Specimen ZPAL Ga.12/1 from the Late Oxfordian of Kłęby (Western Pomerania) in Lateral and Apical view.

Diagnoza

The large last whorl expands strongly abaxially. The shell is ornamented adapically by a concave ramp. The lateral flanks are strongly convex, with the widest part located abapically. The ornamentation consists of strong, weakly prosocyrt and prosocline axial ribs.The ribs originating at the adapicalmost part of the whorl are strongest and have weak nodes at the transition from the ramp onto the lateral flank. The axial ribs weaken abapically and finally fade out on the base. Somewhat above mid-whorl, a weak spiral rib forms weak nodes at the intersections with the axial ribs. An additional 6-7 spiral ribs appear abapically. The growth lines are slightly enhanced and run parallel to the axial ribs. The large aperture is semi-circular. The inner lip develops a wide septum. The straight edge of the inner lip is divided by a notch in the middle.

Porównanie

The type material of L. pellatus (Loriol, 1874) differs from the specimens from Kłęby in having more numerous and weaker axial ribs, more spiral ribs, and a broader shell, possibly as  intraspecific variability. The type material of L. concinnus (Roemer, 1836) differs in having numerous but weak axial ribs and only two strong spiral ribs.

Autekologia

Występowanie geograficzne

France; in Poland only in Kłęby (Western Pomerania) 

Zasięg czasowy

Oxfordian.

Materiały muzealne

Material from France, two specimens from collection of Schmidt (BGR X 05179-80) and six other specimens (BGR, Buchholz, Beckert, 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, 121‒157.

Kaim, A. & Sztajner, P. 2005. The opercula of neritopsid gastropods and their phylogenetic importance. Journal of Molluscan Studies, 71, 211-219.

Loriol, P. & Pellat, E. 1874. Monographie Paléontologique et géologique des étages supérieurs de la Formation Jurassique des environs de Boulogne-sur-Mer (Pt. 1). Mémoires de la Société de Physique et d’Histoire Naturelle de Geneve, 23, 261-407.

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