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AW: Ancient neognaths without much generic diversity.

> -Loons (all species in _Gavia_)
> -Pelicans (all species in _Pelecanus_)
> -Tropicbirds (all species in _Phaethon_)
> -Frigatebirds (all species in _Fregata_)
> -Cormorants (nearly all species in _Phalacrocorax_)
> -Anhingas (all species in _Anhinga_)
> -Barn Owls (all but one species in _Tyto_)
> -Flamingos (all species usually grouped in
> _Phoenicopterus_)

> What I find so interesting is that in most cases, we are
> dealing with a single surviving genus which also happens to
> be widespread. What I wonder is, are we perhaps looking at
> clades which have only contained a single genus for millions
> of years, are we looking at the sturdy survivors of groups
> that were once more diverse or at a recent radiation in an
> ancient group which has succeeded in replacing all or most
> of its closest relatives? 

In most of the cases you give, the latter. Except pelichns maybe; as far as it 
looks, they either have a huge ghost record or evolved into swimming birds 
(from wading birds) only rather recently.

The others were far more diverse earlier, most in the Paleogene.