def parent_ids_sf_style
      ids = [] 
      (ancestors.push self).each do |a|
        case a.rank
        when 'genus'
          ids.push "#{a.id}g"
        when 'subgenus'
          ids.push "#{a.id}s"
        else
          ids.push a.id.to_s
        end
      end
      ids.join("-")
    end
def parent_ids_sf_style
      ids = [] 
      (ancestors.push self).each do |a|
        case a.rank
        when 'genus'
          ids.push "#{a.id}g"
        when 'subgenus'
          ids.push "#{a.id}s"
        else
          ids.push a.id.to_s
        end
      end
      ids.join("-")
    end
Return a dashed "vector" of ids representing the ancestor parent closure, like:
  0-1-14-29g-45s-99-100.
  Postfixed g means "genus", postifed s means "subgenus.  As per SpecieFile usage.
  TODO: !! malformed because the valid name is not injected.  Note that this can be generated internally post import.