Three situations for the taxon of reference (columns) are to be considered: it is monophyletic, paraphyletic or polyphyletic.

There are also three situations to consider for the components of this taxon in the given area of reference (lines): monophyletic, paraphyletic or polyphyletic. To explain the table, we consider again the example of the non-notothenioid fish family Liparidae. It is monophyletic as a family (first column), however its components of the Antarctic shelf are polyphyletic because they are each related to Arctic liparids (bottom line). So the Antarctic liparid situation is the bottom left cell. Case 2 (when a taxon originating in the area of reference secondarily “exports” a part of its descent outside this area, Fig. 4) is discussed in the text.