True crabs are the most specialized decapod crustaceans and belong to the infraorder Brachyura – meaning ‘short tail’ in Greek. They live in all the world’s oceans, as well as in freshwater and on land. They first appeared during the Jurassic period, around 200 million years ago.
The abdomen is tucked beneath the thorax, no longer forming a tail. The abdominal limbs have lost their original swimming function and serve only to hold eggs in the female or transfer sperm in the male. The tail-fan has disappeared altogether. The first pair of walking legs bears nippers (i.e., a kind of chelipeds) while the remaining four pairs are used for walking. Crabs scuttle sideways, thus lengthening their stride without entangling their legs. The head and thorax are covered by a shield-like carapace which houses gills on either side of the body.
The eggs hatch into planktonic larvae, which can be recognized by their long spine on the back, which settle and are transformed into miniature adults.
F*CK FISH 