The rare and mysterious speartooth shark (Glyphis glyphis) is a rather stocky shark species with a broad, rounded snout and quite uniform colouration (2) (3). Its upperparts are grey and its underparts are white, with smaller individuals having a clearer colour difference between the upper and lower parts of the body (3). The mouth is white, and there is usually a pale ring around the black eye (3).
An identifying feature of the speartooth shark is the size of its second dorsal fin, which is relatively large in comparison to the triangular, slightly curved first dorsal fin. The tail of the speartooth shark has a longer upper than lower lobe, and the pectoral fins have dark tips on the underside, helping to distinguish this species from the closely related New Guinea river shark (Glyphis garricki) (3). Like other ‘river sharks’ of the genus Glyphis, the speartooth shark has very small eyes (2).
The spear-like teeth from which this shark gets its common name are situated at the front of the lower jaw, while the rest of the lower jaw has slender, unserrated teeth and the upper jaw has more broadly triangular, serrated teeth (2) (3).
No speartooth shark specimens have yet been caught that are fully grown and sexually mature. However, estimates based on knowledge of closely related species suggest that the speartooth shark could potentially grow to lengths of two to three metres (1) (3) (4).
- Male length: up to 157 cm (1)
- Female length: up to 175 cm (1)