The Borneo river shark, (Glyphis sp. B), is a scientifically undescribed shark of the family Carcharhinidae, known only from a single specimen from Borneo. Recently, several small specimens have been collected from the Kinabatangan River of Sabah, in northern Borneo. Its length is thought to be up to 2 m.
The extremely rare and little-known Bornean river shark is large and stocky with a broadly rounded short snout and tiny eyes. The anal fin has a concave posterior margin, and the first dorsal fin is large and solid.
Coloration is greyish with a conspicuous dusky blotch on each flank and pectoral fin base.