There are about 400 species of mantis shrimp in the world, most of which are distributed on tropical and subtropical coasts and are benthic. When caught, colorless liquid will be ejected from the abdomen, so it is also known as the urine shrimp (often mistakenly written as the urine shrimp or the urine shrimp). Also known as mantis. Marine crustaceans of the order Stomatopoda, especially species of the genus Squilla. The second pair of appendages is very large and resembles the front legs of a praying mantis, hence its English name meaning mantis shrimp. There are more than 250 species, widely distributed, ranging from 1 to 30 centimeters (0.4 to 12 inches) in length.