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Wildlife of Sri Lanka includes its flora and fauna and their natural habitats. Sri Lanka has one of the highest rates of biological endemism (16% of the fauna and 23% of flowering plants are endemic) in the world.
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Ecological zones
The mountains and the southwestern part of the country, known as the "wet zone," receive ample rainfall (an annual average of 2500 millimeters). Most of the southeast, east, and northern parts of the country comprise the "dry zone, which receives between 1200 and 1900 mm of rain annually.
Mammals
Sri Lanka is home to roughly 23 species of mammals, 41 of which are threatened (9 critically). 16 of the species are endemic, of which 14 are threatened, including the large sloth bear. mammalian orders), with 30 different species. Sri Lanka's surrounding waters are home to 28 species of Cetaceans.
Reptiles
Sri Lanka currently contains 173 species of reptiles, of which 56 are threatened and 103 are endemic. Most of the reptiles are snakes and the largest are two species of crocodile, the mugger crocodile and saltwater crocodile.
Amphibians
Sri Lanka has one of the richest diversity of amphibians in the world, containing over 140 species of amphibians up to 2015, with 109 endemic species. and has been claimed to have the highest amphibian species density in the world though that has been challenged. 52 species of amphibians in Sri Lanka are threatened, all but one of which are endemic.
Birds
Sri Lanka is home to 227 species of birds (though some past estimates put it as high as 486), 46 of which are threatened (10 critically).
Fish
Sri Lanka contains 93 species of freshwater fish, and 50 of which are endemic to the country. 28 species are categorized as threatened by IUCN. There are 8 species of brackish water fish that also come to freshwater, and 24 introduced exotic fish species.
Insects
Insects belonging to all 32 orders except Grylloblattodea have been recorded from the Sri Lanka.
Minor insects
The exact species for other orders is still not classified and documented. Walker on 1861, listed 2,007 species belongs to 9 insect orders and Haly on 1890 identified 1,510 beetle species from Sri Lanka. However, after series of many publications from many foreign entomologists, Two Sri Lankan entomologists, Anura Wijesekara and D.P Wijesinghe precisely documented 11,144 insect species belongs to 30 orders from Sri Lanka in 2003.
Hubbard and co-workers documented 46 species in 8 families of order Ephemeroptera. Henneman in 2002 recorded 69 species in order Orthoptera. He also collected few specimen of order Phasmatodea around central hills. 66 species of order Blattodea are found, but not taxonomic evidences. Few species of the order Mantodea were studies by Henry in 1931. Clear documentation of the species within Dermaptera can be found, which was initiated by Burr (1901) and Brindle (1972). Within the termite infraorder Isoptera, 56 species recorded. In 1913, Green compiled a concise catalogue for isopterans in Sri Lanka.
Only 4 species of order Embioptera are recorded. in the order Psocoptera, two subfamilies studied. They are Epipsocidae and Pseudocaeciliidae. Informations of the species of the orders Thysanoptera, Neuroptera, Mecoptera, and Siphonaptera are very few and more studies are required. Only the family Coniopterygidae of Neuroptera have been studied in 1982.
Sri Lanka is known to home for 794 species of Hemipterans. Detailed work of Sri Lankan hemipterans are recorded in book "Catalogue of Hemiptera of Sri Lanka. Checklists on orders Trichoptera and Strepsiptera are well documented, but recent work is needed.
Major insects
True flies and mosquitoes belongs to order Diptera is much highly recorded from Sri Lanka. There are more than 1,341 dipterans found in the island, which earns fourth largest insect order found.
Hymenopterans, which includes ants, bees, wasps contribute to the third largest insect order in Sri Lanka. Lepidopterans, the moths and butterflies has the second largest number of species in Sri Lanka. Coleoptera, which is the largest order in whole insect world, also the largest in Sri Lanka, contribute with 3,033 documented species.
Bees
There are about 70,000 species of bees of order Hymenoptera described in the world with nearly 450 genera and 7 families. Out of them, Sri Lanka comprises 148 species included to 38 genera and 4 families.
Odonates
Damselflies categorized in to Suborder: Zygoptera; and dragonflies into Suborder: Anisoptera. There are 121 described species within 13 families can be found in Sri Lanka. 59 species from them are endemic.
Lepidopterans
245 butterflies species are recorded from Sri Lanka of which 24 are endemic to the island. 1695 species of moths are also found, but the endemism is unknown.
Aphids
Sri Lanka comprises 74 species in 46 genera and 6 families of aphids within order Hemiptera. 2 endemic aphid species found on Sri Lanka.
Ants
Sri Lanka is home to 181 species of ants that included to 61 genera and 10 subfamilies. One endemic genus Aneuretus is also included to the list.
Mosquitoes
About 131 species of mosquitoes that included to 16 genera are described and documented from Sri Lanka. Though they are primarily vectors of many human diseases, majority of mosquitoes in Sri Lanka are harmless to humans and livestock.
Freshwater crabs
All recorded 51 species along with 5 genera in the family Gecarcinucidae are totally endemic to Sri Lanka. 98% of those crabs are IUCN categorized as threatened, endangered or critically endangered animals.
Mangrove crabs
The exact number of species around mangroves and estuaries within coastal marine regions is not clear. but during a research on diversity of mangrove crabs in Kadolkele, Negombo, five species identified, with two new species earlier not document from Sri Lanka. Most marine crabs are much larger and often caught in fishing nets. They are edible foods with high protein. Some of marine edible crabs from Sri Lanka are
Molluscs
There is known over 246 land gastropods of Sri Lanka with 83% endemicity. Sub class Pulmonata consists of 159 species within 23 families and subclass Prosobranchia by 88 species in four families. A total of five land snail genera, namely, Ravana, Ratnadvipia, Acavus, Oligospira and Aulopoma are endemic to Sri Lanka with 14 species included to these genera. Thirteen more genera such as Ruthvenia, Thysanota, Cryptozona, Euplecta, Mariaella, Eurychlamys, Corilla, Beddomea, Trachia, Leptopomodes, Micraulax, Tortulosa and Nicida are restricted to Western Ghats of India and Sri Lanka. 18 species are recorded as exotic species and agricultural pests.
Fauna of Sri Lanka also include freshwater snails. The number of marine molluscs of Sri Lanka is not known and there is about 240 species listed meantime in 2006.
Myriapods
The diversity of subphylum Myriapoda, is not well studied in Sri Lanka recently. The remaining facts and checklists of these creatures are dated back to Newport in 1845, which is the first known study about centipedes. Many of centipede works are done more than a century. When considering millipede diversity, which is much higher in study than centipedes. Currently, 104 species of millipedes and 19 species of centipedes are known from Sri Lanka.
Spiders
The detailed work on Sri Lankan spiders were done through checklist by Manju Siliwal and Sanjay Molur's detailed checklist of spiders of South Asia including 2006 revision of Indian spider checklist. This checklist provided all the described spider species of South Asia and part of South-East Asia as well.
According to this checklist, Sri Lanka has 501 species of spiders belongs to 45 families and 213 genera. Out of these 360, 250 are endemic spiders to Sri Lanka with 22 endemic genera.
Ant-mimicking spiders
Spiders in genus Myrmarachne are commonly called ant-mimicking spiders. They are grouped in the family Salticidae of order Araneae. Out of 100+ species described, 12 species are found in Sri Lanka. Three species were described in 2015.
Tarantulas
There are 8 species of tarantulas are recorded from Sri Lanka. When considering with Indian subcontinent, 15 species of Poecilotheria are recorded from both countries; seven endemics from India and seven endemics from Sri Lanka. One species found in both countries.
Scorpions
There are 18 species of scorpions which are found in Sri Lanka. Out of these 18 species, 7 species are endemic to Sri Lanka. In addition to the endemic species, 4 subspecies of the 9 non-endemic species are also endemic to Sri Lanka.
Sri Lankan scorpions are included in 3 families.
- Family Buthidae
- Family Chaerilidae
- Family Scorpionidae
Ticks and Mites
Ticks belong to superfamily Ixodoidea of the order Parasitiformes. 27 species of Ixodid ticks, commonly called hard ticks, of the family Ixodidae belonging to nine genera have been reported to date from Sri Lanka.
Flora
Diversity and endemism of plants in Sri Lanka are quite high. There are 3,210 flowering plants belonging to 1,052 genera. 916 species and 18 genera are endemic to the island. Additionally, all but one of the island’s more than 55 dipterocarps are confined to Sri Lanka. Although not lately assessed, Sri Lanka’s ferns are estimated at about 350 species. Diversity, richness, and endemism across all taxa groups are much higher in the wet zone than in the dry zone. Wet zone, which accounts for only a quarter of Sri Lanka’s land area, harbours 88 percent of the flowering plants, and 95 percent of country's flowering plant endemics. The natural forests of Sri Lanka are categorized into eight types.
Sri Lankan Environmentalist, Dr. Gothami Weerakoon has discovered 51 new varieties of Lichens endemic to Sri Lanka, where 8 of them were found from the Knuckles Mountain Range. While Dr. Udeni Jayalal et al found 2 new lichens from Horton Plains in 2012, as Anzia mahaeliyensis and Anzia flavotenuis.
A new Gesneriaceae species Henckelia wijesundarae, endemic to Hiniduma, Galle is described and illustrated in 2016 by Subhani Ranasinghe et. al.