International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

PECTINID BIVALVES FROM THE GRUND FORMATION (LOWER BADENIAN, MIDDLE MIOCENE, ALPINE-CARPATHIAN FOREDEEP) — TAXONOMIC REVISION AND STRATIGRAPHIC SIGNIFICANCE

Pages: 129 - 146

Authors: OLEG MANDIC

Abstract: The present study investigates the pectinid bivalve record characterizing the Middle Miocene Grund Formation from the Lower Austrian part of the Alpine-Carpathian Foredeep. The results provide the first comprehensive compilation of that pectinid assemblage, based on the recent excavation material and historic collections. Updating and revision of genus and species level taxa excluded polyphyletic taxa and allowed a more accurate correlation with occurrences from adjacent regions distributed across the NE Atlantic, Mediterranean, Paratethys and Indian Ocean. Hence 10 species level taxa — ”Chlamys” trilirata, Hinnites crispus, Crassadoma multistriata, Aequipecten malvinae, Ae. macrotis, Costellamussiopecten cristatus badense, Oopecten solarium, Macrochlamis nodosiformis, M. tournali and Pecten subarcuatus styriacus — were identified. Thereby the subgenus Costellamussiopecten was separated from Amussiopecten, elevated to the genus level and applied to the lineage including the European ”Amusium” — C. cristatus. Macrochlamis has been regarded as a valid name, and a senior synonym of Gigantopecten. ”Chlamys” represents a still unavailable genus-name closely related to the Chlamys group. The species level revisions include discovery of H. crispus based on previously erroneously identified specimens. Moreover the new material brought the first evidence of the presence of Ae. malvinae and ”Ch.” trilirata in the Grund Formation. The latter three taxa greatly enhanced the stratigraphic signature of this pectinid assemblage allowing an accurate inference of the Early to Middle Badenian (regional Central Paratethys geochronological unit isochronous with the Langhian, that is early Middle Miocene) age and a regional correlation with the Lower Lagenidae Zone for the NE Austrian Neogene basins.

Keywords: Middle Miocene, Lower Badenian, Central Paratethys, Alpine-Carpathian Foredeep, biostratigraphy, taxonomic revision, pectinid bivalves

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Volume 55 no. 2 / April 2004

Volume 55 no. 2