21164 - Premium Grade Soft Bodied Xiphosurid (Horseshoe Crab Ancestor) Lower Ordovician Unidentified crocodile species Writeup from MB 102:

Writeup from MB 102:

Orthoceras gradatum

Purchased in Mauritania in June 2014

Colorado and the distribution of Prognathodon in North America

without restorations or reparations

21164 - Premium Grade Soft Bodied Xiphosurid (Horseshoe Crab Ancestor) Lower Ordovician Unidentified crocodile species Writeup from MB 102:Xiphosurans 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