Spinosaurus aegyptiacus/ Possible errors and reconstructions

[amargasaurus cazaui]

I had attempted to open a discussion regarding the somewhat dubious nature of the holotype of Spinosaurus aegyptiacus, and the paucity of remains that exist for the animal as well as potential errors regarding said dinosaur. In some fashion the issue has been clouded to argue about other dinosaurs not germane to the point and not part of the discussion.
  In an attempt to clarify and establish the discussion I am opening this thread and hope perhaps it can stay centered more in the topic rather than unrelated issues.
  What I had hoped to learn about and discuss and perhaps get some perspective on is the general acceptance and belief the animal named, Spinosaurus aegyptiacus, has gained in recent years despite being based on extremely poor remains, poor scientific study, and the subsequent loss of the ONLY EXISTING specimen of the dinosaur to date positively identified and recognized as this dinosaur.
  I have no issue with Suchomimus, or Baronyx, for that matter. I am discussing Ernest Stromers animal, the original spinosaur.
  I question the dinosaur based on these things. First, the specimen was named and identified by Stromer, although he was not present when it was excavated. He was working from Munich, working through crates of fossils sent him by his field hand. Within those crates, he also found the mingled remains of another species of Spinosaurus, at least two never identified theropods, Carcharodontosaurus,and at least one massive sauropod, as well at least a half a dozen basic crocodyliforms. 
   In 2003, Oliver Rauhut suggested that Stromer's Spinosaurus holotype was a chimera, composed of vertebrae and neural spines from a carcharodontosaurid similar to Acrocanthosaurus and a dentary from Baryonyx or Suchomimus
Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology 69: 1–213. ISBN 0-901702-79-X
I question if Stromer might have somehow mixed remains from another dinosaur to create something that has never before or since been found. It has been stated this dinosaur has close cousins with tall spines, but this argument is not well stated when you consider the holotype possessed spines that were as much as 5.4 feet tall. I do not see this evidence in closely related spinosaurids, to the degree present here. Another person has stated Spinosaurs possess serrated teeth, which is of course inaccurate as well. Spinosaurs possess smooth cone shaped or awl-like teeth, not serrated. Stromer found this to be one of the more amazing qualities of the animal he discovered. Hans Dieter Sues stated" We distinguish dinosaurs, in part by their teeth.Teeth very markedly from species to species,and their hard enamel preserves them longer than regular bones. It's really a credit to Stomer's tremendous knowledge of fossil animals that he even identified Spinosaurus as a theropod, a meat eater, because Spinosaurus' teeth are completely different from the teeth of usual carnivorous dinosaurs. Most big carnivores have teeth like steak knives, they're long and somewhat flattened side to side, and they have serrated edges front and back. But not Spinosaurus, its teeth were long and cone shaped almost round in cross section-Stromer called them awl-like and while she had sharp edges fore and aft they were NOT serrated. "
Although others in forum have stated the teeth for Spinosaurs are serrated they are in fact not. Two cousins to this dinosaur had serrated teeth, but true Spinosaurs have smooth teeth.The Spinosaurinae share unserrated straight teeth that are widely spaced (e.g., 12 on one side of the maxilla), as opposed to the Baryonychinae which have serrated curved teeth that are numerous (e.g., 30 on one side of the maxilla)
   The dinosaur as Stromer constructed it has never been found again. No bi-pedal , theropod, with spinal shafts five feet tall is known. This dinosaur does have similar cousins yes, but NONE of them share the taller spines and straight teeth of a Spinosaur.
     My intention was to ask why given this lack of true evidence to clearly denote a sailed massive predator we insist on having it identifed as such, without a question mark at least. I ask this because...my favorite dinosaur is Amargasaurus. It is a more well studied and documented animal, but still only one skeleton. It does have spines however, and noone has been able to establish clarity of their purpose. Were they also a sail?When you see reconstructions of this dinosaur they are sometimes with sail, or other times with only spines.  This is the direction i wanted to go with my discussion and question, not establishing the existence of the Spinosaurid family itself. Even Ouranosaurus has spines, and is based on fairly complete evidence. Each spined dinosaur to date I know of is an herbivore.  Are the smaller spines of suchomimus and such then female versions and thus smaller or sub-adults perhaps?
If anyone can help or offer some scientific papers, books, or anything related to this I am most appreciative. Anything at all would help.This is where my direction of questioning and interst lies, thanks

[Gwangi]

I don't think starting a new thread will help your cause and you'll probably mostly get the same responses. It is past my bed time so I'm going to keep this brief for tonight and address a few points.

In 2003, Oliver Rauhut suggested that Stromer's Spinosaurus holotype was a chimera, composed of vertebrae and neural spines from a carcharodontosaurid similar to Acrocanthosaurus and a dentary from Baryonyx or Suchomimus

The notion that Spinosaurus was a chimera has apparently been rejected in at least one paper written since his. This according to wikipedia anyway. Here is that paper...
http://reocities.com/Athens/bridge/4602/spinoskull.pdf
Also keep in mind that in 2006 actual photographs of the spines were recovered and contributed greatly to our understanding of Spinosaurus.

I do not see this evidence in closely related spinosaurids, to the degree present here.

While not as extreme as those in Spinosaurus other spinosaur species (Suchomimus) have relatively tall neural spines.

Another person has stated Spinosaurs possess serrated teeth, which is of course inaccurate as well. Spinosaurs possess smooth cone shaped or awl-like teeth, not serrated. But not Spinosaurus, its teeth were long and cone shaped almost round in cross section-Stromer called them awl-like and while she had sharp edges fore and aft they were NOT serrated. "
Although others in forum have stated the teeth for Spinosaurs are serrated they are in fact not. Two cousins to this dinosaur had serrated teeth, but true Spinosaurs have smooth teeth.The Spinosaurinae share unserrated straight teeth that are widely spaced

This is true, Spinosaurus did not have serrated teeth. I wonder if whoever you're talking about was simply referring to spinosaur teeth in general and not those of Spinosaurus? Regardless, those spinosaurs most closely related to Spinosaurus (Irritator) also lack serrations and it is my understanding that spinosaurs are divided by this characteristic.

Each spined dinosaur to date I know of is an herbivore.

What is the significance of this? How would diet influence the development of spines? If you're looking at relatedness than it might help you to know that Amargasaurus is actually more closely related to Spinosaurs than it is to Ouranosaurus. Dimetrodon, Edaphosaurus, Bison, Chameleons...spines develop in all manner of animals for different reasons. Just because the spines on other spinosaurs were not as tall (though still pretty tall) does not exempt Spinosaurus from having tall spines. Actually, I would argue that the similarity in spines between Suchomimus and Spinosaurs clearly indicate that spines described by Stomer belong to Spinosaurus.

Suchomimus


Spinosaurus


Drawings from Scott Hartman's blog.

Is it really that big of a stretch for you to see the similarity in these animals and how the existence of one helps validate the other?

[amargasaurus cazaui]

I do not  have a "cause" so I will treat that as a baiting remark and move forward with the rest of the response. I actually liked your answers and found them most useful Gwangi. I did not have the rebuttal paper itself, to study and I appreciate your sharing it with me as well. That should help me with my study of the topic for certain. I found your answers more insightful and useful this time by far.
  I will read the rebuttal of the proposed chimera theory this evening, and I appreciate your sharing it. I do state that a conflicting point of view does not necessarily negate the validity of the offered theory, it merely states a conflicting viewpoint. I will read it and see what is offered, thanks.
  I dont see the massive height in sucho spines. I just do not. The animal Stromer suggested had spines more than five feet tall . Many of the larger dinosaurs had a raised chevron type hump down there back above the verts. I do not see evidence for anything more massive than such in the Sucho, or Baronyx.
  The comment about teeth was to debunk a poster on the previous thread stating that Spinosaurs had serrated teeth. They do not, as I posted. Their close cousins do, but true Spinosaurs do NOT.Wether referring to Spinosaur teeth in general or specific the entire remark is incorrect.
  I understand that diet does not create a spined dinosaur. I am attempting to understand the reason for the spines and what they might have been used for. You did not weigh in on a sail or spines so I would like to read your thoughts on this. Remember , to me the Spinosaurs are not the key issue. I am trying to understand the Ouranosaurus, Spinosaurus, and Amargasaurus, all dinosaurs closely geographiclly spaced and why they would all share this adapatation. Perhaps climate? I honestly do not know...I am trying to understand it. So anything you wish to offer would he helpful.I read once that if the amargasaur had dual sails down the rows of spines it would look like a biological rain gutter ...not much sense in it. Ouranosaurus seemed to have a single sail. Spinosaurs we do not even know for sure....spines or sail? The fat hump concept works even less well in my eyes.
As to the similarity in the two dinosaurs validating one another, yes and no. It might well validate it so well in fact I dont see the difference in the two. It has previously been suggested they are the same animal, remember. That is what I am trying to sort.
  Thanks for your time and thoughts tonight gwangi, far less negative, more informative and quite helpful

 

[Horridus]

Spinosaurus isn't the only spinosaur with a sail. There's also Ichthyovenator.

[Gryphoceratops]

Mystery solved!  I said they have serrations on the teeth.  At the museum I was at there is a tooth that is labeled as that of spinosaurus.  Its from Africa.  Its the appropriate size.  Under a microscope it has tiny serrations.  Again, Stromer's research is from the early 1900s.  Its likely the tooth he had wasn't as well preserved as the many spinosaurus teeth that have been uncovered since. 

[amargasaurus cazaui]

Spinosaurus isn't the only spinosaur with a sail. There's also Ichthyovenator.

Now that is amazing. I had not read about this dinosaur at all. Thanks for sharing. It says he even had not just a single sail but multiple sails, unlike other Spinosaurids. This dinosaur sounds much closer to what I am trying to figure out, thanks.

[amargasaurus cazaui]

Mystery solved!  I said they have serrations on the teeth.  At the museum I was at there is a tooth that is labeled as that of spinosaurus.  Its from Africa.  Its the appropriate size.  Under a microscope it has tiny serrations.  Again, Stromer's research is from the early 1900s.  Its likely the tooth he had wasn't as well preserved as the many spinosaurus teeth that have been uncovered since.

I do not claim to understand so you might be able to help me here gryph, since you made this point. It is my understanding that even today the serrations and non serrations in the teeth are how the spinosaurs are identified from their close cousins the baronchyine. Has this criteria been changed or does it still hold, and Spinosaurs do not have serrated teeth? My understanding of the material was this was not just Stromer, but is the modern definition.
  The lack of serrations could well be a relic of the fossilzation process as you stated. That tends to happen with other dinosaur teeth that I read about. So I am asking for some clarity here if you wish and can please. Thanks

[Gryphoceratops]

Not sure about the difference between spinosaurus and its relatives.  The point I was making is that the serrations are there thus making it for sure a theropod dinosaur tooth and not that of a large crocodile which wouldn't have serrations. 

The reason why I find that experience so relevant is that I think I asked something along the lines of "how do they know its a spinosaurus and not something else like a crocodile since they both had similar teeth?" to the paleontologist.  The answer was spinosaurus teeth would have had serrations. 

[Gwangi]

Well to start off...I've learned a lot about Spinosaurs this last week.  This is good as I'm expecting the Papo Spinosaurus in the mail shortly.

I do not  have a "cause" so I will treat that as a baiting remark and move forward with the rest of the response.

I didn't mean it that way, I was just referring to your side of the argument in particular.

I will read the rebuttal of the proposed chimera theory this evening, and I appreciate your sharing it. I do state that a conflicting point of view does not necessarily negate the validity of the offered theory, it merely states a conflicting viewpoint. I will read it and see what is offered, thanks.

Unfortunately from what I've read so far he does not really bring forth any evidence to dismiss Rauhut's hypothesis, just outright dismisses it. I wish it would have gotten into more detail but the bulk of the paper concerns the skull of Spinosaurus.

I understand that diet does not create a spined dinosaur. I am attempting to understand the reason for the spines and what they might have been used for. You did not weigh in on a sail or spines so I would like to read your thoughts on this. Remember , to me the Spinosaurs are not the key issue. I am trying to understand the Ouranosaurus, Spinosaurus, and Amargasaurus, all dinosaurs closely geographiclly spaced and why they would all share this adapatation. Perhaps climate? I honestly do not know...I am trying to understand it. So anything you wish to offer would he helpful.I read once that if the amargasaur had dual sails down the rows of spines it would look like a biological rain gutter ...not much sense in it. Ouranosaurus seemed to have a single sail. Spinosaurs we do not even know for sure....spines or sail? The fat hump concept works even less well in my eyes.

There are many opinions out there regarding the function of sails and spines on dinosaurs, there was even a thread recently (maybe on version 1 of the forum) discussing the function of the sail in Spinosaurus. Most people agree that it was used for display much like many bodily adornments in the animal kingdom. Some speculate it was used to communicate with other Spinosaurs while moving about in the water. The most likely reason IMO for the sail in Spinosaurus I believe was for thermoregulation. Spinosaurus was a very large animal that lived in a very warm part of the globe. The sail would help shed excess body heat like the ears of African elephants and many desert dwelling mammals do for them. If the nights were cold the sail could also help take in heat so it works both ways. The twin sails on Amargasaurus were quite different and I would put my money on them being there for display or maybe they helped it look bigger. Amargasaurus was after all a fairly small sauropod by sauropod standards. I don't believe Spinosaurus had a hump, I think the spines were too tall to support something like that.

As to the similarity in the two dinosaurs validating one another, yes and no. It might well validate it so well in fact I dont see the difference in the two. It has previously been suggested they are the same animal, remember. That is what I am trying to sort.

Well for starters there are the teeth. It is my understanding that Spinosaurus itself lacks serrations on the teeth. Other spinosaurus such as Baryonyx and Suchomimus do have serrations but they're pretty fine. So if you're suggesting that Spinosaurus and Suchomimus are the same animal, they can't be.

Spinosaurus isn't the only spinosaur with a sail. There's also Ichthyovenator.

Thanks Marc, I completely forgot about this guy.

[amargasaurus cazaui]

Not sure about the difference between spinosaurus and its relatives.  The point I was making is that the serrations are there thus making it for sure a theropod dinosaur tooth and not that of a large crocodile which wouldn't have serrations. 

The reason why I find that experience so relevant is that I think I asked something along the lines of "how do they know its a spinosaurus and not something else like a crocodile since they both had similar teeth?" to the paleontologist.  The answer was spinosaurus teeth would have had serrations.

This point is rather confusing me, i admit. Even gwangi seems to be stating Spinosaurus did not have serrated teeth. All of the material i have read suggests the same. That would seem to make the tooth somewhat easy to confuse with an animal other than a dinosaur according to what is given in the material I have read. What I had read is that spinosaurs did not posses serrated teeth and baronchyine did . The nature of the teeth was a determing factor to identifying the animals. If a spinosaur does not have serrations then it would seem the point you were suggesting is incorrect, or rather the paleontologist you are referencing.
  I know Stromer was the one who pointed this out, but from my own reading it seems to have held to modern definitions and is agreed as valid.

[amargasaurus cazaui]

I appreciate your thoughts on this gwangi. I do admit the dinosaur he posted, the recently found spinosaur is an amazing creature and strongly seems to validate Stromers work in many aspects.  I too found the rebuttal paper not well stated and perhaps failing in its purpose to actually rebutt the suggestions earlier put forward. Now I keep wondering if the spinosaur were warm blooded and spent most of its time in water, if the sail might have indeed helped warm the animal and prevent its temperature from falling too sharply while it worked the shallows for fish and hunted. That would seem a working hypothesis.
  In reading your reply I did not understand for certain and hoped you might weigh in on my Amargasarus and its spines. You stated dual sails...does that mean you are suggesting it did have sails or the spines had another purpose? I am interested in any thoughts , ideas and opinions on that question as possible. I had in fact even posted the same question in my sauropods thread. There is no right or wrong answer here, I would like to here any and all points of view. (and thanks for sharing yours so far gwangi)
and yes i do feel this thread is moving more in the direction I wanted, a constructive discussion about Stromers dinosaur and its implications for other dinosaurs, thanks for all your comments. !!!!

[amargasaurus cazaui]

Spinosaurus isn't the only spinosaur with a sail. There's also Ichthyovenator.

I thought to ask if i might, does anyone market a replica of this dinosaur, or are there any drawings, restorations, pictures, models anything I could acquire and study about the animal at all? As new as it is I am sure the answer will be no, but I would be interested.Thanks .

[ZoPteryx]

Spinosaurus isn't the only spinosaur with a sail. There's also Ichthyovenator.

I thought to ask if i might, does anyone market a replica of this dinosaur, or are there any drawings, restorations, pictures, models anything I could acquire and study about the animal at all? As new as it is I am sure the answer will be no, but I would be interested.Thanks .

Ichthyovenator was only described a few months ago, so there's no much out there yet.



I also found these that might be of interest.

[amargasaurus cazaui]

Ichthyovenator was only described a few months ago, so there's no much out there yet.



I also found these that might be of interest.


[/quote]

Ouch he almost looks like something took  a huge bite out of him. They did find a decent piece of this one at least. What is it with these dinosaurs always being so badly damaged and so much of them missing? There seems to be a bias against their preservation of some kind.
You found a photograph of Stromers original restoration as well.
Thanks for all of this, I never knew this new dinosaur existed, let alone the pictures of his material and reconstruction.

[Horridus]

What is it with these dinosaurs always being so badly damaged and so much of them missing? There seems to be a bias against their preservation of some kind.

This is true of the vast majority of dinosaurs - that they are known from pretty scrappy remains. Fossilisation is a very rare process anyway, but being terrestrial animals certainly doesn't help when it comes to preservation.

The 'split' sail might not be damaged, by the way. Although it might be...

[Gryphoceratops]

Not sure about the difference between spinosaurus and its relatives.  The point I was making is that the serrations are there thus making it for sure a theropod dinosaur tooth and not that of a large crocodile which wouldn't have serrations. 

The reason why I find that experience so relevant is that I think I asked something along the lines of "how do they know its a spinosaurus and not something else like a crocodile since they both had similar teeth?" to the paleontologist.  The answer was spinosaurus teeth would have had serrations.

This point is rather confusing me, i admit. Even gwangi seems to be stating Spinosaurus did not have serrated teeth. All of the material i have read suggests the same. That would seem to make the tooth somewhat easy to confuse with an animal other than a dinosaur according to what is given in the material I have read. What I had read is that spinosaurs did not posses serrated teeth and baronchyine did . The nature of the teeth was a determing factor to identifying the animals. If a spinosaur does not have serrations then it would seem the point you were suggesting is incorrect, or rather the paleontologist you are referencing.
  I know Stromer was the one who pointed this out, but from my own reading it seems to have held to modern definitions and is agreed as valid.

I'm going to see if I can get another reliable source that can back that up.  I'll get back to you. 

[amargasaurus cazaui]

I'm going to see if I can get another reliable source that can back that up.  I'll get back to you.
[/quote]
Thanks gryph that would be helpful. I appreciate your doing that, and for your consideration. Please let me know what the established opinion is for sure. Everything I am seeing says Spinosaurs had non serrated teeth quite similar in that regard to a crocodiles teeth. Appreciated !!!

[amargasaurus cazaui]

This is true of the vast majority of dinosaurs - that they are known from pretty scrappy remains. Fossilisation is a very rare process anyway, but being terrestrial animals certainly doesn't help when it comes to preservation.

The 'split' sail might not be damaged, by the way. Although it might be...

Yes what information I found suggested that was the norm for the animal and considered to be two seperate sails. Makes you wonder what this dinosaur was adapted to do and for. I so appreciate your showing it to me. Thanks again !!!

[Yutyrannus]

I had attempted to open a discussion regarding the somewhat dubious nature of the holotype of Spinosaurus aegyptiacus, and the paucity of remains that exist for the animal as well as potential errors regarding said dinosaur. In some fashion the issue has been clouded to argue about other dinosaurs not germane to the point and not part of the discussion.
  In an attempt to clarify and establish the discussion I am opening this thread and hope perhaps it can stay centered more in the topic rather than unrelated issues.
  What I had hoped to learn about and discuss and perhaps get some perspective on is the general acceptance and belief the animal named, Spinosaurus aegyptiacus, has gained in recent years despite being based on extremely poor remains, poor scientific study, and the subsequent loss of the ONLY EXISTING specimen of the dinosaur to date positively identified and recognized as this dinosaur.
  I have no issue with Suchomimus, or Baronyx, for that matter. I am discussing Ernest Stromers animal, the original spinosaur.
  I question the dinosaur based on these things. First, the specimen was named and identified by Stromer, although he was not present when it was excavated. He was working from Munich, working through crates of fossils sent him by his field hand. Within those crates, he also found the mingled remains of another species of Spinosaurus, at least two never identified theropods, Carcharodontosaurus,and at least one massive sauropod, as well at least a half a dozen basic crocodyliforms. 
   In 2003, Oliver Rauhut suggested that Stromer's Spinosaurus holotype was a chimera, composed of vertebrae and neural spines from a carcharodontosaurid similar to Acrocanthosaurus and a dentary from Baryonyx or Suchomimus
Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology 69: 1–213. ISBN 0-901702-79-X
I question if Stromer might have somehow mixed remains from another dinosaur to create something that has never before or since been found. It has been stated this dinosaur has close cousins with tall spines, but this argument is not well stated when you consider the holotype possessed spines that were as much as 5.4 feet tall. I do not see this evidence in closely related spinosaurids, to the degree present here. Another person has stated Spinosaurs possess serrated teeth, which is of course inaccurate as well. Spinosaurs possess smooth cone shaped or awl-like teeth, not serrated. Stromer found this to be one of the more amazing qualities of the animal he discovered. Hans Dieter Sues stated" We distinguish dinosaurs, in part by their teeth.Teeth very markedly from species to species,and their hard enamel preserves them longer than regular bones. It's really a credit to Stomer's tremendous knowledge of fossil animals that he even identified Spinosaurus as a theropod, a meat eater, because Spinosaurus' teeth are completely different from the teeth of usual carnivorous dinosaurs. Most big carnivores have teeth like steak knives, they're long and somewhat flattened side to side, and they have serrated edges front and back. But not Spinosaurus, its teeth were long and cone shaped almost round in cross section-Stromer called them awl-like and while she had sharp edges fore and aft they were NOT serrated. "
Although others in forum have stated the teeth for Spinosaurs are serrated they are in fact not. Two cousins to this dinosaur had serrated teeth, but true Spinosaurs have smooth teeth.The Spinosaurinae share unserrated straight teeth that are widely spaced (e.g., 12 on one side of the maxilla), as opposed to the Baryonychinae which have serrated curved teeth that are numerous (e.g., 30 on one side of the maxilla)
   The dinosaur as Stromer constructed it has never been found again. No bi-pedal , theropod, with spinal shafts five feet tall is known. This dinosaur does have similar cousins yes, but NONE of them share the taller spines and straight teeth of a Spinosaur.
     My intention was to ask why given this lack of true evidence to clearly denote a sailed massive predator we insist on having it identifed as such, without a question mark at least. I ask this because...my favorite dinosaur is Amargasaurus. It is a more well studied and documented animal, but still only one skeleton. It does have spines however, and noone has been able to establish clarity of their purpose. Were they also a sail?When you see reconstructions of this dinosaur they are sometimes with sail, or other times with only spines.  This is the direction i wanted to go with my discussion and question, not establishing the existence of the Spinosaurid family itself. Even Ouranosaurus has spines, and is based on fairly complete evidence. Each spined dinosaur to date I know of is an herbivore.  Are the smaller spines of suchomimus and such then female versions and thus smaller or sub-adults perhaps?
If anyone can help or offer some scientific papers, books, or anything related to this I am most appreciative. Anything at all would help.This is where my direction of questioning and interst lies, thanks

Actually, many incomplete Spinosaurus specimens have been found since then, mostly from the skull.

[amargasaurus cazaui]

No, incorrectly stated. There have been many finds of spinosaurid material. Most classify as baronchyine however. Actual findings of spinosaur material are limited to a possible seperate species from Morocco, and the finding on two occasions of teeth only that identifed as Spinosaurus. In addition to this you also have the irritator fossil, which seems to possess the same unserrated teeth as Spinosaurs do. Remember, suchomimus and baronyx are not Spinosaurs, they are spinosaurids. They also have serrated teeth, and Spinosaurs do not, which makes them similar, and cousins, but technically not Spinosaurs.