Bactroptyxis? subcochlearis ( Muenster in Goldfuss, 1844)

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? subcochlearis ( Muenster in Goldfuss, 1844)

Plate 13: figs 6-8

*1844 - Nerinea subcochlearis Münster - Münster in Goldfuss: 42, pl. 175, fig. 14.

1858 - Nerinea subcochlearis Goldfuss - Quenstedt: 769, pl. 94, fig. 24.

v1881-1884 - Nerinea subcochlearis Goldf. - Quenstedt: 555, pl. 207, figs 12, 13.

non1997 - Aptyxiella subcochlearis ( Münster, 1844) - Hägele: 134, fig. 134 upper right.

Material.

One relatively large specimen (collection Neubauer) and four fragments (collection Lang), of which two are illustrated (SNSB-BSPG 2021 XV 57, 58) from Saal; two specimens from Nattheim ( Tübingen: collection Quenstedt).

Description.

The large specimen is 55 mm high. The shell is slender. The whorls increase regularly in width. The sutures are hardly recognizable. The whorl face is ornamented with two strong spiral cords lacking knobs. The upper spiral cord is in directly subsutural position. The lower spiral cord lies somewhat above the abapical suture. The adapical spiral cord is somewhat stronger than the abapical one. At least on the last whorl, another much weaker spiral cord is intercalated. The base and the aperture are not preserved. The base has a narrow umbilicus.

Relationships.

In Aptyxiella nattheimensis ( d’Orbigny) sensu Hägele (1997), the suture lies on a bulge formed by adapical and abapical swelling of neighbouring whorls; its whorl face has two spiral cords. Nerinea quadricincta Münster sensu Geiger (1901) has a gradate spire, a subsutural bulge and at least two distinct spiral cords on the whorl face. The ornament reported by Geiger (1901: 293) cannot be seen in the illustration provided by this author. Nerinea sulcata Schübler in Zieten 1830 has whorls that are more rapidly increasing in width (conical shape), higher whorls and more distinct sutures. Nerinea bicostata Gemmellaro, 1870 has a broader shell and lacks an umbilicus.

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.