Diagnoza

The shell is broadly conical, with convex coils, the seams recessed. The first recognizable sculpture consists of numerous axial ribs and a spiral rib near the abapical seam. The axial ribs are broken down into a total of four crenulated spiral ribs by successive spiral grooves, beginning abapical and progressing adapical, the adapical one being the weakest. The spiral ribs are crossed by numerous strongly prosoclinic axial ribs (27 on the abapical spiral rib of the last turn). There is another spiral rib in the seam, the axial ribs reach it. The base is convex. The border spiral rib is followed by four more strong, tuberous spiral ribs. A fifth is indicated on the edge of the largely destroyed navel area. The columellar inner lip includes the thickening on the columella; the aperture is rounded with an adapical taper.

Porównanie

The juvenile shell from Brodla is more compact, the turns are somewhat more convex, the transformation of the axial ribs into spiral ribs is already completed on the second teleocon coil, the axial ribs are more numerous than in that from La Motte Bourbon. Spiral striae and the construction of the aperture is similar to Biarmatoidella biarmata.

Autekologia

Występowanie geograficzne

Poland and France.

Zasięg czasowy

Mid Jurassic.

Materiały muzealne

Material from France and one specimen from Brodla, Poland (NHMW 1867/0008/0008).

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.

Hébert, M. & Eudes-Deslongchamps, E. 1860. Mémoire sur les fossiles de Montreuil-Bellay (Maine-et-Loire), 1re partie. Céphalopodes et Gastéropodes. Bulletin de le Société Linnéenne de Normandie, 5, 153–240

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