The "Flying Primate Hypothesis" : A literal and metaphorical tree of primates and relatives. The colugo and the flying fox come off the tree low on the right, from a very early branch near the tree shrew that is poised on the trunk. The earliest branch shown leads to the microbats whose ancient diverse origins (17 living Families) cannot be properly represented. The two high branches on the primate tree show the lorises (bush baby) and lemurs (ruffed lemur)(branch on the left) and anthropoids (woolly monkey and tarsier).
Note on the position of the tarsier:
When I had the drawing commissioned by Peter Schouten in 1986, I was one of the many who did not realise that the tarsier's phylogenetic position was controversial. So I told Peter to put this favourite primate of mine on the anthropoid branch where I thought it belonged.
Evidence is now accumulating that the tarsier originated from the base of the primate tree, near the colugo.
This is no trivial matter, since it would be unfair to throw out a new hypothesis like the "flying primate" hypothesis if there is still no consensus about how to order the primates amongst themselves. If the tarsier really does represent a very deep branch in the primate tree, then the ability of a particular technique to recognise that could be used as a bench mark before one attempts to resolve an even deeper branch such as the proposed flying fox branch.
A more supportable version of the flying primate hypothesis would look like this:-