Rugalindrites 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

Rugalindrites sp. 1

Plate 20: figs 10-12

Material.

Two specimens from Saal, collection Lang, SNSB-BSPG 2021 XV 98.

Description.

The larger specimen is 6 mm high. The overall shape closely resembles that of Rugalindrites cylindracea . The spire is distinctly elevated and gradate. The spire whorls increase more rapidly in height than in width due to a downward shift of the suture. The whorls have a narrow ramp with a more rounded transition to the whorl face. The growth lines are almost straight and weakly prosocline. In the upper part of the whorls, they are strengthened and thread-like. The growth lines are distinctly prosocyrt on the convex base. At about mid-whorl of the last whorl, there is a broad band with a micro-ornament of numerous spiral threads (Plate 20 : fig. 12). The aperture is not preserved.

Relationships.

Rugalindrites cylindracea (Cornuel, 1841) has a more convex whorl face, a higher spire, the edge that borders the ramp is more pronounced, it lacks spiral ornament and strengthened growth lines. Cylindrobullina peroni Cossmann, 1895, Tornatina boutillieri Cossmann, 1895, Cylindrites nitidens Loriol, 1889 (in Loriol and Koby 1889-1892), and Actaeonina cylindracea d’Orbigny sensu Loriol and Pellat (1874) are larger (some of them considerably larger), the edge that borders the ramp is more pronounced, and lack any visible ornament. Cylindrobullina cf. disjuncta Terquem and Jourdy sensu Nalivkin and Akimov (1917) has a stouter shell, is larger, and lacks ornament.

Figures

Plate 20. (1 - 9) Rugalindrites cylindracea (Cornuel, 1841). (1) SNSB-BSPG 2021 XV 93, Saal (collection Lang), lateral view, height 5 mm. (2) SNSB-BSPG 2021 XV 94, Saal (collection Lang), apical view, width 5.5 mm. (3 - 4) Saal (collection Lang), lateral and apical views (specimen lost). (5) SNSB-BSPG 2021 XV 95, Saal (collection Lang), aperture, height 3.5 mm. (6 - 7) SNSB-BSPG 2021 XV 96, Saal (collection Lang); (6) lateral view, height 8.5 mm; (7) aperture, height 3.5 mm. (8 - 9) SNSB-BSPG 2021 XV 97, Saal (collection Lang); (8) aperture, height 6 mm; (9) lateral view, height 9.5 mm. (10 - 12) Rugalindrites sp. 1, SNSB-BSPG 2021 XV 98, Saal (collection Lang); (10) lateral view, height 5.5 mm; (11) apical view, width 2.5 mm; (12) detail of ornament, height ca. 1.3 mm.