Caulostrepsis contorta Bromley & D' Alessandro. Nuevas Aportaciones al Estudio de los Fenomenos Bioerosivos en el Plioceno del Bajo Guadalquivir

One of the most characteristics bioerosive phenomena in the Pliocene organic substrata (bivalves) of the Bajo Guadalquivir Basin is concerning to the boring activity of the annelids, which importance is pointed out. The main observations are centred around Caulostrepsis contorta Bromley & D'Alessandro, specially about the existence of new morphotypes. These are produced because of their preferential ubication. The galleries are located in parallel series to the growth lines if the settlement is during the life of the host, revealing a behaviou motived by a dwellingfood search. The thickest part of the shells or the sockets and interna( cavities of the hinge are the selected areas when the colonization is post-mortem. In this case, an exclusively dwelling search is deduced. The morphologies of the galleries is completely unequal in both circunstantes.