page_title: Speartooth shark
section_title: Taxonomy
hierarchical_section_title: Speartooth shark / Taxonomy
caption_attribution_description: English: Carcharias glyphis (=Glyphis glyphis)
context_page_description: The speartooth shark is an extremely rare species of river shark, belonging to the family Carcharhinidae. It inhabits coastal marine waters and tidal reaches of large tropical rivers in northern Australia and New Guinea. Despite being a member of the river shark genus, it is also found in near-shore marine waters, favoring highly turbid environments 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 is 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 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.
context_section_description: German biologists Johannes Müller and Jakob Henle originally described the speartooth shark as Carcharias (Prionodon) glyphis, in their 1839–41 Systematische Beschreibung der Plagiostomen. They based their account on a stuffed juvenile female 1 m (3.3 ft) long, of unknown origin (possibly the Indian Ocean or the South China Sea). In 1843, Swiss-American zoologist Louis Agassiz proposed the new genus Glyphis for this species and a fossil relative from Britain, G. hastalis. However, the use of Glyphis to encompass the river sharks did not gain wide acceptance until Jack Garrick's 1982 revision of Carcharhinus.
  Müller and Henle's type specimen remained the sole known record of the speartooth shark until specimens of the "Bizant river shark" (Glyphis sp. A) were caught in Australia in 1982. Subsequently, work by Leonard Compagno, William White, and Peter Last confirmed initial suspicions that "sp. A" was the same species as G. glyphis. Thus, in Australia, this shark may also be referred to as the Bizant river shark or the Queensland river shark.
caption: Müller and Henle's original illustration of Carcharias (Prionodon) glyphis
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