Bactroptyxis? tricincta ( Muenster in Goldfuss, 1844), 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 in Goldfuss, 1844)

Plate 13: figs 9, 10

*1844 - Nerinea tricincta Münster - Münster in Goldfuss: 42, pl. 176, fig. 1.

2017 - Nerineoidea Nr. 5 - Gründel: 33, pl. 14 B.

Material.

One specimen from Saal, collection Lang, SNSB-BSPG 2021 XV 52.

Description.

The specimen is 47 mm high. The apical whorls, aperture, and base are missing. The shell is very slender. The whorl face is concave. The sutures are indistinct. The earliest preserved whorls have three spiral cords: a strong subsutural cord and a pair of closely spaced, somewhat weaker spiral cords below mid-whorl, close to the abapical suture. The area between the upper cord and the lower pair of cords is strongly concave. On late whorls, a fourth, weak spiral cord is intercalated between the upper cord and the lower pair of cords. The subsutural spiral cord is strong and crest-like on the latest preserved whorls. The base has an umbilicus.

Remark.

The aperture as well as number and arrangement of the plaits are unknown, therfore the generic assignment is doubtful.

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.