Bactroptyxis? tricincta ( Muenster ) sensu Quenstedt, 1881-1884

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

Bactroptyxis? tricincta ( Muenster) sensu Quenstedt, 1881-1884

Plate 13: figs 11-16

1844 - Nerinea turritella Voltz - Goldfuss: 43, pl. 176, fig. 5.

1852 - Nerinea nattheimensis sp. nov. - d’Orbigny: 144.

v1881-1884 - Nerinea tricincta Goldfuss - Quenstedt: 555, pl. 207, fig. 9.

Material.

Three specimens from Saal, collection Lang: SNSB-BSPG 2021 XV 53-55, one specimen from Nattheim ( Tübingen: collection Quenstedt).

Description.

The largest specimen is 72 mm high. The shell is slender. The whorl face is straight. The suture is weakly impressed. The whorls are ornamented with a strong subsutural spiral cord, two somewhat weaker spiral cords at mid-whorl which are close to each other. The adapical cord of this pair is either weaker or both cords have about the same strength. The spiral cords are weakly knobby (knobby ornament indistinct due to preservation). The base is flat. The transition from base to whorl face is sharply angular at a pronounced bordering spiral cord. The base is umbilicated. Other details are not preserved.

Relationships.

Bactroptyxis? tricincta ( Münster in Goldfuss, 1844) is smaller. It has four spiral cords on the whorl face. As in the present material, two of these cords are close to each other, of which the adapical one is stronger, and both are close to the abapical suture. Nerinella subtricincta ( d’Orbigny) sensu Fischer and Weber (1997: 54, pl. 5, figs 21, 22) is slenderer and has two spiral cords at mid-whorl that are distinctly nodular. Nerinella cf. laufonensis (Thurmann, 1859) and N. subtricincta ( d’Orbigny, 1850) sensu Hägele (1997) are both slenderer and have higher, more concave whorls, and their nodular ornament is more pronounced.

Figures

Plate 13. (1 - 2) Bactroptyxis teres (Muenster in Goldfuss, 1844), from the Nattheim area (collection Sauerborn); (1) last whorl with aperture, height 11 mm; (2) lateral view, height 29 mm. (3 - 5) Bactroptyxis cf. fasciata (Voltz, 1836), SNSB-BSPG 2021 XV 56, Saal (collection Lang); (3) detail of ornament, width 4.5 mm; (4) lateral view, height 36 mm; (5) aperture, width of whorl 4.6 mm. (6 - 8) Bactroptyxis? subcochlearis (Muenster in Goldfuss, 1844). (6 - 7) SNSB-BSPG 2021 XV 57, Saal (collection Neubauer); (6) detail of ornament, height 11.5 mm; (7) lateral view, height 55 mm. (8) SNSB-BSPG 2021 XV 58, Saal (collection Lang), lateral view, height 29 mm. (9 - 10) Bactroptyxis? tricincta (Muenster in Goldfuss, 1844). (9) SNSB-BSPG 2021 XV 52, Saal (collection Lang), lateral view, height 48 mm (original to Gruendel 2017, fig. 14 B). (10) SNSB-BSPG 2021 XV 52, Saal (collection Lang), detail of shell in lateral view, height 21 mm. (11 - 16) Bactroptyxis? tricincta (Muenster) sensu Quenstedt (1881 - 1884). (11 - 12) Collection University Tuebingen (collection Quenstedt); Nattheim, lateral views, height 29 mm (original to Quenstedt 1881 - 1884, pl. 207, fig. 9). (13) SNSB-BSPG 2021 XV 53, Saal (collection Lang), lateral view, height 64 mm. (14) SNSB-BSPG 2021 XV 54, Saal (collection Lang), lateral view, height 55 mm. (15 - 16) SNSB-BSPG 2021 XV 55, Saal (collection Lang); (15) lateral view, height 72 mm; (16) last whorl, width 17 mm.