Semicassis aff. reticulata ( Bellardi & Michelotti, 1840 ) (Bon.)

Kiel, Steffen, Sami, Marco & Taviani, Marco, 2023, Mollusks (Gastropoda, Bivalvia) from Miocene cold-seep deposits in northern Italy: revisions and additions, European Journal of Taxonomy 910, pp. 115-160 : 133-134

Semicassis aff. reticulata ( Bellardi & Michelotti, 1840) (Bon.)

Fig. 6L

Cassis reticulata Bon. Bellardi & Michelotti, 1840: 53 (145) [Bon. refers to an unpublished museum catalog].

Semicassis reticulata – Sacco 1904: pl. 20 figs 18–19. — Ferrero Mortara et al. 1984: pl. 1 figs 9–10.

Material examined

ITALY – Emilia-Romagna • 1 spec.; Castiglion dei Pepoli; MGGC 22310 (H = 48.6, W = 42.0 mm) .

Remarks

This specimen is here assigned to Semicassis based on the similarities with the species outlined below. It should be noted, though, that certain deep-sea buccinids produce very similar globular shells with fine spiral sculpture. Examples include a Latisipho sp. that was recently reported from hydrothermal vent in the Bering Sea ( Nekhaev et al. 2022), and Buccinum cascadiense Clarke, 2022 , from the Northeast Pacific ( Clark 2022).

The Middle Miocene Semicassis reticulata ( Bellardi & Michelotti, 1840) as illustrated in Sacco (1904: pl. 20 figs 18–19) and Ferrero Mortara et al. (1984: pl. 1 figs 9–10) has a less globular last whorl and lacks the distinct shoulder. All species of Semicassis from the Miocene of the Paratethys ( Landau et al. 2009: pl. 4) have a lower spire with less convex whorls than the specimen from Castiglione dei Pepoli. A similar whorl profile as the specimen from Castiglione dei Pepoli has Semicassis miolaevigata Sacco, 1890 , but that species typically has less distinct spirals on the whorls’ flank ( Sacco 1904: 97, pl. 20 figs 5–10) and Ferrero Mortara et al. (1984: pl. 1 fig. 6). Another species with similar fine spiral sculpture on the entire whorl is the Early Miocene Sconsia ottnangensis (Sacco, 1890) . However, the specimens illustrated by Landau et al. (2009: pl. 5 figs 1–2) are somewhat deformed and the similarity in shell shape to the specimen from Castiglione dei Pepoli may be an artifact. Specimens reported as Phalium (Semicassis) bituminatum (Martin, 1943) from a presumed mud volcano or seep deposit in the Late Miocene of Waisiu, Buton Island, Indonesia ( Beets 1942: 277, pl. 28 fig. 58), have much stronger tubercles than the specimen reported here.

A morphologically very similar species was reported by Moroni (1966: 75–76, pl. 3 fig. 2) as Galeodea delibrata Moroni, 1966 , from the Late Miocene Calcari a Lucina deposits in the Santa Sofia area. In addition to being much larger (up to 95 mm high) than Semicassis aff. reticulata from Castiglion dei Pepoli, it also differs by having a slightly more slender shell. Miocene Mediterranean/Paratethyan species of Galeodea Link, 1807 are generally much higher spired than Galeodea delibrata (see Landau et al. 2009) and due to its overall similarity to Semicassis aff. reticulata , we provisionally re-assign that species to Semicassis (as Semicassis delibrata ( Moroni, 1966)) .

Stratigraphic and geographic range

Miocene, northern Italy.

Figures

Fig. 6. Neritimorpha Golikov & Starobogatov, 1975 and Caenogastropoda Cox, 1960 from the Calcari a Lucina seep deposits in northern Italy. A–B. The phenacolepid (Neritimorpha) Thalassonerita megastoma Moroni, 1966, Le Colline (MSF 1223), internal mold showing columellar muscle scars. C–E. The elachisinid (Caenogastropoda) Laeviphitus sp. C. Small specimen with preserved protoconch, from Ca’ Rovereti (NRM Mo 204837). D. Close-up on transition between proto- and teleoconch, from Ca’ Rovereti (NRM Mo 204838). E. Tall specimen (MSF 1204) from Le Colline. F–G. Naticidae indet. sp. 1. F. Shell embedded in rock matrix, from Castiglion dei Pepoli (MGGC 22304). G. Operculum (MSF 1218). H. Naticidae indet. sp. 2 from Guzzano (MGGC 22305). I–K. Pisanianura? pusilla Bellardi 1872, from Castel di Casio. I. Specimen with remains of siphonal canal and shell sculpture (MGGC 22306). J. Small, internal mold (MGGC 22307). K. Large specimen with preserved shell (MGGC 22308). L. Semicassis aff. reticulata (Bellardi & Michelotti, 1840), Castiglion dei Pepoli (MGGC 22310).