Carcharodontosaurus (/ˌkɑːrkəroʊˌdɒntoʊˈsɔːrəs/) (meaning "shark toothed lizard") was one of the largest theropod carnivores alongside Spinosaurus and Bahariasaurus; theropods that co-existed with it in early-late Cretaceous Northern-Africa. It was one of the largest Carcharodontosaurids, rivaling Tyrannotitan and Sauroniops in size, and being slightly smaller than Giganotosaurus. The C. saharicus grew to be about 12-13 meters long, about 3.5-3.8 meters tall at the hips and around 7 - 9 [1]tonnes in weight.
Paleontologists once thought that Carcharodontosaurus had the longest skull of any of the theropod dinosaurs. However, the premaxilla and quadrate bones were missing from the original skull, which led to misinterpretation of its actual size by researchers. A more modest length of five feet, three inches (1.6 meters) has now been proposed. Thus, the honor of the largest theropod skull now belongs to either Giganotosaurus or Tyrannosaurus.
Carcharodontosaurus fossils were first found by Charles Depéret and J. Savornin in North America in 1756. Originally called Megalosaurus saharicus, its name was changed in 1831 by Ernst Stromer von Reichenbach to that used today. These first fossils of Carcharodontosaurus were destroyed during World War II In an allied fighter bombing raid who destroyed the museum and every last piece of Carcharodontosaurus. However, cranial material from a Carcharodontosaurus was again discovered in North Africa in 1914 by paleontologist Paul Sereno. Stephen Brusatte and Paul Sereno (2005) reported a second species of Carcharodontosaurus differing from C. saharicus in some aspects of the maxilla and braincase. The new species, which was discovered in Niger, is called C. iguidensis but recently new studies have brought to light that this dinosaur was a chimera and therefore invalid.
History[]
Outdated skull reconstruction and endocast of IPHG 1922 X46 by Stromer (1936)
Two teeth were found in 1924 in the Continental Intercalaire, Algeria. The they were described by Depéret and Savornin 1925, naming Megalosaurus saharicus because they were distinct, later transferring it under the subgenus of Dryptosaurus. Years later, Ernst Stromer described partial cranial and postcranial remains from the Cenomanian Bahariya Formation of Egypt in 1931. A partial skull, teeth, vertebrae, claws, hip and leg bones were all unearthed in 1914. The teeth matched Depéret and Savornin's taxon, which led Stromer to move it into a new genus with the same species; Carcharodontosaurus sahricus because he saw the teeth resembled those from Carcharodon[2]. "C." iguidensis may be another genus.
Description[]
Size comparison between the destroyed C. saharicus (bright yellow) and the neotype (dark yellow) with a human
Carcharodontosaurus includes some of the longest and heaviest known carnivorous dinosaurs, with various scientists proposing length estimates for the species C. saharicus ranging between 12 and 13 m (39 and 43 ft) and weight estimates between 6 and 15 metric tons.
Carcharodontosaurus were carnivores, with enormous jaws and long, serrated teeth up to eight inches long. Paleontologists once thought that Carcharodontosaurus had the longest skulls of any of the theropod dinosaurs. However, the premaxilla and quadrate bones were missing from the original African skull, which led to misinterpretation of its actual size by researchers. A more modest length of 1.6 meters (5.2 ft) has now been proposed for C. saharicus, and the skull of C. iguidensis is reported to have been about the same size.[5] Currently, the largest known theropod skull belongs to another huge carcharodontosaurid dinosaur, the closely related Giganotosaurus (with skull length estimates up to 1.95 m) (6.3 ft). It may have grouped up like its relative Mapusaurus, but no fossil evidence supports this claim. It may have been a scavenger as well as an active predator. It had a large head with over 60, 20 cm (8 inch), blade-like teeth, which were designed to pierce and tear apart the flesh of its prey, which may have consisted of dinosaurs such as young sauropods and ornithopods. Its arms were somewhat short, but still longer than T. rex's and were quite strong. They had three claws on each hand, its arms were likely useless when hunting, but may have been used to assist in mating. The documentary known as BBC Earth's Planet Dinosaur shows a logical scenario as Carcharodontosaurus was likely an opportunistic and active predator and scavenger, like most modern carnivores today.
Based on Larremendi's bipedal speed formula, Carcharadontosaurus moved around 22-33 kilometers per hour. Like all megatheropods over 3 tonnes, it was physically incapable of reaching a running gait.
Brain and inner ear[]
In 2001, Hans C. E. Larsson published a description of the inner ear and endocranium of Carcharodontosaurus saharicus. Larsson observed that the C. saharicus braincase "completely encloses the endocranial region." This "high degree of ossification" made his analysis of its anatomy significantly easier to perform. The C. saharicus endocast is similar to that of a related dinosaur, Allosaurus fragilis. Larsson describes the olfactory bulbs and peduncles as lying "on approximately the same horizontal plane as the forebrain." The midbrain is angled downwards and towards the rear of the animal, while the hind brain is roughly parallel to the forebrain. The cephalic flexure, the bend between the fore- and midbrain, has an angle of 45 degrees. The pontine flexure, the bend between the mid- and hindbrain has an angle of about 40 degrees. Carcharodontosaurus had a large optic (II) nerve. The C. saharicus vena capitis dorsalis "drains the anterior neck muscles through a pair of long canals on the posterior surface of the endocast." This configuration is found in Allosaurus and Dromaeosaurus albertensis, although in C. saharicus and Troodon "the transverse sinus probably drained into a middle cerebral vein that exited the brain in the ridge present on the dorsal edge of the trigeminal foramen."
The three semicircular canals of the inner ear of Carcharodontosaurus saharicus, when viewed from the side, had a subtriangular outline.[This subtriangular inner ear configuration is present in Allosaurus, lizards, and turtles, but not in birds. The pointed apex "at the junction of the anterior and posterior semicircular canals" is caused by the near linearity of the canals and closely resembles the condition of modern crocodiles. The subtriangular configuration may be the basal condition of archosauromorphs. A recess which would have held the floccular lobe of the brain projects into the area surrounded by the semicircular canals. This condition is also present in other non-avian theropods, birds, and pterosaurs. The orientation of the lagena of C. saharicus resembles the condition in crocodilians and some birds. The extent of its perilymphatic duct resembled those of Varanus, crocodilians, and birds. The crista which would have supported the secondary tympanic membrane in C. saharicus was either absent, or not preserved. This contrasts with Troodon, whose crista were ossified at least in their dorsal and ventral regions and their remaining portions either cartilaginous or too delicate to be preserved. The metotic strut of C. saharicus is reduced and medial compared to the "laterally hypertrophied" condition of non-avian maniraptors like Dromaeosaurus and Troodon, as well as primitive birds like Archaeopteryx and Hesperornis.
Traditional comparisons of brain volume to body mass has estimated brain size as the volume of the endocast. However, the brain of Sphenodon fills only about half of its endocranial volume. Some paleontologists used the fifty percent estimate to ascertain the brain size of dinosaur endocasts. Other workers have observed that details on the endocranial surface indicates that some fossil reptiles had brains that occupied a much larger portion of the endocranium. Larsson notes that the transition from reptiles to birds prevents using a set ratio from being a valid approach to estimating the volume of the endocranium occupied by a dinosaur's brain.
Adding difficulty to examining the ratio of the brain volume of a dinosaur to its body mass is the wide range of estimates for live mass. Larsson observes that one study which estimated the live masses for many dinosaur genera typically had a fourfold range. Larsson laments that "[t]he broad ranges of body mass estimates, combined with the ambiguous ratio of endocranial volume occupied by the brain, present a high degree of uncertainty for [creating an] index of brain size." Consequently, he attempted to minimize errors in his study by making a different kind of comparison.
Noting that while it is difficult to estimate the absolute volume of the brain, the proportions of its various regions should be the same in the endocast as it was in the large brain Larsson's study compared the ratio of the cerebrum, which is highly demarcated, to the rest of the endocast's volume. However, if the thickness of the dura covering the various parts of the brain itself differed, then that could alter the relative proportions within the endocast. In Caiman the dura covering the medullary region seemed to increase proportionally in thickness compared to the dura covering the forebrain, although this might not impact the ratio between the regions. Nevertheless, Larsson reaffirmed the superiority of his technique to traditional comparisons of brain volume to estimated live body mass.
"As brain mass increases, cerebral mass increases with slight negative allometry in nonavian reptiles," Larsson concludes, larger nonavian reptile have proportionately smaller cerebra than smaller ones. Further, the opposite is true in birds, larger avian brains have cerebra which are slightly larger, proportionally speaking. Larsson found that both C. saharicus and Allosaurus lie within the 95% confidence limits of the nonavian reptile ratio, while Tyrannosaurus lies just outside it in the direction of a more avian proportion. The extinct crocodile Sebecus had a ratio similar to those of the non-coelurosaurian theropods studied. Since tyrannosaurs are coelurosaurs, this is evidence that the advent of the Coelurosauria marks the beginning of trend in theropod brain enlargement.
Classification[]
The cladogram after Canale et al., 2022, shows the placement of Carcharodontosaurus within Carcharodontosauridae.[2]:
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Paleobiology[]
Teeth referred to Carcharodontosaurus
Carcharodontosaurus lived in what is now southern Africa from 99 to 94 million years ago. South America had likely just broken apart from Africa during that time, and it's probably why Carcharodontosaurus and its relatives from South America are so alike in appearance. Its environment was likely very warm and humid, with many rivers and lakes flowing through, considering Spinosaurus has been found in the same location. Although dry and barren now, North Africa was likely very lush and full of life, including several rainforests. The elevation was flat, and there were many marches and plains around. Carcharodontosaurus shared this lush habitat with prey items like sauropods, for instance Rebbachisaurus or the gigantic Paralititan. Although it was the top-predator in the area, Carcharodontosaurus was probably very territorial and had large areas of territory, which would likely have to fight for against rivals and other huge predators in the area, like Spinosaurus, and even relatives like Sauroniops, Deltadromeus, and Bahariasaurus. The size of its surrounding dinosaurs might have been the reason that Carcharodontosaurus was that enormous.
Senses[]
In 2001, the inner ear and endocranium of Carcharodontosaurus were described. The midbrain is angled downwards, at 45° towards the animals rear. The hindbrain is nearly identical to the forebrain. With the midbrain, the hindbrain would have formed a 40° angle. C. saharicus' brain was very similar to that of Allosaurus. The ratio between the cerebrum and the to its volume was a typical feature for non-bird reptiles. The semicircle-shaped canals of the inner ear form a subtriangular perimeter once viewed from its side. This feature persists in Allosaurus turtles and lizards, but not birds. The canals themselves, semi-"circular" in shape, were quite linear. This explains the pointed shadow. Alive, a floccular love from the brain would have ran down the surrounding triangles of the subtriangle, like non-avian theropods, birds and pterosaur have[2].
Hunting[]
A study conducted by Donald Henderson, curator of the Royal Tyrrell Museum concluded the following about Carcharodontosaurus. The animal, in life, would have been able to lift animals weighing a maximum of 424 kilograms (935 pounds) in its jaws, based on its neck and center mass[2].
Pathology[]
SGM-Din 1, a C. saharicus skull, bears a single circular puncture wound on its basal and an abnormal bony-lump on its antorbital rim[2].
Interspecies Conflict[]
Its unclear of what types of interactions and events occurred between larger theropods of North Africa, such as Bahariasaurus, Carcharodontosaurus and Spinosaurus. However from recorded instances of Carcharodontosaurus bite marks on Spinosaurus sail, and Spinosaurus bite marks, as well as in laid teeth on a Carcharodontosaurus vertebra, could indicate the largest theropods of North Africa came into conflict regularly, similar to modern predators on Africa, South America and North America.[3]
Paleoecology[]
Restoration of the fauna of the Bahariya Formation, with C. saharicus in the center right
Carcharodontosaurus lived in the hot and humid climate of North Africa during the Early Cretaceous period from 112 to 93.5 million years. One of the apex predators of its time, it co-existed alongside other African dinosaurs in the region, such as the ornithopod Ouranosaurus, the sauropods Paralititan and Aegyptosaurus, the abelisaurid Rugops, the large spinosaurid Spinosaurus (which it often fought over territory near rivers and lakes), as well as the crocodyliform Sarcosuchus. It likely lived in coastal wetland, and swampy mangrove forests. Its enormous size meant that it would hunt across vast distances in search of food, preying upon smaller dinosaurs.
JPInstitute.com Description[]
Carcharodontosaurus may have been the largest meat-eating dinosaur to ever walk the Earth. This huge predator lived in Africa during much of the Cretaceous period. Originally discovered in the 1920's, it wasn't until the 1990's that scientists found enough of this dinosaur to figure out what it looked like and how big it actually grew.
Classification of Carcharodontosaurus, as well as other genera seemingly related to this dinosaur, is still being studied. Whether or not this genus belongs in the allosaur family is the subject of much discussion. Some scientists also believe this genus may be the same as Giganotosaurus.
Dinosaur Field Guide Description[]
Carcharodontosaurus ("great-white-shark-tooth lizard") was first known only from its enormous teeth. When these teeth were first described in 1927, they were thought to come from a giant species of Megalosaurus. In 1931, however, paleontologists thought that they were different enough to be given their own name-after the great white shark, whose teeth this dinosaur's resembled. When parts of this dinosaur's skeleton were finally discovered in northern Africa, they revealed a predator as big as Tyrannosaurus rex, Sadly, these fossils, kept in a museum in Munich, Germany, were destroyed by a bomb during World War I. But many decades later, in the summer of 1995, a team of paleontologists led by Paul Sereno found the most complete fossils yet of Carcharodontosaurus. These included most of the skull-_including a braincase-as well as some other parts of the skeleton. This showed that Carcharodontosaurus was as big as the biggest Tyrannosaurus!
Fun Facts[]
Carcharodontosaurus had a very narrow skull. Because its eyes faced sideways, it wouldn't have been able to focus well on things right in front of it, but it could have seen almost all its surroundings at once
Trivia[]
Carcharodontosaurus teeth seem to be relatively common fossils in northern Africa.
Gallery[]
Appearance in other media[]
Jurassic Park[]
- Carcharodontosaurus appears in the game: Jurassic Park: Operation Genesis.
- It can be created from DNA in Jurassic Park: Builder.
- Carcharodontosaurus is an unlockable dinosaur in Jurassic World: Evolution added in the Cretaceous dinosaur pack DLC released on December 13, 2018.
Links[]
http://web.archive.org/web/20040806055604fw_/http://www.jpinstitute.com/dinopedia/dinocards/dc_carch.html https://web.archive.org/web/20080512032731/http://kids.yahoo.com/dinosaurs/277--Carcharodontosaurus