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| Crurotarsan Radiation; Crocodile relatives dominate | |
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| Topic Started: Mar 1 2010, 03:12 PM (909 Views) | |
| Toad of Spades | Mar 1 2010, 03:12 PM Post #1 |
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Clorothod
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During the Triassic Crurotarsans produced a huge range of body forms, including large quadrepedal herbivores and carnivores, bipedal carnivores, semi-aquatic forms, beaked bipeds, and many others. So during the Triassic, what if the dinosaurs didn't pull through and many kinds of crurotarsans did? How diverse do you think they could have been? Also do you think they could have been as successful as the dinosaurs? Do you think they could have produced something like a bird? I think they could have been just as successful as dinosaurs and that something similar to a bird could have been produced. Though they would have a wing membrane or something like a feather substitute. With their pillar-errect stance there might be some differences with size limits, but I'm not sure. Crocodiles or something similar would have been produced for sure. Any other ideas and thoughts. Edited by Toad of Spades, Mar 1 2010, 03:14 PM.
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Sorry Link, I don't give credit. Come back when you're a little...MMMMMM...Richer. Bread is an animal and humans are %90 aluminum. | |
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| Pando | Mar 1 2010, 03:24 PM Post #2 |
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Obey or I'll send you to the moon
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I would have to say that there could be dinosaur-like forms, except for the ceratopsian frill and theropods. Plus, most were carnivores, only the aetosaurs were herbivores. So if dinosaurs never existed I wonder if aetosaurs would become the herbivores, or if something else would. Then the land forms that didn't dig would be wiped out by the KT, and mammals would reign dominant on land while crurotarsans would reign dominant in the sea, meaning no ceteceans or pinnipeds. Plus, no birds, so mammals would rapidly diversify after the KT, outcompeting any crurotarsan that survived on land. If the land forms survived though, then mammals would still be dominant right now as we are at the coldest time the Earth has experienced in hundreds of millions of years. But back to the crurotarsans, they would diversify, and producing some weird forms, as dinosaurs evolved from bipedal lizards, crurotarsans are quadruped. The bipeds were only a few crocs, at the most. |
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| Carlos | Mar 1 2010, 04:52 PM Post #3 |
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Adveho in me Lucifero
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1. Aetosaurs weren't the only herbivorous crurotarsians; notosuchian crocodillians were omnivores and produced a certain amount of herbivorous forms, while the shuvosaurids were also herbivorous and could evolve in the lines of prosauropods. 2. Considering the fact crurotarsians can't develop vivipary, I doubt they'd triumph over mammals in the seas; most likely both occupied an even amount of niches on land and on the water. 3. Bird like animals could evolve from shuvosaurines, or pterosaurs could still exist in this world. 4. Dinosaurs didn't evolved from lizards, and several linages of crurotarsians develop bipedally |
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| Toad of Spades | Mar 1 2010, 06:56 PM Post #4 |
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Clorothod
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Ctenosauriscids produced some herbivorous forms as well, so there is no shortage of herbivorous crurotarsans. So many crurotarsan herbivores could produce herbivorous dinosaur anologues. So shuvosaurids could produce prosauropod anologues and sauropod anologues, then aetosaurs could produce ankylosaur anologues and stegosaur anologues, and herbivorous ctenosauriscids could produce hadrosaur anologues and iguanadontian anologues. However notosuchids don't appear until the early Cretaceous, but many of the early crocodylomorphs could produce forms like the herbivorous notosuchids or the smaller primitive ornithopods. Carnivores would be much more diverse than theropods because all theropods share a more recent common ancestor and predatory crurotarsans derived earlier from each other than theropods. Also different body forms and hunting methods add to this. So there could be large to small theropod anologues, large to small quadrepedal and bipedal predators, huge carnivores that resemble giant rauisuchians, as well as many kinds of crocodile-like forms and well as many others. Edited by Toad of Spades, Mar 1 2010, 09:52 PM.
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Sorry Link, I don't give credit. Come back when you're a little...MMMMMM...Richer. Bread is an animal and humans are %90 aluminum. | |
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| Carlos | Mar 2 2010, 04:20 PM Post #5 |
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Adveho in me Lucifero
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Some concepts for this world passed entered my head right now. |
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Lemuria: http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/ Terra Alternativa: http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/ My Patreon: https://www.patreon.com/Carliro ![]() | |
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| The Dodo | Mar 2 2010, 09:11 PM Post #6 |
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Prime Specimen
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Sorry, what? Anyway, you should check out Different World by SIngemeister, it has a similar theme to this when the T-J mass extinction didn't occur. |
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| Toad of Spades | Mar 3 2010, 01:20 PM Post #7 |
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Clorothod
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That was pretty interesting. Mine's similar but with a few differences. In mine there was a T-J mass extinction, and almost all the land vertebrates niches are filled by crurotarsans. The only niches they don't occupy are the ones occupied by prolacertiformes, a few relict dinosaurimorphs, and the one occupied by pterosaurs, but they could eventually end up competing with aerial crurotarsans. With an environment like this, the Cenozoic would be dominated by crurotarsans, because mammals wouldn't exist.
Edited by Toad of Spades, Mar 3 2010, 01:32 PM.
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Sorry Link, I don't give credit. Come back when you're a little...MMMMMM...Richer. Bread is an animal and humans are %90 aluminum. | |
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| The Dodo | Mar 3 2010, 04:24 PM Post #8 |
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Prime Specimen
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Didn't mammals first appear in the Triassic, so how did they become extinct? |
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| Toad of Spades | Mar 3 2010, 04:32 PM Post #9 |
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Clorothod
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Smaller crurotarsans with the same lifestyle outcompeted them. |
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Sorry Link, I don't give credit. Come back when you're a little...MMMMMM...Richer. Bread is an animal and humans are %90 aluminum. | |
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| Jurassic-Gothic | Mar 4 2010, 01:08 PM Post #10 |
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Infant
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Well Avemetatarsan (Dinosaurs included) have anyway descended from a Crurotarsan ancestor. Anyway Cretaceous crocodylians showed notable diversification due to occupying several and highly diversified ecological niches. I just think about Notosuchians and Sebecosuchians (or Ziphosuchia). The latter have also survived the K-T crisis up to Miocene (maybe Pliocene too?) |
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| Dean | Mar 4 2010, 04:32 PM Post #11 |
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Infant
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Hmm, I'm not really sure about that. Avemetatarsals have some common features, such as the type of scales that eventually led to feathers in dinosaurs and the very similar hair-like covering in pterosaurs, and a very early trend towards a bipedal gait and an erect stance that is very similar to that of birds. In Crurotarsi, the type of scales are different, bipedal-like gait only appeared on forms who converged strongly with a theropod-like lifestyle, and their erect stace was "pillar-erect" which uses a different bone configuration than the erect stance of Avemetatarsals. But since Crurotarsi appear to share more features with ancestral reptiles than Avemetatarsals, the common ancestor of crurotarsi and avemetatarsals might have been more similar to a crurotarsi than to an avemetatarsal. Edited by Dean, Mar 4 2010, 04:36 PM.
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| SIngemeister | Mar 4 2010, 04:39 PM Post #12 |
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Hive Tyrant of the Essee Swarm
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Thanks for the plug, I owe you. Anyway, on the subject of this, what would said possible aerial crurotarsans derive from? I think Sphenosuchids have the best chance. |
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My Deviantart RRRAAAAAARRRRGGGGHHH!!!!! | |
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| Carlos | Mar 4 2010, 05:15 PM Post #13 |
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Adveho in me Lucifero
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Same here, since those were the smallest crocodillians and the ones with preumably the highest metabolism. If not, notosuchians would come right next |
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Lemuria: http://s1.zetaboards.com/Conceptual_Evolution/topic/5724950/ Terra Alternativa: http://s1.zetaboards.com/Conceptual_Evolution/forum/460637/ My Patreon: https://www.patreon.com/Carliro ![]() | |
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| The Dodo | Mar 4 2010, 06:27 PM Post #14 |
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Prime Specimen
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How do you think they would evolve flight? Maybe a tree-dwelling form that glided between trees maybe chasing pterosaurs or something. |
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7:17 PM Jul 10