EDIT

        // as that solution only swallows and hides the exception, but doesn't

        // actually solve it.

        getSession().merge(taxonBase);

        if (taxonBase instanceof Taxon){ //	is Taxon

            for (Iterator<TaxonRelationship> iterator = ((Taxon)taxonBase).getRelationsFromThisTaxon().iterator(); iterator.hasNext();){

                TaxonRelationship relationFromThisTaxon = iterator.next();