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The discovery and early interpretation of Spinosaurus

The views expressed are those of the author and are not necessarily those of Scientific American.

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Our modern understanding of Spinosaurus, the largest known theropod (perhaps 18 m long). A long-jawed predator with retracted nostrils, a bony cranial crest and massive thumb claws. Photo by Kabacchi, from wikipedia.

In the interests of recycling unused bits of text (another recurrent theme here at Tet Zoo), the recent article on The Great Dinosaur Discoveries prompted me to dig out and recycle the draft text I wrote on Spinosaurus, and here it is (now with citations added). After all, I won’t be using it anywhere else and it’s now redundant. I happily admit that the text is brief, introductory, tells a story that’s been covered by many other authors on previous occasions [Laelaps covered the same story here in 2007], and won’t say anything that isn’t already familiar to anyone who is above level 5 on the scale of dino-geekdom. Whatever, enjoy, and feel free to tell everyone about the many exciting developments that happened in spinosaurid science during recent decades.

Aborted Spinosaurus spread from The Great Dinosaur Discoveries.

In 1915, German palaeontologist Ernst Freiherr Stromer von Reichenbach (1871-1952) described a remarkable collection of theropod remains (Stromer 1915). These were collected from Upper Cretaceous rocks (probably dating to the Cenomanian) by fossil collector Richard Markgraf at the Egyptian site of El-Bahariya during 1912. Stromer named the animal represented by these remains Spinosaurus aegyptiacus: the ‘Egyptian spine lizard’. Despite the fact that – even today – it is poorly known and represented by incomplete and unarticulated bones, its remarkable anatomy means that it has also been one of the most famous, most-remarked upon theropod dinosaurs

Stromer described this material in a very thorough, beautifully illustrated monograph. Photographs of the specimen brought to attention in 2006 have shown that Stromer’s illustrations are essentially accurate (Smith et al. 2006).

Spinosaurus dentary, from Stromer (1915).

Compared to the other theropods known during the early 1900s, Spinosaurus was very different. For one thing, the Spinosaurus dentary bone in the lower jaw had a squared-off end which was deeper than the adjacent body of the jaw. The dentary was also unusual in that the teeth at its tip seemed to be particularly long compared to the others, and in that the teeth were more widely spaced apart than is usual. Its shape indicated to Stromer (1915) that its owner must have had a longer, narrower snout than normal big theropods. The teeth of Spinosaurus also differed from the gently recurved, laterally compressed, serrated teeth more typical for theropods, in that they were rounder in cross-section, had a straight central axis, and lacked serrations.

Spinosaurus vertebrae, from Stromer (1915).

The other way in which Spinosaurus differed from other theropods was in its extraordinarily elongate neural spines. Up to 2 m long in the longest spines, they were definitely present on the dorsal vertebrae: the sacral and caudal vertebrae probably possessed much shorter spines. Stromer was unsure as to why Spinosaurus had these elongated vertebral spines, but briefly compared them with tall neural spines seen on other dinosaurs, and with those of bison and some chameleons and other lizards. In bison, these tall spines are of course covered in muscle and fat and form a huge hump, but Stromer felt it unlikely that a large predator would be equipped with such a structure. Instead, he concluded that Spinosaurus had a tall, narrow sail-like structure. This is an idea that was to remain popular afterwards.

Spinosaurus as reconstructed by Stromer in 1936.

Stromer didn’t provide a reconstruction of Spinosaurus in his original description, but eventually did so in 1936. Spinosaurus was depicted as a gargantuan, sail-backed theropod, and despite his realisation that the lower jaw was peculiar and different from that of other theropods, he imagined it to be associated with a fairly normal, deep-snouted skull like that of a megalosaur or allosaur (Stromer 1936). In fact his reconstruction – depicting Spinosaurus in the kangaroo-like posture established for bipedal dinosaurs by Louis Dollo and other 19th century workers – does not make Spinosaurus look that remarkable, save for its tall vertebral spines. In the absence of further information, this reconstruction persisted for decades and Spinosaurus was still being illustrated this way as recently as the 1980s (it was sometimes depicted as capable of part-time quadrupedality, as in this painting by Giovanni Caselli from the 1970s).

The loss of Stromer’s Spinosaurus

The Spinosaurus specimen wall-mounted, prior to 1944.

Today we know that Stromer actually had the type specimen of Spinosaurus wall-mounted in the museum (the Paläontologische Staasssammlung at Munich). Sadly, however, Stromer’s original material was destroyed during Allied bombing raids on Munich in April 1944. Stromer had made repeated requests to the head of the museum that the fossils be moved away somewhere safer, but this never happened. With the fossil destroyed, palaeontologists working in the decades that followed had to rely on Stromer’s drawings and descriptions when comparing this dinosaur with others. Not until the last decades of the 20th century were scientists to get a better idea of what Spinosaurus really looked like.

Spinosaurus timeline

  • 1912 – original material discovered by Richard Markgraf
  • 1915 – Markgraf’s material described by Ernst Stromer: Spinosaurus aegyptiacus is officially named
  • 1936 – Stromer publishes more information, produces first reconstruction
  • prior to 1944 – specimen wall-mounted at Paläontologische Staassammlung, Munich
  • 1944 – specimen destroyed in Allied bombing raid
  • 1995 – photo of the original specimen donated to the museum by Wolfgang Stromer

For previous Tet Zoo articles on Spinosaurus and other spinosaurids, see…

Refs – -

SMITH, J., LAMANNA, M., MAYR, H., & LACOVARA, K. (2006). NEW INFORMATION REGARDING THE HOLOTYPE OF SPINOSAURUS AEGYPTIACUS STROMER, 1915 Journal of Paleontology, 80 (2), 400-406 DOI: 10.1666/0022-3360(2006)080[0400:NIRTHO]2.0.CO;2

Stromer, E. 1915. Ergebnisse der Forschungreisen Prof. E. Stromers in den Wüsten Ägyptens. II. Wirbeltier-Reste der Baharîje-Stufe (unterstes Cenoman). 3. Das Original des Theropoden Spinosaurus aegyptiacus nov. gen., nov. spec. Abhandlungen der Königlich Bayerischen Akademie der Wissenschaften Mathematisch-physikalische Klasse 28 (3), 1-32.

- . 1936. Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. VII. Baharije-Kessel und -Stufe mit deren Fauna und Flora. Eine ergänzende Zusammenfassung. Abhandlungen der Bayerischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Abteilung, Neue Folge 33, 1–102.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Brad McFeeters 1:44 pm 11/16/2011

    It’s interesting that Spinosaurus and Baryonyx have both been occasionally reconstructed as quadrupeds, but apparently independently and before they were known to be related. Also, the 1984 novel Carnosaur features Altispinax as a quadruped- I wonder what the inspiration for that was?

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  2. 2. naishd 1:53 pm 11/16/2011

    Altispinax (= Becklespinax) was reconstructed in what might be interpreted as a quadrupedal pose by Peter Snowball in a diorama featured in Alan Charig’s A New Look at the Dinosaurs. This might be the reason. Then there’s also the fact that the Becklespinax vertebrae were incorporated into Owen’s quadrupedal megalosaur reconstruction.


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  3. 3. Christophe.Hendrickx 2:49 pm 11/16/2011

    Hi Daren!

    Excellent post on the discovery and early interpretation of Spinosaurus, as always. As you have lot’s of readers on your blog, I’m taking this opportunity to promote my website on Spinosauridae ( and especially the chapter I wrote a couple of years ago on their discovery ( The page on the description of Spinosaurus is quite big and as exhaustive as possible I hope ( The website is in French though!

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  4. 4. BilBy 8:22 am 11/17/2011

    Ah, I remember that Caselli illustration! I remember trying to reproduce it with crayons at an early age. One thing I really enjoy about Darren’s dinosaur articles is, apart from all the learning n’ edukashun n’that, is the time travel aspect from seeing old, barely-remembered pictures. Is that one from a book called ‘Ecology and Evolution of the Dinosaurs’ or something similar? If so, I particularly remember a double-page spread of sauropods swimming and leaving traces of tail tracks and claw marks in the mud below. Two of them were entangled and struggling. I may have been about 12 when I last saw that but it still stays with me.

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  5. 5. naishd 9:27 am 11/17/2011

    BilBy – yes, the illustration is from L. B. Halstead’s 1975 The Evolution and Ecology of the Dinosaurs, still one of my favourite dinosaur books (I say this for the art, not Halstead’s frustrating text). There is indeed a double-spread of swimming sauropods, but those two entangled individuals are not ‘struggling’, they’re coiled together in a mating pose! As is well known, Halstead liked his dinosaur sex postures.

    For previous discussions or mentions of this book, go here and here.


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  6. 6. David Marjanović 1:28 pm 11/17/2011

    Altispinax was thought to be a spinosaurid, and Spinosaurus was thought to be probably quadrupedal…

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  7. 7. Andreas Johansson 4:10 pm 11/17/2011

    My father has* what must be a Swedish translation of the Halstead book. It helped form my early ideas of dinosaurs, and I recall the quadrupedal spinosaur quite well.

    * Or had, depending on whether it survived the fire in my parents’ house of 2004.

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  8. 8. naishd 4:43 pm 11/17/2011

    Little known fact about Halstead’s book: there are two editions (1975 and, I think, 1981). The only difference is that, while the first one talks excitedly about the flippers and swimming habits of Compsognathus corallestris, the second one says that it was all a mistake and, alas, based on misinterpretations. I accidentally gave away my copy of the 1981 edition (to Tim ‘dinosaur sex’ Isles), stupidly thinking it was a duplicate of the 1975 one. Need another one.


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  9. 9. BilBy 8:51 pm 11/17/2011

    “but those two entangled individuals are not ‘struggling’, they’re coiled together in a mating pose!” – I was twelve and a late developer. I remember two duckbills at it like dino-rabbits on another page though.

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  10. 10. Prof.Pedant 10:09 pm 11/17/2011

    Amusingly last week’s episode of the egregiously badly written “Terra Nova” appeared to feature a giant Spinosaurus. And it seemed to alternate between bipedality and quadripedity. []

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  11. 11. Halbred 1:54 pm 11/18/2011

    Guh. The less said about Terra Nova, the better.

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  12. 12. Mythusmage 11:02 pm 11/18/2011

    Guess who showed up on American Movie Classics (AMC) recently in a Thursday morning airing of Jurassic Park III?

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  13. 13. Mythusmage 11:07 pm 11/18/2011

    re: Terra Nova

    As I understand it,, it’s not suppposed to be set in our past, but that of a time line where different species arose. Then again, we can’t say certain things could not have happened.

    Then there is the fact that people do tend to come up with names for things a scientist would much rather they didn’t. :)

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  14. 14. naishd 7:25 am 11/19/2011

    Terra Nova is boring. I watched one episode – it was about a murder mystery, with the background and setting and such being incidental or irrelevant. Have you seen Andrea Cau’s article on the theropods? And is there any sign yet of the dinosauroids predicted by SV-POW?


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  15. 15. Cameron McCormick 12:46 pm 11/20/2011

    Darren, your first link also directs to SV-POW!

    I gave up on the show when they found those equations carved into rocks in the first episode. An Ancient Astronauts, Dinosauroid, or equally stupid plot twist appears inevitable.

    Link to this
  16. 16. naishd 3:08 pm 11/20/2011

    Oops, thanks, will go correct…


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  17. 17. Cahokia 12:46 am 09/14/2014

    From Twitter: “I guess this is now looking a >little< dated"

    If you're correct about Spinosaurus *not* being a quadruped, then I'd say the pendulum is about to shift back a bit.

    This seems to repeatedly happen with reconstructions of prehistoric fauna. For example, I recall you describing how some depictions of pterosaurs made them appear more bird-like than birds.

    Link to this

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