The Horseshoe Crab, or Japanese Horseshoe Crab, is a species of arthropod with the scientific name Tachypleus tridentatus.
"Its body is brown with a length of 80cm and covered with a hard shell. The top section is in the shape of a crescent moon, and the lower section has six spines along each side. At the rear is a thin and pointed sword-like tail. Prefers enclosed, special environments in which it can be seen all year round."
"Often described as a living fossil, the shape of this hard-shelled crab has not changed for about two hundred million years. It has two types of eye; one which can detect light, called ocelli, and another known as compound eyes which are used to distinguish different objects. Although they live on the sea bed, they occasionally swim on their backs just below the surface.
[Power of Blood]
The blood of the Japanese horseshoe crab is utilised in medicinal and pharmacological research. It has a variety of uses, which include making it possible to quickly test for endotoxins such as those produced by toxigenic strains of E. coli bacteria."
Groups of these can be seen in the Underwater Ruins of Marige Atoll, found packed together with other Horseshoe Crabs. A large group can be found clustered together on top of a round boulder sitting atop the Ruins in the centre of coordinates H-3.
These cling to walls or rocks, usually with several others of their kind.