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The 50 million year old fossil shows the school of juvenile fish in their last moments

  50-Million-Year-Old Fossil Shows The School Of Youngfishes In Their Last Moments

This 50-million-year-old fossil, kept in a museum in Japan, shows 259 fish swimming in a school The earliest known example of coordinated group behavior of all times.

Credit: Mizumoto et al./Proceedings of the Royal Society B

One fish, two fish, dead fish, cool fish.

There is room for all species in a newly described fossil showing 259 juveniles swimming together in a school about 50 million years ago. According to the authors of a new study published on Wednesday (May 29) in the journal Proceedings of the Royal Society B, this former school may be the earliest known fossil evidence that prehistoric fish have swum in unison, as it has Modern fish do today. 1

9659005] A team of researchers from Arizona came across this remarkable rock during a visit to the Oishi Fossils Gallery of the Mizuta Memorial Museum in Japan. In collaboration with the museum, researchers found that the fish-like fossil is believed to come from America's Green River Formation, a geological stratum in present-day Colorado, Wyoming, and Utah that holds a fossil treasure of between 53 and 48 million years. [19659005] The fish in question all belonged to the extinct species Erismatopterus levatus and were apparently buried in the middle of a routine swimming pool, possibly from an underwater avalanche of sand, the investigator wrote. All but two tiny specimens swam in the same direction and in a close-knit formation.

To prove that the fish were actually swimming in a school and not just randomly petrified that way, the researchers performed a series of simulations to reproduce the probable movements of the group. The simulations showed that fish did not seem to be swimming in unison, but did so according to a timeless set of rules of behavior that still apply today.

"We found traces of two rules for social interaction that resemble those used by" Received fish: repulsion from close individuals and attraction to distant neighbors, "the researchers wrote in their study. In other words, individual fish swam close together, but not so close that they crashed.

According to the authors, this ancient group of dead swimmers demonstrated that fish (and possibly other animals) developed a coordinated group behavior of at least 50 million years. This synchronized swim seems to have successfully saved the fish from being eaten by a predator, even though it did not prevent it from becoming a museum exhibit.

Originally published on Live Science .

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