''Oncorhynchus rastrosus'' (originally described as ''Smilodonichthys rastrosus''Cavender, T., & Miller, R. R. (1972). ''Smilodonichthys rastrosus: A new Pliocene salmonid fish from Western United States''. Museum of Natural History, University of Oregon.'') ''also known as the saber-toothed salmon (now known to be a misnomer), or spike-toothed salmon is an extinct species of

salmon Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...

that lived along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

coast of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. They first appeared in the late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, then died out some time during the Early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Oncorhynchus ''Oncorhynchus'', from Ancient Greek ὄγκος (''ónkos''), meaning "bend", and ῥύγχος (''rhúnkhos''), meaning "snout", is a genus of ray-finned fish in the subfamily Salmoninae of the family (biology), family Salmonidae, native to col ...

'', which contains living pacific salmon. ''O. rastrosus'' was possibly the largest member of the family

Salmonidae Salmonidae (, ) is a family (biology), family of ray-finned fish, the only extant member of the suborder Salmonoidei, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmo ...

, rivalling or exceeding the largest living salmonid ''

Hucho taimen Siberian taimen (''Hucho taimen''), also known as the common taimen (), Siberian giant trout or Siberian salmon, is a species of salmon-like ray-finned fish from the genus '' Hucho'' in the family Salmonidae. These fish are found in rivers in Si ...

'' in size, with estimates varying from standard length (without tail fin) of and to total length of and . Members of this species had a pair of small "fangs" protruding from the tip of the snout, thus explaining the common name and synonym. Adults of ''O. rastrosus'' had larger

gill rakers Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

compared to their smaller, modern relatives, leading scientists to suggest that the adults ate

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

. These salmon are believed to have been

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

like their living relatives.Thomas P. Eiting, Gerald R. Smith, Miocene salmon (Oncorhynchus) from Western North America
Gill Raker evolution correlated with plankton productivity in the Eastern Pacific
Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 249, Issues 3–4, 19 June 2007, Pages 412-424, ISSN 0031-0182 Scientists once thought the teeth pointed straight down, like a

saber-toothed cat Machairodontinae (from Ancient Greek μάχαιρα '' machaira,'' a type of Ancient Greek sword and ὀδόντος ''odontos'' meaning tooth) is an extinct subfamily of carnivoran mammals of the cat family Felidae, representing the earliest ...

's teeth. Now it is believed the teeth stuck out sideways from the mouth. The salmon's spike teeth grew in size as it transitioned from life in the ocean to fresh water. The salmon bred in fresh water, as Pacific salmon do today. Tooth wear patterns suggest the salmon used its teeth to defend territory and mark nests during the breeding phase. The species was first described in 1972 from remains found in the Madras Formation near Gateway in Jefferson County, Central Oregon. Other specimens have been described from other parts of Oregon as well as California, as well as central Japan. Additional material subsequently collected from the Gateway locality has included articulated skull material.

References

Miocene fish Pliocene fish Pliocene extinctions Oncorhynchus Neogene fish of North America Fossil taxa described in 1972 {{Salmoniformes-stub