Taxonomy doesn't give a damn about personal preferences. As "Brontosaurus" taught us, a favored name can easily be overtaken by a less-popular moniker according to the arcana that dictate how species are named and arranged in the tree of life. So it was with the saber-toothed salmon.

Back in 1972 paleontologists T. Cavender and R.R. Miller named a huge fossil fish from the Pliocene deposits of Oregon. They called it Smilodonichthys rastrosus - the "knife fish." The fish's impressive teeth were thought to stick straight down, like those of a sabertooth cat, and so it became known as the sabertooth salmon.

But now the same fish is known by different names. The official title is now Oncorhynchus rastrosus - a species in the same genus as today's Pacific salmon - and those impressive teeth have been rearranged to stick out sideways rather than down. This fish is the sabertoothed salmon no more. It's the spike-toothed salmon.

These fish didn't use their teeth to slash open prey. In a new paper on this impressive swimmer, paleontologist Julia Sankey and colleagues confirmed that this ancient salmon behaved much like its modern counterparts. 

Oncorhynchus rastrosus didn't have spike teeth its whole life, but rather developed them as they transitioned from life in the ocean to their breeding phase in freshwater. Pacific salmon undergo the same kind of metamorphosis today. On top of that, Sankey and colleagues found, the large teeth found in freshwater deposits are more worn-down than those found in the ocean, indicating that these fish were using their teeth to defend their territories and make their nests. Imagine if these fish were still around. We might see grizzly bears grappling spike-toothed fish as large as themselves out of the water during salmon runs, making the annual displays of life and death all the more impressive.

Teeth
Teeth from the freshwater phase of the spike-toothed salmon. Credit: Sankey et al. 2016

Fossil Facts

Name: Oncorhynchus rastrosus

Nickname: The spike-toothed salmon.

Age: Pliocene, 12-5 million years ago.

Where in the world?: California, Oregon, and Washington, U.S.A.

What sort of critter?: A salmon.

Size: About eight feet long.

How much of the creature’s body is known?: Multiple specimens, including the gill rakers and teeth.

Reference:

Sankey, J., Biewer, J., Basuga, J., Francisco, P., Wagner, H., Garber, D. 2016. The giant, spike-toothed salmon, Oncorhynchus rastrosus and the Proto-Tuolumne River (early Pliocene) of Central California. PaleoBios. 33: 1-16

Previous Paleo Profiles:

The Light-Footed Lizard
The Maoming Cat
Knight’s Egyptian Bat
The La Luna Snake
The Rio do Rasto Tooth
Bob Weir's Otter
Egypt's Canine Beast
The Vastan Mine Tapir
Pangu's Wing
The Dawn Megamouth
The Genga Lizard
The Micro Lion
The Mystery Titanosaur
The Echo Hunter
The Lo Hueco Titan
The Three-Branched Cicada
The Monster of Minden
The Pig-Footed Bandicoot
Hayden's Rattlesnake Demon
The Evasive Ostrich Seer
The Paradoxical Mega Shark
The Tiny Beardogs
The Armored Fish King
North America's Pangolin
The Invisible-Tusked Elephant
The Mud Dragon