MADRID, 7 May. (EUROPA PRESS) –
Fossils of the oldest acquaintances of salmon and the tent have been discovered well above the Arctic Circlean environment with months of winter darkness and icy temperatures.
Using the most advanced 3D image technology, Lisa Van Loon and Neil Banerjee, from the University of Western Ontario, and its collaborators analyzed fossilized bones of fish found in the rocks of the Prince Creek training in Alaska to reveal A polar ecosystem so far unknownwhich deta deta of the late cretaceous. The findings were published in the magazine Papers in Paleontology.
“These discoveries suggest that this remote region could have been an evolutionary launch platform for the fish that now dominate the northern rivers and lakes of the world,” he said In a statement Van Loon, attached research professor in the Departments of Earth Sciences and Anthropology of Western.
Some of the fossils discovered in Alaska were barely larger than the head of a pin and were deeply embedded in the rock. The traditional preparation of fossils, which implies the manual and careful extraction of the surrounding sediments, was not an option; The specimens were simply too fragile.
Using the computed microtomography scanning technology (Micro-CT) in the advanced protons source, with the support of Canadian Light Source, the researchers scanned fossiliferous rocks without physically altering them. The high -resolution ultra -resolution X -rays allowed them digitally reconstruct the anatomy of these old fish in 3Drevealing intricate structures such as jaws, teeth and fins radios with an extraordinary detail.
“Many of these fossils were so delicate and were so deeply embedded in the rock that traditional preparation would have destroyed them,” said Banerjee, professor of Earth Sciences at Western. “Through the Computerized syncrotron microtomographywe were able to observe the interior of the rock with an extraordinary detail, deciphering tiny maxillary bones and teeth without using a chisel. This technology has completely transformed the way we study ancient life. “
The scanners allowed to identify completely new species, some of which represent the first known members of the groups of fish that today dominate the rivers and lakes of the north, such as salmon, tent and lucio.
-An ancestor of the tents
Side Strait Alankensis, quue Significa “First salmon from Alaska” In Iñupiaq, he is now the oldest known member of the salmon family, eclipsing the previous records for almost 10 million years. The first known cypriniform was also found, part of the same group as the peccelillos and current tentswhich marks its first appearance in North America (since they were previously only in Asia and Europe).
Newly discovered species of fish similar to Lucio also lived in the Prince Creek formation about 73 million years ago, including Archaeosiil Gilmulli and Nunikuluk Gracilis, successfully adapting to the long winters of the Arctic. Squatina sharks (a relative of the angel), sturgeons and spatula fish were also discovered in fossil samples.
“The syncrotron allowed us to reconstruct these 3D fish, bone bone “said Van Loon.
Cold
These old fish were survivors. At the end of the Cretaceous, the Arctic experienced four months of total darkness per year, with average annual temperatures of around 6 ° C and icy winters. Fossils show adaptations – such as depressible teeth, complex mandibular structures and cold tolerance – that indicate the early evolution of these fish to adapt to life in the cold.
“This discovery changes our understanding of the evolution of the fish. It suggests that high latitudes ecosystems such as Alaska not only received species from the south, but also created them,” said Banerjee. “The characteristics we observe in the salmon and the current north fish probably evolved in polar environments like this, millions of years ago.”
In fact, this study supports the idea of a specific Arctic Ecosystem, known as the province of Paanaqtat, where unique animals -dinosaurs, mammals and now fish- They evolved in isolation.
These discoveries, made with avant -garde image technology, were possible thanks to a thorough field work in Alaska Arctic, where researchers collected sediments rich in fossils through screen washing techniques. The collaboration between institutions, such as the University of Alaska, the University of Florida, the University of Colorado in Boulder, the Real Tyrrell and Western Museum, was essential to face the challenges of such an ambitious project.
“Thanks to this discovery, we now have a clearer vision of a lost polar world a long time ago and a new understanding of how some of the most emblematic fresh water fish today began their evolutionary trip,” said Van Loon.
