Diagnoza

The shell is trochoid with a blunt apex. The early teleoconch whorls have a flat lateral flank. Concave flanks appear only on the latest whorl of the largest specimens. The suture is hardly incised. The lateral flanks as well as the base are densely covered by numerous spiral ribs, which are broader than the interspaces. Axial ribs are absent. The upper part of the inner lip shows a distinct node, which together with the crescent-like callus, forms a shallow half-moon shaped depression.

Porównanie

The juvenile whorls of Proconulus aequilineatus (Münster in Goldfuss, 1844) sensu Brösamlen (1909) from the Tithonian of Germany are more strongly convex and the species is distinctly larger, having also more whorls. Proconulus virdunensis (Buvignier, 1852) sensu Loriol & Pellat (1874) from the Late Jurassic of the Boulonnais (northern France) has straight (not concave) flanks, the transition to the base is angulated, and the spiral ribs are crenulated.

Autekologia

Występowanie geograficzne

Kłęby (Western Pomerania), Poland

Zasięg czasowy

late Oxfordian.

Materiały muzealne

Three specimens in collection of Schmidt (1905); moreover six specimens (BGR, Buchholz, GG, and ZPAL).

Literatura

Dmoch, I. 1971. Osady i fauna górnojurajska z Kłębów na Pomorzu Zachodnim. Studia Societatis Scientarum Torunensis. Sectio C (Geographia et Geologia), 7, 1‒60.

Gründel, J & Kaim, A. 2006. Shallow-water gastropods from Late Oxfordian sands in Kłęby (Pomerania, Poland). Acta Geologica Polonica 56, 2, 121-157.

Karczewski, L. 1980. Gromada Gastropoda Cuvier, 1797 In: Malinowska, L. (ed.), Budowa Geologiczna Polski. Tom III: Atlas skamienianiałości przewodnich i charakterystycznych. Część 2b, Mezozoik, Jura, 414‒434. Wydawnictwa Geologiczne; Warszawa.

Schmidt, M. 1905. Über Oberen Jura in Pommern. Abhandlungen der Königlich Preußsischen Geologischen Landesanstalt und Bergakademie, Neue Folge, 41, 1-222.