Discovery of the 100 millionth crab petrified in amber

“The main challenge is the changes associated with osmoregulation,” explains Heather Brecken-Grissom, the way the body controls the metabolism of water and electrolytes such as salt in its body. Another problem to consider: new predators that are ready to devour them.

Despite this, crabs many times left the oceans to reach the mainland. Modern crabs live not only on beaches, among coral reefs and in the depths of the ocean. They also inhabit estuaries, rivers and lakes. Some species, such as the Caribbean purple land crab, spend most of their time on land. Others have chosen a unique lifestyle, such as coconut crab; this huge arthropod, which can weigh up to 4 kg, climbs trees in the islands of the Indian and Pacific Oceans.

Researchers specializing in genealogical trees based on biomolecules, such as genes, believe that non-sea crabs first appeared about 130 million years before our era, during the Early Cretaceous. The oldest known fossilized crabs were only 70 million years old before the discovery of the new Burmese fossil, which makes more sense than genetic estimates.

THE WINDOW WAS OPENED IN THE PAST

Although the fossil is the oldest of the non-sea crabs, it may not have been the first (or last) crustacean to emerge from the oceans. “We believe that real crabs have adapted to a predominantly freshwater lifestyle at least six times and to terrestrial and brackish waters at least twelve times,” says Javier Luke.

And these crustaceans are not the only organisms that have undergone such transformations by leaving the oceans. For example, the ancestors of rainbow trout that inhabit Lake Michigan first lived in seawater and then adapted to living in freshwater less than 120 years ago. Several species of whales and dolphins have also invaded the freshwater environment, such as the Amazon.

No set of standard devices allows the animal to move from the marine environment to the freshwater environment. This is what makes this repetitive evolutionary process so wonderful. Due to this fossil crab Cretaceous frozen in full transition, scientists now have a new perspective on this mysterious evolution.

However, even if amber fossils are a window into the past, their study raises ethical questions. In addition to the dilemma of the amber trade, the fossil belongs to the Amber Museum in Lunin, far from Burma. Paleontologists are increasingly afraid of the repatriation of fossils in order to preserve the heritage of natural history.

According to researchers, Burmese laws regarding the removal of fossils caught in amber contradict each other. In a letter to the magazine Ecology of nature and evolution In June, Mandalay University of Zin Maung and Maine Thain and University of Tasmania’s Khin Zau called on paleontologists to report significant amber discoveries to the government or Burmese scientists to prevent the spread of precious fossils at four corners. world.

“In this way, the country’s research standards will improve and Burmese people will gain a better understanding of the significance and scientific value of their own natural heritage, rather than being deprived of it.”

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