[Taxacom] What exactly is or is not a Gondwanan distribution?

[Leavengood,John]

Hello, everyone.

   I am not well-versed in biogeography; hardly versed at all, in fact.  
I have encountered many references to Gondwanan distributions often 
pointing to taxa which span Australia, New Zealand, Southern Africa and 
Chile/Argentina bound by the Andes.  Definitions seem to match this 
notion.  So if a taxon (say, a tribe) has genera in New Zealand, 
Australia, Chile and Argentina, but one genus among them occurs only 
east of the Andes from northern Argentina all the way to Guatemala, is 
that tribe still considered of Gondwanan distribution?

Why or why not?  Or perhaps it points to a certain type of Gondwanan 
distribution attributed to a particular timeframe facilitating that one 
lineage propagated east of the Andes but has no members west of them?

I would appreciate answers accompanied by references, but all guidance 
is appreciated.

-- 
--------------------------
John M. Leavengood, Jr.
Doctoral Candidate
University of Kentucky
Department of Entomology
S-225 Agricultural Science
Center Building - North
Lexington, KY 40546-0091
(859) 257-3169