Bactroptyxis? subcochlearis (Münster in Goldfuss, 1844)

Gründel, Joachim & Nützel, Alexander, 2024, Late Jurassic (Upper Kimmeridgian) gastropods from Saal near Kelheim (Germany, Bavaria), Zitteliana 98, pp. 19-72 : 19-72

Bactroptyxis? subcochlearis (Münster in Goldfuss, 1844)

Plate 13: figs 16–18

2022 – Bactroptyxis? subcochlearis (Münster in Goldfuss, 1844) – Gründel, Keupp, Lang and Nützel: 199, pl. 13, figs 6–8 (here more chresonymy and synonymy).

Material.

6 specimens and fragments, illustrated specimen SNSB-BSPG 2016 XXI 1921 .

Remarks.

The illustrated specimen is 69 mm high. What was suspected in 2022 can now be proven: The early whorls have only 2 strong spiral cords, one directly subsutural, the other well above the abapical suture. Only gradually a weaker spiral cord is formed between the primary spiral cords. The secondary spiral cord remains significantly weaker than the other two throughout ontogeny.

Aptyxis kehlheimensis Schlosser, 1882 (pl. 11: figs 3, 5–7; non fig. 4 in Schlosser) has weaker spiral cords and lacks a secondary third spiral cord.

Figures

Plate 13. (1) Endoplocus staszycii (Zeuschner, 1849)?, SNSB-BSPG 2016 XXI 1905, lateral view, height 27 mm. (2) Endoplocus staszycii (Zeuschner, 1849)?, SNSB-BSPG 2016 XXI 1906, tranverse section of whorl showing plaits, height 9 mm. (3, 4) Endoplocus sp. 1, SNSB, SNSB-BSPG 2016 XXI 1909, lateral view and columellar section, height 41 mm. (5, 6) Endoplocus sp. 2, SNSB-BSPG 2016 XXI 1912, (5) whorls in transverse section, height 45 mm, (6) columellar section, height 74 mm. (7, 8) Endoplocus sp. 2, SNSB-BSPG 2016 XXI 1913, lateral view and columellar section, height 74 mm. (9) Ptygmatis bruntrutana (Thurmann, 1832), SNSB-BSPG 2016 XXI 1915, lateral view, height 11 mm. (10) Ptygmatis bruntrutana (Thurmann, 1832), SNSB-BSPG 2016 XXI 1916, whorl in transverse section, height 11 mm. (11, 12) Ptygmatis clio (d’Orbigny, 1852), SNSB-BSPG 2016 XXI 1917, (11) detail of columellar section, height 36 mm, (12) lateral view, height 69 mm. (13) Ptygmatis clio (d’Orbigny, 1852), SNSB XXI 1918, 13 a) lateral view, height 60 mm, (13 b) whorl in transverse section, height 11 mm. (14, 15) Ptygmatis clio (d’Orbigny, 1852), SNSB XXI 1919, lateral views, height 45 mm. (16–18) Bactroptyxis? subcochlearis (Münster in Goldfuss, 1844), SNSB XXI 1921, (16) lateral view, height 69 mm, (17) lateral view of early whorls, height 32 mm, (18) lateral view of late whorls, height 36 mm. (19) Cryptoplocus subpyramidalis (Münster in Goldfuss, 1844), SNSB-BSPG 2016 XXI 1922, lateral view, height 142 mm.