Exelissa? aff. corallense ( Buvignier, 1843 )

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

Exelissa? aff. corallense ( Buvignier, 1843)

Plate 9: figs 10–12

Material.

1 specimen from Saal, SNSB-BSPG 2016 XXI 1835 : locality 1985, above coral stock, level 2 (“ Fundort 1985, über Korallenstock, Sohle 2 ”) and a questionable specimen from Saal, SNSB-BSPG 2016 XXI 1931 .

Description.

Shell high-spired, slender with slightly convex flanks; the certain specimen has 6.5 whorls, 12 mm high; sutures distinct; 5 bulging axial ribs per whorl that are aligned from whorl to whorl; whorl face ornamented with 5 slightly nodular spiral cords; spiral cords wider than interspaces separating them; intersections of axial ribs and spiral cords not knobby; one axial rib on last whorl thickened, varix-like; base incompletely preserved, moderately convex, covered with spiral cords; axial ribs continue onto base; questionable, poorly preserved specimen larger (height 16 mm), with distinctly broader shell shape; whorls increasing more rapidly; axial ribs also continue onto base; base with at least 2 distinct spiral cords.

Remarks.

Exelissa ursicina ( Loriol, 1889 in Loriol and Koby) sensu Gründel et al. (2022) has 6–8 axial ribs per whorl and 6–7 spiral cords on whorl face. Forms are described in the literature as Cerithium / Uchauxia corallense (mostly from the Oxfordian) that are very similar to the present form (e. g., Buvignier 1852; Thurmann and Étallon 1861–1864; Quenstedt 1881–1884; Gründel et al. 2022; and herein), which differ in details (e. g., in the number of spiral cords on whorl face, in the number of axial ribs per whorl, in the convexity of the whorls). It is not always clear which of these differences are diagnostic for species or represent intraspecific variability or reflect preservation. Cerithium mojisovici Zittel, 1873 has a broader shell, about 7 strong spiral cords on whorl face and a weak axial rib between two strong axial ribs. Exelissa diacritica Cossmann, 1913 is less slender, its whorl face is more convex (more distinct sutures) and it has more axial ribs per whorl that form only indistinct rib strands stretching over the shell.

Figures

Plate 9. (1, 2) Ditretus sp., cf. rostellaria (Buvignier, 1852), SNSB SNSB-BSPG 2016 XXI 1808, (1) lateral view, height 25 mm, (2) detail of ornament, height 12 mm. (3, 4) Ditretus sp., cf. rostellaria (Buvignier, 1852), SNSB-BSPG 2016 XXI 1809, lateral views, height 23 mm. (5) Cryptoptyxis? spinosus sp. nov., holotype, SSNSB-BSPG 2016 XXI 1824, apertural and abapertural lateral views, height 22 mm. (6, 7) Coninoda strekwera Gründel, Keupp & Lang, 2019, SNSB-BSPG 2016 XXI 1827, lateral view and longitudinal section, height 33 mm. (8, 9) Tropacerithium cumaritum Gründel, Keupp & Lang, 2019, SNSB-BSPG 2016 XXI 1830, (8) detail of last whorl, height 4 mm, (9) lateral view, height 7 mm. (10–12) Exelissa? aff. corallense (Buvignier, 1843), SNSB-BSPG 2016 XXI 1835, locality 1985, above coral stock, level 2 (“ Fundort 1985, über Korallenstock, Sohle 2 ”), (10) lateral view, height 12 mm, (11) apex in lateral view, height 5 mm, (12) last two whorls in lateral view, height 7 mm. (13, 14) Exelissa ursicina (Loriol in Loriol and Koby 1889), SNSB-BSPG 2016 XXI 1836, (13) l ateral view, height 10 mm, (14) basal view, width 4.5 mm. (15–17) Turritella lucagrita sp. nov., holotype, SNSB-BSPG 2016 XXI 1840, (15) lateral view, height 75 mm, (16) earliest preserved whorls in lateral view, height 40 mm, (17) last whorls in lateral view, height 46 mm. (18) Nudivagus? sp. 2, SNSB-BSPG 2016 XXI 1844, lateral view, height 35 mm. (19) Neuburgensia angulata sp. nov., paratype, SNSB-BSPG 2016 XXI 1848, collection Lang, last whorl with aperture, height 6 mm.