Although the horseshoe crab appears to be and is named a crab, it is not. It is, in fact, related to Arachnids.
The horseshoe crab is a "living relic" of the Merostomata, most of which went extinct millions of years ago.
IUCN Red List of Threatened Species: lower risk - near threatened
The study of a horseshoe crab's central nervous system processing functions provided the principles necessary to understand information processes in virtually every other organism investigated.
The horseshoe crab feeds at night on worms, small molluscs, and algae. Food is picked up by the chelicerae and passed back to the bristle bases, where it is "chewed." The food is then moved forward to the mouth.
Along the Atlantic Coast, from Nova Scotia to the Yucatan.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); atlantic ocean (Native )
The horseshoe crab can generally be found in shallow water, over sandy or muddy bottoms.
Aquatic Biomes: coastal
The first pair of the six, flap-like appendages on the underside of the abdomen acts as a cover for the genital pore. The egg or sperm are released through this pore during spawning.
