Is this the new face of Tawa the basal theropod dinosaur?

Readers have wondered why I did not include the missing maxillary extensions on Tawa. Here I provide them while continuing to use the bone photo in a reconstruction that still differs from the freehand sketch we’ve all come to know, Sept. 15, 2015.

Figure 1. Tawa skull reconstructed using assembled images of the bones rather than a freehand attempt. Guys, Photoshop is our friend, not something to be avoided.

Figure 1. Tawa skull reconstructed using assembled images of the bones rather than a freehand attempt. Guys, Photoshop is our friend, not something to be avoided. Note the bad fit of the the prefrontal on the lacrimal in the longer restoration. 

Since its publication
a freehand reconstruction of the skull of Tawa (Nesbitt et al. 2009; Theropoda, Dinosauria, Fig. 1) has been our only guide to its in vivo morphology.

However,
if you put the published bone images together, you get a slightly different face (Fig. 1), whether you add the maxillary and mandible extensions or not, and that affects its scoring on phylogenetic matrices. The new reconstruction also does away with the need for those maxillary extensions. The mandible, if correctly restored, helps confirm the new shorter skull length.

Like Herrerasaurus
a sister to Tawa, the lacrimal and quadrate lean anteriorly, the maxilla (part of the jugal block) extends to mid orbit and the squamosal descending process is more robust than originally reconstructed. If valid, this is one more case (of several hundred) of not needing to see the actual fossil firsthand in order to make a contribution to paleontology.

So, this reminds me of joke…
Tawa walks into a bar. Bartender says, “Hey, why the long face?”

References
Nesbitt SJ, Smith ND, Irmis RB, Turner AH,Downs A and Norell, MA 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs”, Science 326 (5959):1530–1533,

wiki/Tawa

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13 thoughts on “Is this the new face of Tawa the basal theropod dinosaur?

  1. Wow, that head is horrible. One thing, Photoshop is NO REPLACEMENT for actual handling of the bones. I believe that the maxillary extensions are drawn as that in the skull of Nesbitt et al. because the posterior surface is BROKEN. Think about that Peters.

  2. You said, “believe”. We don’t believe anything in Science. We test for validity. So, you like imagination and supposition over the real deal? Broken yes, but how much is missing? And why is that jugal so deep? That’s an oddity with regard to dinos. Does it include the posterior maxilla? Apparently so. And then note the new skull is the perfect size for the mandible. And compare this recon to Herrerasaurus… it all fits. Think about Reid. Thanks for your comment. Sorry you missed the point.

  3. ‘To believe’ means ‘to hold to be true’, it is an attitude taken to a proposition. Of course we believe stuff in science! If we didn’t, nothing we would say would make any sense.
    Don’t confuse ‘belief’ with ‘faith’, they are not the same thing, that notion is a fideist equivocation that has sadly entrapped many scientists with only a naïve understanding of philosophy.
    Knowledge itself is a form of belief, to say ‘we don’t know anything in science’ is nonsense, one cannot start out from ignorance and then proclaim ‘we will not know/believe’ and then hope to know something about the world. There is a required openness to knowledge (again, a form of belief), and a necessary responsiveness to propositions that must be in place. Then a hypothesis needs to be made that involves a certain degree of knowledge (belief), about the world.
    Justified (i.e. logical), true (i.e. corresponding to the actual state of the external world) belief is the best thing science provides us, and science is notable for being better than any other method at doing so.

    • Sorry, Mike, the word ‘believe’ is often used by journalists to describe what scientist learn, so that’s where you see it most often, especially when news hits. In Science, we can ‘show,’ ‘demonstrate,’ ‘measure’ and ‘replicate’ — or we can’t. If we can’t, we should not say ‘we believe.’ That’s bad Science. Belief is defined by lack of evidence. Science is defined by evidence.

      • That’s precisely where you’re wrong, ‘faith’ is defined by lack of evidence, ‘belief’ neutral on the matter, ‘knowledge’ is a type of belief that backed up by evidence, ‘science’ is a method used to obtain evidence. Journalists are not the go to people for matters pertaining to philosophy of science. You really need to read up on your epistemology before talking about this, what you said here doesn’t make any sense. I’d say start by reading some Russell and Hume, then take a step back to Kant, Locke, and Descartes, and a step forward to Popper, Wittgenstein, and Kuhn. There is a rich discourse about how it is that we know anything, and it is intertwined with an understanding of science, how it developed, and how it operates. One thing you will never find, however, is the colloquial equivocation of ‘faith’ and ‘belief’ that you find in journalism, or polemical works by scientists who have no background in philosophy. Belief, defined properly as ‘holding a proposition to be true’ is considered essential to knowledge and scientific inquiry by every philosopher of science or epistemologist. In general, epistemologists and philosophers of science will define terms more or less as such: Belief: “to hold a proposition to be true”. Knowledge: “to have belief that is logically justified and corresponds to the state of the actual external world”. Faith: “to have belief that is not supported by logic or evidence”. ‘Knowledge’ and ‘faith’, as you can see, are opposing subsets of ‘belief’. Journalists, philosophically naïve scientists, and fideists frequently equivocate belief and faith, but that is improper usage of the terms, whether in a philosophical sense, or as defined by the dictionary, by the bloody dictionary.

  4. Mr. Peters, does it mean that we are going to restore every theropod with crushed, deformed or broken skull as a puzzle?
    I don’t want to be unrespectful, but that’s insane!
    This lack of interpretation, this reasoning dangerous, misleading, childish and literal.
    Your jugal is still deep, depending on its position, and it’s crazy that it’s got a maxillary tooth!

    Taphonomical issues are always the first ones to be considered.

    • Hardly. This is simply a case of putting the pieces back together. Now if I’ve made a mistake or two, let me know by documentation or by repeating the experiment in a different fashion. The manus of Tawa is distinctive and you accept that. Perhaps you’ve just gotten used to the original restoration. Please do put the parts together yourself and see what you get. Then let me know if you support or refute this little experiment. Remember the headline here ends in a question mark. I can’t be certain because I’m dealing with pixels.

      • The fact is that putting the pieces together in a fossil implies also considering the missing parts or points where the sediment has infiltrated or rock deformed shape of the bones and displaced their location. It’s clear that in Tawa maxillary processes are missing as well as the back of postorbital and other small parts.

        You can’t make a puzzle if you don’t have all the dowels.

    • Your comment really reveals quite overtly a willful ignorance of philosophy of science, the scientific method, theory of knowledge, and basic English vocabulary, by simply dismissing any attempts at correction and declaring them to be ‘a waste of time’, and, on top of that, then dismissing what you cannot see as ‘anger’ on the part of the other party.

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