Speartooth shark | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Superorder: | Selachimorpha |
Order: | Carcharhiniformes |
Family: | Carcharhinidae |
Genus: | Glyphis |
Species: | G. glyphis |
Binomial name | |
Glyphis glyphis (J. P. Müller & Henle, 1839) |
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Range of the speartooth shark |
The speartooth shark (Glyphis glyphis) is an extremely rare species of requiem shark, belonging to the family Carcharhinidae. It inhabits coastal marine waters and tidal reaches of large tropical rivers in northern Australia and New Guinea. It is exclusively found in fast-moving, highly turbid waters over a wide range of salinities. This robustly built, gray-colored shark is characterized by a short and broad snout, tiny eyes, a relatively large second dorsal fin, and a black blotch beneath each pectoral fin near the tip. Another identifying trait are its teeth, which are large, triangular, and serrated in the upper jaw and narrow, spear-like, and serrated only near the tips in the lower jaw. Adults grow to about 2.6 m (8.5 ft) long.
Preying on demersal bony fishes and crustaceans, the speartooth shark is adapted for hunting in near-complete darkness. It is not as active as other requiem sharks, moving upstream and downstream with tidal currents so as to save energy. Reproduction is viviparous with females forming a placental connection to their young, though details are unknown. The speartooth shark is threatened by incidental capture in commercial and recreational fisheries, as well as by habitat degradation. Given its small population, restricted range, and stringent habitat requirements, this species is highly susceptible to these pressures and has been listed as Endangered by the International Union for Conservation of Nature.