Largetooth sawfish
Leichhardt's sawfish in aquarium in Shanghai
Leichhardt's sawfish ( Pristis microdon ) is a sawfish of the family Pristidae. The German name is derived from the naturalist Ludwig Leichhardt.
Description
The up to 6.5 meters long animals have a strong body with a flattened, broad head. The usually not very long saw sitting on a broad base at the top and tapers significantly forward. It contributes between 14 and 22 strong teeth on each side. The saw is used as a tool in search of food, but also serves the defense.
The large, triangular pectoral fins are at right angles to the body; the first of the two dorsal fin sits just before the ventral fins, they also sit at right angles to the trunk and are triangular. The heterocerke caudal fin is provided at the bottom with a fleshy lobe. The color of the fish varies from greenish or gray to golden brown on the top. The belly is cream-colored.
Leichhardt's sawfish multiplies viviparous.
Nutrition
P. microdon feeds on ground- dwelling molluscs, crustaceans and small schooling fish. The fish dig in the ground with the saw or injured with her fish in a swarm by shaking of the head. The injured victim of the saw are then eaten.
Occurrence and distribution
P. microdon lives in shallow tropical seas of the western Pacific and the Indian Ocean. Its distribution extends to south of Australia from the coasts of East Africa to New Guinea and Vietnam and the Philippines.
The animals inhabiting the sandy or muddy bottom flat coastal waters or estuaries and rivers and freshwater lakes. In rivers, the fish prefer turbid, muddy areas. The adult birds prefer to live in the brackish water zones, while the juveniles also venture into the freshwater zones of the rivers. Adult animals are rare in fresh water.
Populations from Australia are rare, but distributed across the entire northern coast. They spawn here obviously in seawater. The first 3 to 4 years to spend the pups up to a size of about 2 meters in fresh water. There were copies of 300 km upstream of the Fitzroy River, 325 km upstream in the Mitchell River and 500 km upstream in one Leigh River found.
Populations from New Guinea sometimes spawn in fresh water. They are relatively well represented in the major rivers Fly, Sepik, Ramu, Mamberamo and Digul. Particularly common are they in the middle Fly River and Lake Murray, where they inhabit the main arms and oxbows. It copies were spotted up in the upper reaches in the area near Kiunga.
The species is performed on the Red List as threatened by extinction (CR).