Biology:Northern river terrapin
| Northern river terrapin | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Cryptodira |
| Superfamily: | Testudinoidea |
| Family: | Geoemydidae |
| Genus: | Batagur |
| Species: | B. baska
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| Binomial name | |
| Batagur baska (Gray, 1830)[2]
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| Synonyms[3] | |
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The northern river terrapin (Batagur baska) is a species of riverine turtle native to Southeast Asia. It has been classified as Critically Endangered on the IUCN Red List and considered extinct in much of its former range; as of 2018, the population in the wild was estimated at 100 mature individuals.[1]
Description
The northern river terrapin is one of Asia's largest freshwater and brackwater turtles, reaching a carapace length of up to 60 cm and a maximum weight of 18 kg.[4] Its carapace is moderately depressed, with a vertebral keel in juveniles. The plastron is large, strongly angulate laterally in the young, convex in the adult. The head is rather small, with a pointed and upwards-tending snout. The legs have band-like scales.[5]
The upper surface of the carapace and the soft parts are generally olive-brown, while the plastron is yellowish. Head and neck are brown with reddish bases. Males in breeding coloration have a black head and neck with a crimson or orange dorsal surface and red or orange forelegs. The colour of the pupils also changes during this period, to brown in females and yellow-white in males. During the breeding season, the color of the pupils of a female brown whereas the pupils in the males become yellowish-white.[5][6]
Distribution and habitat
The species is currently found in Bangladesh and India (in the Sunderbans), Cambodia, Myanmar, Indonesia and Malaysia. It is regionally extinct in Singapore, Thailand and Vietnam. It is strongly aquatic but uses terrestrial nesting sites, frequenting the tidal areas of estuaries, large rivers, and mangrove forests.[1]
Ecology
The northern river terrapin is omnivorous, taking waterside plants and small animals such as clams.[7] The species prefers freshwater habitats and moves to brackish river mouths or estuaries in the breeding season (December–March), returning after laying their eggs. Individuals have been known to undertake long seasonal migrations of 50 to 60 miles to the sand banks where they were hatched. Females usually lay three clutches of 10–34 eggs each.[7][8]
Conservation
The species is considered Critically Endangered by the IUCN, principally due to exploitation as a food item (including egg harvesting). Previously, immense numbers were shipped into the fish markets of Calcutta from throughout India ; among the Bengali Hindus, the river terrapin was considered the most delectable of all turtles.[9] It is still illegally exported from Indonesia and traded in large numbers in China . Loss of nesting beaches and pollution are also impacting the species.[1]
A hatchery and captive breeding project was established in Bhawal National Park in Bangladesh and another in Sajnakhali Wildlife Sanctuary in the Sunderban Tiger Reserve in India with support from Turtle Survival Alliance.[9]
Taxonomy
Two subspecies are recognized: B. b. baska (Gray, 1831) and B. b. ranongensis (Nutaphand, 1979).[2]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Praschag, P.; Singh, S. (2019). "Batagur baska". IUCN Red List of Threatened Species 2019: e.T97358453A2788691. doi:10.2305/IUCN.UK.2019-1.RLTS.T97358453A2788691.en. https://www.iucnredlist.org/species/97358453/2788691. Retrieved 18 November 2021.
- ↑ 2.0 2.1 Rhodin, A. G.J.; van Dijk, P. P.; Inverson, J. B.; Shaffer, H. B.; Roger, B. (2011). "Turtles of the world, 2011 update: Annotated checklist of taxonomy, synonymy, distribution and conservation status". Chelonian Research Monographs 5. http://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v4_2011.pdf.
- ↑ Fritz, U.; Havaš, P. (2007). "Checklist of Chelonians of the World". Vertebrate Zoology 57 (2): 212–213. doi:10.3897/vz.57.e30895. http://www.cnah.org/pdf_files/851.pdf. Retrieved 29 May 2012.
- ↑ "Northern River Terrapin (Batagur baska)". http://www.turtlesurvival.org/component/taxonomy/term/summary/36/37#.Vejy931y5WE.
- ↑ 5.0 5.1 Boulenger, G. A. (1890). The Fauna of British India, including Ceylon and Burma: Reptilia and Batrachia. Taylor & Francis. https://archive.org/details/in.ernet.dli.2015.207330.
- ↑ "An endangered terrapin". The New Indian Express. http://www.newindianexpress.com/education/student/article594045.ece.
- ↑ 7.0 7.1 "Batagur baska field guide". http://www.asianturtlenetwork.org/field_guide/Batagur_baska.htm.
- ↑ "Batagur baska". http://www.arkive.org/batagur/batagur-baska/.
- ↑ 9.0 9.1 "Batagur baska : Northern river terrapin". http://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_037_baska_v1_2009.pdf.
Further reading
- Das, Indraneil (1989). "Batagur baska in Orissya". Hamadryad: The Journal of the Madras Crocodile Bank Trust 14 (1): 2–3.
- Gray, J.E. (1857). "Notice of some Indian tortoises (including the description of a new species presented to the British Museum by Professor Oldham)". Annals and Magazine of Natural History 19 (2): 342–344.
External links
- Centre for Turtle Research and Conservation (archived 19 May 2007)
- Batagur baska at the Reptarium.cz Reptile Database
Wikidata ☰ Q810705 entry
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