First report on the occurrence of the echinoderm classes Soluta and Stylophora in a new Lower Devonian (Pragian) Konservat-Lagerstätte from southern Belgium

In the Neufchâteau–Eifel Synclinorium (southern Belgium), remnants of the spoil heap of the disused and now flooded underground Sainte-Barbe Quarry (Warmifontaine) yielded an invertebrate Pragian assemblage occurring in the dark monotonous slates of the La Roche Formation (Martelange Member). This locality is considered as a new Belgian Konservat-Lagerstätte (fossil conservation deposit) due to the presence of both biomineralised and soft-bodied organisms. Two specimens from the Sainte-Barbe Quarry Biota are described and assigned to two distinct classes of extinct echinoderms. The first one corresponds to an almost complete, flattened and distorted dendrocystitid solutan, which is tentatively identified as Dehmicystis? sp., based on similarities with D. globulus from the Hunsrück Slate (Emsian) of Germany. The second echinoderm specimen is a well-preserved, flattened, fully articulated and almost complete mitrate stylophoran, morphologically close to Mitrocystites? styloideus-like peltocystidans from the Lower and Middle Devonian of Germany. Taphonomic attributes of the two echinoderms from Warmifontaine (e.g. both fully articulated; mitrate with its aulacophore preserved in feeding position) suggest they were probably killed and entombed by obrution deposits in an otherwise quiet and deep setting. Other echinoderms (asteroids, crinoids, blastoids, cyclocystoids, ophiuroids) reported from the Lower Devonian of Belgium are also briefly discussed and illustrated (e.g. holotypes).