Giant prehistoric salmon had tusk-like teeth, just like a warthog's

A massive prehistoric salmon had tusk-like teeth that protruded from either side of its snout, a new study finds. 

Capable of reaching 8.8 feet (2.7 meters) in length by some estimations, Oncorhynchus rastrosus, a Pacific species, was the largest salmon ever known to live — over double the size of the largest Pacific salmon alive today, the Chinook salmon (Oncorhynchus tshawytscha), which typically grows to around three feet (0.9 meters) long.

Scientists have long been intrigued by O. rastrosus‘s exceptional teeth, a physical feature reflected in the anatomy of fossilized skulls. Initially, they thought the teeth curved downward like those of a saber-toothed cat, leading the common name of "saber-toothed salmon" to be bestowed upon the species. 

However, a new study published Wednesday (April 24) in the journal PLOS One shows that the teeth more resembled a warthog's tusks, projecting sideways, not downward. 

"[O. rastrosus had] these very unique features that don't exist everywhere else," study first author Kerin Claeson, professor of anatomy at the Philadelphia College of Osteopathic Medicine, told Live Science.

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First described in the 1970s, O. rastrosus swam in what are now the waters of the Pacific Northwest. A 2016 paper on O. rastrosus reported that fossils date to between 12 and 5 million years ago.