def self.valid_parents
    [NomenclaturalRank::Icn::GenusGroup::Genus.to_s] + [NomenclaturalRank::Icn::GenusGroup::Subgenus.to_s] + [NomenclaturalRank::Icn::GenusGroup::Section.to_s] + [NomenclaturalRank::Icn::GenusGroup::Subsection.to_s]