One of the great dinosaurs of the Cretaceous period was the species Spinosaurus aegyptiacus, whose name means “spiny lizard” due to its large dorsal fin.

Although at present, the remains of a possible second species have been found, called Spinosaurus maroccanus, it is thought that both may belong to the same species.

The Spinosaurus is generally known as a semi-aquatic theropod, with a skull similar to that of a crocodile and a large dorsal sail.

A giant off-road carnivore, although it did not always have this image, especially when its first remains were found.


Spinosaurus taxonomy

  • ORDER Saurischia
  • SUBORDER Theropoda
  • INFRAORDER Tetanurae
  • SUPERFAMILY Megalosaurid
  • FAMILY Spinosauridae
  • GENDER Spinosaurus
  • SPECIES Spinosaurus aegyptiacus

But let’s get to know this giant animal in more detail.

Characteristics of the Spinosaurus

The Spinosaurus was a theropod that measured between 12 and 15 meters long, although some scientists estimate that it could have reached 18 meters and weighed between 4 and 6 tons.

The Spinosaurus is bigger than the Tyranosaurus Rex!

But its main and most striking feature is its dorsal fin, with which it could reach a height of up to 4 meters!

What were its legs like?

Studies of recently found remains in Morocco of a Spinosaurus specimen indicate that the theropod had smaller hind legs than originally estimated.

Legs that were too developed for swimming and would have acted as giant “oars” that would propel its body into the water by having a totally solid bone similar to that of today’s water birds like the penguin, for example.

However, their hind legs, besides being used for swimming, would also have been able to perfectly support their great weight on land. Although it is thought that it would not have made long runs chasing its prey as a Carcharodontosaurus would have done for example.

In addition to the bone that we have mentioned about the leg that would help it to swim, it has also been discovered that the structure of the foot (tarsus, metatarsus and phalanges) was longer than those of the terrestrial theropods, and also flatter.

This confirms that their legs had a characteristic more similar to that of semi-aquatic birds.

In fact, it is being thought that between the toes of their legs they could have a membrane similar to that of ducks, for example. This would allow them to move perfectly in the water as well as on land.

Its tail

Another singularity of the Spinosaurus is its tail, as it had at least 55 vertebrae which decreased in size as they reached the tip but with less difference.

It is usual for theropods to have between 40 and 50 vertebrae, which descend constantly and symmetrically.

This finding indicates that the tail was quite long, as well as muscular; so it could have been used for propulsion in the water by moving it sideways in a similar way as crocodiles do.

The head of the Spinosaurus

It has a skull similar to that of a crocodile of approximately 2 meters in length.

It has a jaw that fits perfectly below the palate, so that it is “hermetically sealed”, similar to that of crocodiles. Although the nose of the Spinosaurus curves slightly downwards, preventing the prey from escaping.

At first, it was expected to find hard, curved and serrated teeth, similar to those of other powerful carnivores such as the Tyrannosaurus, the Carcharodontosaurus or the Allosaurus.

However, conical, narrow and sharp teeth were found, more common in piscivores such as Pteranodon, the relative Baryonyx or the current crocodiles, for example.

Another curiosity is that the teeth had different placements, as some were oriented slightly forward and others backward.

The characteristic of its legs (which we have already mentioned) together with the arrangement of its teeth makes us think that the Spinosaurus was a closer and better prepared animal for the aquatic environment than the terrestrial one. Although, as we have already mentioned, it could perfectly maintain itself in both environments.
Another very peculiar feature of the Spinosaurus head is that the nostrils are not located at the end of the snout, but are located practically in front of the eyes.

In addition, recent studies have found a series of cavities called foramina which connected with the nasal cavities, so that they could notice the pressure and the changes of tension in the water produced by the movement of nearby animals.

It would be like a “water sense of smell” that would tell them the estimated size of the animal, so they could deduce whether the animal would be prey or if it was something dangerous they would have to flee from.

While these forensics were very useful to them, their nostrils could not capture odors very well, hence their hunting was focused on water.

Although it is also believed that he could have been a scavenger, having found Iguanodon remains near some Spinosaurus specimens, using their size to intimidate smaller animals.

The dorsal fin

Its main and most striking feature is the large dorsal fin, which is located on the back, exceeding one meter in height and giving the Spinosaurus a gigantic and terrifying appearance.

At first it was thought that it could be used for thermoregulation of the body, similar to how the Dimetrodon could have used it.

But knowing that its prey were mainly aquatic animals, the thought was changed that this large dorsal fin could be used for swimming, so that it would control the direction and help it to be more hydrodynamic.

However, there is also the possibility that it was very striking because it had different colors and could serve as a sexual attraction for females in the breeding season.

But the latter is just a guess.

Discovery and changes of the Spinosaurus

The first remains of Spinosaurus were found in Egypt, to be exact in the Sahara desert in 1910 by the German paleontologist Ernst Stromer, hence its specific name Spinosaurus aegytiacus. These remains were moved to the museum in Munich, but unfortunately the museum was destroyed in World War II, with the remains inside.

However, these remains, which were found in 1915 and consisted of teeth, dorsal vertebrae, dental bone (jaw bone) and ribs, were not completely lost as photographs and scale representations are preserved and are still used today for size estimation and study along with new Spinosaurus remains that are being found.

Estimates and representations made in 1915 described the Spinosaurus with a skull similar to that of the Allosaurus.
This happened because they only had a part of the jaw and some teeth and they represented it with the shape of the skull of the dinosaurs that were known up to that moment.

It wasn’t until 1996 and 1998 when the remains of the jaw, conical teeth and skull of a Spinosaurus were found in Morocco that a more detailed representation of this water giant’s appearance could be made.

Although the material was “poor” at first, it was compared to the remains found of the Baryonix in England and the Suchomimus in Nigeria; two species that belonged to the same family as the Spinosaurus, which allowed to obtain a much more approximate description of the Spinosaurus with a colossal size for the few remains that were kept until then.

The late 20th century representation was maintained until 2014, when a new group of researchers made a representation in which the Spinosaurus was represented as a “forced” quadruped, not like the previous ones which was a typical bipedal theropod similar to Baryonyx.

This new representation was due to the fact that the new remains, together with the previous ones and the lost remains, were reconstructed in a computer in a three-dimensional way.

In this representation they could observe that the pelvis and the posterior extremities were smaller than thought, so those extremities would not have been robust enough to support all the weight of the body of the spiny theropod by themselves.

However, this representation is not very accepted yet, because they think that they have used the remains of several specimens and introduced them in only one, so that they have created a “chimera” of Spinosaurus. That is to say, by introducing the remains of different specimens of the same animal, not everything would be perfectly balanced, since some remains are larger than others and could have influenced the final representation.

Although there are also other researchers who support the hypothesis of the four-legged Spinosaurus. These researchers indicate that, although the Baryonyx and Suchomimus were only bipeds, the specimens found were juveniles or sub-adults, so that the adults could have a reduction in the growth of the hind limbs in a similar way to other theropods such as Albertosaurus.

In addition, Baryonyx and Suchomimus date from the early Cretaceous while Spinosaurus is from the late Cretaceous, so it had millions of years of adaptation and could have moved from a bipedal to a quadrupedal position for better adaptation to the aquatic environment.

On the other hand, the dorsal remains that we currently know as the dorsal sail of the Spinosaurus, were imagined as a big hump.

With the subsequent reconstructions and new findings, the theory of the Spinosaurus hump has almost been discarded although there are still some scientists who support it, but the vast majority believe that the structure of the back was actually a sail.

And although its function is unknown, recent studies have found evidence of blood vessels between the bones of the expansions of the vertebrae that form the sail, enough to water it but not enough to thermoregulate the animal.

With this what is finally believed is that the candle could change its tone to a more striking color to attract females or to fight for territory with another Spinosaurus or another large theropod.

Where can you find the Spinosaurus?

Well, until September 3, 2017 you can see it at the Blau Museum in Barcelona, Spain; in a temporary exhibition that has been running since July 12, 2016 and is organized by the National Geographic Society in collaboration with the University of Chigado in the United States.

So if you’re in Barcelona, you’re a dinosaur enthusiast, it’s a unique occasion not to be missed!

And you can also find it at the Natural History Museum in Berlin, Germany. There they have a 4-meter high and 12-meter long Spinosaurus skeleton called Tristan, whose remains were found in Montana, USA.

The Berlin Museum also works closely with the National Geographic Society and the University of Chicago to redo the entire environment and ecosystem in which this huge predator lived.

And as a curiosity, or rather gossip, we will tell you that you can also find this dinosaur in the movie Jurassic Park III, “supposedly” fighting with a Tyrannosaurus Rex. We say “supposedly” because they never coexisted, both species are separated by millions of years and thousands of miles. But you know… the magic of the cinema that to give more spectacularity and emotion to the film, in this case of Jurasik Park, it skips a little how the story really was.