EDIT

import eu.etaxonomy.cdm.model.taxon.TaxonNode;

    protected List<TaxonNode> getNextTaxonNodePartition( int limit, int partitionCount, List<String> propertyPaths) {

        List<TaxonNode> result = new ArrayList<>();

        List<OrderHint> orderHints = null;

        @SuppressWarnings("unchecked")

        List<TaxonNode> list = this.getTaxonNodeService()

            .list(TaxonNode.class, limit, limit * partitionCount, orderHints, propertyPaths);

        if (list.isEmpty()){

            return null;

        }

        for (TaxonNode tn : list){

            if (isPesiTaxonNode(tn)){

                result.add(tn);

            }

        }

        return result;

    }

    protected boolean isPesiTaxonNode(TaxonNode tn){

        TaxonBase<?> fromTaxon;

        Taxon toTaxon;

        fromTaxon = tn.getTaxon();

        toTaxon = tn.getParent()== null? null: tn.getParent().getTaxon();

        return (isPesiTaxon(fromTaxon, true) && isPesiTaxon(toTaxon, true));

    }