Goldius angusticalix was named by Van Viersen and De Wilde (2010) [Paratypes: NHMM 2009062a+b, positive and negative moulds of a partially exfoliated cephalon (Pl. 1, Fig. B); NHMM 2009063a+b, positive and negative moulds of a pygidium (Pl. 1, Fig. C); both situated on the same rock slab as the holotype. NHMM 2009065, librigena (Pl. 1, Fig. G). NHMM 2009064a-d, disarticulated, incomplete specimen (Pl. 1, Figs F, H, I). NHMM 2009066, mostly exfoliated cranidium with librigenal remains (Pl. 1, Figs D, E); NHMM 2009067, negative print of fragmentary pygidium (unfigured); both on the same rock slab. NHMM 2009068, fragmentary pygidium (unfigured).]. Its type specimen is NHMM 2009061a+b, a pygidium, and it is a 3D body fossil. Its type locality is Disused Nismes quarry, which is in an Eifelian marine carbonate in the Couvin Formation of Belgium.