Lectotype NHMW 1867/0008/0027 (original illustration from laube 1867, plate 3, fig. 9) from Mid Jurassic in apertural and apical view.

Diagnoza

Shell is low trochospiral, the coils are convex with recessed seams. On the first two coils, numerous but weak axial ribs (prosoclin and opisthocyrt) between the adapical suture and selenizone are crossed by equally weak spiral ribs. The spiral ribs disappear in the 2nd, the axial ribs in 3rd coil. The narrow selenizone is close to the abapical suture. At first it is deeply deepened with opisthocyrt reinforced growth lines. Later it forms a weak, sculptureless bulge, bound on both sides by a narrow furrow. The transition to the flat base is broadly rounded. The base has a large umbilicus. Apart from weak growth lines, no sculpture can be seen on it. Faint folds can be seen inside the umbilicus and the edge is covered with weak knots.

Porównanie

Similar to Pleurotomaria callomphala Hébert & Eudes-Deslongchamps, 1860, Pleurotomaria agathis Eudes-Deslongchamps, 1849 and Obornella wuerttembergica Sieberer, 1907, but all those species have a clear spiral sculpture throughout the ontogeny and often a subsutural row of cusps. Pleurotomaria okensis Gerasimov, 1992 has more convex coils without rounded edge to the base, the seams are deeper, the spiral sculpture is also better developed.

Autekologia

Występowanie geograficzne

Only in type locality.

Zasięg czasowy

Mid Jurassic.

Materiały muzealne

Only 2 specimens: Lectotype NHMW 1867/0008/0027 and NHMW 2009z0128/0009. 

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.