Unveiling Unexpected Ancient Waters

When you picture the Cretaceous Period, you might conjure images of massive dinosaurs roaming lush landscapes. But in what is now northern Alaska, the scene was captivatingly different—a watery world thrumming with life, showcasing ancient fish species, including the early ancestors of salmon.

A Groundbreaking Discovery

Recent research from the University of Alaska Fairbanks has identified three new fish species from 73 million years ago, revolutionizing our understanding of the period. Among these, Sivulliusalmo alaskensis shines as the oldest known member of the salmon family ever unearthed.

The Fascinating Name

Sivulliusalmo alaskensis aptly combines the Inupiaq word for "to be first" with Latin for salmon, reflecting its groundbreaking status. Previously, the oldest salmonid fossils were traced back to British Columbia and Washington, but this new discovery pushes their lineage back by roughly 20 million years.

Fish in a Warmer World?

The presence of these ancient salmonids in the Arctic is surprising, especially considering that today’s salmon thrive in cold waters. However, during the Cretaceous, despite the warm global temperatures, the Arctic environment experienced dramatic seasonal fluctuations.

Adaptable Ancestors

Researchers propose that these primitive salmon adapted remarkably to temperature changes and varying daylight, a resilience that has allowed their descendants to flourish in the frigid north today. 'Salmon thrived when temperatures swung wildly,' states fish curator Andrés López.

Dinosaurs and Ancient Rivers

The fish fossils were discovered in the Prince Creek Formation, famous for its dinosaur remains. While the dinosaurs command the scene, it's often the smaller fossils that unravel the intricate tales of ancient ecosystems.

The Challenging Quest for Fossils

Locating these fossils proved challenging; many were too minuscule to detect in the field. Researchers meticulously sifted through buckets of sediment back at the lab, relying on advanced technology like micro-computed tomography to reconstruct these tiny yet significant remains.

Roots of the Salmon Family

This discovery suggests that salmon may not have migrated from warmer areas, but rather, their evolutionary saga may have started right here in the icy cradle of the Arctic. Patrick Druckenmiller asserts that these northern regions could be seen as the "crucible of their evolutionary history," as lower-latitude fish species are notably absent from the same geological layers.

A Polar World in Flux

In summary, the narrative of salmon begins alongside the majestic dinosaurs, thriving in rivers that once flowed through a polar world defined by its tumultuous climate shifts—both warm and cold.

Explore Further

The full study, brimming with groundbreaking revelations, has been published in the journal Papers in Palaeontology. Delve into the deep past and understand the intricate web of prehistoric life!