Geography Reference
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is unsolved, allowing any combination of biogeographic processes and any
resolution of the polytomy, being even more flexible than assumption 2.
Figure 5.3
Procedure to deal with widespread taxa proposed by van Soest (1996).
(a-d) Four taxon-area cladograms, two of them with a widespread taxon in areas A
and E; (e-f) general area cladograms obtained: (e) area E is the sister area of A; (f)
area E is the sister area of D.
Ebach et al. (2005a) suggested that assumptions 1 and 2 may inadvert-
ently use paralogy and widespread taxa or masts and yield spurious res-
ults. They proposed that the “transparent method,” along with paralogy-free
subtree analysis, is appropriate to deal with this problem. This is done by
treating all taxon-area cladograms as individual points that may be part of a
common pattern (the general area cladogram). Area cladograms with masts
