If you take a look at Figure 19 in the GEOCARBSULF paper, you'll see a plot of Bergman's 2004 model, which spikes up to near 35% in the Cretaceous. Berner has some critiques of Bergman's modelling in that section.
So it's possible the idea of high Cretaceous oxygen comes from either the dodgy old amber data, or Bergman's fairly recent model, or confusion with the Carboniferous. (I did some googling recently concerning Sato's pronouncement on pterosaur wing-loading, and it was interesting how many people seemed to think that pterosaurs and giant dragonflies lived at the same time in the same high-oxygen environment. Frankly, I just despise people who can't keep geological periods straight in their heads. )

Grant Hutchison

Good to know you're taking a responsible attitude to selecting the Leader Of The Free World.
(My mother got a name she hates because my grandfather had a few drinks and changed his mind on the way to the registry office: eighty-five years of misery and counting. Be careful out there, Don. )

A polar broad-leaf forest! I'd certainly pay to see that.

Grant Hutchison

Yes indeed. With herds of Triceratops roaming the forest edge and lake plains in Alberta.

What trees grew on the north coast?

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

something was bugging me about this line of argument ...

dinosaurs (and insects) didn't need to float; they only needed to support their own weight ... >>thinking: whales and ocean critters<<

increased atmospheric density => reduced density gradient (difference);
it does improve bouyancy ...

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And I now realize that Big Don's comment referred to after the K/T; oops.

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

so, substitute triceratops with "super-size-me" turkeys, and things that looked a bit like rhinos (but weren't), etc ... and you're there!

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(By the way, I hate it that so many papers in the areas of planetary science and geology are not easily available to the dreaded "non-subscribers". It is like they are screaming at me: "YOU CAN'T HANDLE THE TRUTH". Good, I feel better now.)

"Quaerendo inventis"

What's interesting is, the question isn't really "how did dinosaurs get so big?" The biggest non-sauropods (Shantungosaurus, Lambeosaurus) were only a little bit bigger than Indricotherium, Deinotherium, and the biggest Mammuthus species. The question is really "how did sauropods get so big?" Everything else seems to top out at 15-25 tons (rhinos (biggest Indricotheres) and theropods (biggest Spinosaurs) ~15, proboscideans 15-20, hadrosaurs 20-25...), but sauropods reached at least 80-100 tons (Argentinosaurus), maybe more (Amphicoelias fragillimus and Bruhathkayosaurus, if they're as big as estimated, are mindboggling, but based on little evidence).

genetic predisposition?
steroids?
inappropriate diet and exercise regime?

but you're right, Vultur; that's an awful lot of mass to shift on land ...
and worthy of further research ...

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I see your point. Thanks. ...was mixing bouancy with floating.

(i.e. that an object in a more dense medium still "feels lighter" even if fully immersed. Doh! e.g. Water tanks used to train crews for space-walks!)

I guess I need to try to calculate the density of a Dragonfly, compare to the density of air; and then with the density of air at higher pressures... that would provide a % improvement in natural bouancy. A lunch-time "project".

{But would the more-dense air create more drag and thus make it harder to move?}

[

What I was thinking about, was arguements about whether a sinking ship would ever go down far enough that it hit water at such a high pressure that it stops sinking. Turns out "no". As long as the ship is denser than the water, it will keep sinking, and it always is. (The twist was apparently that at high enough pressure the water would turn into ice - and that would stop the ship sinking... but it wouldn't occur on Earth.).

]

Apology to Toothdust.

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Please call me chrissy, thank you.

The evidence just points to "a Sauropod is not able to raise its neck too high because of a left ventrical pressure if it lifts its head too high", but that doesn't discount the fact it has a long neck and it ate lower to the ground.
They are still finding out new things about many dinosaurs, and when that mummy was found, it gave evidence that the dinosaurs were much larger.

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You can please some of the people all of the time and all of the people some of the time. But you can not please all of the people all of the time.

"Why change passwords when you've got a baseball bat?"

not sure - the best modern analogy would be to ask some of the deep sea critters whether it's harder to swim ...

one of the design concepts incorporated into the Titanic* (and, I believe, submarines) was water-tight compartments within the structure - a ship (or sub) sinks because water displaces air - if the air cannot be displaced, then sinking will only continue until the total of air and container reaches equilibrium with the water [edit: that should be total of remaining air ... and it only holds true if it doesn't hit the seafloor first ] ...

*of course, it didn't work on the Titanic ...

back to your dragonfly - if, within its structure, there are locations to trap air (pockets, sacs, whatever), and that air can be warmed with respect to the outside air ...?

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