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The Cretaceous crab revolution was a major diversification event of brachyuran crabs (also known as true crabs) that took place during the Cretaceous Period, from 145 to 66 million years ago. [ 1 ] [ 2 ] Nearly 80% of modern groups of crabs originated during this event. [ 3 ]
More than 99 percent of all species that ever lived (over five billion) [1] are estimated to be extinct. [2] [3] Estimates on the number of Earth's current species range from 10 million to 14 million, [4] with about 1.2 million or 14% documented, the rest not yet described. [5]
Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to 4 m (13 ft). [6] Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation.
Since its ancestors were long-tailed decapods, and its successors were short-tailed crabs, Eocarcinus has been described as "the lobster who decided to become a crab". [5] Previously considered to be the oldest known true crab , a 2010 revision concluded that Eocarcinus could not be accommodated among the Brachyura, and was instead transferred ...
The mass of this world ocean is 1.35 × 10 18 metric tons or about 1/4400 of Earth's total mass. The world ocean ... or anatomical, record. ... crab is long-lived and ...
While counting snow crabs at sea in 2021, fisheries biologist Erin Fedewa saw that something was deeply amiss.Fedewa, a National Oceanic and Atmospheric Administration (NOAA) scientist, spends ...
Loxorhynchus grandis, commonly known as the sheep crab or spider crab, is a species of crab in the family Epialtidae. [1] It is the largest crab found on the California coast. [ 2 ] The species was first described to science by William Stimpson in 1857. [ 3 ]
For the study, scientists analyzed what could have triggered the disappearance of the snow crabs beginning in 2020 and boiled it down to two categories: the snow crabs either moved or died.