- Source: Lepidocephalichthys jonklaasi
Lepidocephalichthys jonklaasi, known as the Jonklaas's loach or the spotted loach, is an endemic fish species restricted to the wet zone of Sri Lanka. The species was first recorded from the Wilpita area (Daraniyagala 1952). It is currently known from 12 locations in the wet zone including Beraliya, Dombagaskandha, Madakada, Gilimale, Hiyare, Kottawa, Kanneliya, Weddagala, Nakiyadeniya, Pahiyangala and Boralugoda. It is recorded from a wide range of altitudes. Due to its restricted range and the threats to its habitat Lepidocephalichthys jonklaasi, is listed as an Endangered species. The species has already begun to disappear from some of the sites mentioned above due to destruction and fragmentation of its habitat and many other threats that are operating on the species.
Named in honor of Rodney Jonklaas (1925–1989), a Sri Lankan diver who was an underwater photographer and also a zoo administrator.
Morphology
Members of the genus Lepidocephalichthys have a sharp, erectile spine on their cheeks. In some species the spine is sharp enough to puncture easily one's hand during handling of the live fish. However, it is not venomous or harmful. These fish have an ancillary respiratory mechanism where they swallow air, which is then used to oxygenate the blood that passes through the walls of the intestines. Unlike the case of the channids and anabantids, the air is not expelled through the mouth or gills, but via the anus. This enables them to survive in very poorly oxygenated water although in Sri Lanka, by and large, they occur in habitats that do not require this facility and are not generally considered as “air breathers”. The loaches are small, eel-like or worm-like fish, often attractively colored. They have (often rudimentary) cycloid scales and three pairs of barbells. Mature males in many species have highly modified pectoral fins (Roberts, 1989). Little is known about the breeding habits of the members of this family Cobitidae and only a few species have been bred in captivity to date.
= Related species and diagnosis
=Also Lepidocephalichthys thermalis is found in Sri Lanka. Jayaram (1981) reports that at least six other species occur in the north-eastern part of India (Assam to Burma). Tilak & Hussain (1981) have written a review on the systematics of the Indian members of the genus.
Lepidocephalichthys jonklaasi is distinguished from L. furcatus, L. micropogon, L. manipurensis, and L. goalparensis by rounded/truncated (vs. forked) caudal fin, from L. irrorata and L. kranos by absence of scales on top of head, from L. guntea, L. hasselti, L. tomaculum, L. alkaia, and L. annandalei by broad regularly spaced dark bars (vs. reticulations, spots, or stripe) on caudal fin, from L. thermalis, L. arunachalensis, L. coromandelensis, and L. berdmorei by vertically elongated, dark spots on side that form irregular, thin bars (vs. round spots that sometimes form squares or thin stripe), and from L. lorentzi by thinner, more irregularly spaced dark side bars, dorsal-fin origin anterior (vs. posterior) to pelvic-fin origin, and larger size (to 45 vs. 33 mm SL), (Havird & Page 2010).
The two Sri Lankan species L. jonklaasi and L.thermalis are not very closely related. They are easily differentiated by body shape and proportions, colour pattern, and form of sexual dimorphism that is unique to L. jonklaasi. Further, a mature adult L. jonklaasi is significantly longer than L. thermalis. It is not easily confused with L. thermalis owing to its distinctive colour pattern and robust, tubular body.
Colouration
The sides are yellow, darkening dorsally, and are mottled with several chaotically arranged, large spots.
Secondary sexual characters
Daraniyagala 1956, and De Silva 1963, observed that the last pectoral fin ray was ossified in some specimens, but did not consider this as a secondary sexual character. However, it is in fact present only in males and can therefore be used to differentiate between males and females.
Reproduction
Breeding of this has not observed either in the wild or captive conditions.
Habitat and microhabitats
Very little is known of the biology of this species. It has been recorded by Pethiyagoda only from its type locality in Wilpita, Akuressa. This stream traverses through thick forest with dense undergrowth. The stream is very shallow and the substrate is entirely of fallen leaves and silt. The flow of water in the stream is very slow, in terms of volume perhaps only several litres per minute. The fish are not visible from the surface, being always concealed beneath leaf debris in the water.
Distribution
L. jonklaasi was originally described in 1952 by PEP Daraniyagala as member of the genus Lepidocephalus (synonymous with Lepidocephalichthys). The locus typicus is Wilpita Estate near Akuressa in the southern wet zone of Sri Lanka, 500m above sea level. Since then Pethiyagoda reported four additional localities of this species. This species was named in 1956 by Deraniyagala and in 1963 it was reconfirmed by De Silva presenting sufficient data.
There are only 12 site records for this species to date; it's elevated between highest 1000 feet at Gilimale and lowest 350 feet at Hiyare, which belongs to southern-west wet zone in Sri Lanka. Diminutive is known about the biology and ecology of this species. This so even more important as the species has already begun to disappear from number of its recorded locations and soon will be threatened with extinction. Therefore, the sooner the habitats are restored and protected the better to ensure the long-term survival of the species.
Conservation status
According to the 2007 red list of threatened fauna and flora of Sri Lanka, Lepidocephalichthys jonklaasi (Deraniyagala, 1956) is listed in the Endangered category. In the previous redlist published in 2002 it was listed as Endangered as well. In the 1999 red list it has been listed as Threatened species.
L. jonklaasi is listed as protected fish, by the fauna and flora protection ordinance.
Most of factors that have pushed the species towards extinction are interrelated with each other, such as habitat degradation. Due to the changes in land use pattern with increased human population, forest cover of Sri Lanka has reduced from 70% to about 22% of its land area during the twentieth century (anon. 1991). Deforestation, improper cultivation practices in upper catchment areas of drainage basins of rivers and gem mining cause heavy siltation in streams and rivers. Further, as a result of deforestation the shade that is much needed by Lepidocephalichthys jonklaasi (Pethiyagoda 1991) has been lost. These threats should be minimized through appropriate strategies in order to ensure the survival of this endemic freshwater fish.
Utility
Lepidocephalichthys jonklaasi is too rare to be of value to the aquarium fish trade which, in any case, exports large numbers of the superficially very similar L. thermalis.
References
Amarasinghe, U. S.; Shirantha, R. R. A. R.; Wijeyaratne, M. J. S. (2006). "Some aspects of ecology of endemic freshwater fishes of Sri Lanka". In Bambaradeniya, C.N.B. (ed.). The Fauna of Sri Lanka: Status of Taxonomy, Research and Conservation (PDF). The World Conservation Union, Sri Lanka and the Government of Sri Lanka. pp. 113–124. hdl:123456789/4371.
Bambaradeniya, C.N.B. (2003); An overview of the flora and fauna of the Kanneliya- Dediyagala-Nakiyadeniya forest Complex- A Proposed Biosphere Reserve in Sri Lanka; Journal of the National Science Foundation of Sri Lanka.
Bambaradeniya, C.N.B., Perera, M.S.J., Perera, W.P.N., Wickramasinghe, L.J.M., Kekulandala, L.D.C.B., Samarawickrama, V.A.P., Fernando, R.H.S.S., & Samarawickrama, V.A.M.P.K. (2003); Composition of faunal species in the Sinharaja World Heritage Site in Sri Lanka; The Sri Lanka Forester.
Chamikara S.S. (2001); fauna diversity of Beraliya-Mookalana- Pituwala; Ministry of Environment, The Society for Environmental Education; Unpublished report.
Chamikara S.S. (2002); The diversity of freshwater fishes and current status. The Society for Environmental Education; Unpublished report.
Chamikara S.S. (2003); Dombagas kanda mathsya vividatwaya ha warthamana thtwaya (The diversity of freshwater fishes of Dombagas kanda and present status). Parisara sangrahaya (May–June) The Society for Environmental Education; Unpublished report.
Chamikara S.S. (2003); Fish diversity and present status of wet forests in Pahiyangala, Weligalpotta and Horanekanda; The Society for Environmental studies. Unpublished report.
Daraniyagala, P.E.P., (1952); A colored atlas of some vertebrates from Ceylon, volume one, Fishes, Ceylon national museums, Colombo.
De Silva, M.P. (1998); Biodiversity in the catchments of Hiyare Reservoir; Proceedings of the 2nd Annual Forestry Symposium 1996.
Ekaratne, K., Fernando, R.H.S.S., De silva, S., Bambaradeniya, C.N.B., De silva, D., (2003); A Comparison of the Conservation and Legal Status of the Fauna and Flora of Sri Lanka, IUCN Sri Lanka.
Gamage, S. N., Liyanage, W. K. D. D., Gunawardena, A. & Wimalasuriya, S. ; 2006; Vertebrate diversity in a thirty year old analogue forest in Pitigala, Elpitiya, in the Galle District of Southern Sri Lanka; RUHUNA JOURNAL OF SCIENCE, Faculty of Science, University of Ruhuna.
Gerhard, H. F. & Hans-jurgen, (2003- Unbublished); A new record of Lepidocephalichthys jonklaasi (Daraniyagala, 1956) (Teleostei; Cypriniformes, Cobitidae); (Unpublished).
Havird, J. C. and Page, L. M. ; 2010; A Revision of Lepidocephalichthys (Teleostei: Cobitidae) with Descriptions of Two New Species from Thailand, Laos, Vietnam, and Myanmar; Copeia online publication
Herath, T. & Jayasinghe, H., (2005); Diversity of freshwater fish species of Pahiyangala & Yatagampitiya Proposed Reserve area; (Unpublished).
IUCN, (2000); The 1999 list of threatened fauna and flora of Sri Lanka, IUCN Sri Lanka.
IUCN, (2007); The 2007 list of threatened fauna and flora of Sri Lanka, IUCN Sri Lanka.
Jayaneththi, H. B. & Madurapperuma P. L., (2004); A new record of Lepidocephalichthys jonklaasi Daraniyagala, 1956 (Cobitidae; Cypriniformes) from Pahiyangala, Kalu River basin., SRI LANKA NATURALIST, JOURNAL OF ECOLOGY AND NATURE, Young Zoologist's Association of Sri Lanka.
Jayaweera, S. & Herath, T., (2009); Biodiversity Report- Boralugoda, Organisation for Aquatic Resours Management (OARM) (Unpublished).
Manamendra-Arachchi, K. N. (1987) ; The Loaches of Sri Lanka, Loris, Journal of the wildlife and Nature Protection Society of Sri Lanka.
Ministry of forestry & environment (2000); Statistical compendium on natural resources management Sri Lanka-2000, Ministry of forestry & environment.
Pethiyagoda, R., (1991); Fresh water fishes of Sri Lanka; WHT publications, Colombo.
Pethiyagoda, R., (2000) ; The fauna and flora protection ordinance; Loris, Journal of the wildlife and Nature Protection Society of Sri Lanka.
Pethiyagoda, R., (2006); Conservation of Sri Lankan Freshwater Fishes; The Fauna of Sri Lanka Status of Taxonomy, Research and Conservation, IUCN Sri Lanka.
Ranasinghe, P. N. & Rathnayayake, A.,(1992); Fauna and Flora of Dombagaskanda forest and its conservation, Young Zoologist's Association of Sri Lanka.
Senanayake, F. R. (1980); The biogeography and ecology of the inland fishes of Sri Lanka, (unpublished; Ph.D. Dissertation, Department of Wildlife & fisheries biology, University of California, Davis.
Senanayake, F. R. (1987) ; A checklist of the freshwater fishes of Sri Lanka, Loris, Journal of the wildlife and Nature Protection Society of Sri Lanka.
Senanayake, F. R., Soule, M., & Senner, J. W. (1977); Habitat values and endemicty in the vanishing rain forests of Sri Lanka, Nature.
Wildlife conservation society (2008); the study of the faunal diversity in Galle district, southern Sri Lanka, Wildlife conservation society, Galle Sri Lanka.
External links
http://www.mapress.com/zootaxa/2010/f/zt02557p018.pdf
Kata Kunci Pencarian:
- Lepidocephalichthys jonklaasi
- Lepidocephalichthys
- Lepidocephalichthys thermalis
- IUCN Red List endangered species (Animalia)
- List of endangered fishes
- List of freshwater fish of Sri Lanka
- List of data deficient fishes
