A 50 million year old fish fossil has been discovered trapped in limestone. Scientists are not sure caused the fish to get trapped but the discovery nonetheless should shed light on the evolution of current species.
Among the various fossils found by paleontologists, fish fossils are not among the most numerous. So when scientists discover one in a good state of conservation, it is an essential discovery. Recently, researchers have highlighted a limestone slab containing more than 200 fossilized fish 50 million years old. A discovery that should help to better understand the evolution of current species.
Not less than 259 extinct Erismatopterus levatus were found in a limestone slab in the Green River Formation in North America. Researchers at the University of Arizona and the Mizuta Memorial Museum in Japan hypothesized that a sand dune in shallow water could have collapsed above these tiny creatures.
These fish once lived in the mountain lakes of the Green River region during the Eocene, 56 to 34 million years ago. Adult E. levatus should be about 6.5 cm long, but these are babies that the researchers have highlighted – many not exceeding 20 mm.
Marine biologists know that fish have long been grouped in shoals, and this fossil evidence confirms the current bio-dynamic models. Taking advantage of this unique opportunity to examine the movement of schools of a long-lost species, the team measured each tiny fish, mapped their positions and executed 1000 different simulations of the movements of the bench.
The discovery reveals that fish have began to truly gather in schools for at least 50 million years. And the species that make it today are distinct from these Eocene fish, in terms of evolution. Yet, like many fish in the world now, they probably tried to reduce their chances of being caught by a predator – until a sudden phenomenon forever traps them in stone.