye and ear (orbito-tympanic); The snout is short and blunt and the space between the eyes is broader than the upper eyelid width. The ear drum or tympanum is very distinct and is at least as wide as two thirds the diameter of the eye. The first finger is often longer than the second and the toes at least half webbed. A warty tubercle is found just before the junction of the thigh and shank (sub-articular tubercle) and two moderate ones are on the shank (metatarsus). There is no skin fold along the tarsus. The "knee" (tarso-metatarsal articulation) reaches the tympanum or the eye when the hind leg is held parallel along the side of the body. The dorsal side is covered with spiny warts. The parotoids are prominent, kidney-shaped or elliptical and elongated. The dorsal side is yellowish or brownish and the spines and ridges are black. The underside is unmarked or spotted. Males have a subgular vocal sac and black pads on the inner fingers that help in holding the female during copulation.
Distribution and habitat
Asian common toads occur widely from northern Pakistan through Nepal, Bangladesh, India including the Andaman and Nicobar Islands, Sri Lanka, Myanmar, Thailand, Laos, Vietnam, Cambodia and southern China, Taiwan, Hong Kong and Macau to Malaysia, Singapore, and the Indonesian islands of Sumatra, Java, Borneo, Anambas and Natuna Islands. They have been recorded from sea level up to 1,800 m (5,900 ft) altitude, and live mostly in disturbed lowland habitats, from upper beaches and riverbanks to human-dominated agricultural and urban areas. They are uncommon in closed forests.
They were introduced to the Indonesian islands of Bali, Sulawesi, and Ambon and to (Indonesian) New Guinea at Manokwari on the Vogelkop Peninsula. The species is now common at Sentani in far eastern Papua Province. The species arrived in Madagascar in 2011 at the port of Toamasina and by 2014 was found in a 100 km2 zone around that city 
Ecology and behaviour
Asian common toads breed in still and slow-flowing rivers and temporary and permanent ponds and pools. Adults are terrestrial and may be found under ground cover such as rocks, leaf-litter, logs, and are also associated with human habitations. The larvae are found in still and slow-moving waterbodies. They are often seen at night under street lamps especially in times when winged termites swarm. They have been noted to feed on a wide range of invertebrates including scorpions. Tadpoles grown in sibling groups metamorphosed faster than those that were kept in mixed groups. Tadpoles have been shown to be able to recognize kin.
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- Boulenger, G. A. (1890). Reptilia and Batrachia. Fauna of British India. London: Taylor and Francis. pp. 505–507. doi:10.5962/bhl.title.5490.
- Frazier, S. (Dec 15, 2011). "Asian Common Toad". Project Noah. 8077245.
- Frazier, S. (Jun 13, 2011). "Southeast Asian Toad, Asian Common Toad, Spectacled Toad". Project Noah. 6894260.
- R., Arnaud (2014-04-17). "Invasion de crapauds venimeux à Toamasina: une menace pour l'écosystème malgache". Midi Madagasikara.
- Berry, P. Y.; Bullock, J. A. (1962). "The Food of the Common Malayan Toad, Bufo melanostictus Schneider". Copeia 1962 (4): 736–741. JSTOR 1440674.
- Saidapur, S. K.; Girish, S. (2001). "Growth and Metamorphosis of Bufo melanostictus Tadpoles: Effects of Kinship and Density". Journal of Herpetology 5 (2): 249–254. JSTOR 1566115.
- Saidapur, S. K., Girish, S. (2000). "The Ontogeny of Kin Recognition in Tadpoles of the Toad Bufo melanostictus (Anura; Bufonidae)". Journal of Bioscience 25 (3): 267–273. doi:10.1007/BF02703935. PMID 11022229.
Lu, W.; Qing, N. (2010). "Bufo melanostictus (Asian Common Toad). Record size". Herpetological Review 41 (1): 61.