Itieroptygmatis sp. 1

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

Itieroptygmatis sp. 1

Plate 18: figs 15, 16

Material.

Two juvenile specimens from Saal, collection Lang, SNSB-BSPG 2021 XV 88, 89.

Description.

A specimen is 47 mm high. The shell is moderately high-spired and coeloconoid. At least the first six whorls are moderately slender with whorls increasing slowly in width. The sutures are impressed. The whorls are smooth. The last two preserved whorls increase rapidly in width and at the same time, a furrow-like ramp is forming. The whorl face below the ramp is straight and the transition to the moderately convex base is evenly rounded. The base is smooth and has a wide umbilicus. The aperture is not preserved and it is unknown whether it has plaits.

Remarks.

This incompletely preserved species shows the same ontogenetic change in shell shape as I. cylindrata sp. nov. but is distinctly larger.

Relationships.

Itieroptygmatis cylindrata sp. nov. is considerably smaller and more gracile. Phaneroptyxis cf. nogreti sensu Hägele (1997) has whorls that are more regularly increasing in width across the entire shell and lacks a distinct ramp.

Figures

Plate 18. (1 - 10) Itieroptygmatis cylindrata sp. nov., morphotype 1. (1 - 2) Holotype, SNSB-BSPG 2021 XV 80, Saal (collection Lang); (1) lateral view, height 15 mm; (2) oblique view, width 5.5 mm (Gruendel 2017, fig. 15 B). (3 - 4) Paratype, SNSB-BSPG 2021 XV 81, Saal (collection Lang), apical and lateral views, width 14 mm. (5 - 6) Paratype, SNSB-BSPG 2021 XV 82, Saal (collection Lang), apical and lateral views, width 16 mm (original Gruendel 2017, fig. 15 C). (7 - 8) Paratype, SNSB-BSPG 2021 XV 83, Saal (collection Lang), basal and lateral views, width 15 mm. (9 - 10) Paratype, SNSB-BSPG 2021 XV 84, Saal (collection Lang); (9) columellar section, height 16 mm; (10) detail of (9), height 7.5 mm. (11) Itieroptygmatis cylindrata sp. nov., transition from morphotype 1 to morphotype 2, paratype, SNSB-BSPG 2021 XV 85, Saal (collection Schaefer), lateral view, height 33 mm. (12 - 14) Itieroptygmatis cylindrata sp. nov., morphotype 2, paratype, SNSB-BSPG 2021 XV 86, Saal (collection Lang), (12) lateral view, height 27 mm; (13) apex in lateral view, height 12 mm; (14) apical, width 13 mm. (15 - 16) Itieroptygmatis sp. 1. (15) SNSB-BSPG 2021 XV 88, Saal (collection Lang), lateral view, height 47 mm. (16) SNSB-BSPG 2021 XV 89, Saal (collection Lang), base, width 21 mm.