Designating an arthropod of the chelicerate family Xiphosuridae (also called Limulidae), characterized by a distinctive horseshoe-shaped carapace and a long spine-like telson; of or relating to this family.
The horseshoe crab Limulus and its allies are the only extant members.
A xiphosurid arthropod.
1960s; earliest use found in Proceedings of the Geological Society of London. From scientific Latin Xiphosurus, former genus name (L. J. FitzingerNeue Classification der Reptilien 48; from Xiphosura, former genus name) + -id, after scientific Latin Xiphosurida, family name and later order or suborder name.