Eunerinea sp. 1

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 sp. 1

Plate 17: figs 1-8

non1836 - N. punctata Voltz in litt. - Bronn: 559, pl. 6, fig. 23.

1886-1888 - Nerinea subelegans Étallon - Loriol in Loriol and Bourgeat: 110, pl. 11, figs 4-6.

1997 - Nerinella elatior ( d’Orbigny, 1852), forme juvenile - Fischer and Weber: 52, pl. 5, fig. 5.

Material.

Seven specimens from the Nattheim area (five specimens collection Quenstedt/ Tübingen, two specimens collection Sauerborn), four specimens from Saal, collection Lang, one of which is illustrated (SNSB-BSPG 2021 XV 71) .

Description.

A large specimen is 30 mm high. The shell is very slender. The whorls are slowly increasing in width. The apical angle is somewhat variable. The whorl face is concave and ornamented with a subsutural bulge (smooth or knobby), with a strong and distinctly knobby spiral cord at approximately mid-whorl, and a narrow projecting bordering spiral cord that emerges above the suture. This cord demarcates the flat base from whorl face. Only very well preserved specimens show further weak spiral cords between adapical bulge and median spiral cord, and another between median spiral cord and abapical suture. They are at least partly knobby. The base lacks ornament. The rhomboid aperture has a siphonal canal. It shows a columellar, a parietal, and a palatal plait.

Remarks.

The present material assigned to this species is somewhat variable. The subsutural bulge is of various strength and, even if well preserved, is either smooth respectively knobby (in silicified specimens). It is possible that two very similar species are present. A possible identity with Nerinella nodosa (Voltz, 1836) remains unclear. This species differs from Nerinella sp. 1 by having a broader shell and more rapidly increasing whorls, an always knobby adapical bulge, a knobby spiral cord that is situated in most cases below mid-whorl, and a less projecting bordering spiral cord at the transition to the base. It is unclear whether these differences reflect preservation differences or not.

Relationships.

Differences to Nerinella subscalaris ( Münster in Goldfuss, 1844) are discussed under this taxon. Nerinea punctata Voltz, as described by Bronn (1836), with which Quenstedt (1881-1884) identified his species ( Nerinea punctata Voltz sensu Quenstedt, 1858 and 1881-1884), has three knobby spiral cords of about equal strength and lacks the pronounced projection of the bordering spiral cord. Nerinea ornata d’Orbigny sensu Loriol in Loriol, Royer and Tombeck (1872) is similar but its subsutural bulge is less pronounced. Nerinea hoheneggeri Peters, 1855 has a row of knobs directly above the abapical suture and several crenulated, relatively weak spiral cords between the suprasutural row of knobs and a knobby spiral cord situated somewhat above mid-whorl. Eunerinea hoheneggeri Peters sensu Wieczorek (1998) has distinct knobs on the bulges. Nerinea ornata d’Orbigny and N. tricincta d’Orbigny sensu Cossmann (1898) have three strong knobby spiral cords as well as weaker not knobby spiral cords in their interspaces.

Figures

Plate 17. Eunerinea sp. 1. (1 - 3) SNSB-BSPG 2021 XV 71, Saal (collection Lang); (1) lateral view, height 15 mm; (2) last two whorls, height 4 mm; (3) base, width 3.7 mm. (4 - 5) Collection Sauerborn, Nattheim area; (4) lateral view, height 10.5 mm; (5) last whorls with aperture, height 3.4 mm. (6 - 8) Collection Sauerborn; Nattheim area; (6) last whorl with aperture, height of detail 6.5 mm; (7 - 8) lateral views, height 26 mm.