Holopodidae Zittel, 1879

Martinez-Soares, Pablo, Roux, Michel, Giusberti, Luca, Gatto, Roberto, Eléaume, Marc & Améziane, Nadia, 2024, New Eocene species of the crinoid genera Holopus and Cyathidium (Cyrtocrinida: Holopodidae) from north-eastern Italy, Zootaxa 5541 (4), pp. 401-437 : 412

Family Holopodidae Zittel, 1879

Remarks. Sieverts-Doreck (1951) believed that some ossicles and deformed Eugeniacrinus cups figured by Remeš (1902: pl. 19, figs. 11 a–c, 12–15) from the Štramberk Tithonian could belong to an Upper Jurassic species of Cyathidium . However, the figure is too imprecise to confirm an attribution to Holopodidae . The mere inclusion of Cyathidium depressum in a long list of cyrtocrinids cited from Lower Cretaceous Štramberk-type limestones ( Salamon & Gorzelak 2010: 871) cannot be taken into account without a critical analysis of the material concerned. Moreover, the attribution to C. senessei (Valette in Lambert & Valette, 1934) of a very poorly preserved axillary from the Santonian of Poland by Salamon and Gorzelak (2011: 311, fig. 2C, D) is highly questionable. Here, we consider that the appearance of Holopodidae prior to the Cenomanian has not been demonstrated.

It appears that the H/Wd ratio of IBrax is the best quantitative character to discriminate between the two genera in the family (> 0.7 in Holopus , <0.7 in Cyathidium ) ( Fig. 7 ).

Stratigraphic distribution. Upper Cenomanian–Recent.

Figures

FIGURE 7. Main quantitative characters of aboral cup and IBrax in fossil Holopodidae. S: Cyathidium holopus from Seymour Island. Straight lines: values of H/D and H/Wd. Other values in mm.