Dinosaurs lived in a low oxygen world

Corvidius

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Jul 2017
3,047
Crows nest
I don't see ankylosaurs and stegosaurs being the fasted kids on the block. Ceratopsians I think somewhat faster, maybe capable of a burst of speed in a charge, if they did charge, but surely they did. But with hadrosaurs there may be some capability for decent speed. I'm not sure what the current consensus is for average hadrosaur speed, it varies depending on who you read, but it seems that the size of the hadrosaur caudofemoralis muscles may be bigger than has been previously thought, and so given them the ability to run, at least short term, reasonably fast, fast enough for a T-rex to have to run after them and just manage to get a bite on it's tail as it flees. So, even without the avian respiratory system, because of it's large tail and muscle group, which mammals do not have, hadrosaurs at least, could have potentially shifted themselves, and so their predators would also have needed to run as fast, or faster in the initial charge.
 

oshron

Ad Honorem
Jun 2009
3,690
western Terranova
Magnus beat me to this point, but I’ll say it anyway
Just to say, when dinosaurs walked on this planet, enormous dragonflies [70cm!] flied above them ...
except that, no, they didn't. giant "dragonflies" (actually griffenflies) like Meganeura lived some 70-125 million years before the dinosaurs ever appeared. they never coexisted.
Look at the date it went extinct (299 million years ago), those paleozoic insects never existed in the Mesozoic.
thanks, Magnus ;) for everyone else, the reason those giant arthropods could exist then and not later is because their respective period, the Carboniferous, had a much higher concentration of oxygen than other periods, allowing the passively-breathing insects to get bigger
 

starman

Ad Honorem
Jan 2014
4,115
Connecticut
I don't see ankylosaurs and stegosaurs being the fasted kids on the block.
They were fast enough, not at fleeing but pivoting when they needed to.

But with hadrosaurs there may be some capability for decent speed. I'm not sure what the current consensus is for average hadrosaur speed, it varies depending on who you read, but it seems that the size of the hadrosaur caudofemoralis muscles may be bigger than has been previously thought, and so given them the ability to run, at least short term, reasonably fast, fast enough for a T-rex to have to run after them and just manage to get a bite on it's tail as it flees. So, even without the avian respiratory system, because of it's large tail and muscle group, which mammals do not have, hadrosaurs at least, could have potentially shifted themselves, and so their predators would also have needed to run as fast, or faster in the initial charge.
Right; the the big tome on hadrosaurs includes a chapter by Phil Currie who sees tyrannosaurs and hadrosaurs as similar to zebras and lions. Or gazelle and cheetahs.
 

Corvidius

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Jul 2017
3,047
Crows nest
Right; the the big tome on hadrosaurs includes a chapter by Phil Currie who sees tyrannosaurs and hadrosaurs as similar to zebras and lions. Or gazelle and cheetahs.
Is that the work by Eberth & Evans? if so it is still on my to get list. I presume it is similar in layout to "Feathered Dragons" by Currie et al
 

Corvidius

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Jul 2017
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Crows nest
I'm not professional, least not in this field, so I don't really have the time to read all the papers that come out. Major finds are usually news items anyway, but for the more in depth studies, which do interest me, otherwise I would never have got Feathered Dragons, or Carpenter's Acrocanthosaurus, among others, it is a better option to get the book. I read various blogs of course, but sometimes they vary in interpretations of the same data and it is difficult to untangle this. Some, not yours, can seem way out, but then Bakker was seen as way out back in the days, so it is difficult to believe them or not.