Comparative analysis of bioerosion in deep and shallow water, Pliocene to recent, Mediterranean Sea

Bioerosion by macroborers in recent and fossil coral material from deep‐sea environments, analyzed ichnologically, exhibits several noteworthy trends. Sponge borings/Entobia dominate all samples. Stenomorphism of sponge borings in these restricted substrates causes some problems of identification. In particular, odd combinations of hitherto discrete ichnospecies of Entobia occur within individual borings; these combinations seem only partially to be due to stenomorphism. The deep‐water recent and fossil ichnofaunas also contrast with shallow‐water counterparts. For Entobia, the deep‐water communities are much reduced in ichnospecies diversity and most of the dominant ichnospecies are rare in shallow water. However, the quantity of entobian borings of substrates is not reduced. Other ichnogenera show a different pattern: both diversity and especially abundance are reduced in deep water.