Borneo river shark

Small, rare river shark in Borneo

The Borneo River shark (Glyphis fowlerae) is an extremely rare small species of shark that is thought to reach lengths of about 2 feet. They are found in the Kinabatangan River in Borneo.

Family: Carcharhinidae – Requiem sharks

Genus: glyphis

Species: fowlerae


Phylum– Chordata

Class– Chondrichthyles



Common NameGround Sharks


Common NameRequiem Sharks




Average Size and Length: Not much is known about the full length of the Borneo River shark at adulthood. Scientists do know they are born around 50cm and immature species were documented between 50 and 78 cm. Scientists believe the could possibly reach 200 cm.

Teeth and Jaw: The upper teeth are high and broad with serrated triangular cusps. The first few lower front teeth have weakly serrated cutting edges. And low cusplets on the crown foot. The lower teeth are erect, and slightly hooked. The total tooth row counts could be 28-31/29-32 or 60-63.

Head: The snout of the Borneo River shark is broad and short and round. Its eyes are small. The distance from the nostrils and the mouth is minimal.

Demographic, Distribution, Habitat, Environment and Range: The Borneo River shark, like its name can be found in Borneo. They prefer brackish turbid water to river freshwater. They were witnessed on low banks with a slope. The salinity levels are 1.7-1.9, pH 6.4-7.5, and temperatures between 25.5-29.9°C.

Aesthetic Identification: The Borneo River shark is large and stalky. It is dusky in color to blackish fin margins and tips. They have conspicuous dusky blotches on each flank and the pectoral base. There is no interdorsal ridge present. There is a longitudinal upper precaudal pit. The first dorsal fin originates a third over the rear of the pectoral bases. The second dorsal fin originates slightly over more than half to two-thirds of the first anal fin and has a deeply notched posterior margin.

Biology and Reproduction: At this point scientists believe the Borneo River shark is viviparous, but that is not confirmed as of yet.  

Borneo River Shark Future and Conservation: Their environment is subject to degradation and therefore that is a major threat, as well as over-fishing and logging.

Borneo River Shark Recorded Attacks on Humans: Not a threat to humans.