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> I find this *really* hard to accept.  The rorqual feeding structures
> are so specialized, and so *extremely* *similar*, I find it hard to
> see how they could be convergently acquired - even down to the expanding
> throat sack.
> Is it possible that the grey and humpbacks have *lost* the rorqual
> adaptation?  This would make the rorquals *para*phyletic, not poly-
> phyletic.
Humpbacks have the same baleen-throat morphology as other rorquals, and haven't
lost it. The grey whale has, seemingly because it's become specialised as a
mud-grubber, so if this is correct, you were right: rorquals would be
paraphyletic (the grey whale not traditionally being regarded a 'rorqual'). But
the issue remains unresolved - weighting of things called satellites in whale
genomes show piked whales to be well divergent from rorquals + grey whale. At
best, this area remains speculative. They MIGHT have been polyphyletic. Depends
on who you ask.
As some are now fond of saying, is it likely that evolution must have followed
the most 'parsimonious' of pathways? Now there's a can of worms...

There are whale lists on the internet, I could take the debate up there.. what
do you say?