What was Spinosaurus?

[Gwangi]

This topic was started in the thread about the new feathered dinosaur Sciurumimus. In an attempt to prevent the hijacking of that thread I'm starting this one in order to carry on the conversation started with Amargasaurus on the true nature of Spinosaurus.

ding the other day and there was a paleo writer that commented that Spinosaurus is one of the more ridiculous dinosaurs to date, as there is not even enough evidence at this point to speculate beyond it having been some form of crocodile, by actual known evidence.  I do find it odd there is not more fossil evidence for such a widely accepted animal.

I would be interested in reading that if you could provide a link. The reason we can reliably reconstruct Spinosaurus is because we have material from related animals like Baryonyx and Suchomimus. I mean sure, we cannot be certain without more fossil material but we at least know what is was related to and that it wasn't a crocodile.

Just google or reference online to the dinosaur and the relatively tiny amount of material that has ACTUALLY been found, post Romer. Then get a book that shows what material he used for his reference. It is shocking how little material has been recovered and used to suggest the animal existed at all. His reconstruction is possibly incorrect. And yes the majority of what has been found are elements of the skull, none of which preclude the likelihood of this animal being a form of crocodile.
   As for the comment I posted , i read it in a book that I have here. When i return from work this evening I will track down the exact title, page and quote if at all possible for you. I know it was a paleo-artist referring to how he chooses what to illustrate and that he had refused to even attempt a Spinosaur based on the flimsy evidence the dinosaur even existed, and was quite possibly a crocodilian. I will do my best to get you the exact reference.

Thanks. I still don't know how Spinosaurus could be classified as anything but a theropod dinosaur however. I know there is little fossil material for Spinosaurus but If nothing else the jaw material matches up pretty good with other spinosaurs, enough to allow us to properly classify it among them.

[Horridus]

Enough of Spinosaurus is known to determine that it most certainly wasn't a crocodile. Maybe if it was only known from teeth...in which case it would be a dubious genus anyway.

[Seijun]

Here is a drawing by Scott showing a comparison of known spinosaurus material vs material known from suchomimus and baryonyx.
http://www.skeletaldrawing.com/psgallery/images/spinosaurcomparison.jpg

Assuming his drawing is accurate, I second spinosaurus being a theropod. The upper and lower jaw match the others very well, and I'm not aware of any extant or extinct crocodilians that have jaws like that (although there is always the possibility of convergent evolution I suppose).

[Gwangi]

There are members of crurotarsi with a similar jaw structure, but still not as similar to Spinosaurs as the jaws of other spinosaurs and of course I can think of none with the tall neural spine. I'm really interested in finding out who made that statement.

[amargasaurus cazaui]

Myself I see similarities in the jawline of the three as well. I do not see it so much in body structure and if given the task would not place Spinosaurus in the same category as the other two animals given its unique implied form. I think where the issue lies with the animal is that when you speak of "known Spinosaurus material" you are referring to the Romer material, of which parts were not photographed, and others were not drawn, prior to their destruction the night of April 24/25 in the bombing of the museum they were mounted in at the time. How well they are known and how well it is established for certain what they were or were not has been a topic of debate since.As the original fossil material was destroyed, it is difficult to review that work and state for certain. There have been papers over the years suggesting the dinosaur was a cobble of elements from other dinosaurs or was a mixture of a croc and a therapod etc, although the paper I am most familiar with was considered questionable....You will also make note under known Spinosaurus material there are no known limb elements, so the restoration of the animal as a bi -pedal dinosaur is assumptive, if indeed it turns out there is no relationship between Spinosaurs and Baronyx and Suchomimus. Regardless, the direct reference I made is given below.
  As to my comment and remark, here is the actual reference where I read it. "Dinosaurs Past and Present" Vol. 1 Natural History Museum of Los Angeles County.   As the chapters are not seemingly numbered I will refer to the chapter provided  by Mark Hallett,  and the remarks given on page 99 of the book. The following quotes are the actual material that appear in the book, and you can verify yourself. " The artist and consultant must sometimes decide wether a restoration should be attempted at all. Spinosaurus, confidently depicted in popular illustrations as a megalosauridlike theropod with a "sail", is very poorly known and may not even be a dinosaur. When it was proposed as an illustration for a recent book, my consultant, Robert A. Long at the University of California, Berkley, and I decided that a painting of this animal would be an exercise in pure fantasy and should not be attempted until more complete remains are described.

[Himmapaan]

I'm the least qualified of all to comment with any insight, though I wonder if it might be worth pointing out that Dinosaurs Past and Present was published in 1987. I have a feeling that there must surely be good reason for the consensus regarding Spinosaurus since?

[amargasaurus cazaui]

I'm the least qualified of all to comment with any insight, though I wonder if it might be worth pointing out that Dinosaurs Past and Present was published in 1987. I have a feeling that there must surely be good reason for the consensus regarding Spinosaurus since?

It is quite possible if not outright likely. The only thing that bothers me with this entire issue is the complete lack of fossil evidence to support Spinosaurus at any level beyond meager jaw sections. Despite the passage of time, the dinosaur has still not been found despite intense search and effort.What is known of him remains less than was, a hundred years ago.

[Dinoguy2]

Myself I see similarities in the jawline of the three as well. I do not see it so much in body structure and if given the task would not place Spinosaurus in the same category as the other two animals given its unique implied form. I think where the issue lies with the animal is that when you speak of "known Spinosaurus material" you are referring to the Romer material, of which parts were not photographed, and others were not drawn, prior to their destruction the night of April 24/25 in the bombing of the museum they were mounted in at the time. How well they are known and how well it is established for certain what they were or were not has been a topic of debate since.As the original fossil material was destroyed, it is difficult to review that work and state for certain. There have been papers over the years suggesting the dinosaur was a cobble of elements from other dinosaurs or was a mixture of a croc and a therapod etc,

Those were all before the discovery of more spinosaurs beginning in the 1980s. The discovery of croc-like jaws with theropod bodies proved that Spinosaurus was not a croc/theropod chimera (though I have heard it suggested that it may be a baryonychine/carcharodontosaur chimera). To suggest that Spinosaurus is part croc but Baryonyx is not is to deny the entire science of comparative anatomy.

[amargasaurus cazaui]

The only issue I see with any of that is rather basic. There is no Spinosaurs to compare anatomy with. None. You have some elements from a lost fossil, and you have elements from proposed cousins of that fossil, but you have no Spinosaurus to shape that comparison around. Not prior to Romer and never again since has anyone come forth with a dinosaur fossil that displayed a set of the adaptations this dinosaur possessed. No spiny fish catching bi pedal predator has ever been brought to the table. The holotype went extinct during world war 2, and is not subject for comparison.

[Gryphoceratops]

Sure not much of spinosaurus has really been discovered but what we DO have combined with other animals that we know were related to it judging by the way the actual spino bones look gives us a pretty decent image of the animal.  I could easily say the same thing about animals like Utahraptor, Megalosaurus and Deinocheirus, yet nobody seems to have a problem making life reconstructions up the wazoo of them either.

Also if you really know your bones and fossils (not so much me) you CAN tell if something as fragmentary as a single vertebra or a tooth is from a dinosaur or a crocodile.  This being said as far as I am concerned Spinosaurus is a theropod not a crocodile until any real evidence saying otherwise is brought to the table. 

[amargasaurus cazaui]

I agree about the other animals you named as well. No argument there. I just like seeing fossil evidence more than speculation and inference. For me Spinosaurs can remain a unique possibility, until more substantive information presents itself.
  A dinosaur with no specimen other than the holotype, and even then only fragments long since lost, is somewhat dubious. If it is out there, I am sure someone will find it. Until then I will just collect my sauropods and be happy.

[Gwangi]

There are spinosaurs to compare Spinosaurus to, they are other spinosaurs! Other spinosaurs show the same characteristics as Spinosaurs only they're more complete. Suchomimus, Baryonyx and the other known spinosaurs show the same jaw anatomy and even have tall neural spines (though not as tall). They all show the same fish hunting adaptations, they're all bipeds. Honestly, we really don't need the rest of Spinosaurus thanks to its more complete cousins but of course it would be nice. This sort of comparative anatomy happens all the time in paleontology, you might be surprised at how scant the material is for many well known dinosaurs (in addition to those mentioned by Grypho). Aside from dated material I see no up-to-date reference questioning the identity of Spinosaurus. When Ernst Stromer described Spinosaurus there were no other spinosaurs known to science. To the best of my knowledge all additional spinosaur genera and Spinosaurus material has been found since the 80's. So with that said I can see why the author of a dated book would question the material and the description of Spinosaurus but not anymore.

I agree about the other animals you named as well. No argument there. I just like seeing fossil evidence more than speculation and inference. For me Spinosaurs can remain a unique possibility, until more substantive information presents itself.

Fossil evidence is great, we can all agree on that but with dinosaurs much is based on speculation and it has to be, we don't have a choice. That is how science works and we just have to hope more material will be found. Until then we need to learn from what we have. The discovery is half the fun, I love not knowing if for no other reason that I may eventually find out.
BTW, thanks for the reference.

[amargasaurus cazaui]

Delighted to provide it for you, as requested of course. The only disagreement I have with your statement is of course the one I had stated from go..we DO not have  a Spinosaurus ! We have Spinosaurids, but no Spinosaurus. The only one we had was based on a few jaw fragments, verts, and so forth. It no longer even exists. We are then somehow comparing that to dinosaurs we do have, that are considered cousins, IF the original was properly identified and reconstructed correctly which sadly there is ZERO way to know for certain. That is not comparative anatomy nor science to me. It somewhat resembles the insistence on calling Oviraptor egg thief, or placing a Camarasaurus skull on an Apatosaurus  it seemed to best fit. Time will tell, but if the spinosaurs is out there, i am sure we will find it and validate the point. Meantime I will continue collecting my misnamed oviraptors, and psittacosaurs.

[amargasaurus cazaui]

BTW Gwangi ty for seperating the thread. I should have thought about what the string was where I was posting and so forth. Thanks for moving this so I did not further impede the other thread. Appreciated. Will try to watch better what I am doing. Sorry.

[Gwangi]

BTW Gwangi ty for seperating the thread. I should have thought about what the string was where I was posting and so forth. Thanks for moving this so I did not further impede the other thread. Appreciated. Will try to watch better what I am doing. Sorry.

No need to apologize, I've derailed my fair share of threads too. I actually had a response written out in the other thread and then realized that this topic could get pretty lengthy. I would hate to take attention away from a potential feathered megalosaur.

Delighted to provide it for you, as requested of course. The only disagreement I have with your statement is of course the one I had stated from go..we DO not have  a Spinosaurus ! We have Spinosaurids, but no Spinosaurus.

But WE DO have material for Spinosaurs (and also some good photographs and sketches of the type specimen). Maybe you don't know this but new Spinosaurus material has been found since the original material was lost. There is a list of specimens on the wikipedia entry for the animal. All of them have been found between now and the mid 90's. They include fossils like the one pictured below...

This material was described in 2005.


I don't see how we can come to any other conclusion. We may need to work out some details but I think we have a pretty good idea of what Spinosaurus was all things considered. Hopefully we get more material, a more intact Spinosaurus would certainly be among the holy grails in paleontology.

[amargasaurus cazaui]

I looked through all of the current material, that I could find online before I ever commented. I see no limb or lower anatomy at all. Nothing to reinforce it is truly bi pedal for instance. I was hoping to find that. Zip. If you found anything like that please show me or send me a link, I couldnt . All I found were skull pieces, which for me are not diagnostic as a bi pedal spinous dinosaurs . That is what I was looking for...limbs, arms, a pelvic, a fused saccral, anything to indicate the actual structure of the animal. As for the material lost, sadly not all of it was illustrated nor pictured. Most yes, but there was some material we did not ever get to view. I still have my misgivings about Romers reconstruction. Are you aware of anything other than skull elements that were found recently? That I would love to look at, and if you do know of any send them my way please Sir.

[Gryphoceratops]

I looked through all of the current material, that I could find online before I ever commented. I see no limb or lower anatomy at all. Nothing to reinforce it is truly bi pedal for instance. I was hoping to find that. Zip. If you found anything like that please show me or send me a link, I couldnt . All I found were skull pieces, which for me are not diagnostic as a bi pedal spinous dinosaurs . That is what I was looking for...limbs, arms, a pelvic, a fused saccral, anything to indicate the actual structure of the animal. As for the material lost, sadly not all of it was illustrated nor pictured. Most yes, but there was some material we did not ever get to view. I still have my misgivings about Romers reconstruction. Are you aware of anything other than skull elements that were found recently? That I would love to look at, and if you do know of any send them my way please Sir.

Like I mentioned before, people who know their bones/fossils CAN look at those jaws alone and know they are in fact from a dinosaur and not something else.  They can do it with just one tooth.  They can easily do it with what we currently have of spinosaurus.  Its mind-blowing but that's the difference between professionals with years of experience and folks like us.  If they say it is so than that's our best, most scientific answer until further facts are discovered.

[amargasaurus cazaui]

I am sorry, I dont buy it. You dont look at a tooth and say this one was bi pedal and this one was quadrapedal. You can diagnose diet, and way of life, and if you analyze the tooth you can even determine if it was more of a water type than land based lifestyle. But, thats going a bit far stating you can identify it as a spinous bi pedal dinosaur from a tooth. Dinosaur yes...diet yes, perhaps even a species yes, for the better known dinosaurs.
    The only Spinosaurs skeleton , and the holotype of the species does not exist anymore. There are no other finds that contain verts with the long thin arms, combined with jaw elements from a theropod, and leg elements that suggest a bi pedal dinosaur.
In point of fact the holotype did not provide those either. There were no limb elements. No arms, no saccral, nothing to infer the reconstruction given. The dinosaur was lost before the dinosaur could be studied and a serious effort made to reconcile it with the fossil material.
  Find a fossil, find evidence. This is the same kind of speculation that led to the creation of Brontosaurus, and trachodon, and my precious egg thieves, the Oviraptors. Therizinosaurs......the list goes on and on. Just seems simpler to wait for actual evidence instead of always guessing. That is more my understanding of science, sorry.

[Seijun]

Wikipedia names 5 specimens attributed to spino, not counting the one that was destroyed. All of those specimens presumably pointed to the creature being a spinosaurid. At this point, the only thing that one might question is whether or not the sail really belonged to spino, but it seems very well established that spinosaurus, with or without a sail, was a spinosaurid.

My opinion is, if spinosaurus was a spinosaurid, and if all other spinosaurids (for which limb material is known) were bipeds, then spino was almost certainly a biped. I would assume this in the same way that I would assume Zhuchengtyrannus was biped even though we only have fragments of his skull.

[amargasaurus cazaui]

The five specimens I saw as being named were at best dubious and were of course skull elements and jaw fragments and in one case a few teeth shards. None of them is what I would consider a very strong endorsement for the existence of a massive 45 foot predatory spined dinosaur . They could each and all as easily be assigned to one of the other Spinosaurids. Just not the solid case I would have expected for such a popular animal. The cousins might be legit but I am just not seeing that strong of case for the fragments that are used to justify this animal.