Ptygmatis? polyspira (Quenstedt, 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

Ptygmatis? polyspira (Quenstedt, 1884)

Plate 12: fig. 4

v*1881-1884 - Nerinea polyspira - Quenstedt: 554, pl. 207, fig. 3.

1901 - Aphanoptyxis polyspira Quenstedt - Geiger: 301.

1997 - Aphanoptyxis polyspira (Quenstedt, 1884) - Hägele: 133, fig. p.133, lower left.

Material.

Quenstedt’s (1881-1884) figured specimen (holotype by monotypy) from Nattheim ( Tübingen, Quenstedt collection).

Description.

The specimen consists of 7 whorls and is 32 mm high (apex missing). The shell is moderately slender and the whorls are increasing regularly in width. The sutures are somewhat pronounced by a subsutural bulge. The whorl face is straight and entirely covered by spiral cords (7-8 spiral cords on last whorl). The transition from whorl face to base is angular. The aperture is not preserved, plaits are not visible.

Remarks.

The studied holotype of Nerinea polyspira Quenstedt, 1884 is a poorly preserved specimen. Its systematic and taxonomic position remain unclear because aperture and plaits are unknown.

Relationships.

Nerinea ursicina Thurmann, 1861 (in Thurmann and Étallon 1861-1864) differs in having a strong adapical bulge, making the whorl face distinctly concave, fewer spiral cords, and four apertural plaits. Nerinea punctata Voltz sensu Bronn (1836) has a narrow but distinct ramp, and only three spiral cords on its whorl face. Nerinella calliope d’Orbigny sensu Cossmann (1898) has 5-6 spiral cords on the whorl face, some of them having fine knobs. Its aperture has three plaits. Nerinella turritella Voltz sensu Cossmann (1898) lacks a bulge and has four strong, knobby spiral cords on the whorl face and additional weaker cords between them. Nerinella cyane Loriol in Loriol & Pellat, 1874 has higher whorls with a smooth portion above the suture.

Figures

Plate 12. (1 - 3) Ptygmatis clio (d'Orbigny, 1852). (1 - 2) SNSB-BSPG 2021 XV 59, Saal (collection Lang); (1) section of fragment, height 21 mm; (2) detail, height 3.7 mm. (3) SNSB-BSPG 2021 XV 60, Saal (collection Lang), lateral view, height 108 mm. (4) Ptygmatis? polyspira (Quenstedt, 1881 - 1884), holotype, collection University Tuebingen (collection Quenstedt); Nattheim, lateral view, height 32 mm (original to Quenstedt 1881 - 1884, pl. 207, fig. 3. (11 - 12) Bactroptyxis teres (Muenster in Goldfuss, 1844), collection Sauerborn, Nattheim area. (5 - 7) Ptygmatis? ursicina (Thurmann in Thurmann & Etallon, 1861). (5 - 6) SNSB-BSPG 2021 XV 30, Saal (collection Lang); (5) last whorl with aperture, height 4 mm; (6) lateral view, height 9.5 mm. (7) SNSB-BSPG 2021 XV 31, Saal (collection Lang), aperture and ornament of base, width 2.5 mm.