Spinosaurus

Description
Spinosaurus, meaning Spine Lizard, is a very large Theropod Dinosaur from Africa. It lived through the Albian and Cemonian stages about 103 - 93.5 million years ago. Modern maximum size estimates range from 12-18m long and 7-20t tonnes in weight making it the largest known Theropod by some margin. However, the lower lengths and high weight estimates have been criticised for issues including the study's skull reconstructions and the other Theropods used for comparison. Spinosaurus exceeds the other large Theropods by a considerable margin. According to an estimate by Cau on his Theropooda blog, Spinosaurus was up to 12.9t Roughly twice the weight (and as such overall size) as the once famed largest Theropod Giganotosaurus. Its skull was very large, at 1.75m long it was the longest of any Spinosaurid and one of the longest of any Theropod, being only shorter than the long skulled Giganotosaurines Giganotosaurus, Mapusaurus and possibly Tyrannotitan. It possesed a small flutted crest in the region in front of the eyes. This may have been brightly coloured and used for display. Two species have been named, S.aegyptiacus and S.morrocanus.

Sail
On its back were tall neural spines with estimates for their max height ranging from 1.5-2m. It has been suggested that these spines held up a skin sail and used it for Thermoregulation and display. However, the spines were not thin, but thick rods like seen in the fatty humps of modern day Bison. This has lead some to suggest that the spines held up a fatty hump. Regardless of their use, some sort of environmental pressure seemed to be forcing animals to grow some sort of sail. The un-related African iguanodont Ouranosaurus and its contempory Theropod Suchomimus both grew small sails. While at the same time the north american Carcharodontosaurid Acrocanthosaurus also had similar spines running down its back.

Fossils
Spinosaur fossils in general are very rare, and Spinosaurus is no exception. There are very few Spinosaurus remains that have been found, out of these the Holotype is the most complete.

Specimens
Six partial specimens of Spinosaurus have been described. The probable size of these individual spinosaurs can be estimated using comparison to known material from other spinosaurid dinosaurs. The estimates below are based on the | Theropod Database and Dal Sasso et al., 2005.

IPHG 1912 VIII 19, described by Stromer in 1915 from the Bahariya Formation, was the holotype. This specimen, from a subadult individual, was destroyed in World War II. However, detailed drawings and descriptions of the specimen remain. The individual is estimated to have been around 14 meters (46 ft) long and to have weighed about 6.7 tonnes (7.4 short tons). The material consisted of a maxilla (upper jaw) fragment, an incomplete dentary (lower jaw) measuring 75 centimetres (30 in) long, (the skull is estimated to have been 1.45 meters (5 ft) long with a mandible approximately 1.34 meters (4 ft) long), nineteen teeth, two incomplete cervical vertebrae, seven back vertebrae, dorsal ribs, gastralia, and eight caudal centra. The longest preserved vertebral spine was 1.69 metres (5.5 ft) long.

ParisCMN 50791, described by Russell in 1996 from the Kem Kem Beds of Morocco, is the holotype of Spinosaurus marocannus. The material it is based on includes a mid-cervical vertebra which is 19.5 centimetres (7.7 in) long, an anterior dorsal neural arch, an anterior dentary, and a mid-dentary.

MNHN SAM 124, described by Taquet and Russell in 1998 from Algeria, consists of partial premaxillae, partial maxillae, vomers, and a dentary fragment. They came from an individual estimated to have been about 14 meters (46 ft) long and to have weighed about 6.7 tonnes (7.4 short tons). The skull is estimated at approximately 1.42 meters (5 ft) long.

Office National des Mines nBM231, described by Buffetaut and Ouaja in 2002, consists of an anterior dentary from the Chenini Formation of Tunisia which is very similar to existing material of S. aegyptiacus.

Specimen MSNM V4047 of S. aegyptiacus, described by Cristiano Dal Sasso of the Civic Natural History Museum in Milan and his colleagues in 2005 from the Moroccan Kem Kem Beds, consists of premaxillae, partial maxillae, and partial nasals, which together measure 98.8 centimetres (38.9 in) long. The massive skull is estimated at 1.75 meters (6 ft) long, and the entire animal is estimated to have been around 16 to 18 metres (52 to 59 ft) in length and weighed around 7 to 9 tonnes (7.7 to 9.9 short tons). UCPC-2, also described by Dal Sasso et al. in 2005, consists of a 'fluted crest' from the region in front of the eyes.

Other known specimens consist mainly of very fragmentary remains and scattered teeth. For example, teeth from the Echkar Formation of Niger have been referred to S. aegyptiacus. Possible material belonging to Spinosaurus has also been reported from the Turkana Grits of Kenya and the Cabao Formation of Libya (which dates to the Hauterivian stage), though the assignment of the later to the genus Spinosaurus is tentative. Jack Horner also apparently found some fragments of a Spinosaurus skull. He estimated the skull at a massive 8ft long. The animal would in life have been over 24m long. However, he not published his estimates, nor has anybody actually seen the specimen. So every body is guessing it is either a mis identification, or a lie by Horner. It seems to be a similar case to the T rex specimen nicknamed 'Celeste'. Who was also 'found' by Jack Horner.

Diet and bite mechanics
Spinosaurus and its relatvies have been a puzzle to scientists for quite some time. Their Crocodilian 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. It also had deeply rooted teeth. 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 both the upper and lower jaws. The rear portion of its skull is typically renederd as very wide, around the magnitude seen in Tarbosaurus. From a birds eye view, it has a skull that resembles the prehistoric reptile Champosaurus. Champosaurus, despite it having a very Gavial esc jaw, and its whole body length was a mere 5ft, it 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 strong as large Tyrannosaurines.The potential prey of Spinosaurus could include many species of fish, Crocodylomorphs and youngsters of the many Sauropods alive at the time.

Habitat
At the time of Spinosaurus living in Africa, Africa was a desert with scattered poccets of marshy terrain which were home to Spinosaurus. Spinosaurus's massive size has in the past lead some to suggest Spinosaurs in general may have been semi-aquatic. It has recently been confirmed that Spinosaurus was a semi-aquatic Theropod. Wether Spinosaurus had a lifestyle like a modern day Crocodile or Gavial is unknown. However, Spinosaurus was the least semi-aquatic out of the Spinosaurids tested but still more aquatic than its surrounding Theroods.

In The Media
Spinosaurus was a forgotten Dinosaur until it featured in Jurassic Park 3 in 2001. It was shown to be larger and more powerful than Tyrannosaurus (though both of these large Theropods were rather small in comparison to life size). the two engaged in battle resulting in a Spinosaurus victory. After Jurassic park 3, it featured in related merchandise, including Jurassic park Operation genesis for PS2, Xbox and PC. It was again shown being able to duel with Tyrannosaurus, though the outcome can go either way this time.

It also recently featured in the 2009 documentary titled Monsters Resurected. it was shown as the apex predator of its time. It did though have many innacuracies. Including pronated hands, Spinosaurus having a wider and more flat skull than in reality and Rugops being severely undersized. In life it was 9m long, however Spinosaurus was able to fit one in its jaws in Mosnters Ressurected. Spinosaurus also took out Sacrosuchus (which it probally never encountered) and Carcharodontosaurus, it took out the latter with one swipe of the arm to the head.