About five million years ago, the North American Pacific Northwest was teeming with some pretty big fish that would have made the continent’s biggest salmon runs look small. An eight to 10-feet-long prehistoric salmon species called Oncorhynchus rastrosus stalked the seas and streams of the Miocene. It weighed upwards of 400 pounds and was almost twice as long and three times heavier than today’s largest salmon species–the Chinook/king salmon.
Oncorhynchus rastrosus also sported a formidable pair of front teeth that projected out from the sides of their mouths like tusks, but not like fangs as scientists previously believed. This major dental update is detailed in a study published April 24 in the open-access journal PLOS ONE.
Oncorhynchus rastrosus was first described in 1972. At the time, scientists believed that its large oversize teeth pointed backwards into the month like fangs. This largest known member of the Salmonidae family was commonly called the “saber-toothed salmon” due to the position of its teeth. However, CT scans of some newer Oncorhynchus rastrosus fossils and analysis in the study confirmed that these two-inch long curved chompers were more similar to a warthog’s tusks. This makes the species more of a “spike-toothed salmon.”
“This is all part of the scientific process. You have an idea and you get new information,” study co-author and University of Oregon paleobiologist Edward Davis tells PopSci. “It’s a good reminder of the humility you need to have as a scientist.”
[Related: A gator-faced fish shaped like a torpedo stalked rivers 360 million years ago.]
Scientists are not exactly sure what these signature tusks were used for, but believe they were primarily used to fight off other salmon or predators. They also may have been a way for female fish to dig nests for…
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