List of freshwater fauna of Sri Lanka
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Freshwater habitats
Freshwater animals are important to the economy of a country. The animal life in freshwater comprises a great diversity. The organisms ranging from tiny protozoa to large mammals in size. Sri Lanka is a hydraulic civilization. First civilizations in Sri Lanka were originated closer to main rivers in Sri Lanka such as Mahaweli, Kelani, Malwathu and Gin Ganga. Rivers in Sri Lanka flow in a radial pattern, from central hills where there are numerous waterfalls, the rivers flowing to the west, east and south being shorter than thoe flowing to north., north west and north east. Several streams join these rivers. Some of the streams in the hill country and mid country are quick flowing streams known as torrential streams.
Sri Lankan freshwater habitats can be divided into 6 major types - river, stream, lake, pond, villu and paddy field - according to size, depth, rate of flow and type of bottom. Medium-sized rivers are called Oya and fast flowing streams torrential streams are called Dola in Sinhalese. The following list provide the freshwater fauna of Sri Lanka.
Adaptations of freshwater fauna
The life history of any animal is divisible into 3 phases, initially a period of slow development, followed by a rapid growth with a voracious appetite and finally to an adult which breeds at regular intervals and continue to grow slowly. Most freshwater animals breed during or after monsoon rains where water is available for the young to spread over a wide area where crowding is less and there is a plentiful supply of food in the form of minute plants and animals.[1]
During dry season, conditions in temporary habitats become less and less favourable for aquatic animals. Those cut off in small habitats are quickly killed off, others in larger habitats survive longer. During this period, food become scarce and water level reduces. Animals become weakened or diseased and die or are eaten by birds and terrestrial animals. Many freshwater animals show adaptations to drought conditions. Fish with air breathing ability, utilize atmospheric oxygen to moisten gills, mud burrowing ability are some of them. Smaller crustaceans, produce eggs with hard resistant covering capable of surviving even a severe drought. These cysts are blown by wind and the species is dispersed. Freshwater crabs and prawns carry their eggs until they hatch out, while leeches carry the young in a pouch.
Researches on Sri Lankan freshwater fauna
Knowledge of Sri Lankan freshwater fauna has been considerably enhanced in the last twenty years or so in two ways. One is through the publication of monographs. The other way is through Swedish Expedition and Smithsonian Institution.[2] Several animals groups were identified extensively from Sri Lanka, such as fish, amphibians, odonates and arthropods.[3] Other freshwater fauna of Sri Lanka need more detailed work, which are currently based on the notes of way back in British period.[4] According to the National Red Data List in 2012, many freshwater habitats are degraded at an alarming rate due to rapid human interference. Habitat destruction, fragmentation and loss of forest cover has increased in past decade rapidly. The result becomes severe, where many amphibians have been not recorded after their discovery, which led the scientists to categorize Sri Lanka as a biodiversity hotspot.[5]
Protozoa
Family: Amoebidae
Phylum:
Family: Actinophryidae
Phylum:
Family: Arcellidae
Phylum: Amoebozoa
Class: Tubulinea
Order: Arcellinida
- Arcella discoides
- Arcella vulgaris
- Sphenoderia lenta
Family: Centropyxidae
Phylum: Amoebozoa
Class: Tubulinea
Order: Arcellinida
- Centropyxis aculeata
Family: Ceratiaceae
Phylum:
Family: Clathrulinidae
Phylum:
Family: Codonellidae
Phylum:
Family: Difflugiidae
Phylum: Amoebozoa
Class: Tubulinea
Order: Arcellinida
- Difflugia acuminata
- Difflugia arcula
- Difflugia constricta
- Difflugia corona
- Difflugia globulosa
- Difflugia lobostoma
- Difflugia pyriformis
- Difflugia urceolata
- Lesquereusia spiralis
Family: Epistylidae
Phylum:
Order: Sessilida
Family: Euglenaceae
Phylum:
Order: Euglenales
- Euglena sp.
Family: Euglyphidae
Phylum: Cercozoa
Class: Imbricatea
Order: Euglyphida
Family: Glaucomidae
Phylum:
- Colpoda cucullus
Family: Hyalospheniidae
Phylum: Amoebozoa
Class: Tubulinea
Order: Arcellinida
Family: Ichthyophthiriidae
Phylum:
Family: Oxytrichidae
Phylum:
Family: Parameciidae
Phylum:
- Paramecium sp.
Family: Pelomyxidae
Phylum:
Family: Peridiniaceae
Phylum: Myzozoa
Class: Dinophyceae
Order: Peridiniales
Family: Trichodinidae
Phylum:
Family: Volvocaceae
Phylum: Chlorophyta
Class: Chlorophyceae
Order: Chlamydomonadales
- Volvox aureus
Family: Vorticellidae
Phylum:
- Vorticella sp.
Moss animals
Phylum:
Family: Pectinatellidae
Family: Plumatellidae
Hairybacks
Phylum:
Order: Chaetonotida
Family: Chaetonotidae
Sponges
Phylum:
Order: Spongillida
Family: Spongillidae
Cnidarians
Phylum: Cnidaria
Class: Hydrozoa
Order: Anthoathecata
Family: Hydridae
Wheel animals
Phylum:
Sri Lankan freshwaters are home for 124 species of wheel animals.[6]
Flatworms
Phylum: Xenacoelomorpha
Order: Acoela
Family: Convolutidae
Phylum:
Order: Rhabdocoela
Family: Scutariellidae
Family: Typhloplanidae
Phylum:
Family: Pleurogenidae
Phylum:
Family: Bothriocephalidae
Roundworms
Phylum:
Family: Dorylaimidae
- Dorylaimus sp.
Class: Chromadorea
Order: Rhabditida
Family: Camallanidae
- Zeylanema anabantis
- Zeylanema fernandoi
- Zeylanema kulasirii
- Zeylanema mastacembeli
- Zeylanema pearsi
- Zeylanema sweeti
- Procammallanus spiculogubernaculus
- Procammallanus planoratus
Gordian worms
Phylum:
Order: Chordodea
Family: Chordodidae
Segmented worms
Phylum:
Family: Aeolosomatidae
Class: Clitellata
Order: Haplotaxida
Family: Naididae
- Allonais paraguayensis
- Aulophorus michaelseni
- Aulophorus tonkinensis
- Bothrioneurum iris
- Chaetogaster sp.
- Dero digitata
- Dero zeylanica
- Limnodrilus hoffmeisteri
- Pristina (Pristina) breviseta
- Pristina (Pristina) proboscidea
Family: Almidae
- Glyphidrilus sp.
Order: Rhynchobdellida
Family: Ozobranchidae
Family: Galeommatidae
Family: Glossiphoniidae
- Paraclepsis vulnifera
- Placobdella ceylanica
- Placobdella emydae
- Placobdella undulata
- Limnatus paluda
- Dinobdella ferox
Order: Arhynchobdellida
Family: Hirudinidae
Molluscs
Phylum: Mollusca
Class: Gastropoda
Order: Cycloneritida
Family: Neritidae
Order: Caenogastropoda
Family: Pachychilidae
- Faunus ater
- Melanoides broti
- Melanoides crenulata
- Melanoides lineata
- Melanoides tuberculata
Family: Thiaridae
- Thiara datura
- Thiara rudia
- Thiara scabra
References
- ^ "Some aspects of ecology of endemic freshwater fishes of Sri Lanka". University of Kelaniya. Retrieved 12 April 2019.
- ^ "Guide to the Freshwater Fauna of Ceylon (Sri Lanka)" (PDF). Bull. Fish. Res. Stn., Sri Lanka (Ceylon), Vol. 25, Nos. 1 and 2, 1974 pp. 27-81. Retrieved 12 April 2019.
- ^ "Sri Lanka Freshwater Fauna and Fisheries. A Guide to the Freshwater Fauna of Sri Lanka and a Genesis of the Fisheries by CH Fernando and SR Weerewardhena (2002)". African Journal of Aquatic Science. Retrieved 12 April 2019.
- ^ "A guide to the freshwater fauna of Ceylon". Bulletin of the Fisheries Research Station, Ceylon. Retrieved 12 April 2019.
- ^ "The National Red List 2012 of Sri Lanka" (PDF). Biodiversity Secretariat of the Ministry of Environment. Retrieved 12 April 2019.
- ^ "Rotifera froin Sri Lanka (Ceylon) new Species with a List of Rotifera Recorded and their Distribution in Different habitats from Sri Lanka" (PDF). Bull. Fish. Res. Stn., Sri Lanka (Ceylon), Vol. 25, Nos. 1 and 2, 1974, pp. 83-96. Retrieved 12 April 2019.