Gallery and print store

Friday, 12 February 2016

Jaw gaping in Spinosaurus hinges on modern birds














Enjoyed this post? Support me on Pateon!






  1. The authors do compare the helical mandibular joint to pelicans, pterosaurs, and other fast biting/weak jawed theropods I think that they do this more on the presumption of piscivory and/or swallowing prey whole and looking for a suite of characteristics that unite this lifestyle. Yes they do compare spinosaurids and pelicans but - as you mentioned - the unique bowing of the mandible for pelicans really is what sets them apart. From what I gather reading their paper it is the combination of loosely connected mandibular symphysis and the helical joint that allowed deglutition of large food parcels in spinosaurids. Really I think it is the press that spun this comparison between pelicans and spinosaurs to an extreme. The question that needs asking is how far the mandibular symphysis could spread apart - maybe snakes offer some comparison?

    1. Now there's an interesting idea. I, too, felt that the pelican comparison was a tad too extreme.

  2. Hi Mark,

    Thanks for your comments and interest in my research, appreciated! I just wanted to say that we basically share the same opinion about similarities and differences between spinosaurs and pelicans, and that the large majority of your comments do not really go against what is written in this papers. We mostly compare the jaw mechanism of spinosaurs with pelicans mainly because it was done by other authors in regards to the diagonally oriented helicoidal intercondylar sulcus of the mandibular articulation of the quadrate, also seen in pterosaurs. And, because spinosaurs have a mandibular symphysis restricted to the anterior part of the jaw and linked by connective tissue, we made a further comparison with pelicans (as the pterosaur mandibular symphysis extends much along the dentary and is fused as far as I know). That's pretty much it and we are deeply aware, my colleague and I, that the mandibular ramus of spinosaurids and possibly most non-avian theropods could not bent like that of pelicans and that spinosaurids probably did not have a pouch (which is why we didn't add one in the reconstruction of the two spinosaurids by Sergey Krasovskyi). Likewise, we are aware that the lateral movement of the two rami was not that significant, yet you often refer to the length of the skull when talking about this but the most important aspect of this lateral displacement goes with the width of the back of the skull, which is relatively narrow in spinosaurids, and might have been even narrower in derived spinosaurs. And when you say "we could also call spinosaurid mandibular joints 'heron-like', 'potoo-like', or even 'hummingbird-like'", I totally agree with you. Yet people tend to portray this wideness of the mouth much better when we tell them it's similar to that seen in pelicans. And I don't really think we are misleading them by saying that. Likewise, because this adaptation in spinosaurs helped them to swallow large prey items a whole, and most likely fish considering they were at least partially piscivorous animals, the comparison with pelicans is not stupid either. Hope you agree with my points, Duane Nash qt least seems to share my opinion on this regards! Cheers, C.

  3. Hi guys,

    Thanks for the comments. Perhaps the issue here is that the 'established' go-to bird for lateral motions at jaw joints is now known to have a lot of functional baggage that complicates it as a suitable analogue for most other animals (as noted by some recent research, the only animals with pelican-like jaws are rorquals). Given what research conducted in the last few years has shown, maybe it's time to move away from pelicans - or at least include other birds - when talking about jaw motion. Christophe, as you indicate, this can be more complex when dealing with the public as the pelican is the best known bird for this trick, but one neat thing about dinosaur science is that it provides a gateway to introducing new concepts to lay audiences. In this instance, spinosaurs can be used to introduce the fact that a lot of birds have mobile jaw joints - pelicans are just one (and an extreme) example.

  4. Yet another paper criticizing Ibrahim's reconstruction. This is why I wasn't quick to jump on the bandwagon and get caught up in all the height behind the new findings. It's best to wait a few years and see what new evidence and subsequent analysis of the material before jumping to conclusions. Still, all this news about Spinosaurus is really exciting. After so many years of almost nothing new being proposed about this fascinating creature, the 2014 find and the subsequent discoveries made in recent years is really exciting! Spinosaurus has always been a favorite of mine, and all these new finds and theories are delightfully thrilling! Thanks for posting this, Mark, especially that link to the new paper!

  5. So out of curiosity I went around on the internet and looked at some other blogs regarding the spino's life appearance and found this:

    I'm not sure if you have read it already but I thought the concept wasn't too far-fetched, maybe. I think it's a three part post. Just a thought.