If crocs and birds share a common ancestor with the dinosaurs, then what is the common ancestor of dinosaurs?

Is the Eoraptor considered the common ancestor of dinosaurs or merely resembling the common ancestor of dinosaurs? Where can I find out more about this subject? What are some reliable websites for research?

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7 Responses to “If crocs and birds share a common ancestor with the dinosaurs, then what is the common ancestor of dinosaurs?”

  1. ceddog86 said:

    I recommend the Tree of Life (TOL) web project: http://tolweb.org

    According to this site, Archosauria is the group containing dinosaurs and modern birds and crocodiles (http://tolweb.org/Archosauria/14900 ). It looks like Eoraptor was a theropod dinosaur (http://tolweb.org/Theropoda/15726 ), and theropods are just one of the groups of true dinosaurs, so it is would not have been the common ancestor for all dinosaurs. Unfortunately this site does not have as much information on dinosaurs as it does on currently living organisms, but the pages I linked to do have a lot of references and will at least give you a sense of the types of words to search for. The pages on diapsids (http://tolweb.org/Diapsida/14866 ) and diapsid phylogeny (http://tolweb.org/accessory/Diapsid_Phylogeny?acc_id=464 ) have more background on the origin of archosaurs. Diapsida is the group that includes reptiles like lizards and snakes, and birds, crocodiles and dinosaurs.

  2. Richard Head said:

    They don’t have a common ancestor, u should read the bible God created them all.

  3. Aishwarya G said:

    archeopteryx?????

  4. Dancefly said:

    It’s believed that the most recent common ancestor of dinosaurs resembled Eoraptor. Sereno PC (1999). “The evolution of dinosaurs”. Science 284 (5423): 2137�2147. It’s alway hard to show that any particular species or genus was THE common ancestor of any group of organisms because the fossil record is incomplete. We will never know for sure.

  5. Cal King said:

    To answer your question, one must first define dinosaur. As the Wikipedia points out, there are precious few shared derived characters that define Dinosauria. Some scientists have even called these defining characters “trivial.” For example, Alan Feduccia points out that it is not clear whether Eoraptor is a late thecodont (basal archosaur) or whether it is an early dinosaur.

    Feduccia further points out that Postosuchus, a Late Triassic thecodont, also has a number of theropod dinosaur features, and even posesses interdental plates, which were mistakenly thought to be a link between Archaeopteryx and theropod dinosaurs. To find the common ancestor of dinosaurs, we would probably need to go all the way back to the Middle Triassic, and look for them among such fossils as Lagosuchus and Lagerpeton. Lagosuchus is a small, foot long thecodont that is a part time biped. In fact, the similarities shared between the two great groups of dinosaurs, the Ornithischia (bird-hipped) and the Saurischia (lizard-hipped) may well be due to their common bipedal stance, which may have evolved independently in the two groups. The ancestors of both groups of dinosaurs were bipedal, although some members of both groups (e.g. sauropods among saurischians and ceratopsians among ornithischians) have gone back to being quadrupeds.

  6. BeckF said:

    icr.org
    creation ministies.com
    etc. on their links
    God made them.
    Romans 1.20 you’re without excuse.
    ev-o-loot-ion is not science. it’s atheism’s way of denying God and thinking they sound respectable.
    Rather than telling people “I deny God”, they lay their “religion” on goo-to-you “proved by facts”, which we haven’t seen.

  7. � John M � said:

    The whole theory of evolution is truly nonsense and crabs, and wasting time to find out further. Each animal is uniquely being created by God. Thank you for putting up this question, for it will give the evolutionist headache to answer.




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