Holopus Orbigny 1837

Genus Holopus Orbigny, 1837 Type-species. Holopus rangii Orbigny, 1837, by monotypy. Remarks. For main discriminating characters between Holopus and Cyathidium, see Table 3. H. fabianii sp. nov. and H. spileccense are the only fossil species of Holopus for which both the aboral cup and brachials are described. H. plaziati is known only from brachials, and the Campanian species in Jagt et al. (2010) is known exclusively from a single aboral cup. We here present the first description of well-differentiated keystone plates as well as distal brachials in a fossil Holopus species. Included fossil species and occurrences. Holopus fabianii sp. nov. (lower Lutetian of Chiampo Valley, north-eastern Italy), H. plaziati (lower Ypresian, Corbières, southern France), H. spileccense (lower Ypresian, Spilecco Hills near Bolca, north-eastern Italy), Holopus sp. in Jagt et al. (2010) (upper Campanian, Kronsmoor, northern Germany). Stratigraphic distribution. Upper Campanian–Recent.