Nododelphinula oblonga, Gründel & Nützel, 2024

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

Nododelphinula oblonga sp. nov.

Plate 3: figs 5–9

Etymology.

Latin oblongum – protruding, because of the protruding keel.

Holotype.

SNSB–BSPG 2016 XXI 1721 (Plate 3 : figs 5–7), collection Sylla.

Paratype.

1 specimen, SNSB–BSPG 2016 XXI 1930 , collection Lang.

Type locality and stratum.

Upper Jurassic (Kimmeridgian) reefal limestones from the locality Saal near Kelheim, Lower Bavaria ( Gründel et al. 2015, 2022).

Diagnosis.

Whorl face with strongly projecting keel and subsutural row of nodes; base entirely covered with spiral cords, one of them encircles umbilicus and is stronger with larger nodes; aperture is more or less pentagonal.

Description.

Shell lowly trochiform with gradate spire, about as wide as high; larger specimen is 29 mm wide; earliest whorls are poorly preserved; first recognizable sculpture is an edge roughly in the mid-whorl, which is reinforced to form a keel; area adapical to the edge / keel forming broad, oblique ramp; whorl face below edge / keel approximately vertical, concave; during growth, keel first approaches abapical suture and then moves away again as suture sinks; keel nodular (not always clearly); nodes weaken during ontogeny; a row of nodes present below adapical suture; whorl face completely covered with spiral cords; weak, blurry, barely recognizable axial ribs run from suture to suture; spiral cord at border to base slightly weaker than keel; whorl face between these keel and border spiral cord concave, covered with slightly nodular spiral cords; base flat with angular transition to whorl face where spiral cord is situated; base distinctly phaneromphalous, covered with several spiral cords; particularly strong spiral cord surmounts umbilicus, having significantly larger nodes than those on whorl face; nodes have a pit in apertural portion and thus resemble hollow spines; aperture only incompletely preserved, having pentagonal outline.

Remarks.

Delphinula serrata Buvignier, 1852 has a lower shell, the keel has stronger nodes, lacks the strong spiral cord surrounding the umbilicus, and has fewer but stronger spiral cords on the base. Turbo valfinensis Étallon sensu Loriol in Loriol and Bourgeat 1886–1888 (pl. 20, fig. 2, non fig. 3) has a more pronounced tuberculate ornament, the axial ribs are more distinct, the spiral cords are weaker and more numerous, and it lacks the strong spiral cord surrounding the umbilicus. The latter characteristic applies also to Turbo plicatocostatus Zittel, 1873 and to the species of the same name sensu Loriol in Loriol and Koby (1894). In both cases, the keel is weaker and the subsutural row of nodes is missing, the aperture is more rounded.

Figures

Plate 3. (1) Caryomphalus globatus (Buvignier, 1843), SNSB – BSPG 2016 XXI 1713, lateral view, width 15 mm. (2, 3) Caryomphalus sp., cf. concavus Gründel, Keupp & Lang, 2017, SNSB – BSPG 2017 XXI 1717, lateral and basal views, height 14 mm, width 12 mm. (4) Proconulus? sp. 1 sensu Gründel, Keupp and Lang (2017), SNSB – BSPG 2016 XXI 1718, lateral and basal views, height 11 mm. (5–7) Nododelphinula oblonga sp. nov., holotype, SNSB – BSPG 2016 XXI 1721, lateral views, apertural and abapertural, basal view, width 26 mm. (8–9) Nododelphinula oblonga sp. nov., paratype, SNSB – BSPG 2016 XXI 1930, collection Lang, shell in lateral and dorsal view, width 27 mm. (10–12) Serrettella gerberi (Gründel, Keupp & Lang, 2017), SNSB – BSPG 2016 XXI 1722, lateral, basal views and aperture, width 13 mm. (13) Serrettella gerberi (Gründel, Keupp & Lang, 2017), locality 1985, above coral stock, level 2, SNSB – BSPG 2016 XXI 1723, lateral view, width 9.5 mm. (14, 15) Heliacanthus sp. 1, SNSB – BSPG 2016 XXI 1726, abapertural and apertural lateral views, height 12 mm.