Holotype NHMW 1867/0008/0012 (original illustration from Laube, 1867, pl. 2, fig. 8) from Mid Jurassic of Balin; tip from the side.

Holotype NHMW 1867/0008/0012 (original illustration from Laube, 1867, pl. 2, fig. 8) from Mid Jurassic of balin in lateral and apical view

Diagnoza

The shell is conical, with straight flanks, only the suprasutural bulge protrudes slightly. The seams are sunk a little and the bulge can be seen very early on. It is crenulated and bears several spiral ribs. Numerous strongly prosocline axial ribs are formed on the early coils. Their number increases sharply on the following coils and they become weaker. On the last coil they are little more than reinforced growth lines. The area between the adapical seam and the bulge is covered with several, roughly equally strong, slightly crenulated spiral ribs, about five at the beginning there, ten on the last coil. They also weaken in the course of ontogeny. 1–2 spiral ribs are also formed between the bulge and the abapical suture. A second rounded edge is visible only on the last coil, carved with several weak spiral ribs. The slightly convex base is offset from it at an angle. The small umbilicus is covered by a widening of the columella. The circumference of the umbilicus is crenulated. The columella is thickened in a callus.

Porównanie

It differs from other Amphitrochus species with additional spiral sculpture by the more numerous spiral ribs and very numerous weakening (but not completely disappearing) axial ribs and the missing row of adapical cusps.

Autekologia

Występowanie geograficzne

Only in type locality.

Zasięg czasowy

Mid Jurassic

Materiały muzealne

Only Holotype NHMW 1867/0008/0012.

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.