Vertebrate Group

Reptiles

The reptilian fauna of Sinharaja is represented by 45 species, of while 21 are endemic. This includes a large proportion of snakes, several lizards, tortoises and skinks (Table 9). Among the snakes, two very rare species have been recorded. These are the burrowing fossorial species Rhinophis tricolorata and Haploceros ceylonensis. Rhinophis was first described as recently as 1975 and was sighted at Sinharaja in 1982, the first time it was found in the wild. Haploceros was considered to be a rare montane species found at elevations of 1,700 to 2,300 meters, until it was recorded in Sinharaja at elevations of 300 to 500 meters

Among the venomous species that occur in the forest are the Green-pitviper while is arboreal, the Hump-nosed Viper and the Krait while frequents the forest floor. The Cobra is seen occasionally while the Russel's Viper has been observed in secondary vegetation, although not seen in the undisturbed forest.

Among the lizards, the commonest is the familiar Green Garden Lizard. Several rare and endemic species of lizards are found in the forest (Table 11). Among these are Calotes liopepis, an arboreal species while is one of the rarest the island, the Hump-nosed Lizard, the largest lizard in the island; the Earless Lizard and the Rough-nose Horned Lizard are species of the forest floor with very restricted distribution being confined to undisturbed rain forests. A few species of geckos are also common.

The skinks found in the wet-zone of Sri Lanka are of evolutionary significance. The five genera of limbless lizards or the Acintoniae exhibit a progressive series from limbed to limbless forms. The only other centres of distribution of these genera are Madagascar and South Africa. In the Sinharaja, this group is represented by Nessia burtoni or the Three-toed Skink, an endemic genus. However, it is most likely that several more species of unidentified skinks may be present.   

Amphibians

The rain forest is the habitat parexcellence for amphibians. It is not surprising therefore that half the total number of amphibian species in sri Lanka and nearly half the endemic amphibian are represented in Sinharaja. These amphibians are mainly frogs and toads and a single limbless form (Table 12).

Table 12. Amphibians of Sinharaja.

One of the commonest frogs in the forest is the Wrinkled Frog heard frequently from marshes and streams. Several species of tree frogs and the Reed frog while has a call similar to that of a bird can be heard distinctively at night.

The moist environment is conducive for the Sharp-nosed Tree Frog to lay its eggs in a nest of foam on the underside of Cardamom leaves overhanging a stream. This enables the young tadpoles to drop straight into the water when they hatch out. The Lesser Sharpnosed Tree Frog adopts a different strategy. It lays eggs on leaf little where rain water has accumulated. The life cycle is completed within the egg thereby avoiding a free swimming tadpole stage. Others such as Ramnella palmata live their whole life cycle in tree rot holes filled with rain water. The Guenther's Cliff Frog inhabits vertical rock faced covered with dripping water. the young tadpoles are adapted to living on the wet rock face. These strategies among the amphibia could only be possible in an ever-wet environment. The discovery of Guenther's Cliff Frog in 1982 is particularly significant because its sighting at Sinharaja is the first since the type specimen was collected in 1890.

The Yellow-banded Caecilian the only limbless amphibian recorded at Sinharaja, inhabits marshy edges and lives under the wet earth.

Fish

The fish show little diversity with only three species commonly occurring in all forest streams. All these species are endemic to the island. The Comb-tail (Belontia signata) with red tinted fins and tail is found slow moving streams. The Stone-sucker (Garra lamata ceylonensis) is found clinging to rocks where if feeds on moss and the striped loach (Neomachilus notostigma) is found among the leaf little at the bottom of streams.

Invertebrate Fauna

Although the forest teems with all kinds of insects and other invertebrate fauna, very little information is available on these groups of animals. So far only two groups of insect have been considered in depth viz. mosquitoes  and butterflies. However, the Sinharaja has featured prominently in surveys of Sri Lanka insect fauna conducted by the Smithsonian Institution. It is evident from these studies that there is much scope for detailed investigations of the invertebrates.

Studies on the mosquito fauna have shown that at least 27 species have been recorded as adults. The majority, 21 species, were found to breed in surface water sources. The rest used more specialised habitats for breeding. For instance Orthopodomia flavithorax and Culex uniforms breed in tree rot holes filled with water, while C. uniformis and Tripteroides affinis and a few other species use water filled bamboo culms. The most fascinating of all, are the two species Tripteroides dofleini and Armigeres magnus that breed exclusively within the pitcher of Nepenthes distillatoria.

The butterfly fauna of the forest has only been listed, and so far 65 species have been recorded in the western sector of the forest. These include 2 endemic species and 19 endemic subspecies (Table 13). Among the common and more interesting butterflies one comes across in the forest are the Tree Nymph, a large black and white butterfly that inhabits the forest canopy, the Common Bird-wing reputed to be the largest butterfly in the country, the Clipper, the Cruiser and the most beautiful of all, the iridescent Blue-banded Peacock. One of the rarest species in Sri Lanka, the Five bar Swordtail, can also be seen during the months of March and April, the season of butterfly migration

Table 13. A few common and interesting butterflies of Sinharaja.

                 * Endemic species 

Of the insects at sinharaja, of species interest are two endemic species of wasps of the family Loboscelidae. They are parasitic on Stick insects. The Sinharaja is the only known location where they have been recorded from the Asian region, the other centres of distribution of this family being New Guinea and Australia.

 Of the invertebrate forms, the land leech Haemadipsa ceylanica is the one most frequently encountered, a fact that becomes all too evident to any visitor to the Sinharaja. Several other commonly encountered species are worthy of mention; the Giant earthworm (Megascoles coeruleus) at least half a metre in length, and three centimeters in diameter and deep three centimeters in diameter and deep blue in colour, the Giant millipede (Spirostreptus sp.) and the Giant pill-box millipede (Arthosheaera versicolor). One of the commonest spiders encountered is the Giant woodspider (Nephila maculata). The large and beautiful spider seen on the web is the female while the small almost unnoticeable little red spider is the male. Several species of Tarantula (Poccilotheria spp.) are also common in the forest. At night the Scorpion (Heterometrus spp.) can be seen along the logging roads and skid trails.      

Future Directions

Although faunal studies have been established only recently, scientists and students have begun to show great interest in continuing the research work. It is hoped therefore that all forms of fauna would soon be under systematic surveillance and study. Existing base-line data on the vertebrates should be completed by conducting similar inventories for the relatively undisturbed eastern sector of the reserve. Detailed studies of their population and distribution are vital if these species are to be conserved. Meanwhile, systematic studies on invertebrates should be stepped up since many new species await discovery.   

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