Perturbations observees chez la palourde Ruditapes decussatus et la datte de mer Lithophaga lithophaga collectees au nord de la Tunisie

Abstract

The present study concerned a morphological abnormality observed at the European clam Ruditapes decussatus collected in the north lake of Tunis and the shell disturbances raised to Lithophaga lithophaga taken in the bay of Bizerta. The examination of the soft part and the shell of these two sorts of bivalves revealed a deformation at the European clam who consists of the differentiation of two siphons inhaling and exhaling originating supernumeraries both usual siphons, siphons in the form of Y so possesses 4 functional openings instead of 2. To the sea date Lithophaga lithophaga, we raised the presence of shell disturbances which get the valve of the external and internal side. We put in evidence the presence of perforating annelids and sipunculians living inside intravalves galleries dug credibly by these invertebrates. The soft thickness of the shell provided with galleries entails morphological shell deformations and fragility observed to this lithophagous bivalve.