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Spinosaurus was a giant theropod that lived in Africa 105 to 93 million years ago, in the Early Cretaceous.

Fact File

Length: 18 metres (?)

Height:

Spiny.jpg

Weight: 7 to 9 tonnes (?)

Diet: Piscivorous

Hunting

Diet and bite mechanics

File:630px-Spinosaurus skull en svg.png

A diagram showing the different bones in a Spinosaurus skull

Spinosaurus and its relatvies have been a puzzle to scientists for quite some time. Their crocodilian-like skulls and conical teeth seem ill suited to hunting large prey. This has lead to the now common place suggestion that Spinosaurs in general were specialized fishers. However, some Spinosaurs (specifaically Irritator and Spinosaurus) have much more crocodile-like jaws. Also Spinosaurus itself was the second largest animal in its environment. This combined with a Baronyx being preserved with Iguanodont bones in its stomach, could mean at least Spinosaurus was a hunter.

File:Spinosaurus tooth.png

Spinosaurus tooth, length aproximatly 14cm (5.5 inches)

Some notable adaptations for withstanding forces in the skull include the cross section of its rostrum, the nasal crest as a point of discharge of the forces, and most particularly the presence of a strong secondary palate(crocodilians have this as well) which is an adaptation partly for resisting torsion that comes from biting into prey and the subsequent struggle that comes with it. Also the fact that its nostrils are placed so far back means before that point, the skull is entirely made of compact solid bone; this would be another adaptation for strength.

It's teeth were deeply rooted within the skull allowing them to withstand high forces without breaking. Roughly 50% or more of each tooth was buried within the skull. Also the fourth tooth in the Maxilla was in line with the jaw muscle meaning more force was excerted by that tooth, which was also the largest tooth in the whole jaw at between 5 and 6 inches (between 12.7cm and 15.2cm)

File:Spino skull.png

A rearward view of a Spinosaurus skull

. The teeth had a D-shaped cross section, akin to Tyrannosaurus teeth.

The rear portion of Spinosaurus' skull is typically renedered as very wide, around the magnitude seen in Tarbosaurus. From a birds eye view, it has a skull that resembles the prehistoric reptile Champsosaurus. Champsosaurus, despite having a very Gavial esc jaw, and its whole body length being a mere 5ft, had a bite force roughly equal to that of a large Grey wolf. So, although it is speculation, it is very reasonable to think that Spinosaurus had a very strong bite, stronger than the ill suited Carcharodontosaurids, but not as powerful as some tyrannosaurids.

The potential prey of Spinosaurus could include many species of fish, Crocodylomorphs and youngsters of the many Sauropods alive at the time. Many animals in its environment were small compared to Spinosaurus. Infact, Spinosaurus was roughly 70% larger at least than all its contempories barring Paralititan, a rare case for a carnivorous animal.

WWII

Spinosaurus remains were first discovered in Egypt by German palaeontologist Ernst Stromer. These remains, unfortunately, were destroyed by bombing in World War II. Little has been found since then, apart from some skull remains, so Spinosaurus remains quite a mystery.

The sail

Spinosaurus had one distinguishing feature - the sail that ran along its back. It is supported by bony spines rising from the backbone, some of which are two metres high. These spines were covered with a layer of skin, but the use of the sail is unknown. It may have a similar use to Stegosaurus' plates - controlling temperature, or maybe it would have changed colour, and be used for display.

Popular Culture

Spinosaurus, as depicted in Jurassic Park III

Spinosaurus is the main predator in the 2001 film, Jurassic Park III. It is a good swimmer, and is seen killing a T-rex. It was also seen eating people and dinosaurs, instead of fish. Spinosaurus was also featured in merchandise related to the Jurassic Park films, including action figures and video games. In documentaries such as the "Biggest Killer Dino" episode of Monsters Resurrected a Spinosaurus was featured.

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