New (but very old) preprint: A survey of dinosaur diversity by clade, age, place of discovery and year of description

July 11, 2014

Today, available for the first time, you can read my 2004 paper A survey of dinosaur diversity by clade, age, place of discovery and year of description. It’s freely available (CC By 4.0) as a PeerJ Preprint. It’s one of those papers that does exactly what it says on the tin — you should be able to find some interesting patterns in the diversity of your own favourite dinosaur group.

Fig. 1. Breakdown of dinosaur diversity by phylogeny. The number of genera included in each clade is indicated in parentheses. Non-terminal clades additionally have, in square brackets, the number of included genera that are not also included in one of the figured subclades. For example, there are 63 theropods that are neither carnosaurs nor coelurosaurs. The thickness of the lines is proportional to the number of genera in the clades they represent.

Taylor (2014 for 2004), Figure 1. Breakdown of dinosaur diversity by phylogeny. The number of genera included in each clade is indicated in parentheses. Non-terminal clades additionally have, in square brackets, the number of included genera that are not also included in one of the figured subclades. For example, there are 63 theropods that are neither carnosaurs nor coelurosaurs. The thickness of the lines is proportional to the number of genera in the clades they represent.

“But Mike”, you say, “you wrote this thing ten years ago?”

Yes. It’s actually the first scientific paper I ever wrote (bar some scraps of computer science) beginning in 2003. It’s so old that all the illustrations are grey-scale. I submitted it to Acta Palaeontologica Polonica way back on on 24 October 2004 (three double-spaced hard-copies in the post!) , but it was rejected without review. I was subsequently able to publish a greatly truncated version (Taylor 2006) in the proceedings of the 2006 Symposium on Mesozoic Terrestrial Ecosystems, but that was only one tenth the length of the full manuscript — much potentially valuable information was lost.

My finally posting this comes (as so many things seem to) from a conversation with Matt. Off work sick, he’d been amusing himself by re-reading old SV-POW! posts (yes, we do this). He was struck by my exhortation in Tutorial 14: “do not ever give a conference talk without immediately transcribing your slides into a manuscript”. He bemoaned how bad he’s been at following that advice, and I had to admit I’ve done no better, listing a sequence of old my SVPCA talks that have still never been published as papers.

The oldest of these was my 2004 presentation on dinosaur diversity. Commenting on this, I wrote in email: “OK, I got the MTE four-pager out of this, but the talk was distilled from a 40ish-page manuscript that was never published and never will be.” Quick as a flash, Matt replied:

If I had written this and sent it to you, you’d tell me to put it online and blog about how I went from idea to long paper to talk to short paper, to illuminate the process of science.

And of course he was right — hence this preprint.

Fig. 2. Breakdown of dinosaurian diversity by high-level taxa. "Other sauropodomorphs" are the "prosauropods" sensu lato. "Other theropods" include coelophysoids, neoceratosaurs, torvosaurs (= megalosaurs) and spinosaurs. "Other ornithischians" are basal forms, including heterodontosaurs and those that fall into Marginocephalia or Thyreophora but not into a figured subclade.

Taylor (2014 for 2004), Figure 2. Breakdown of dinosaurian diversity by high-level taxa. “Other sauropodomorphs” are the “prosauropods” sensu lato. “Other theropods” include coelophysoids, neoceratosaurs, torvosaurs (= megalosaurs) and spinosaurs. “Other ornithischians” are basal forms, including heterodontosaurs and those that fall into Marginocephalia or Thyreophora but not into a figured subclade.

I will never update this manuscript, as it’s based on a now wildly outdated database and I have too much else happening. (For one thing, I really ought to get around to finishing up the paper based on my 2005 SVPCA talk!) So in a sense it’s odd to call it a “pre-print” — it’s not pre anything.

Despite the data being well out of date, this manuscript still contains much that is (I think) of interest, and my sense is that the ratios of taxon counts, if not the absolute numbers, are still pretty accurate.

I don’t expect ever to submit a version of this to a journal, so this can be considered the final and definitive version.

References

 

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9 Responses to “New (but very old) preprint: A survey of dinosaur diversity by clade, age, place of discovery and year of description”

  1. Andrea Cau Says:

    I may undestant why it was followed, but excluding the “Archaeopteryx + Neornithes” node from a survey of Dinosauria is something completely arbitrary, as – for example – excluding sauropods from a survey of Archosauria. It is the last remnant of the pre-cladistic division of “birds” and “reptiles”, and hope we’ll soon stop following that tradition. Exclusion of birds automatically underestimates the taxonomic and diversity importance of all clades birds are included in, from Paraves to Saurischia.

  2. Mike Taylor Says:

    Excluding the “Archaeopteryx + Neornithes” node from a survey of Dinosauria is something completely arbitrary.

    Yes, it is. So is any taxonomic selection.

    It is the last remnant of the pre-cladistic division of “birds” and “reptiles”, and hope we’ll soon stop following that tradition.

    Of course we won’t — not at long as their are studies that are interested in non-avian dinosaurs but not birds (i.e. always).

  3. Andrea Cau Says:

    Arbitrary definition of taxa (for example, giving more relevance to Sauropoda than to Massopoda) is different from using paraphyletic groups. Dinosauria is a natural group derived from evolutionary processes, “dinosaurs excluding birds” is a posteriory product of the human mind. The diversity of the former adds information on a natural phenomenon, the diversity of the latter is just a measure of a cultural convention. :-)

  4. Mike Taylor Says:

    I have never understood this religious belief that triangle-shaped groups are the only ones that may be discussed.

  5. Anonymous Says:

    Except, there are plenty reasons why one might want to avoid including bird diversity in a survey of fossil non-avian dinosaurs. Surveys of fossil mammal diversity often do something similar by ignoring bats (as well as the occasional freshwater representatives of taxa such as cetaceans), since in most cases finding bat fossils is more dependent on the types of localities being looked at as well as sheer luck rather than actual paleodiversity or presence at a site. Therefore, including bats into the analysis greatly obscures relationships between different sites. Although birds clearly need to be mentioned if discussing dinosaurs in a morphological or phylogenetic context, the fact that the factors that affect the fossil record of birds are often different from other dinosaur groups (except maybe maniraptorans and some ornithopods) gives one a good reason to consider them separately.

    Case in point, if one were doing a survey of fossil fishes, should we include tetrapods into the analysis?

    At the same time, keep in mind that this study was done back in 2004, where paleobird diversity was like what, a tenth of what is known a decade later?

  6. Mike Taylor Says:

    Case in point, if one were doing a survey of fossil fishes, should we include tetrapods into the analysis?

    Thank you! That is perfectly expressed.

  7. Andrea Cau Says:

    Mike, it’s not a religion, just a suggestion to consider the taxa in their monophyletic and natural sense, not following arbitrary grades because it’s boring to list the branches you don’t consider as relevant.
    Some of your “non-avian dinosaurs” are so bird-like that it is nonsense to consider them and at the same time exclude birds. Such list of taxa would be poorly significant for any relevant discussion on evolution of diversity and disparity. I understand that for a sauropod worker this is poorly relevant, but for those interested in the “reptile-bird” transition it is very significant. The same if a palaeontologist interested in Paleozoic sarcopterygians will find bizarre lists where at some arbitraty point half of the Paleozoic sarcopterygians are excluded from the survey just because are called “tetrapods”. And where, along the tree, a fish stops being a fish and becomes something else?
    Next time, we’ll have the interesting list of non-brachiosaurid reptiles, a very useful compendium of the only relevant fossils (that is, all true reptiles, excluding those bizarre huge-nared, long-armed, long necked, pneumatic giants… that are clearly too alien that cannot be listed in a list of fossil reptiles). ;-)

  8. Mike Taylor Says:

    Mike, it’s not a religion, just a suggestion to consider the taxa in their monophyletic and natural sense [...]

    That isn’t religious …

    [...] not following arbitrary grades because it’s boring to list the branches you don’t consider as relevant.

    … But this is. You’ve arbitrary anointed one class of taxa an anointed them as holy, and cast them all into outer darkness. You’ve said that anyone who wants to study both Eocursor and Panphagia must atone for that sin by the penance of also studying Triceratops, Malawisaurus and Passer. That is simply irrational. People are interested in the taxa that interest them; you can’t (and shouldn’t try to) also make them take an interest in all descendents of their common ancestor.

    I understand that for a sauropod worker this is poorly relevant, but for those interested in the “reptile-bird” transition it is very significant.

    Yes. That is those workers will include birds in their studies — perhaps omitting sauropods even though their reptile-bird transition studies involve Euparkeria, which by your religion should mean that they are forced to study sauropods too.


  9. […] Recently, I published an old manuscript of mine as a PeerJ Preprint. […]


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