21162 - Premium Grade Soft Bodied Xiphosurid (Horseshoe Crab Ancestor) Lower Ordovician Heterodiadema libycum Taylor and Naish 2005

Taylor and Naish 2005

Name: Northwest Africa 859

http://www

Size (the biggest): 48

Impressive huge vertebra of this species of Elasmosaurus

21162 - Premium Grade Soft Bodied Xiphosurid (Horseshoe Crab Ancestor) Lower Ordovician Heterodiadema libycum Taylor and Naish 2005Xiphosurans are an order of arthropods related to arachnids, or, according to one recent study, actually arachnids. They are sometimes called horseshoe crabs (a name applied more specifically to the only extant family, Limulidae). They first appeared in the Tremadocian (Lower Ordovician) from Fezouata Fm in South Morocco. Currently, there are only four living species. They are members of the order Xiphosura, which contains two suborders, Xiphosurida