Ptygmatis mandelslohi ( Bronn, 1836 )

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

Ptygmatis mandelslohi ( Bronn, 1836)

pl. 9: figs 1–5 in Gründel et al. (2022)

2022 – Ptygmatis mandelslohi ( Bronn, 1836) – Gründel, Keupp, Lang and Nützel: 191; pl. 9, figs 1–5 (here more chresonymy and synonymy).

Material.

9 specimens (6 specimens from Saal, 3 specimens Saal, locality 1, level 4 (“ Sohle 4, Fundstelle 1 ”).

Remarks.

The weak adapical spiral groove described by Gründel et al. (2022) is not recognizable in the present material (due to preservation?). Gründel et al. (2022) emphasized the difficulties in distinguishing P. mandelslohi from similar species. The distinction between the species Ptygmatis mandelslohi and P. bruntrutana is problematic. Various authors (e. g., Fischer and Weber 1997) considered both to be conspecific. In our opinion, P. mandelslohi is characterized by a moderately wide shell, the apical angle decreases during ontogeny (resulting in cyrtoconoid shell shape), it usually has a straight to slightly concave whorl face, relatively low whorls and a sharp edge between flank and base. P. bruntrutana , on the other hand, has a more slender shell (with the same plate pattern), whorls are evenly increasing in width over the entire shell (not cyrtoconoid), whorls are generally higher, the whorl face is straight to slightly convex, the transition between whorl face and base lacks a sharp edge. However, there are specimens in the present material that cannot be clearly assigned to one of the two species (real differences or due to preservation?).