Fig. 7A–C
Chrysodomus Hörnesi Bellardi, 1873: 153, pl. 11 figs 14–15.
Neptunea (Neptunea) hoernesi (Bellardi) subdilatata Moroni, 1966: 76, pl. 19 fig. 1.
Eosipho hoernesi – Brunetti & Della Bella 2016: fig. 19f. — Kovács 2021: 72, figs 22–23. — Kaim 2022: 332.
ITALY – Emilia-Romagna • 1 spec.; Ca’ Piantè; MSF 1070 (H = 54.7 mm) • 1 spec.; Ca’ Rovereti; NRM Mo 204839 (H = 45.8 mm).
This species was originally placed in Neptunea Röding, 1798 or its synonym Chrysodomus Swainson, 1840, but Harzhauser et al. (2014) regarded it as not belonging to this genus. Both Brunetti & Della Bella (2016) and Kovács (2021) placed it in Eosipho, and this treatment is followed here. Moroni (1966) introduced a new subspecies – Neptunea hoernesi subdilatata – for a buccinid from the Calcari a Lucina deposits. We find our specimens difficult to distinguish from Bellardi’s (1873: pl. 11 fig. 14) original illustration of Chrysodomus hoernesi, though his “Varietá A” (Bellardi 1873: pl. 11 fig. 15) does have less convex whorls with a shallower suture. Brunetti & Della Bella (2016: fig. 19f) illustrated a specimen of Chrysodomus hoernesi from the Bellardi-Sacco collection, which differs marginally by its slightly broader last whorl from the Calcari a Lucina specimens available to us. A specimen identified as Eosipho hoernesi from the Middle Miocene of Romania (Kovács 2021: figs 22–23) has a distinctly higher spire and more oblique axial ribs than the Italian specimens assigned to this species. Buccinoid species are known to show variation in shell shape, especially the height of the spire, along depth gradients (Bouchet & Warén 1985; Olabarria & Thurston 2003). Hence, we are not in favor of distinguishing subspecies or variants among Eosipho hoernesi.
A similar species is Siphonalia (Pseudoneptunea) semisulcata Martin in Beets (1942: pl. 28 fig. 68) from a presumed, Late Miocene seep deposit in Buton, Indonesia, but its spirals are less distinct on the whorls’ flanks but stronger on the base than in E. hoernesi. Neptunea (Sipho ?) altenai Beets, 1942, from the same locality also has very similar axial and spiral sculpture, but a much short siphonal canal than E. hoernesi. The late Eocene to Oligocene Colus sekiuensis Kiel & Goedert, 2007, from organic substrates and seep deposits in western Washington State, USA (Kiel & Goedert 2007), has similar though more incised sculpture, is smaller, and its siphonal canal is more strongly twisted than that of E. hoernesi.
Middle to Upper Miocene, northern Italy.