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Re: cause of Gigantism in sauropods



On 2/12/2011 4:20 PM, David Marjanovic wrote:

There's a reason why the hypothesis that sauropods 1) lived in swamps
and 2) theropods weren't able to go there was abandoned in the late
1970s, some 35 years ago.

Yes, I remember the '70's.

3 comments -- 1) The thesis I advance does not include any statements implying or indicating that "theropods were not able to go in swamps". Sorry about that!

I state that theropods attacking sauropods in swamps were total toast in the tactical sense.

2) The idea that one simply divides weight by foot area (or implied foot area) and magically creates an index that universally determines the ability to traverse a given piece of soft ground is extremely simplistic, w/ all due respect. I will expand later.

3) I also label as simplistic the notion that the giant sauropods either needed to, or had the option of evolving webs or other "aquatic adaptions" on their feet -- it really does not matter what their real range of habitat utilization was.

Logically, they had no choice but to retain terrestrial competence generally -- apparently all the dinosaurs needed to nest on dry substrate, including the giants. Also, the fact is that most swampland periodically dries up (or would get grazed out), therefore mandating considerable overland trekking ability under any scenario.

Given their size, it follows that low variability in foot morphology would be present in all the various scenarios of habitat utilization.

The notion that they went through swamps rather than around them, and loitered therein whenever it suited them, is NOT falsified by their feet.

Lastly -- much as I hate it, I am necessarily going "otherwhere" for a while, especially relative to time spent posting. I will reply at greater length in a week or three.