How many species of horseshoe crabs are there now?
Global Distribution
Tachypleus tridentatus
Carcinoscorpius rotundicauda
It was believed that there were hundreds of species of horseshoe crab and their relatives, such as sea scorpions long time ago. However, nowadays, sea scorpions are extinct and only four species of horseshoe crabs remain. Three of them occur in the South East Asia (Tachypleus tridentatus, T. gigas and Carcinoscorpius rotundicauda), ranging from Japan to Vietnam. The fourth species (Limulus polyphemus) is found along the Atlantic Coast of America.
