New observations on some poorly known protasterid ophiuroids from the Lower Devonian Hunsrück Slate of Germany

Four genera and species of protasterid ophiuroids have been reported from the Lower Devonian Hunsrück Slate: Bundenbachia beneckei, Palaeophiomyxa grandis, Mastigophiura grandis, and Palaeophiura simplex. In addition, the species Miospondylus rhenanus has traditionally been recognized as a member of the Lapworthuridae, a group of ophiuroids with paired but unfused ambulacrals. This ambulacral arrangement would make it unique among Hunsrück Slate ophiuroids. Palaeophiura simplex and M. rhenanus were originally based on Single, poorly preserved specimens, and their morphology has remained poorly understood. A restudy of the type material of P. simplex and M. rhenanus and a detailed comparison to other Hunsrück ophiuroids warrants reassignment of these taxa to Bundenbachia beneckei.Palaeophiura simplex is a juvenile example of this species and M. rhenanus is a peculiarly preserved adult. A newly prepared, well-preserved specimen of Bundenbachia beneckei expands our knowledge of the morphology of its mouthframe. In addition, Mastigophiura grandis is revised and redescribed based on newly recognized fossil material