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The Evolutionary Odyssey of Crabs: Shifting Habitats and Back Again
Scientists have discovered that over the last 100 million years, crabs have evolved multiple times to change their environment. They moved from water to land and then returned.
Crabs (Brachyura) are short-tailed crustaceans. They represent the most numerous group of decapods, where the first pair of walking legs has transformed into claws. In total, around 10,500 species of these creatures have been described. They have a distinctive abdomen covered by a shell and appendages used for carrying eggs or as copulatory organs. They are incredibly agile, moving forward, sideways, and backward with ease.
Crabs are constantly evolving.
Most crab species cannot swim, with exceptions such as members of the Portunidae family, which exhibit this ability. These crustaceans inhabit all types of marine environments as well as freshwater and terrestrial ecosystems. They live at various depths. While most have adapted to warm seas, some families have adapted to extreme conditions, such as the Arctic Ocean. Three crab species also live in the Baltic Sea.
However, recent research has shown that the habitat of crabs over the past millions of years hasn’t been as straightforward as it might seem. An article in the journal “Systematic Biology” describes…
