Re: Protopenguins and pterosaurs

[Michael Habib <mhabib5@jhmi.edu>]

Well, I'm not sure that entirely follows.  In theory, if one takes the 
62 mya date as the split between penguins and their sister group 
(storks in this case), then you get the first penguins proper just 
after 62 mya (ie. barely post-K/T).  As such, that is actually the most 
_conservative_ approach, assuming the date is correct, and that Waimanu 
is actually closer to penguins than anything else.

The more liberal estimate, which would actually imply the existence of 
more pre-K/T neorithines than above, is to assume that the 62 mya 
marker is the date of the first node WITHIN Sphenisciformes (ie. the 
split between Waimanu and all other penguins).  Since the calibration 
will still make every node further up the tree older than the 
calibration point, this makes more nodes older than 62 mya than if the 
node is placed as the penguin/stork split.

I agree that the dates seem dubious in some cases, but I think the 
reasons are separate from the assumption that the 62 mya date is the 
Sphenisciform/Stork divergence date.

Cheers,

--Mike Habib

On Sunday, April 9, 2006, at 05:39 PM, Richard and Jo Cowen wrote:

> Nick Pharris nailed the flaw. IF you assert first that penguins and 
> storks diverged at 62 Ma, OF COURSE you end with the conclusion that 
> there were Cretaceous penguins, and other neornithine lineages. And 
> that gets you into all sorts of wild speculation. For example, I 
> didn't know until I read their paper that the decline of small 
> pterosaurs in the late Cretaceous was because they were eaten by 
> raptors (and I don't mean velociraptors, I mean Falconiformes!!!). No 
> matter that we don't have a single Cretaceous falconiform in the 
> fossil record. But read the paper for yourself: it is alleged to be 
> open-access.
>
> mbe.oxfordjournals.org/cgi/reprint/msj124v1
>
> I hope Euan Fordyce is squirming with embarrassment at what his 
> co-authors have written above his name!!
>
> Cheers
>
> Richard Cowen