Specimen NHMW 1853/0038/0088 from Mid jurassic of Balin in apical and lateral view

Diagnoza

The spire is slightly lower than the base that is convex. The coils are edged by the selenizone, which form a strongly protruding bead. The wide area from there to the adapical suture is inclined, the narrow area to the abapical suture is almost perpendicular. The sculpture consists of prosocline axial ribs that curve more backwards near the selenizone. The axial ribs are initially relatively narrow and very numerous. In the course of ontogeny they become stronger, more extensive and more numerous. On the dorsal side, spiral ribs are only hinted at on very early coils, they are missing later. The selenizone is crenulated and crenulae are very numerous. A strongly rounded edge forms the transition to the base. It is also crenulated and crossed by about 12 spiral ribs. There is no furrow between the edge of the bend and the base. The base is covered with numerous sigmoidal curved axial ribs. Spiral ribs are missing.

Porównanie

Pleurotomaria granulata Sowerby, 1818 differs in a higher spire and a (variable) spiral sculpture. Also simlar Pleurotomaria cypris d'Orbigny, 1860, Pleurotomaria discus Eudes-Deslongchamps, 1849, Bathrotomaria buvignieri (d 'Orbigny, 1845), Pleurotomaria intermedia Terquem & Jourdy, 1871, Pleurotomaria montreuilensis Hébert & Eudes-Deslongchamps, 1860, Pleurotomaria palaemon d'Orbigny, 1855 var. serpentina Sieberer, 1907, Pleurotomaria septentrionalis J. Roemer, 1911 sensu Gründel 2003.  All these species have a clear spiral sculpture on the apical and basal sides. They also differ in the very numerous and closely set axial ribs on the early turns, the relatively strong convex base and the lack of furrow between the bent edge and base.

Autekologia

Występowanie geograficzne

France and Poland (Balin).

Zasięg czasowy

Mid Jurassic

Materiały muzealne

Material from France (including type specimen) and 2 specimens from Balin (NHMW 1853/0038/0088 i  NHMW 2009z0128 / 0010).

Literatura

Gründel, J. 2012. Neubearbeitung der von Laube 1867 beschriebenen Gastropoden fauna aus dem mittleren Jura von Balin/Polen. Annalen des Naturhistorischen Museums in Wien. Serie A, 114, 193–288.

Laube, G. C. 1867. Die Gastropoden des braunen Jura von Balin. Denkschriften der kaiserlichen Akademie der Wissenschaften, 28, 1–28.

Terquem, O. & Jourdy, E. 1871. Monographie de l’étage Bathonien dans le département de la Moselle. Mémoires de la Société géologique de France (2), 9, 1–175.