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Description
A large, robust toad. 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 elliptical, 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 peel off in preserved specimens; head is almost smooth.
Khan (2001) has distinguished the 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.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Bangladesh, Bhutan, Brunei Darussalam, Cambodia, China, Hong Kong, India, Indonesia, Lao People's Democratic Republic, Malaysia, Maldives, Myanmar, Nepal, Pakistan, Singapore, Sri Lanka, Taiwan, Thailand, Viet Nam Malaysian region distribution from AmphibiaWeb's database: Peninsular Malaysia, Sabah, Sarawak
The Asian Common Toad is a widespread species occurring throughout South-East Asia and southern China, south to East Java and Bali and as far west as India and Pakistan.
Until recently this species was reported 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 the rugged mountains of District Hazara, Northwestern Frontier Province, Alpine Punjab and Azad Kashmir (Mertens, 1969a; Khan, 1972a).
It is a human commensal species often occurring in disturbed habitat or man-made habitat.
Life History, Abundance, Activity, and Special Behaviors
Life history: 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, coming 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 synchronized 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).
Trends and Threats
Breeds in paddy fields, where pollution by chemicals affect its eggs and larvae.
Relation to Humans
Exterminates crop pests and other insects.
Possible reasons for amphibian decline General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Prolonged drought
Drainage of habitat
Local pesticides, fertilizers, and pollutants
Long-distance pesticides, toxins, and pollutants
Comments
In Pakistan, this toad is a highland species and does not extend in the Indus Valley.
Recent geographic, genetic and ecological analysis show that Duttaphrynus melanostictus is comprised of three distinct lineages: Asian mainland, coastal Myanmar, and Sundaic islands. Likely these lineages represent at least three and possibly multiple species, which have higher conservation value than currently recognized. The species complex has been introduced to such distant places as Borneo, Sulawesi and Seram, and even Madagascar (Wogan et al 2015). However, more work is required to determine species delineations and even which species have been introduced.
This Species was featured in News of the Week 18 July 2022:
Amphibians are generally considered saltwater intolerant, although many amphibian species are found in coastal areas. How will climate changes such as increasing temperature, sea levels, and storm surge events impact amphibian survival? Using three coastal frog species (Duttaphrynus melanostictus, Fejervarya limnocharis and Microhyla fissipes), Chuang et al. (2022) tested the effects of salinity on both tadpole survival and the ability to withstand high temperatures (critical thermal maxima or CTmax). They found in all species exposure to high salinity treatments lowered survival, the maximum temperature that tadpoles could withstand, and development rate. Their study shows that rising temperatures and increased salinity exposure might be a double whammy for tadpoles. This study highlights the importance of including and measuring multiple stressors in climate changes studies because environments are predicted to change in multiple ways that can have compounding effects on organisms. (Written by Molly Womack)
References
Church, G. (1960). ''The invasion of Bali by Bufo melanostictus.'' Herpetologica, 16(1), 15-21.
Khan, M.S. (1982). ''Collection, preservation and identification of amphibian eggs from the plains of Pakistan.'' Pakistan Journal of Zoology, 14, 241-243.
Khan, M.S. (1991). Morphoanatomical specialization of the buccopharyngeal region of the anuran larvae and its bearing on the mode of larval feeding. Unpublished Ph.D. dissertation, University of the Punjab, Lahore, Pakistan.
Mertens, R. (1969). ''Die Amphibien und Reptilien West-Pakistans.'' Stuttgarter Beiträge zur Naturkunde, 197, 1-96.
Natarajan, R. (1953). ''A note on the chromosomes of Cacopus systoma.'' Proceedings of the 40th Indian Science Congress, Part 3, 180-181.
Wogan, Guinevere O. U., Stuart, Bryan L., Iskandar, Djoko T., and McGuire, Jimmy A. (2015). ''Deep genetic structure and ecological divergence in a widespread human commensal toad.'' Biology Letters, 12(1).
Originally submitted by: M. S. Khan (first posted 2000-08-30)
Edited by: Michelle S. Koo (2022-07-17)Species Account Citation: AmphibiaWeb 2022 Duttaphrynus melanostictus: Southeast Asian Toad <https://amphibiaweb.org/species/236> University of California, Berkeley, CA, USA. Accessed Nov 7, 2024.
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Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 7 Nov 2024.
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