Re: mosasaur babies/no marine dinos

[John Bois <jbois@umd5.umd.edu>]

On Wed, 2 Jan 2002, David Marjanovic wrote:

> Why are there no penguins in the northern hemisphere and never have been?
> Today they only live in cold currents that produce blooming ecosystems, and
> they evolved in the south, so I'd say they have never got farther north than
> Galápagos and are unable to cross the equator.

Then two competing hypotheses: equatorial barrier and unsuitable nesting
sites.  What do you propose as a significant barrier that stops penguins
but not any other body form from extending their range.  I mean, they
could edge up the coast of South America or Africa.  Granted "blooming
ecosystems" fuel penguin ecology...but I can't see this as forcing
complete exclusion...one might expect, for example, changing weather
patterns (el Nino) to temporarily extend their range...