Paleontologists have found the fossils of three new species of fish – including the first known salmonid fish, Sivulliusalmo alaskensis – to the formation of Prince Creek in northern Alaska, the United States.
“”Sivulliusalmo alaskensis is not only a new species, it is the oldest salmonid in the fossil file, “said Dr. Patrick Druckenmiller, director of the northern museum of the University of Alaska.
“Our article also documents several other species of old new fish in the Arctic, including two new species of pike – Archaeosiilik gilmulli And Nunikuluk gracilis – and the oldest group record that includes carp and men. »»
“Many groups of fish that we consider being distinctive today in the high latitude environment in Alaska were already in place at the same time as dinosaurs.”
The discovery of Sivulliusalmo alaskensis Adds another 20 million years to the history of fossils of the salmon family.
Previously, the oldest documented salmonid was in fossils found in British Columbia and Washington.
“It should be noted that salmonids, which tend to prefer cooler water, prosper even during the heat of the Cretaceous and that they have lived for millions of years in regions that have undergone spectacular changes in geography and climate,” said Dr. Andrés López, fish curator at the northern museum of the University of Alaska.
“Although it was warmer in the Arctic at that time, there would still have been large seasonal oscillations of temperature and light, just as there are today.”
“The salmon was already the kind of fish that is doing well in a place where these dramatic changes were going.”
“Despite all the changes that the planet has undergone, all the changes in geography and climate, you always had the ancestors of the same groups of species that dominate the cool waters of the region today.”
New species are the latest to come from the formation of Prince Creek, famous for dinosaurs fossils found in a series of sites along the Colville river in northern Alaska.
In the Cretaceous, Alaska was much closer to the North Pole than today.
“Fish fossils are one of the most abundant types of fossils to the formation of Prince Creek, but they are very difficult to see and distinguish in the field,” said Dr. Druckenmiller.
“So we transported buckets of fine and gravel to our museum laboratory, where we used microscopes to find bones and teeth.”
“Our new discoveries are mainly based on tiny fossilized jaws, some of which would easily adapt at the end of a pencil gum.”
To have a good overview of the fossils, the authors used micro-composed tomography to digitally reconstruct the tiny jaws, teeth and other bones.
“We found a jaw and other truly distinct parts that we recognized as a member of the Saumon family,” said Dr. Druckenmiller.
“The presence of salmonids in the polar regions of the Cretaceous and the absence of fish common to the latitude at the same period indicate that the salmon family is probably from the north.”
“The regions of northern high latitude were probably the crucible of their evolutionary history.”
THE paper was published in the journal Paleontology documents.
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Donald B. Brinkman and al. 2025. Fish of the formation of the upper Cretaceous of the Cretaceous, northern slope of Alaska, and their paleobiogeographic meaning. Paleontology documents 11 (3): E70014; DOI: 10.1002 / SPP2.70014
