''Oncorhynchus rastrosus'' ( synonym ''Smilodonichthys rastrosus') ''also known as the saber-toothed salmon, or spike-toothed salmon is an extinct species of

salmon Salmon () is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus ''Salmo'') and North Pacific (genus '' Oncorhy ...

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 definition, to Antarctica) in the south, and is bounded by the contine ...

coast of North America and Japan. 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 state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, then died out some time during the Early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

'' Oncorhynchus'', varying from and to 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 t ...

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

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

. These salmon are believed to have been anadromous 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 cats's teeth. Now it is believed the teeth stuck out sideways from the mouth. According to paleontologist Julia Sankey, the salmon did not possess spike teeth throughout its life; the fish developed the teeth 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.

References

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