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Some observations of malformation, eye disease,
parasitic and viral infection and the effects of
agrochemicals on amphibians in Sri Lanka
By Anslem de Silva
There is archaeological, historical and literary evidence to
show that from early Christian times amphibians have
attracted the attention of the people of Sri Lanka. This is
evident from the discovery of bronze casts of frogs belonging to the
6 th to 8 th century AC, including a unique and accurately made gold
cast of a Euphlyctis cyanophlyctis or the Skipper frog (Figure 1).
Figure 1. Gold
casts of a frog
(6 th to 8 th century
AC). Photo
Anslem de Silva
1.1. Lower jaw deformity (Brachygnathia)
A case of deformed lower jaw in a female Fejervarya kirtisinghei
(Manamendra-Arachchi & Gabadage, 1996) measuring 45 mm from
Ambagamuwa (Figure 2).
1.2. Body Deformities (Curvature/Scoliosis)
Body deformities in frog species Sphaerotheca breviceps and
Fejervarya kirtisinghei. The conditions were also evident in the
radiographs (Figures 3, 4).
There are also about 150 villages, ponds and marshes with names
associated with frogs dating from the time of the early Sinhalese
kings. Thus, it is reasonable to assume that the early inhabitants
of the island would have understood the ecological role played by
amphibians in agriculture, their association with water and the
beneficial effects played by frogs through preying on insect pests.
A study was conducted in the 3 main climatic zones (wet,
intermediate and dry zones) of the country from July 2008 to July
2009 during which various malformations, eye diseases, infections
and the effects of agrochemicals on amphibians were identified
(de Silva, 2009). Others have also shown assorted threats to the
amphibian populations in Sri Lanka (de Silva, 2001a; de Silva,
2001b; de Silva and de Silva, 2001; de Silva et. al., 2008; de Silva
et. al., 2009a; de Silva et. al., 2009b; de Silva and Dawundasekara,
2010; Rajakaruna at al., 2007).
Figure 3. (left) Scoliosis, Sphaerotheca breviceps. Photo Anslem de Silva
Figure 4. (right) Radiograph of Sphaerotheca breviceps. Photo Anslem de Silva
1.3. Forelimb malformations
Several adult frogs (e.g. Fejervarya greenii, Fejervarya
limnocharis, Hylrana gracilis, Microhyla ornata, Kaloula
taprobanica, Duttaphrynus scaber and Pseudophilautus auratus)
with various stages of deformities ranging from missing fingers to
no hand (wrist downwards) (Figure 5).
The following are some of what we recorded during the study:
1. Malformations
Among the malformations to amphibians observed were:
Figure 5. Hylrana
gracilis with no hand.
Photo Anslem de
Silva
1.4. Hind limb malformations
The following examples of malformed hind limbs:
a. Ectromelia of the left hind limb in a male Ramanella variegata
(Stoliczka, 1872) measuring 25 mm and weighing 0.8 g in
anthropogenic habitat in Mihintale (Figure 6).
Figure 2. Opaqueness
and Brachygnathia
Fejervarya kirtisinghei.
Photo Anslem de Silva
b. Ectromelia of the right hind limb in a Euphlyctis cyanophlyctis
Schneider, 1799 measuring 23 mm in a stream at Labugama (Figure
7).
24 | FrogLog Vol. 98 | September 2011