Re: Penguins and pandas in PNAS

[evelyn sobielski <koreke77@yahoo.de>]

--- Jeff Hecht <jeff@jeffhecht.com> schrieb:

> I covered it for New Scientist at
>
<http://www.newscientist.com/article/dn12127-when-giant-penguins-roamed-the-tropics.html>
> which has a reference to the journal article, and a
> copy of the reconstruction. 
> 
> It's a neat paper, and a weird penguin --er,
> flightless diving avian dinosaur --  particularly
> considering that it lived in a warm period about 36
> million years ago. 

't ain't the largest, heaviest, oldest or northernmost
penguin - but it represents a range extension of the
gigantic forms which were common around the
Priabonian.

The more northernly distribution is not that
surprising. See
http://www.polish.polar.pan.pl/ppr27/ppr27-003.pdf for
a summary of the known diversity on Seymour Island
(then subantarctic). Huge size in prehistoric penguins
was probably due to resource partitioning rather than
thermoregulation; there is a rough N-S trend in size
in the crown group, which indeed might be for reasons
of thermoregulation - but as _Icadyptes_ shows, the
prehistoric giant lineage(s) occurred quite far north.

But note that the system of cold subantarctic ocean
currents was different then from what it is now. IIRC,
the Peruvian coast was (though Earth was warmer
overall) relatively colder than it is today, because
part of the cold water that nowadays goes round the
Antarctic was diverted northwards W of South America
(How that interacted with the Humboldt upwelling I
don't know).

Ah, they should put up the paper already - need to
check out the phylogeny of the 2 new guys...

Regards, 

Eike


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