Northern river terrapin

Northern river terrapin
Conservation status
Critically Endangered  (IUCN 2.3)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Family:	Geoemydidae
Genus:	Batagur
Species:	B. baska
Binomial name
Batagur baska (Gray, 1830)[2]
Synonyms[3]
click to expand Emys baska Gray, 1830 Emys batagur Gray, 1831 Testudo baska Gray, 1831 Trionyx (Tetraonyx) cuvieri Gray, 1831 Tetronyx longicollis Lesson, 1834 Tetronyx baska Duméril & Bibron, 1835 Tetraonyx lessonii Duméril & Bibron, 1835 Tetraonyx longicollis Duméril & Bibron, 1835 Clemmys (Clemmys) batagur Fitzinger, 1835 Hydraspis (Tetronyx) lessonii Fitzinger, 1835 Emys tetraonyx Temminck & Schlegel, 1835 Tetraonyx batagur Gray, 1844 Batagur (Batagur) baska Gray, 1856 Clemmys longicollis Strauch, 1862 Tetraonyx baska Gray, 1869 Batagur batagur Lindholm, 1929 Tetraonyx lessoni Bourret, 1941 (ex errore) Batagur ranongensis Nutaphand, 1979 Batagur basca Anan'eva, 1988 (ex errore) Batagur batagur batagur Joseph-Ouni, 2004 Batagur batagur ranongensis Joseph-Ouni, 2004

The northern river terrapin (Batagur baska) is a species of riverine turtle native to Southeast Asia. It is classified Critically Endangered by the IUCN and considered exticnt in much of its former range.

Description

River terrapins of different age cohorts: (from top to bottom) hatchling of about a week old, one year old and two years old.

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]

Two subspecies are recognized: B. b. baska (Gray, 1831) and B. b. ranongensis (Nutaphand, 1979).

Distribution and habitat

The species is currently found in Bangladesh (in the Sundarbans), Cambodia, India (parts- West Bengal & Odisha), Indonesia and Malaysia. It is regionally extinct in Myanmar, 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 form 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 Vawal National Park at Gazipur in Bangladesh and another in Sajnekhali Forest Station in the Sunderban Tiger Reserve in India.^[9]

See also

• Southern river terrapin

References

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
• Batagur baska at the Reptarium.cz Reptile Database
• http://www.turtlesurvival.org/component/taxonomy/term/summary/36/37#.Vejy931y5WE

Turtle family Geoemydidae
Genus	Species of the family Geoemydidae
Batagur	Burmese roofed turtle Northern river terrapin Painted terrapin Red-crowned roofed turtle Southern river terrapin Three-striped roofed turtle
Cuora	Amboina box turtle Bourret's box turtle Indochinese box turtle McCord's box turtle Keeled box turtle Pan's box turtle Southern Vietnamese box turtle Chinese three-striped box turtle Yellow-headed box turtle Yellow-margined box turtle Yunnan box turtle Zhou's box turtle
Cyclemys	Asian leaf turtle Assam leaf turtle Eastern black-bridged leaf turtle Enigmatic leaf turtle Myanmar brown leaf turtle Oldham's leaf turtle Western black-bridged leaf turtle
Geoclemys	Black pond turtle
Geoemyda	Black-breasted leaf turtle Ryukyu black-breasted leaf turtle
Hardella	Brahminy river turtle
Heosemys	Arakan forest turtle Giant Asian pond turtle Spiny turtle Yellow-headed temple turtle
Leucocephalon	Sulawesi forest turtle
Malayemys	Malayan snail-eating turtle Mekong snail-eating turtle
Mauremys	Balkan pond turtle Caspian turtle Chinese pond turtle Chinese stripe-necked turtle Japanese pond turtle Red-necked pond turtle Spanish pond turtle Vietnamese pond turtle Yellow pond turtle
Melanochelys	Indian black turtle Tricarinate hill turtle
Morenia	Burmese eyed turtle Indian eyed turtle
Notochelys	Malayan flat-shelled turtle
Orlitia	Malaysian giant turtle
Pangshura	Assam roofed turtle Brown roofed turtle Indian roofed turtle Indian tent turtle
Rhinoclemmys	Black river turtle Brown wood turtle Colombian wood turtle Furrowed wood turtle Large-nosed wood turtle Maracaibo wood turtle Mexican spotted wood turtle Painted wood turtle Spot-legged turtle
Sacalia	Beal's eyed turtle Four-eyed turtle
Siebenrockiella	Black marsh turtle Philippine forest turtle
Vijayachelys	Cane turtle
Phylogenetic arrangement based on turtles of the world 2011 update: annotated checklist.