Re: Some questions

[Stan Friesen <swf@ElSegundoCA.ATTGIS.COM>]

From: Martin Baeker <baeker@x4u2.desy.de>
 > 
 > I am somewhat confused about the widespread agreement that sauropodes 
 > definitely lived on land. I agree that they look like being built for it,

Very much so - tall narrow rib cage (relatively speaking), relatively
small foot size.  Very much elephant-like.

 > but I have read in several different books about sauropod footprints 
 > showing that they were swimming (at least sometimes), because only tracks 
 > of the forelimbs are left. If they did not like water and swampy ground 
 > very much (as suggested in the "heresies"), were did these come from?

They were undertracks.  The front feet may press deeper because they
bear more weight per square inch than the rear feet. This will press
the front prints deeper into the soil, into older layers.  If the
higher layers later erode away, only the fore-underprints will remain.

 > Now I just read that one hypothesis is that this is due to the larger 
 > pressure exerted by the forelimbs, but I also read (don't know where or 
 > when) that sometimes a hindlimb print can also be seen and then the 
 > track changes direction. So this would definitely mean they were 
 > swimming. Or were they hydrogen-filled after all and these were their 
 > landing tracks?

Or that, when turning, they put more pressure on their legs (think
about it - they are accelerating laterally).

 > To be more specific: Is it true what they write about the hadrosaurs: 
 > Those with large, high crests lived in climatically different regions from 
 > those with small ones?

Not that I know of.  Kritosaurus, Corythosaurus, Parasaurolophus,
and Proaurolophus are all known from the *same* formations. These
cover the full range of crest types.

 > And could ceratopian (note the ommission of the 
 > "s"!) horns really be used for thermoregulation?

No - insufficient surface area.

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.