Comments on: The Dinosaurs That Never Were

By: RONNYJ

RONNYJ — Sat, 21 Jan 2012 19:36:08 +0000

Since none are here that we know of, except birds, it’s a moot point.

By: RONNYJ

RONNYJ — Sat, 21 Jan 2012 19:35:24 +0000

Since none are here that we know of, it’s a moot point.

By: AnJaCo

AnJaCo — Sun, 15 Jan 2012 22:14:29 +0000

Interesting post. But one small quibble:

“Dinosaur species did not last very long—even the longest-lived species were around for only about two million years or so”

Aren’t there a number of genera/species that span the full depth of the Morrison Formation which covers about 10 MY? And to belabor the point – there is no logical reason to think the these genera/species had their origins and extinctions coincide precisely with the laying down of the first and last sediments of the Morrison. IOW, the duration of the these genera/species was LONGER than 10 MY, but how much longer is impossible to say.

By: Henrique Niza

Henrique Niza — Fri, 13 Jan 2012 17:04:47 +0000

“Why are you so sure dinsosaurs today would be ‘radically different’ from the types of the Mesozoic? The fossil record says otherwise.”

I’m afraid it doesn’t but that relies on the meaning which individual gives to the word “different”. For all three geological periods non-avian dinosaurs thrived they drastically changed. You couldn’t expect in the Jurassic that ceratopsians would evolve in the Cretaceous. Or looking at a Coelophysis who could expect sixty five million years later things like Allosaurus, Torvosaurus, etc. would live.

By: J. S. Lopes

J. S. Lopes — Fri, 13 Jan 2012 11:10:48 +0000

Along more than 150 millions of years, theropod evolution continuously recreated agile “coelurosaurian” and powerful “carnosaurian” morphotypes, so it would not be impossible to infer that this trend would continue. Maybe Maniraptorans became bigger, with some velociraptor descendents becoming as bigger as tyrannosaurs. Maybe hadrosaurs would outcompete titanosaurs, or wouldn’t. Small arboreal mammals could evolve as in our real world.

By: Tom Hopp

Tom Hopp — Fri, 13 Jan 2012 00:42:38 +0000

You’ve got a good point, there’s no reason to assume modern dinosaurs would take on an old-fashioned look. In fact, recently published comparisons of head-ornamentation virtually guarantees that the dinos of today would look very different from those of ancient time. http://thomas-hopp.com/blog/2012/01/07/those-crazy-crested-kra/
Not only would one expect ceratopsians to have evolved ever more fantastic horns and frills, but those incredible theropods were notorious for trying out new fashions in head crests and ornamentation. Let’s don’t even get started with pterosaurs. Whatever form dinosaurs might have taken, I’m sure it would have been astounding!

By: Dan Peterson

Dan Peterson — Thu, 12 Jan 2012 22:55:06 +0000

Why are you so sure dinsosaurs today would be ‘radically different’ from the types of the Mesozoic? The fossil record says otherwise. Just look at their fellow archosaurs and see how wrong that statement is. Many Cretaceous birds look very much like the birds of today, and look how succesful crocodiles and their kin have been. The crocodile body shape and amphibious lifestyle was firmly in place before the dinosaurs and is still just as succesful today, and quite possibly will be 100 million years from now.

And what makes a crocodilian archosaur a dumb, plodding reptile, and a dinosaurian archosaur a smart, quick er…reptile? Are you not aware that a crocodile can outrun a man for short distances, and probably many dinosaurs too? After the KT event, some crocodilians assumed the terrestrial niche of the extinct theropods and ran down mammals on hoof-like feet.

By: Matt Martyniuk

Matt Martyniuk — Thu, 12 Jan 2012 21:04:40 +0000

Great article! I read the Slate column and was kind of grateful they didn’t tackle this one… so much room to lend credibility to crazy ideas like the Dinosauroid (though any article on possible alternate dinosaur evolution isn’t complete without mentioning the Speculative Dinosaur Project! http://www.unet.univie.ac.at/~a0000265/Spec/).

One thing that always gets me is this, which is also always brought up in conjunction with alternate dino history…
“If the end-Cretaceous extinction was canceled, our species would not have evolved to debate the question of what would have happened in alternate timelines.”

Obviously slight changes could have changed things dramatically over 65.5 million years, but human evolution kinda seems like it would be least altered of all mammals. Primate evolution progressed mainly in the trees, and unless the ancestors of primates were being held back by direct competition with enantiornithines, I doubt it would have been impacted much at all. Arboreal dinosaurs are precisely the ones that DID survive, and yet we’re still here. The only difference is that australopithecines may have had to face deinonychosaurs and abelisaurs on the African plains instead of large mammalian predators.

Matt