Nilssonia gangetica (Cuvier, 1825)

Indian softshell turtle (Nilssonia gangetica) is one of the largest freshwater turtles that grows upto 940 mm. They breed from April to May and the clutch size is 25-35. The species is widesread in deep rivers, streams and pond with sand bottoms of northern parts of India. The species is omivorous and feeds on bith invertebrates and small vertebrates like frog, fishes, birds . It is also observed to feed on dead bodies and religious wastes from temples. It is one of the most exploited species for its flesh and oil.

No subspecies have been described.

Nilssonia gangetica was described as Aspideretes gangetica by Cauvier, 1825. The type specimen was from river Ganga, India.

Clutch size 25–35, incubation period 217 –287 days

Breeding takes place from April- May. Males become territorial during breeding season. Large males bite the conspecific males until they leave the pond. Nesting takes place 3.5 m away from the river. In some cases females are reported to travel a distance of 500 m to lay eggs under the shade of Acacia tree. The clutch size is 25-35. incubtion period 260 days.

No information available

72 cm

Maximum carapace length is repoted to be 940mm.

Males have longer and thicker tail in comparison to females, with cloaca at the tip.

Carapace oval and flat. A preneural and one neural plates present between first pair of pleurals. Pleuralsin eight pairs.Triturating surface of upper jaw ridge less. Five callouses present on plastron of adults. Digits strongly webbed with large claws present in three digits. Carapace grey or green with black reticulation. Head with oblique black lines running from behind eyes to nape.Plastron cream in colour.Juvenile with 3–6 dark circular spots on carapace.

Low and oval carapace of grey black, green or grey color. Typical black reticulations are present on carapace. pLatron is cream, pale yellow or pinkish. Head is green and several black oblique stripes running from eye to nape, are present on forehead. Mandible is projected into a ridge at symphesis and raised at inner margin. Juveniles have yellow bordered eye like markings which disappear later.

Similar to Nilssonia hurum.The carapace in N. hurum is dark olive and lacks the black reticulations on the head as is present in N. gangetica.

An aquatic species, mainly found in rivers, lakes. Predominantly carnivorous.

N. gangetica is found in deep rivers, lakes and ponds with sandy banks. N. hurum and N. gangetica are reported to be living together in many temple tanks of India.

N. gangetica is very aggressive and reported to be territorial during breeding season. Also , show cannibalism in captivity, eating both eggs and adults.

The species is predominantly omnivorous. The species feed on invertebrates and small vertebrates. It is observed to feed on waterbirds like coot (Fulica atra), little cormorant (Phalacrocorax nigerII).

Genetic work on the species has been conducted by Praschag et al. (2007), that allocate it to Nilssonia genus.

No information available

River and wetlands. Remain buried at bottom under mud and sand

mainly found in rivers, lakes

Species inhabit deep rivers, stream, large canals,lakes and ponds with mud and sand bottoms.

No information available on populations in India, though appear to be widespread across the Indus. Ganges and Brahmpautra river systems

Population appears to be stabe across its range, no detailed information available.

Considered Endangered in Bangladesh and Vulnerable in India, its main range state. Traded in East Asian markets at volumes of 30–40 tons per week.

IUCN Redlist Status: Vulnerable

Vulnerable

The species is not threatened by extinction in the immediate future, but certain populations are declining rapidly due to commercial exploitation and habitat alteration.

Capture for food and harvest of egg. Also affected by river development projects and removal of sand

N. gangetica is a common species found in illegal international markets. Calipee of turtles are used to make traditional chinese medicines and their flesh is a delicacy in many countries. Noureen (2009) reported a capture of 200 turtles per week in Karachi for trading in Asian countries.

N. gangeticais listed in Schedule I of Indian Wildlife (Protection) Act, 1972.

Nilssonia gangetica is primarily carnivorous and also act as a scavenger (Lovich et al. 2018). In 1987, the species along with other turtles was released in river Ganga to clear half burnt corpses. The species is also found in various temple tanks in Gujarat, and Assam that can be used as sites for ex- situ conservation and breeding of turtles. (Author obs.)