Re: Climate Changes Mid-late Dinosaur era.

[His Dark Lordship <darklord@compusmart.ab.ca>]

Twas 01-Jul-01, whence Daniel Bensen didst dost proclaimeth to me...

>>> The reason being is that, as I understand it, we notice a significant
>>> drop
> in the Sauropod and gigantic plant eaters and a larger rise in the lower
> to the ground plant eaters, such as Hadrosaurs, Anklyosaurids and others,
> whilst the Carnivore side of the spectrum appears to be somewhat similiar
> (although there is a shift from the classic Carnosaur to the Tyrannosaur
> in the northern hemesphere.)<<

> I don't know about that. Titanosaur sauropods were still hearty and hale
> in South America and Africa during the Cretaceous. I have the feeling
that
> the changes in herbivore diversity during the time were due to the rise
of
> angiosperm plants (didn't HP Bakker say something of the kind). Anyway,
> what is "global climate"? You can't say much for Earth's climate, at the
> moment, except that temperature tends to hover between the freezing and
> boiling points of water.

Okay, well, maybe I'm just ill informed (most of my infomation comes from
Discovery Channel and the Newspaper.)

Anyway, I'll lay it out;

What possibilities would there be of an "Ice Age" (or several of them)
during the course of the Jurassic and Cretacious? It just strikes me as odd
that landbound creatures would develope feathers for the purpose of
handling their body temperatures (since they probably weren't using them to
fly) when scales would suffice (assuming it was continually warm.)

The other thing that bothers me is this Bering Strait. In more recent times,
the only time North America and Asia have been connected was during an ice
age; now, while it's equally likely that there was a large rock formation
between the two continents, that would basically mean that there was a
constant flow of migrations between the two continents (which we don't seem
to see that frequently either.)

Some other things I was thinking was an Ice Age could explain the rise of
the gigantic sauropods. Think about it; if you're going to have large
quantities of creatures ranging from 30-90 ft in length, you are going to
need a HUGE expanse of land, and imagine a 20 ton Sauropod trying to cool
off on a hot day?

The last thing that bothers me is the migration patterns of the Hadrosaurs.
It seems they were migrating (or spread out, at least) between Australia,
Antartica, North and South America, and probably Asia (I'm not sure if any
have been found in Asia.) Now, it would make more sense that these intense
migrations were possible due to the land bridges that would be above sea
level due to expanding ice caps.

And of course, how would the dinosaurs exist in these conditions? Well, if
they're warm blooded, they most likely could survice in cool temperate
areas with little trouble, and if they had feathers, well...

Anyway, food for thought.

Twas 01-Jul-01, whence Rob Gay didst dost proclaimeth to me...

> Not to mention NA. _Alamosaurus_, anyone?

Like I said, I'm feeling very outclassed here. Either way, I never said they
were gone completely, I just said there was a decline in the Sauropod
variantions (which may or may not be true, but to my knowledge that is what
the evidence points towards.)

Twas 02-Jul-01, whence Brian Choo didst dost proclaimeth to me...

> And if we take footprint evidence into account, sauropods were extremely
> large and numerous in Cretaceous Australia (eg. Broome) and Asia (eg.
> Korea)...

> So in short...what significant drop in the sauropod and gigantic plant
> eaters?

Well, then again, what point in the Cretecious are we talking about here? =)
It's an awfully long span of time. =)