Belinurus was another aquatic chelicerate. It was not a eurypterid, but a member of the group called xiphosurans ('sword tails'), which includes the horseshoe or king crabs of today. (These are not true crabs from the crustacean group, but are more closely related to scorpions and spiders.) possessed the large spine or dagger-like telson, or tail. Other features that are characteristic of the group include the large, hoof-shaped prosoma, or head, bearing the mouth, eyes and legs, and a shorter abdomen.