The Lack of Spinosaurus Remains?

[wings]

Well, here is a second paper with the same finding (http://www.palarch.nl/wp-content/bertin_tor_2010_catalogue_and_review_of_spinosauridae_pjvp_7_4.pdf). So potentially there is only one species and we might have more materials from other assigned Spinosaurus species from N. Africa. Again, if you still think that what Stromer statement is correct then that is fine. Your stand on this is that there are two distinct species, right?

[amargasaurus cazaui]

Well, here is a second paper with the same finding (http://www.palarch.nl/wp-content/bertin_tor_2010_catalogue_and_review_of_spinosauridae_pjvp_7_4.pdf). So potentially there is only one species and we might have more materials from other assigned Spinosaurus species from N. Africa. Again, if you still think that what Stromer statement is correct then that is fine. Your stand on this is that there are two distinct species, right?

My own stand, which I stated in a seperate thread many weeks ago is that I disagree with even the holotype as a valid specimen actually, let alone two seperate species as Stromer had suggested. I feel the method used for recovering the fossils, the way they were then dragged through a world war, and finally deposited, smashed and jumbled, thousands of miles from the dig site, all suggest a littany of mistakes, many of which have since been heavily documented, in the books dedicated to this material and Stromer's work. I am not comfortable with even the intial species, let alone others. I have previously stated this opinion in great detail and much to most peoples chagrin.
   My statement was this . There has been no other fossil evidence since put forward for a massive, crocodilian snouted, bi-pedal predator with six foot spines down its back, that has smooth awl-shaped teeth, non serrated and similar to a crocodiles. These were defining characteristics of the holotype itself, prior to its destruction.This makes evidence for Spinosaurs since the original finding marginal to non existent.
 

[wings]

This makes the difference between you and I, I regard the term "non existent" as to nothing was found. However, subsequent finding do exist in this case (which was documented by at least the two papers listed above). Does these finding get us more of the animal? Probably not that much, regardless it is hardly non existed. On a side note, it seems Spinosaurus teeth are finely sculptured rather the smooth (http://www.gmnh.pref.gunma.jp/research/no_14/bulletin14_2.pdf).

[amargasaurus cazaui]

And I am fine with those differences. I accept them. My opinions are just that, and nothing more. I also believe you are overlooking my use of the term marginal. And yes the discussion about spinosaurus teeth versus spinosaurid teeth was also covered previously. Gryph provided a paper that suggested Spinosaurus teeth have a different patterning , called carania if I remember the word correctly. This is what seperates the Spinosaur from the Spinosaurids, and Baronchyines, or at least is one identifying characteristic. And surprisingly the teeth are quite similar to crocodile teeth.
  Hans Dieter Sues had this to say about the teeth of Spinosaurus . " It's really a credit to Stromer's tremendous knowledge of fossil animals that he even identified Spinosaurus as a theropod, a meat eater, because Spinosaurus's teeth are completely different from the teeth of usual carnivorous dinosaurs.Most big carnivores have teeth like steak knives, they're long and 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 they had sharp edges fore and aft, they were not serrated. They weren't for slicing and dicing, they were for puncturing and tearing ............"The Lost Dinosaurs of Egypt" page 104 , published by Random House.


  As that specimen was blasted to pieces during world war 2, we cannot be certain if the teeth had the sculpting you mention or not. We do know Stromer did not indicate that was the case in his findings, and that the teeth were indeed smooth. If we accept his comments about the unique spines, it seems fair we should also accept his description of the dinosaurs teeth.  That being the case, no other dinosaur fossil has ever been found that matches the described holotype before or since, with the massive spines, smooth teeth and being a massive bi pedal predator. So I do consider the findings marginal to non existent for this animal to date.
 

[wings]

Well, I didn't overlook the term "marginal", since if you look at the wiki page for Spinosaurus, there are potentially be more than one or two specimens of the animal (apart from Stromer's-BSP 1912 VIII 19, there are also NMC 50791, MNHN SAM 124, BM231, UCPC-2, MSNM V4047 and other fragmentary remains, not to mention those random teeth sold commercially (probably not every one but potentially some of them are Spinosaurus "proper"), if they are all belonging to the same species for the reasons listed above). As to smoothness of the tooth, if you look at the first link that I sent then you can clearly see the parallel striations along the teeth (Figure 2b, the one in between the lines pointing at the maxilla and the premaxilla, also 2e but it's not too clear due to the lighting/scanning). Unless MSNM V4047 is not a S. aegyptiacus, then I don't see it as being smooth. Sure they are not serrated however they do have longitudinal ridges. If there is no photos of the tooth in question then sure I'll take your word for it as being smooth but we can clearly see it on this "particular" specimen. I think it would be fair to say that regardless whether I've found a spine or not, even a tooth could be considered as a specimen of a particular animal.

... Its teeth were long and cone shaped, almost round in cross section-Stromer called them "awl-like" and while they had sharp edges fore and aft, they were not serrated. They weren't for slicing and dicing, they were for puncturing and tearing ............"The Lost Dinosaurs of Egypt" page 104 , published by Random House.


...and that the teeth were indeed smooth.
 

Unfortunately, I've tried to accept it but I don't see the word "smooth" even from your reference (the bit in BOLD)

[Gryphoceratops]

Here is the paper I have that was mentioned. 

http://www.gmnh.pref.gunma.jp/research/no_14/bulletin14_2.pdf

The Spinosaurus teeth aren't really smooth.  They are similar to crocodile teeth but there are differences to be seen if the tooth's root is present apparently (not mentioned in the paper). 

[amargasaurus cazaui]

Yes I see what you are both saying here, except the issue remains, we do NOT know for certain what a Spinosaurs tooth was like . The specimen was destroyed, and in Stromer's description the teeth were not described with carania nor ridges, nor striations. If they had such features surely he would have stated such. He described the teeth as awl-like . I am trying to accept it but having trouble visualizing an awl with ridges or striations as that was not how the teeth were described for HIS specimen. In fact the teeth he descibed more matched the species of crocodilyforms he also named from the material he recovered. Stromer went on to name at least four new species of crocodilyforms from the material he recovered that included the Spinosaurus remains. This is part of the bothersome issue with the initial restoration of the animal. An interesting aside to the matter is within the material he felt there was material from at least other four predatory dinosaurs including what he named "Spinosaurus B" There was also interestingly enough a single vert found, that was originally identified as being Dicraeosaurus, but has since been placed as belonging to either Amargasaurus ( a tall spined sauropod)or a species ofRebbachisaurid.

Teeth found since then attributed to Spinosaurus may not in fact meet the criteria to match the original animal as there is no way to compare or know for certain.That would seem to eliminate those findings as Spinosaurus remains. Until or unless you can establish they match the holotype they should not be classified as matching.
Either you have an animal that was not properly described and mounted originally, or nothing of accurate placement being found since within the species. The total amount of confirmable Spinosaurus Egypticus remains found since the original is indeed marginal. I made note of the material you stated as likely Spinosaurus finds. My question remains why they are such few isolated scraps and nothing of anatomical significance exists. To my own thinking  these meager finds, which I had been aware of, do seem to be marginal finds, and have for the most part controversial as even being Spinosaurus material.

[wings]

Isn't this the whole point of my original comment, if we aren't definitive to the identification at the moment then why bother closing up other potential options so soon and almost like stating this as fact?

Whether Stromer's Spinosaurus specmen lacks these striations, I have no idea since I've never seen the original paper. However, I don't see how the teeth can't be spike-like and have shallow striations at the same time. Here is another description of the teeth from a blog (http://qilong.wordpress.com/2011/10/07/for-a-few-spinosaurus-more/) "... Spinosaurids are generally divided into two clades, primarily defined on the structure of their teeth: Spinosaurinae, and Baryonychinae. The former have unserrated teeth with distinct vertical fluting (or ribbing) and relatively smooth enamel surfaces, and relatively low recurvature, and are generally broader along the tooth than in baryonychines. Alternately, baryonychines have serrations, low fluting or ribbing, distinctly wrinkled enamel, and higher recurvature..."

Now, of course having said this, potentially we could still have multiple Spinosaurus species in the area.

...This makes evidence for Spinosaurs since the original finding marginal to non existent.
 

...My question remains why they are such few isolated scraps and nothing of anatomical significance exists. To my own thinking  these meager finds, which I had been aware of, do seem to be marginal finds, and have for the most part controversial as even being Spinosaurus material.

Perhaps this depends on the preservation potential of the area (let's say the Bahariya Formation for example since this is where Stromer's Spinosaurus was found). If we are just looking at the theropods found in the area namely Deltadromeus, Carcharodontosaurus, Bahariasaurus and other indeterminate theropod remains, how much of these animals did we find? Not a lot really. There are many factors that effects preservation (necrolysis), there are different biological agents (i.e. predators, scavengers, bacterias) and mechanical agents (i.e. wind, wave, currents) in the works. One of the key factors that would prevent destruction is rapid burial against biological agents while the shape density, and thickness of the bone determines its survival against mechanical breakdowns. There is also chemical breakdown as well like the different in acidity level in the soil. Unlike fishes or smaller creatures which have a greater potential to get a rapid burial, maybe the condition at the time doesn't favor preservation of large animals. Living near the water doesn't guarantee perfect preservation for large animals (take Deinosuchus or Purussaurus for example, we don't really have much of these animals, although we are pretty sure that they lived very close to water). I have no idea what the exact factor (since if I really have to give you a reason then I'll need to research on the topic to write up a paper like this http://app.pan.pl/article/item/app20120077.html) is but I just don't see what is so unusual about not finding too many Spinosaurus around.

[amargasaurus cazaui]

Isn't this the whole point of my original comment, if we aren't definitive to the identification at the moment then why bother closing up other potential options so soon and almost like stating this as fact?

Whether Stromer's Spinosaurus specmen lacks these striations, I have no idea since I've never seen the original paper. However, I don't see how the teeth can't be spike-like and have shallow striations at the same time. Here is another description of the teeth from a blog (http://qilong.wordpress.com/2011/10/07/for-a-few-spinosaurus-more/) "... Spinosaurids are generally divided into two clades, primarily defined on the structure of their teeth: Spinosaurinae, and Baryonychinae. The former have unserrated teeth with distinct vertical fluting (or ribbing) and relatively smooth enamel surfaces, and relatively low recurvature, and are generally broader along the tooth than in baryonychines. Alternately, baryonychines have serrations, low fluting or ribbing, distinctly wrinkled enamel, and higher recurvature..."

Now, of course having said this, potentially we could still have multiple Spinosaurus species in the area.

...This makes evidence for Spinosaurs since the original finding marginal to non existent.
 

Yes, and the point of my original comment is that if you do not KNOW and cannot state for sure why would you insist on closing off other potential identifications and insisting the material MUST be Spinosaurus because you THINK it MIGHT resemble the holotype but do not KNOW. There is nothing wrong with placing a fossil in the I do not know yet category and many things very wrong with placing it in the ...it is a Spinosaurus category based on speculation.
  If I am understanding your assertion correctly you are advocating using the classification of Spinosaurus for anything that might resemble or could be argued loosely to possibly fit. Similar to the trash basket created for the species Trachodon or many other dinosaurs over the years.
  As to the comment about spikes and teeth.....awls are often used for piercing leather or materials that are tough. ANY form of ridging or striations would make this rather difficult. Stromer did not use a spike as his example, he chose the word awl to describe the teeth intentionally.Awls are smooth and broad and wide in cross section, but lack any form of ridging that would interfere with piercing the intended target. Taking his description at his words, I do not believe he saw any form of striations or ribbing on those teeth.
  Is it possible he was actually placing crocodilyform teeth in the wrong context? I would say far more likely than the final result he published precisely due to the fact all other spinosaurid teeth have been described with some form of patterning. Hence one of my serious issues with the specimen and its reconstruction.

[wings]

I'm talking about potential and by no mean absolute here. That was never my intention. At the moment we don't have enough materials for comparison, on top of that the original was destroyed which makes comparison very difficult, it seems like the variations shown on the newer finds aren't different enough to be warranted for a new species based on recent researches, however this could still be overturn when more complete Spinosaurus specimens being discovered (and at no point I said it must be one way or another, if you don't agree that is fine, what has been presented is just possibilities).

From your original reference you were using the term "awl-like" instead of just the word awl, which to me awl-like is very similar to spike-like (just something pointy). Is having striations so inefficient for puncturing? It seems to be working for MSNM V4047.

  Is it possible he was actually placing crocodilyform teeth in the wrong context? I would say far more likely than the final result he published precisely due to the fact all other spinosaurid teeth have been described with some form of patterning. Hence one of my serious issues with the specimen and its reconstruction.

Like I said earlier, I've never read the original paper but I highly doubt that he mixed that up since there seems to be teeth sitting in their corresponding sockets as the specimen was found (http://upload.wikimedia.org/wikipedia/en/1/1e/Stromer1915SpinosaurusMandibleDrawings.png). Maybe the tooth pattern changes during ontogeny, or perhaps they worn out (during life, or fossilization), if they were indeed existed (just a guess). If you go back to the first link that I sent it seems like these kind of structures/patterns is not such a concerning characteristics to define spinosaurs (please see below).

"...We agree with Sereno et al. (1998) in recognizing some features of the snout that differentiate the Baryonychinae (premaxillary alveolus 1 slightly smaller in diameter than alveoli 2 and 3; curved tooth crowns; teeth with fine serrations) from the Spinosaurinae (premaxillary alveolus 1 less than one half of the diameter of alveoli 2 and 3; unserrated teeth; tooth crowns hardly curved or straight)..."

See these vertical grooves were never mentioned in the passage.

[Spino-rex13]

I read somewhere that larger creatures fossilise less often.

[suspsy]

http://archosaurmusings.wordpress.com/2012/08/28/variation-of-tail-length-in-dinosaurs/

I like this article because the skeletal illustration shows how little we actually know about the anatomy of Spinosaurus. Shoot, even the original specimen discovered by Stromer only consisted of this:



It really is a shame, because until a more complete skeleton is discovered, any interpretation of Spinosaurus is tentative at best (like in Planet Dinosaur) and laughably idiotic at worse (JP3 and Monsters Resurrected).

[Blade-of-the-Moon]

The thing is we do have a bit more material than that to go from and close relatives like Suchomimus and Baryonyx so a pretty good guess can be made from that info.

[suspsy]

True, but Baryonyx and Suchomimus are incomplete themselves. Giganotosaurus is not just an oversized Allosaurus and Tyrannosaurus rex is not just an oversized Daspletosaurus. We can only deduce so much about Spinosaurus from studying its relatives.

I'm not suggesting that Spinosaurus looked radically different from the way most paleoartists currently portray it, but we certainly don't know its maximum length or just how far along its vertebrae the sail went.

[Gryphoceratops]

True, but Baryonyx and Suchomimus are incomplete themselves. Giganotosaurus is not just an oversized Allosaurus and Tyrannosaurus rex is not just an oversized Daspletosaurus. We can only deduce so much about Spinosaurus from studying its relatives.

I'm not suggesting that Spinosaurus looked radically different from the way most paleoartists currently portray it, but we certainly don't know its maximum length or just how far along its vertebrae the sail went.

I don't think anyone is saying Spinosaurus is a bigger clone of its relatives. 

[suspsy]

I'm not saying anyone here did.

I just find all these popular claims (not in this thread, but in pop culture) that Spinosaurus measured up to 60 feet long and weighed 23 tons annoying.

[wings]

http://archosaurmusings.wordpress.com/2012/08/28/variation-of-tail-length-in-dinosaurs/

I like this article because the skeletal illustration shows how little we actually know about the anatomy of Spinosaurus...

I thought the article is more about the variation of the tail length in dinosaurs, regardless of the animals' completeness variation do occur and in Hone's paper the tail region in particular. The Spinosaurus diagram on his blog is just an example of the possible range of these variations (and I don't think that the reason for the differences of the tail length in Scott's drawing is because we didn't have enough of the animal, it was drawn that way to illustrate the focal point of his paper which is about variation). Having said all these, even if we have a complete Spinosaurus specimen, we can not guarantee that this is the "norm" of the species (potentially, it still could have been a few metres out).