Septacja w muszlach ślimaków frańskich z Gór Świętokrzyskich

Abstract

Septation in shells of Frasnian gastropods from the Holy Cross Mountains.A b s t r a c t. Amongst several known Paleozoic gastropod species having transverse septa in the apical parts of shells, three species (Straparollus aff. circularis, Orecopia kadzielniae and Donaldiella karczewskii) have been found in the Frasnian limestones of Grabina and Bolechowice-Panek in the Holy Cross Mountains (Central Poland). Septation in gastropod shells is a rare phenomenon and is an adaptive feature. Septa occur either in the thick-shelled gastropods living in high-energetic (reef) environments, preventing against negative effects of destruction of the apical parts of shells, or in the thin-shelled gastropods living on muddy substrate, lowering the inner volume of a habitable part of shell and increasing outer surface of gastropod body.