DETECTION OF THE PRESENCE OF BOTH SPECIES SINANODONTA WOODIANA (LEA, 1834) AND SINANODONTA LAUTA (MARTENS, 1877) (BIVALVIA, UNIONIDA, UNIONIDAE) IN THE LATE HOLOCENE SEDIMENTS OF SOUTHERN IRAQ

The new pelecypod Sinanodonta lauta (Martens, 1877) (Bivalvia, Unionida, Unionidae), represented by specimens collected from seven sites on both banks of the Euphrates River (NW of Basrah Province), was recorded for the first time in southern Iraq. The following was the analysis to recognize the sediments at these sites and also of the different species shells in the area. It was found that the mud sediment was the most common compared to silt and sandy mud sediments. Two pelecypod species were recognized in the study region, Sinanodonta woodiana (Lea, 1834) and S. lauta (Martens, 1877), and one species of barnacles Amphibalanus subalbidus (Henry, 1973) (Maxillopoda, Sessilia, Balanidae). The presence of such species indicates that the area has already experienced an environmental change which occurred in the Late Holocene, when all such species were introduced from the outside the native ecosystem.