Monday, April 13, 2020

Freshwater Turtles of Ponds, Streams and Rivers of Northeast India

Contribution and Photo credits by
Dr.Chittaranjan Baruah 
Assistant Professor (Sr. G), Post Graduate Department of Zoology,
Darrang College, Tezpur, Assam, India
Member, IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. 
E-mail: chittaranjan_21@yahoo.co.in


A total of 22 turtle species so far recorded from northeast India, belonging to 3 families namely Geoemydidae (13 species), Trionychidae (7 species) and Testudinidae (2 species i.e. land-dwelling tortoise). The freshwater turtle population is declining due to wanton killing, destruction of eggs or destruction of their natural environment. Out of 20 water-living species found in Northeast, 4 species namely Pangshura sylhetensis, Cuora mouhotii, Nilssonia nigricans and Chitra indicia are listed by IUCN as most endangered species of Asia. Some of the species found in ponds, streams and rivers of northeast India are highlighted below.


1. Assam Roofed Turtle - Pangshura sylhetensis

Pangshura sylhetensis is locally known as Asomi Dura and Phulen Dura in Assam. 


It is a small (carapace length to 20.5 cm) freshwater turtle with thirteen pairs of marginal scutes. The head is moderately small, snout pointed, shorter than the orbit and projecting much beyond the lower jaw. It has the narrowest distribution range compared to the other three Pangshura species. It lays 6-12 eggs per clutch. The species is fully aquatic and inhabits stagnant and slow-running waters in the hilly terrain with plenty of aquatic vegetation. Bask communally on logs on water. They lay up to 6 -8 elongated eggs from October to February of a year.



2. Indian Roofed Turtle -Pangshura tecta

It is locally known as Futuki Salika Dura in Assam. 

Females do not exceed about 24 cm in length and the shell is strikingly elevated, the first two vertebral scutes being somewhat keeled and the third rising to a sharp point. This species is common in northeast India. It is also an inhabitant of ponds in Kamakhya and Hajo. Two clutches of 3-12 eggs are laid during the winter season in sandy or muddy banks of the water bodies. 

 


3. Pangshura tentoria  


It is locally known as Tambu Dura in Assam. 

The species grows to 26.5 cm straight carapace length. Three subspecies have been described: tentoria (Gray, 1834) from peninsular India, circumdata (Mertens, 1969) from the western tributaries of the Ganga and Brahmaputra and flaviventer (Gunther, 1864) from the northern tributaries of the Ganga. This species is represented by the subspecies P. tentoria tentoria and P. tentoria flaviventer in Assam. It is found throughout Brahmaputra and Barak rivers. This species is the most common by-catch during fishing activities in river Brahmaputra. Nesting takes place during the months of September to November in the sandy riverine chars. In ponds and marshlands, the species is seen to nest on the mud bank. A clutch of 3-8 eggs are laid by digging nearly 30 cm pit. The eggs are consumed by the people and other predators like dogs and Jackals.


4. Brown Roofed Turtle- Pangshura smithii 

It is locally known as Muga Dura in Assam. 


The females may reach a length of 22.7 cm and the males are just 10.8 cm in the carapace length. The species occupies an elongate, narrow band of territory in the northern and northeastern parts of the Indian subcontinent. It is a common species in the river Brahmaputra in Assam. The species communally bask on the river banks. It lays 6-12 eggs per clutch.

Two subspecies are recognized. In India, P.smithii smithii is has been reported from Assam (Manas National Park, Kaziranga National Park and Orang National Park) and the other subspecies P. smithii pallidipes is reported from Bihar and Uttar Pradesh (Gangra River system).



5. Spotted Pond Turtle - Geoclemys hamiltonii

The spotted pond turtle is locally known as Nal Dura and Futuki Dura in Assam.

It is a medium-sized (carapace length to 40.5 cm) freshwater turtle from lentic water bodies of the northern and northeastern India. The species is observed in Assam and Meghalaya. Significant population exist in the Kaziranga National Park, Rajiv Gandhi Orang National Park and Dibru Saikhowa National Park in Assam. It lays two clutches of 18-30 eggs that hatch within 60-76 days. The species is primarily carnivorous, feeding on snails and insect larvae along with vegetative material.



6. Black Soft-shell Turtle -Nilssonia nigricans 

It is locally known as Bormuria Kacho in Assam. 


The Black Softshell Turtle, Nilssonia nigricans, is a large (carapace length up to 91 cm), invariably aquatic species.   Its distribution in the wild is limited to the River Brahmaputra and its tributaries. The species was described from a Shrine pond in Nasirabad near Chittagong, Bangladesh. Also found in captivity in the Temple ponds of Tripura and Assam, Northeast India. It lays spherical eggs numbering 10 to 38 per clutch. There are several nestings per year.



                             7. Gangetic Soft-shell Turtle -Nilssonia gangetica 


This species is locally known as Ganga Kaso in Assam. 

This is a large (carapace length to 70 cm) freshwater turtle, with a round or somewhat oval carapace. Though widespread, this species is restricted to only a few localities in the region. This species is found in river Brahmaputra, Barak and their tributaries, specifically in the Jia Bharali River, Kulshi River, Chandubi beel, Deepor beel and temple ponds of Assam. Nesting takes place during winter and hatchlings were seen during the monsoon period. This species nests in the sandy bank and also in sandy loam soils near ponds and other water-bodies. A clutch of 8-85 spherical eggs are laid by digging a deep pit.  Incubation lasts 217 to 287 days. It is omnivorous in feeding habit and individuals were seen feeding on cattle or even carcasses near the river banks. It is mostly exploited for meat and medicinal value of the calipee.


8. Indian Peacock Soft-shell Turtle -Nilssonia hurum

This species is locally named as Bor Kaso in Assam. 

It is a relatively abundant large (carapace length to 60 cm) riverine species, found in rivers and reservoirs. The carapace is flat and oval or slightly domed shaped. It is beautifully marked and the background colour is dark green, but in juveniles, the disk bears four to six large ocelli. Plastron light grey. The centre of each ocellus is a black disk surrounded by concentric yellow circles. Head is large with black reticulation; large yellow or orange patch behind the eye and one across the snout. This species is found in the wetlands of Assam. The juveniles of the species are worshipped due to the prominent eye-spots resembling the eyes of Lord Vishnu.  It is a common species in Assam and Tripura. This species occurs in several protected areas within its natural range, including the Pakhui Wildlife Sanctuary (Arunachal Pradesh) and Chandubi Reserve Forest (Assam). This species is worshipped in many of the temple ponds in the northeast. It lays 20-38 spherical eggs per clutch from July to September. Incubation lasts for 180 days. The species is primarily nocturnal and omnivorous. Individuals maintained in the temple tanks and village ponds in Assam was seen to feed on puffed rice, bread and materials generated as garbage as a result of religious activities (Noureen and Baruah, 2010).


9. Narrow-headed Soft-shell Turtle- Chitra indica

Locals describe it as “Baghia Kacho” (tiger turtle) in Assam.

 
The narrow-headed softshell turtle is an extremely large (carapace length to 110 cm), highly aquatic species. The dorsum carries a striking pattern of deep yellow and black closely resembling the colour pattern of a tiger.  This species is observed in the Brahmaputra River and its tributaries in Assam and very good population size in the Ganges river system. It inhabits rivers with a sandy bottom and remains buried at the bottom under the sand, keeping only the eyes and snout out to catch prey at lightning speed. It is widely distributed on the Indian subcontinent. It is highly aggressive in disposition and prefers steep river banks for basking. A large clutch of 65-193 eggs are laid during June- August near the sandy bank. Eggs are sometimes predated by people, dogs and jackals. 



10. Indian flap-shelled Turtle Lissemys punctata

It is locally known as ‘Benga Kaso’ in Assam.


It is one of the most common freshwater turtle species in Assam, Meghalaya and Tripura. This species is known to live in rivers, ponds, low-land agricultural fields and swampy areas. It lays 2-15 eggs per clutch. The species aestivates during winter and dry summer. It secretes a foul-smelling fluid when disturbed as a reflex action, to protect itself from predators. This species is widely poached for the freshwater turtle trade in Tripura. 






7 comments:

  1. Great work.. It will help us in further studies..

    ReplyDelete
  2. Great effort sir. Hope to see more work of you in the future☺️

    ReplyDelete
  3. Great work Sir. We are proud of you.

    ReplyDelete
  4. Excellent information and nicely oriented for students for making project as well as for their academic scope..

    ReplyDelete