A study on Gigantopecten nodosiformis (Pusch and de Serres in Pusch, 1836) (Bivalvia, Pectinidae) from the Middle Miocene of Poland and Ukraine

Abstract

The year of publication and bibliographic reference of Pecten nodosiformis have been quoted incorrectly. It is concluded herein that the name was originally published in Pusch’s Geognostische Beschreibung von Polen, and that the correct year is 1836. This highly distinctive pectinid species, with the left valve ornamented with nodules, and presently assigned to the genus Gigantopecten Rovereto, 1899, is a reliable guide to the Lower Badenian (upper Langhian, Middle Miocene) of Poland and Ukraine. Its occurrence in this area, restricted to carbonate deposits dated to the Orbulina suturalis planktonic foraminifera zone and the upper NN5 calcareous nannoplankton zone, help to refine the knowledge of palaeoclimatic changes during the Middle Miocene in individual Paratethyan basins. The comparison of many Polish, Ukrainian and Slovak specimens allows the demonstration of changes in the shape of the shell and its ornamentation during ontogeny. This was the reason for assigning herein numerous species as junior synonyms of Gigantopecten nodosiformis. Moreover, this paper presents a review of studies on the Middle Miocene sedimentary succession and its fossil content in Skotniki Quarry, the type locality of Gigantopecten nodosiformis, one of the most important geological exposures in the Holy Cross Mountains, studied already in the early 19th century by Pusch.