21150 - Great Soft Bodied 2 Xiphosurids (Horseshoe Crab Ancestor) Lower Ordovician Phacodus As all the Elasmobranchii

As all the Elasmobranchii

The discovery of some connecting skeleton

Simple copper carbonate (CuCO3) is not known to exist in nature

It is an Asaphid

It was initially assigned to the family Trematochampsidae

21150 - Great Soft Bodied 2 Xiphosurids (Horseshoe Crab Ancestor) Lower Ordovician Phacodus As all the ElasmobranchiiXiphosurans 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