[Taxacom] Lineage sorting and wing dispersal

[John Grehan]

As a sideline to the recent discussion of characters (morphological or
molecular) and phylogeny there is the interesting (to some at least)
case of wing dispersal. This is where differentiation of vicariant
descendants of a common ancestor involves a reassortment of characters
so that taxa that are geographically separated by other vicariants end
up being more closely related to each other in shared characters than
the intervening taxa (so the relationship is closer at the 'wings' of a
distribution range as in the wings of a stage). 

This incongruity cannot be recognized without knowing the distribution.
Wing dispersal is documented for both morphological and molecular
similarities. Michael Heads has written on this in one of his recent
articles. Wing dispersal is sometimes explained away as an error, or
special migrations are invoked to connect the wings.

John Grehan