Eunerinea? sequana (Bronn ex Thirria, 1836)

Gruendel, Joachim, Keupp, Helmut, Lang, Fritz & Nuetzel, Alexander, 2022, Late Jurassic (Upper Kimmeridgian) Heterobranchia (Gastropoda) of the coral-facies of Saal near Kelheim and the viciniy of Nattheim (Germany), Zitteliana 96, pp. 179-221 : 179

Eunerinea? sequana (Bronn ex Thirria, 1836)

Plate 16: figs 1, 2

*1836 - Nerinea sequana Thirr. - Bronn: 561, pl. 6, fig. 6.

?1852 - Nerinea speciosa Voltz - d’Orbigny: 123, pl. 269, figs 1, 2.

?1997 - Cossmannea (Eunerinea) sequana (Bronn ex Thirria, 1836) - Fischer and Weber: 49.

Material.

One specimen from Saal, collection Lang, SNSB-BSPG 2021 XV 74.

Description.

The almost complete specimen is 42 mm high. The shell is slender. The whorls are regularly increasing in width forming an acutely conical shell. The whorls are relatively low with concave whorl face. The earliest whorls are poorly preserved. Later whorls seem to have a subsutural, weakly knobby bulge. The suture is barely visible. One or two weak knobby spiral cords below the bulge are present. The knobs of the bordering spiral cord emerge from the abapical suture. The whorl face is ornamented with broad, barely visible axial ribs. The base is flat and its transition to the whorl face is almost rectangular with a distinctly knobby bodering spiral cord. The base is entirely covered with numerous densely spaced, fine spiral cords. The aperture is not preserved; it probably has at least a columellar and a parietal plait.

Relationships.

Nerinea visurgis Roemer sensu Bronn (1836) lacks a subsutural bulge, the knobs on the bordering spiral cord are smaller, the base is more convex and seemingly devoid of any ornament. Nerinea tuberculosa Defrance sensu Cossmann (1896) has a slenderer shell with higher whorls, lacks a weakly knobby spiral cord at mid-whorl, the knobs on the bordering spiral cord are smaller but more numerous and its base is smooth. Nerinea speciosa Voltz sensu Cossmann (1898) is slenderer, its whorls increase less rapidly in width and are higher and it has five spiral cords on the whorl face. Nerinea posthuma Zittel sensu Cossmann (1898) is much larger, its whorls are higher and its base lacks spiral cords.

Figures

Plate 16. (1 - 2) Eunerinea? sequana (Bronn ex Thirria, 1836), SNSB-BSPG 2021 XV 74, Saal (collection Lang); (1) lateral view, height 42 mm; (2) base, width 13 mm. (3 - 9) Eunerinea? biplicata (Quenstedt, 1858). (3 - 4) SNSB-BSPG 2021 XV 75, Saal (collection Lang); (3) lateral view, height 36 mm; (4) shell detail, height 17 mm. (5) SNSB-BSPG 2021 XV 76, Saal (collection Lang), oblique view of base, width 16 mm. (6 - 7) SNSB-BSPG 2021 XV 77, Saal (collection Lang), lateral view and section, height 58 mm. (8 - 9) SNSB-BSPG 2021 XV 107, Saal (collection Lang), height 57 mm; (8) columellar section; (9) lateral view showing concave whorl face encrusted by colonial coral. (10 - 13) Eunerinea sp. nov. 1. (10 - 11) collection Sauerborn, Nattheim area; (10) lateral view, height 46.5 mm; (11) aperture, width 10 mm. (12 - 13) Collection Sauerborn, Nattheim area; (12) lateral view, height 120 mm; (13) detail of ornament, height 26 mm. (14) Eunerinea sp. 2; SNSB-BSPG 2021 XV 79 (collection Lang), lateral view, height 32 mm.