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The Crocopocalypse is upon us

The views expressed are those of the author and are not necessarily those of Scientific American.

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I’ve been drawing crocodylomorphs. Lots of them. Crocodylomorpha, as if you need reminding, is the archosaur clade that essentially includes all archosaurs traditionally dubbed ‘crocodilians’: the living crocodiles, alligators and gharials and all their fossil relatives. These animals were hugely diverse in the past, and hopefully you can get some idea of that diversity (by which I mean: morphological disparity) here…

I could talk about the nomenclatural issues concerning this group a whole lot – I mean, as goes the differences between the names crocodylomorph, crocodyliform, crocodilian and crocodylian (for previous discussion, see the article on dwarf crocodile anatomy), but that’s not why we’re here. We’re here because this illustration – and we’ll be seeing a lot more of it later on – depicts most (but not all) of the diversity present in Crocodylomorpha: that is, representatives of most lineages are shown here. In much simplified, approximate order (heading crown-wards in the cladogram), we’re talking about sphenosuchians, protosuchians, gobiosuchids, notosuchians, peirosaurids, tethysuchians, thalattosuchians, atoposaurids, goniopholidids, gavialoids, crocodyloids and alligatoroids (e.g., Bronzati et al. 2012).

The plan, then, is to discuss these animals – err, all of them – here in time. As every human surely knows, there just aren’t enough reviews of crocodylomorph and/or crocodyliform diversity out there in the literature: there’s Steel (1973), Russell & Wu (1998) and Naish (2001), but none are up-to-date, or comprehensive. Anyway, for now, I thought I should share one version of the picture I’ve done. And because the whole illustration, as used above, is too small to be of use for anything, here are enlarged versions of the different sections…

More soon! And due credit to Henry Peihong Tsai for the title of this article. For some previous Tet Zoo coverage of crocodylomorphs (wholly crocodyliforms, and mostly crocodylians), see…

Refs – -

Mario Bronzati, M., Montefeltro, F. C. & Langer, M. C. 2012. A species-level supertree of Crocodyliformes. Historical Biology DOI: 10.1080/08912963.2012.662680

Naish, D. 2001. Fossils explained 34: Crocodilians. Geology Today 17 (2), 71-77.

Russell, A. P. & Wu, X.-C. 1998. The Crocodylomorpha at and between geological boundaries: the Baden-Powell approach to change? Zoology 100, 164-182.

Steel, R. 1973. Handbuch der Paläoherpetologie. Part 16. Crocodylia. Gustav Fischer Verlag (Stuttgart).

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Heteromeles 10:41 pm 09/2/2012

    When’s the 3D version of the above coming out?

    Link to this
  2. 2. Rajita 12:13 am 09/3/2012

    Stupendous! I wonder if you might be doing a Pakasuchus or Yacarerani. I guess the guy to the front 2nd from bottom is Simosuchus?

    Link to this
  3. 3. dmaas 2:44 am 09/3/2012

    ok. This one got me to register. Hot!
    I hope you have them all individually, because they kind of turn to a grey mush all on top of each other like that…
    also – what is that Barney-Croc in the middle? Nature does toon. Bizarre!

    Link to this
  4. 4. naishd 5:10 am 09/3/2012

    The figures will be appearing in different formats later on. I know that many of them appear smudged together in the format shown here.

    Rajita: I originally planned to illustrate Pakasuchus, but Adamantinasuchus takes the role of small, gracile, short-faced notosuchian instead (it’s the crouching animal in foreground of far left segment). Yes, notosuchian “2nd from bottom” is Simosuchus, hidden behind sphenosuchian Barbarenasuchus and Zosuchus.


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  5. 5. naishd 5:49 am 09/3/2012

    Oh – “Barney croc in the middle”? I guess you’re referring to the gigantic, hippo-headed caiman Purussaurus. Previously covered here on Tet Zoo ver 2.


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  6. 6. BilBy 9:04 am 09/3/2012

    @naishd – technical question: how do you prepare your pictures like this? Do you design their layout carefully or do you go free form? What media do you use? Very cool – glad to see the crocs are back

    Link to this
  7. 7. naishd 9:18 am 09/3/2012

    Preparation: each figure has been drawn individually and can be used stand-alone. To stack the images up as shown above, I used Corel Graphics Suite 11 (familiar to some, not so familiar to others). In Corel Photo-Paint, imported illustrations can be cut out from the background using either a (near always ineffective) magnetic mask or a freehand mask tool; the ‘cut-out’ figures are then compiled in CorelDraw 11 where they can be positioned, sent backwards or forwards as required. Once you have the composition you want, you export the illustration to create a jpeg or whatever. One of the downsides is that the CorelDraw files are large – I mean, over 100MB, so saving and such can take a while (by which I mean a few minutes, but still annoying when time is scarce).


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  8. 8. Wilbert Friesen 12:17 pm 09/3/2012

    Wow. let the show begin.

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  9. 9. neovenator250 12:24 pm 09/3/2012

    WHOOOOOOOH! Crocopocalypse! Can’t wait! and there really isn’t enough literature out there on these guys. With Croc Stock (get it?) pointing up, that will hopefully change soon

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  10. 10. naishd 12:32 pm 09/3/2012

    Mark Young tells me that my metriorhynchoids ain’t so hot; both need to be updated (one of them is old, and I’ve been lazy in not replacing it).

    Large version of the image now available at my deviantART gallery.


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  11. 11. Wilbert Friesen 12:53 pm 09/3/2012

    Another blog concerning archosaurs which I find highly interesting.

    Long live Godzilla and friends !

    Link to this
  12. 12. cmchenry 9:29 pm 09/3/2012

    Darren, this is awesome! And great inspiration as I finish off a croc MS… ;-) . I thought I had a feel for croc skull mechanics but some of these things have me scratching my head.

    Link to this
  13. 13. Glendon Mellow 11:57 pm 09/3/2012

    Fantastic Darren! Mola Ram’s worst nightmare.

    Link to this
  14. 14. Jerrold Alpern 5:37 pm 09/4/2012

    Stunning! Looking forward to more!

    Darren, I’d be interested in your opinion of the accuracy of Safari’s Prehistoric Crocodiles Toob, and . It includes a Postosuchus, a Desmatosuchus, a Euparkeria, a Montealtosuchus, a Champsosaurus, a Sarchosuchus, a Chasmatosaurus, a Rutiodon Validus, a Dakosaurus and a Pristichampsus.

    If you think they’re good, I will take my Toob to work with me to show visitors in the AMNH Vert. Origins Hall when I’m working there as an Ed. Vol.


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  15. 15. jwmorenob 1:46 pm 09/6/2012

    If someday a colored poster version appears, I´ll buy it.

    Link to this
  16. 16. David Marjanović 1:59 pm 09/6/2012

    Safari’s Prehistoric Crocodiles Toob

    Postosuchus is a “rauisuchian”, Desmatosuchus an aëtosaur, Euparkeria outside the archosaur crown-group (birds are closer to crocs than E. is), and Rutiodon is a phytosaur (thought till 2011 to be juuust closer to crocs than to birds, but now thought to lie juuust outside the archosaur crown-group).

    Also, Sarcosuchus with one h in total, and Rutiodon validus with one capital letter in total.

    Link to this
  17. 17. farandfew 8:49 am 09/7/2012

    I just coincidentally saw that ‘Toob’ in the Sedgewick Museum. Despite the name (marketing dept?) I’m still kind of impressed it exists at all.

    But I’m even more impressed with these montages, this and the South American one. More of these please, Darren!

    Link to this
  18. 18. Jerrold Alpern 10:23 pm 09/8/2012


    Thank you for the additional information. The exact phylogenetic position of each animal can be worked in easily as the Hall covers most of the various archosaur taxa. What I am really concerned about is whether the toy models reflect the actual morphology or not. If they do not, then they should not be shown to visitors.

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  19. 19. David Marjanović 5:46 pm 09/9/2012

    I wanted to leave that to Darren, who knows the animals in question at least as well as I do… My computer is overloaded, so I won’t watch the video today. The photo in the forum thread shows that the models are quite small and therefore somewhat imprecise; taking that into account, they’re quite good! Not like the Guanlong higher on the page with its horribly dislocated elbows. :-)

    Of course they’re not all to the same scale.

    Link to this
  20. 20. Jerrold Alpern 7:12 pm 09/26/2012


    I would really like to know your thoughts on this. Thanks.

    Link to this

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