First report of the bivalve Placuna placenta (Linnaeus, 1758) from the Late Miocene–Early Pliocene strata of the Minab region and Qeshm Island, Persian Gulf, Southern Iran: Palaeoecology, systematic and taphonomy

Abstract

The Late Miocene–Early Pliocene bivalve Placuna placenta (Linnaeus 1758) is reported for the first time from southern Iran. The shells of this species are extremely thin and fragile, and mostly disarticulated in our material, affected by compression, bioerosion, encrustation, and abrasion. In the Qeshm Island, midlate Miocene samples from Rahgostar were collected from marly deposits of the Guri Member of the Mishan Formation, Zagros basin. In the Minab region, samples from Bandzark were collected from MiocenePliocene sandstones of the Tiab Anticline in the Makran Basin. The studied species and their taphonomic features revealed tidal/intertidal shallow marine environment with high productivity, high rate of sedimentation, and rapid burial processes in low energy and high environmental stress, caused by strongly reduced salinity. Specimens of both assemblages affected by reworking processes, are represented by the following ichnospecies: Maeandropolydora sulcans, Oichnus simplex, and Trypanites weisei. © 2024 University of Isfahan.