Cyathidium gastaldii

Cyathidium gastaldii (Michelin, 1851) Figures 8F, G; Table 6 Synonymy. Micropocrinus gastaldii Michelin, 1851: 93–94; Michelotti, 1861: 354; Jaekel, 1891: 621; Sieverts, 1931: 173; Biese & Sieverts-Doreck, 1939: 11; Cyathidium gastaldii Manni, 2005: 214, pl. 1 fig. 8, text fig. 4 Non Cyathidium gastaldii Manni & Pacioni, 2021: 68–69, fig. 3. Type material. A single aboral cup (holotype) from the Miocene of the Superga Hill near Turin and two plaster casts are housed in the palaeontological collection of the MNHN in Paris (MNHN-F-R68284). Several casts of this holotype were sent to collections outside of France. Two of them are housed in the Palaeontological Museum of Turin University (Manni & Pacioni 2021). The cast of an aboral cup (MPURLS NS 6/800) having nearly the same size and belonging to the Palaeontological Museum of Rome (Manni 2005) is also a cast of the holotype. Emended diagnosis. Aboral cup rounded subpentagonal, diameter up to 14.2 mm, ratio of height to diameter 0.7, dense regular granulation developed especially on upper part of external surface, interradial processes conspicuous, no marked growth bands. Description of the holotype. Aboral cup rounded subpentagonal, with granulated external surface as indicated in Michelin’s diagnosis. Quantitative characters listed in Table 6. Wall relatively thick (2.5–2.7 mm); interradial processes conspicuous but irregularly preserved; synarthrial articulation of radials worn, aboral ligament pit inconspicuous (Fig. 8G). Lateral view asymmetrical (H/h 1.6); side of maximum height with a convex subconical growth discontinuity of smooth surface related to the undulating attachment surface (Fig. 8F). Dense regular granulation especially well developed on the upper part of the external surface and extended very close to the fulcral ridge of radial articulation, no marked growth bands. Other specimen. Manni (2005) figured a small aboral cup (quantitative characters listed in Table 6) with a granulated external surface belonging to the Michelotti Collection housed in the Museum of Palaeontology of “La Sapienza” University of Rome (MPURLS 2534). He attributed it to a juvenile of C. gastaldii corresponding to the specimen cited by Michelotti (1861) from the Miocene near Turin. Remarks. Jaekel (1891) considered Micropocrinus gastaldii to be very similar to the Cretaceous C. holopus and deemed that the difference in granulation was a result of better preservation. Rasmussen (1961, p. 246) pointed out that C. gastaldii is “very similar to large specimens of C. depressum and to specimens of C. holopus with low theca and a broad base”. Manni and Pacioni (2021) attributed to C. gastaldii three poorly preserved specimens from Cava Boschetto (= Cengio dell’Orbo quarry, Chiampo Valley, Lutetian), specimens here maintained in open nomenclature (see above). However, at the species rank, all these presumed affinities are not well supported by discriminating characters. Additional new material is required to confirm the validity of C. gastaldii. Occurrence. Serravallian (Middle Miocene) of Superga Hill near Turin, northwestern Italy.