KNIFETOOTH SAWFISH OR POINTED SAWFISH OR NARROW SAWFISH
A sawfish with the saw partly devoid of rostral teeth
The Knifetooth sawfish (Anoxypristis cuspidata), also known as the Pointed sawfish or Narrow sawfish, is a species of sawfish in the family Pristidae. They are found in warm marine and freshwater habitats. They are characterized by the long, narrow, flattened rostrum or extension on their snout. It is lined with sharp transverse teeth, arranged in a way that resembles the teeth of a saw.
Family: Pristidae – Sawfish
Super Order– Batoidea
Common Name– Rays
Common Name– Sawfish
Status: IUCN Red List ENDANGERED
Average Size and Length: The Knifetooth sawfish reaches a length of 11 feet.
Teeth and Jaw: They have multiple rows of blunt teeth with rounded cusps and smooth surfaces, in both jaws.
There are 16-22 pairs of rostral teeth, but in some locations as many as 26. These teeth are short and flat and are roughly triangular in shape.
Head: It has a flattened head which is extended forward in a blade-like bony snout. The Knifetooth sawfish has a narrower rostral saw than the Longtooth sawfish. It has numerous teeth on the distal part and no teeth on the basal one-quarter (the toothless section is about one-sixth in juveniles). The blade does not taper towards its point and in adults the basal one-quarter is devoid of teeth. In juveniles about one-sixth of the base is toothless. The nostrils are narrow and partially concealed by nasal flaps.
Denticles: The skin of young sawfish is smooth but on older individuals it is thinly covered in dermal denticles. Body and fin denticles are very small and have a flat crown with three posterior cusps. The denticles along the rostrum and edges of fins are similar in shape and arrangement, although fin denticles are slightly larger. Denticles of adults are widely spaced except where concentrated along the anterior edges of the head and fins (Deynat, 2005), while fetal specimens and young up to 25.3 inches are devoid of denticles. In a specimen measuring 28 inches, denticles were present only on the anterior portion of the rostrum and along the anterior edge of all fins.
Demographic, Distribution, Habitat, Environment and Range: It is found in the shallow coastal waters and estuaries of the Indo-West Pacific, ranging from the Red Sea and the Persian Gulf to southern Japan, Papua New Guinea and northern Australia. They prefer warm marine and freshwater habitats. Primarily a benthic species, preferring sand, mud, and seagrass. They are found in estuaries, bays, and river mouths. It has a depth range from the shallows to 131 feet.
Diet: The Knifetooth sawfish feeds on small fish, squid and invertebrates such as crabs and shrimps.
The Knifetooth sawfish is prey to Hammerhead sharks, Bull sharks, and Copper sharks, as well as the Saltwater Crocodile.
Aesthetic Identification: The dorsal side of the Knifetooth sawfish is greyish and the ventral side is a paler grey color. The fins are pale. The rostrum is grey with white teeth and sometimes has a chocolate-brown base portion.
Biology and Reproduction: The Knifetooth sawfish is ovoviviparous, though not much is known about their breeding behavior. Knifetooth sawsharks typically reach maturity at 2-3 years of age, males measuring 6.5 feet, while females reach 7.5 feet. Pups are born after a suggested gestational period of about five months. Litter sizes of 6 to 23 young have been recorded. The pups are probably 1.8-2.7 feet long at birth and their rostral teeth are not fully developed, being covered by a membrane, and this prevents them from damaging the mother’s tissues.
There are parasites that inhabit the gills of other sawfishes, and possibly the Knifetooth sawfish as well.
Behavioral Traits, Sensing and Intelligence: The Knifetooth sawfish uses its rostrum in a side-to-side thrashing action to stir up the sediment and uncover hidden prey and also among schools of fish to debilitate or stun individual fish.
Knfietooth Sawfish Future and Conservation: Overfishing and habitat degradation are the main threats for the Knifetooth sawfish. They are endangered. The saws are partially prone to being tangled in fishing nets.
Knifetooth Sawfish Recorded Attacks on Humans: Not a threat to humans. However, they will defend themselves with their saw if threatened or captured and can inflict serious injuries.