Eosipho hoernesi ( Bellardi, 1873 )

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 : 134-135

Eosipho hoernesi ( Bellardi, 1873)

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.

Material examined

ITALY – Emilia-Romagna • 1 spec.; Ca’ Piantè ; MSF 1070 (H = 54.7 mm) • 1 spec.; Ca’ Rovereti ; NRM Mo 204839 (H = 45.8 mm) .

Remarks

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 .

Stratigraphic and geographic range

Middle to Upper Miocene, northern Italy.

Figures

Fig. 7. Neogastropoda Wenz, 1938 and Heterobranchia Burmeister, 1837 from Miocene Calcari a Lucina seep deposits in northern Italy. A–C. The eosiphonid Eosipho hoernesi (Bellardi, 1872). A–B. Specimen with well-preserved aperture, from Ca’ Piantè (MSF 1070). C. Specimen showing details of spiral ornament, from Ca’ Rovereti (NRM Mo 204839). D. The buccinid Neptunea? sp. from Le Colline (MSF 2359). E–F. The olivid Olivella longispira Bellardi, 1882. E. From Le Colline (MSF 1202). F. From Guzzano (MGGC 22310). G. The turrid Turris citima (Bellardi, 1877), from Ca’ Cavalmagra (MSF 1307). H–I. The turrid Turricula sp., from Ca’ Piantè (MSF 1081). J. The pyramidellid (Heterobranchia) Turbonilla sp., from Ca’ Cavalmagra (MSF 1305).