Toads of Pakistan

 

 

 

 


Souteast Asian Toad

Bufo melanostictus

 

Description:

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.

 

Distribution and Habitat:
Country distribution from AmphibiaWeb's database: Bangladesh, China, Hong Kong, India, Indonesia, Lao People's Democratic Republic, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Taiwan, Province of China, Thailand, Vietnam.

 

Until recently Bufo melanostictus was reported to as the common toad of Indo-Pakistan subcontinent (GŁnther, 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).

 

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).

 

Trends and Threats:
Species of rugged mountains. Breeds in paddy fields, where pollution by chemicals affect its eggs and larvae.

 

Relation to Humans:
Exterminates crop pests and other insects.

 

Comments:

In Pakistan this toad is a highland form, does not extend in the Indus Valley.

 

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

 

Reference:

None

 

Credits: All information, pictures and maps property of:

  • Dr. Muhammad Sharif Khan

  • AmphibiaWeb(http://elib.cs.berkeley.edu/aw)

Click to Enlarge

Click to Enlarge

copyright 1999-2002-wildlife of Pakistan-all rights reserved

1