Diagnoza

The shell is highly trochospiral, the first coils are particularly slim. Later, it increases in width, so that its sides become weakly concave and also the coils are more or less concave. The concavity correlates with the bulge located directly above the suture and followed by several spiral riblets. The selenizone is located slightly above the suture. It is wide and has one or more spiral ribs on it. Initially it is depressed, on later coils it forms a distinct bulge. The flanks of the shell are covered with spiral ribs, those under the adapical suture being the strongest. Strongly prosocline axial ribs run between the adapical suture and the selenizone and the spiral ribs cusp. They are strongest under the seam. Their strength varies and they disappear on later coils. The base is flat, imperforate and covered with numerous spiral ribs. These are somewhat stronger near the center of the base than in the other areas. The aperture is much wider than it is high.

Porównanie

Pleurotomaria niobe differs in a wider selenizone, the lack of a bulge and a more concave base.

Autekologia

Występowanie geograficzne

France, European part of Russia; Balin and Brodla in Poland.

Zasięg czasowy

Mid Jurassic

Materiały muzealne

material from France, Russia and 5 specimens from Balin (NHMW 1867/0008/0022, NHMW 2009z0128/0001; NHMW 1853/0038/0075; NHMW 1853/0038/0092; NHMW 1853/0038/0092; NHMW 1867/0008/0025) and 2 from Brodla (NHMW 1856/0035/0765, NHMW 1867/0008/0021).

Literatura

Couffon, O. 1919. Le Callovien du Chalet, commune de Montreuil-Bellay (M.-&-L.). 245 pp.; G. Grassin, Angers.

Gerasimov P.A. 1955. Rukovodiashchiye iskopayemyye mezozoya centralnych oblastey evropeyskoy chasti SSSR. Chast' I. plastinchatozhabernoye mollyuski i plechenogiye jurskich otlozhenii. 375 pp. Gosgeoltehizdat, Moskva.

Gerasimov P. A. 1992. Gastropody yurskih i pogranichnyh nizhniemielovyh otlozhenii evropeiskoi Rossii. 190 pp. Nauka, Moskva.

Gerasimov, P. A., Mitta, V. V., Kotschakova, M. D. & Tesakova, E. M. 1996. Iskopaemye kellovejskogo jarusa Zentralnoj Rossii. 127 pp. VNIGNI, Moskva.

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.

Lahusen, I. 1883. Die Fauna der russischen Bildungen des Gouvernements Rjasan. Mémoires du Comité Géologique, 1, 1–94.

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