My question is where geographically the group Psittaciformes originated. My layman's guess is Australasia, since the deepest branches are around that area, but I'd like to get an expert's opinion.

Hi,

The evidence suggests that you're right - several authors seem agree that the geographical origins of Psittaciformes lies within Australasia, and parrots radiated outwards from there. A 2008 paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2727385/) has even traced their origins back to Gondwana, suggesting that Psittaciformes began to diversify during the Cretaceous!

Another paper from 2011 suggests that several radiations occcured at different times from Australasia into different parts of the world (http://www.researchgate.net/publication … nd_eustacy)

Hope this helps!
Rachel