Mesozoic Birds

While obviously the title of the blog covers birds, they get rather short shrift on here as I try to focus on the Mesozoic archosaurs. However, even this definition doesn’t rule out all the various birds that lived in the Jurassic and Cretaceous. Here then are a couple of them, first off (above) a not-that-great photo of the not-that-great holotype specimen of Jeholornis.

Secondly (above and below) the near ubiquitous Confuscisornis. I’ve seen well over a hundred specimens of this without having troubled many of the museums in Liaoning that have extensive birds collections so it’s a pretty safe bet that there are several hundred specimens of this in China and probably well into the thousands when private collections are taken into account. Although I’ve not heard of anyone actually trying to crunch the numbers, I’d not be surprised if it was one of the most common tetraopods from Liaoning (certainly apart from a couple of the amphibians and near infinite hyphalosaurs) and there seem to be few museums now, inside or outside China, that don’t have a specimen or two somewhere.

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7 Responses to “Mesozoic Birds”

  1. 1 Mickey Mortimer 10/01/2010 at 11:55 am

    That’s not the Jeholornis holotype, but rather the referred specimen IVPP 13550 (Zhou and Zhang, 2003). I still think Shenzhouraptor should be the name used- .

  2. 3 Olaf van Kooten 19/01/2010 at 3:02 am

    Being an enthusiastic amateur ‘armchair’ paleontologist, I’m always searching the web for interesting sites and blogs on this subject. Recently, I (literally) ‘stumbled upon’ the Archosaur Musings and I have a question regarding Confuciusornis.

    I’ve read that Confuciusornis shares some features with Oviraptorosaurs. Is this true? If it is, what does it mean for the origin of birds? After all, according to current consensus, the first true birds are almost certainly close relatives of Deinonychosaurians.

    If a primitive bird like Confuciusornis shared certain traits with Oviraptorosaurians, what does this imply?

    1. The similarities between Confuciusornis and Oviraptorosaurs are completely convergent and Confuciusornis was just another true bird.

    2. The similarities between Confuciusornis and Oviraptorosaurs are convergent. However, Confuciusornis developed it’s flight capabilities independent from true birds (Avialae) – in other words, the similarities between Confuciusornis and Avialae are convergent as well, without effecting the monophyly of Paraves.

    3. Paraves is actually polyphyletic and the Oviraptorosauria are instead the closest relatives of the line leading to Confuciusornis, who not only developed it’s flight-capabilities independent from true birds (Avialae), but was even not a Paravian at all! In other words, the similarity between Confuciusornis and Oviraptorosauria are due to common ancestry, while it’s the similarity between Confuciusornis and Paravians (as a whole) that is convergent.

    4. Paraves is paraphyletic and the Oviraptorosauria are the closest relatives of the line leading to Confuciusornis, but both groups actually descended from within Paraves. In other words, the similarity between Confuciusornis and Oviraptorosaurs AND between Confuciusornis and other birds is due to common ancestry, while it’s the similarity between both groups and non-Paravian dinosaurs that is convergent.

    5. ALL Maniraptorans are actually daughterclades of Avialaea – not the other way around. This means that both Confuciusornis and Oviraptorosauria descended from true birds and the similarities between the entire Maniraptora and all other dinosaurs are convergent.

    So, which of the 5 scenarios I described is most likely to be correct? Although I do admit it’s quite possible that none of them are correct, as I am just a ‘member of the public’ and far from an expert on these matters.

    Please ignore any spelling and grammar mistakes that may exist in this post (although I don’t believe there are many), as I am not a native speaker of English.

    Olaf van Kooten
    The Netherlands

    • 4 David Hone 19/01/2010 at 1:10 pm

      Sorry for the delay in replying, all comments by new commenters have to be approve and since I’m based in China, I typically get to these 12 hours after they get posted.

      As to your question, the very short answer is that oviraptorosaurs are maniraptoran dinosaurs and the confusciuornithids are birds and thus any derived characteristics that they share are the result of convergence. Obviously they have a lot in common (like feathers!) which is a result of shared ancestry, but their phylogenetic positions are really quite stable and agreed on by pretty much everyone. There’s no recent support that I’m aware of for oviraptorosaurs being derived from birds, or the confusciuornithids being dervived from non-avian dinosaurs. Thus your scenario 1 is pretty much the answer.

  3. 5 Olaf van Kooten 19/01/2010 at 10:18 pm

    Thanks for your reply. ‘Birds-came-first’ scenario’s clearly don’t work for you (and for good reason, as there is no recent support for it) – I believe ‘birds-came-first’ is still a fascinating hypothesis though, even if it turns out to be spectaculary wrong 😉

    • 6 David Hone 20/01/2010 at 7:52 am

      I think it is as it relies too much on questionable selectivity of data. Darren Naish did a very comprehensive review of this over on Tetrapod Zoology a while back if you want the full story.

  4. 7 Olaf van Kooten 21/01/2010 at 12:32 am

    Thank you for your suggestion! I’ve googled ‘Darren Naish’ + ‘Birds Came First’ and found some interesting articles on this subject. I’ve read the article you are likely refering to, in which Naish criticizes all the main arguments used by BCF-believers – and I have to admit, he does so rather convincing 🙂

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