Rusophycus morgati: an asaphid produced trace fossil from the Cambro- Ordovician of Brittany and northwest Spain

A new species of trilobite resting trace, Rusophycus morgati, is described from the upper part of the Gres Armoricain (Arenigian: Lower Ordovician) of Finistere, Brittany, France and from the top of the Barrios Formation, Cantabrian Mountains, northwest Spain. In both areas it occurs with Cruziana rugosa, C. furcifera and C. goldfussi. The morphologies of impressions of appendages, podomeres, hypostome and pygidial doublure differ from similar features in previously described Rusophycus and suggest an isotelinid-asaphid, possibly Plesiomegalaspis, as the trace maker.