Diagnoza

Shell elongate, 1.9 times as high as broad. Protoconch hyperstrophic, diverging about 130° from teleoconch axis, ornamented by adapical an abapical axial folds. Teleoconch starting with two prominent and one subsutural spiral rib. Later in ontogeny, additional spiral ribs appearing. Whorls angulated at lower spiral rib. Spiral ribs crossed by weaker, prosocline axial ribs (about 61–62 per whorl) and axial lirae.

Porównanie

P. conoidea has a much broader shell than P. concava. The most important difference from P. naricata is the stable number of spiral ribs and the stronger lower spiral rib.

Autekologia

Występowanie geograficzne

Gnaszyn and Kłęby, Poland

Zasięg czasowy

Bathonian (Mid Jurassic).

Materiały muzealne

Ten shells from Gnaszyn and material from Kłęby

Literatura

Gründel, J. 1997. Heterostropha (Gastropoda) aus dem Dogger Norddeutschlands und Nordpolens. I. Mathildoidea (Mathildidae). Berliner Geowissenschaftliche Abhandlungen, Reihe E25, 131–175.

Kaim, A. 2004. The evolution of conch ontogeny in Mesozoic open sea gastropods. Palaeontologia Polonica 62, 3–183.