Carcharodontosaurus Temporal range: Late Cretaceous (Cenomanian), | |
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Reconstructed C. saharicus skull, Science Museum of Minnesota | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Carcharodontosauridae |
Subfamily: | † Carcharodontosaurinae |
Genus: | † Carcharodontosaurus Stromer, 1931 |
Type species | |
†Carcharodontosaurus saharicus | |
Other species | |
Synonyms | |
List
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Carcharodontosaurus ( /ˌkɑːrkəroʊˌdɒntoʊˈsɔːrəs/ ; lit. 'shark-toothed lizard') is a genus of carnivorous theropod dinosaur that lived in North Africa from about 99 to 94 million years ago during the Cenomanian stage of the Late Cretaceous. Two teeth of the genus, now lost, were first described from Algeria by French paleontologists Charles Depéret and Justin Savornin as Megalosaurus saharicus. A partial skeleton was collected by crews of German paleontologist Ernst Stromer during a 1914 expedition to Egypt. Stromer did not report the Egyptian find until 1931, in which he dubbed the novel genus Carcharodontosaurus, making the type species C. saharicus. Unfortunately, this skeleton was destroyed during the Second World War. In 1995 a nearly complete skull of C. saharicus, the first well-preserved specimen to be found in almost a century, was discovered in the Kem Kem Beds of Morocco; it was designated the neotype in 1996. Fossils unearthed from the Echkar Formation of northern Niger were described and named as another species, C. iguidensis, in 2007.
Carcharodontosaurus is one of the largest theropod dinosaurs known, with C. saharicus reaching 12–12.5 metres (39–41 ft) in length and approximately 5–7 metric tons (5.5–7.7 short tons) in body mass. It had a large, lightly built skull with a triangular rostrum. Its jaws were lined with sharp, recurved, serrated teeth that bear striking resemblances to those of the great white shark, the inspiration for the name. Though giant, its cranium was made lighter by greatly expanded fossae and fenestra, but also making it more fragile than tyrannosaurids'. The forelimbs were tiny whereas the hindlimbs were robust and muscular. Like most other theropods, it had an elongated tail for balance.
Many gigantic theropods are known from North Africa during this period, including both species of Carcharodontosaurus as well as the spinosaurid Spinosaurus , the possible ceratosaur Deltadromeus , the large, dubious theropod Bahariasaurus , and an unnamed large abelisaurid. Studies of the bite force and tooth anatomy of carcharodontosaurids have found them to possess strong, but relatively weak bites compared to other theropod families. North Africa at the time was blanketed in mangrove forests and wetlands, creating a hotspot of fish, crocodyliforms, and pterosaur diversity.
In 1924, two teeth of Carcharodontosaurus were unearthed from wall cuts in different foggaras near Timimoun, French Algeria. These sedimens came from the Cretaceous-aged [1] Continental intercalaire Formation. [2] The fossils were taken to the governor of Timimoun, Captain Burté, who gave them to French geologist Charles Depéret later that year. In 1925, Depéret and his colleague Justin Savornin described the teeth as syntypes (name-bearing specimens) of a new species of theropod dinosaur, Megalosaurus saharicus. These were the first fossils of theropods to be described from the region. [3] The name saharicus refers to the Sahara Desert where the teeth had been found. [4] The genus Megalosaurus was a wastebasket taxon, with many new species referred to it without justification, including M. saharicus. [5] It was later considered to be a species of Dryptosaurus in 1927, [2] though this is unjustified. [6] [7] By accident, another species of Megalosaurus, M. africanus, was named by German paleontologist Friedrich von Huene based on the teeth. [6] It is therefore considered a junior synonym of M. saharicus. [8] Both syntypic teeth of M. saharicus have since been lost, possibly being kept in a collection in Algeria, Paris, or Lyon, and lack distinguishing characteristics from other carcharodontosaurids. [9] In 1960, French paleontologist Albert-Félix de Lapparent reported the discovery of more teeth and several caudal vertebrae from sites in Algeria belonging to Carcharodontosaurus, [10] though some of these fossils might belong to other genera. [8] Later authors have mentioned finds of teeth and isolated fossils from other provinces of Algeria. [11] [1]
However, fossils of C. saharicus were first found in marls near Ain Gedid, Egypt in early April 1914 by Austro-Hungarian paleontologist Richard Markgraf. Marls from this region derive from the Cenomanian-aged Bahariya Formation, one of many Cretaceous-aged sites of North Africa. [7] [12] [13] In Bahariya, Markgraf did extensive collecting of dinosaur skeletons for his employer, German paleontologist Ernst Stromer of the Paläontologisches Museum München (Bavarian State Collection of Paleontology). The skeleton of Carcharodontosaurus (IPHG 1922 X46) consisted of: a partial skull, including much of the braincase, teeth, three cervical and a caudal vertebra, incomplete pelvis, a manual ungual, femora, and the left fibula. An isolated ilium was also considered to be from C. saharicus, [14] but it is likely from a ceratosaur. [8]
Due to political tensions between the German Empire and then British-owned Egypt, the Carcharodontosaurus skeleton took years to get to Germany. It was not until 1922 that they were transported overseas to Munich where they were described by Stromer in 1931. [15] Stromer recognized that IPHG 1922 X46’s teeth matched the characteristic dentition of those described by Depéret and Savornin, which led to Stromer conserving the species name saharicus. However, he found it necessary to erect a new genus for this species, Carcharodontosaurus, for their similarities, in sharpness and serrations, to the teeth of the great white shark (Carcharodon carcharias). [13] World War II would break out in 1939, leading IPHG 1922 X46 and other material from Bahariya to be destroyed during a British bombing raid on Munich during the night of April 24/25, 1944. [16] [17] An endocast was made and survived the war, being the only remaining relic of the specimen. [18]
Few discoveries of Carcharodontosaurus material were made until 1995, when American paleontologist Paul Sereno found an incomplete skull during an expedition embarked on by the University of Chicago. This skull (UCRC PV12) was found in the Cenomanian-aged rocks of the Lower Douira Formation, Kem Kem Beds in Errachidia, southeastern Morocco. The specimen was taken to the University of Chicago and described in 1996 by Sereno and colleagues. In a later paper, UCRC PV12 was designated as the neotype of C. saharicus due to the loss of other specimens and the similar age and geographic location to previously noted material. [7] The taxonomy of Carcharodontosaurus was discussed by Chiarenza and Cau (2016), [19] who suggested that the neotype of C. saharicus was similar but distinct from the holotype in the morphology of the maxillary interdental plates. However, paleontologist Mickey Mortimer put forward that the suggested difference between the C. saharicus neotype and holotype was actually due to damage to the neotype. [8]
Several other fossils of C. saharicus have been unearthed from the Kem Kem Beds, such as dentary fragments, a cervical vertebra, and many teeth. [20] [21] [22] Sereno et al also referred a multitude of cervical vertebrae described as the spinosaurids Sigilmassasaurus and "Spinosaurus B" to C. saharicus reasoning that stout cervicals would be needed to carry the skulls of carcharodontosaurids. [9] [7] Later research proved otherwise, with the vertebrae being placed in Spinosaurus aegyptiacus by Ibrahim et al (2020). [23] French paleontologist René Lavocat was the first to note the possible presence of Carcharodontosaurus in Morocco as early as 1954. [24]
In 2007, a novel species of Carcharodontosaurus, C. iguidensis, was dubbed by paleontologists Steve Brusatte and Paul Sereno. Fossils of C. iguidensis had been uncovered during an expedition to the Echkar Formation of Iguidi, Niger, a partial maxilla (MNN IGU2) being designated the holotype. The species name iguidensis is after Iguidi, where the fossils were unearthed. Several other remains such as a braincase, a lacrimal, a dentary, a cervical vertebra, and a collection of teeth were referred to C. iguidensis based on size and supposed similarities to other Carcharodontosaurus bones. [9] Chiarenza and Cau (2016) identified the referred material of C. iguidensis as belonging to Sigilmassasaurus (later referred to Spinosaurus sp.) [25] and a non-carcharodontosaurine, and therefore chose to limit C. iguidensis to the holotype pending future research. [19] Another carcharodontosaurid from the Kem Kem Beds, Sauroniops pachytholus , was dubbed in 2012 based on a single frontal. [26] This species has been proposed to be synonymous with C. saharicus, [27] though this has seen resistance and the validity maintained in most literature. [26] [28] [19] [29] The South American genus Giganotosaurus was synonymized with Carcharodontosaurus by Figueiredo (1998) and Paul (2010), [30] [31] however no authors have since followed this assessment. [19]
Stromer hypothesized that C. saharicus was around the same size as the tyrannosaurid Gorgosaurus , which would place it at around 8–9 metres (26–30 ft) long, based on his specimen IPHG 1922 X46. This individual was around 15% smaller than the neotype, [45] the latter was estimated to be 12–12.5 metres (39–41 ft) in length and approximately 5–7 metric tons (5.5–7.7 short tons) in body mass. [46] [31] [47] [48] This makes Carcharodontosaurus saharicus one of the largest known theropod dinosaurs and terrestrial carnivores known, being the 3rd biggest carcharodontosaurid and 5th largest theropod overall according to most estimates. [49] [31] C. iguidensis was much smaller, only reaching 10 metres (33 ft) in length and 4 metric tons (4.4 short tons) in body mass. [31]
The largest and most complete skull of C. saharicus would measure 1.6 metres (5.2 ft) when complete, around the same size as the largest Tyrannosaurus skulls. No skulls of the genus preserve premaxillae, complete posterior skull regions, or mandibles. Skulls of carcharodontosaurids tend to be more slender and lightly built than those of later tyrannosaurids, which have robust builds and adaptations for crushing. The neotype cranium tapers towards the front in side view creating a triangular outline. This is similar to that of other carcharodontosaurids like Mapusaurus and Giganotosaurus. Its skull was lighter than that of tyrannosaurids, with the antorbital fenestra composing over 30% of the total skull length as well as being surrounded by fossae in the maxillae (upper jaw bone), nasals (nose bone), jugals (cheekbone), and lacrimals (front orbit bone). Akin to other genera, its nasal is elongated and bears an anterior face covered in a rugose surface. These bumps were likely extended by keratin sheaths, creating a horn-like structure as in Ceratosaurus . A similar rugosity is found on the lacrimal which would also be lengthened by keratin, forming a similar element. [50] [7] The most distinctive trait of Carcharodontosaurus' skull is the sculpted exterior of the maxillae, which is unique to the genus. However, C. iguidensis has antorbital fossae limited to the proximity of the antorbital fenestra, a crest running along the medial face of the maxilla, and a process along its midline. These traits are missing in C. saharicus, differentiating the two species. [9]
The maxilla of IPHG 1922 X46 would have been 70 centimetres (28 in) long when complete, whereas the neotype's complete maxilla is much larger. 14 teeth sockets are present in each maxilla. Parts of the braincase are known though much of their morphology is the same as Giganotosaurus'. However, C. saharicus has a much more prominent nuchal crest, which overhangs the skull roof. The frontal bones are firmly fused, a characteristic evident in most theropods. [51] The jugals are broad and triangle-shaped. The lower jaw articulation was placed farther back behind the occipital condyle (where the neck is attached to the skull) compared to other theropods. [7] Two dentary (lower jaw bone) fragments which were referred to C. saharicus by Ibrahim et al (2020) have deep and expanded alveoli (tooth sockets), traits found in other large theropods. [20] [22] If like Tyrannotitan and Giganotosaurus, the dentary would have 16 alveoli (tooth sockets). [52]
Estimations of the tooth count of Carcharodontosaurus vary, but a recent estimate of 30 dentary, 8 premaxillary, and 24 maxillary teeth for a total of 62 teeth was made. [53] Carcharodontosaurid teeth are some of the largest of any dinosaur group, with a maxillary tooth from IPHG 1922 X46 being 6.8 centimetres (2.7 in) tall and 3.5 centimetres (1.4 in) wide. [13] [54] However, they are extremely thin, with most being under a centimeter thick. Serrations are numerous on the anterior and posterior margins, with over 18 to 20 serrations per centimeter of edge in C. saharicus and up to 32 per centimeter in C. iguidensis. [9] [13] Its teeth are straight, laterally flattened, and spindle-shaped in cross-section. However, dentition towards the back of the mouth became more recurved than those in the maxilla. The posterior margin of these crowns are recurved and convex at its termination. Bowed enamel wrinkles are present on both dorsoventral sides of the crowns. These wrinkles curve towards the marginal serrations, composing a band-shape along the ends. [7] [55] [52]
In 2001, Hans C. E. Larsson published a description of the inner ear and endocranium of Carcharodontosaurus saharicus. Starting from the portion of the brain closest to the tip of the animal's snout is the forebrain, which is followed by the midbrain. The midbrain is angled downwards at a 45-degree angle and towards the rear of the animal. This is followed by the hindbrain, which is roughly parallel to the forebrain and forms a roughly 40-degree angle with the midbrain. Overall, the brain of C. saharicus would have been similar to that of a related dinosaur, Allosaurus fragilis. Larsson found that the ratio of the cerebrum to the volume of the brain overall in Carcharodontosaurus was typical for a non-avian reptile. Carcharodontosaurus also had a large optic nerve. [56]
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 semi-"circular" canals themselves were very linear, which explains the pointed silhouette. In life, the floccular lobe of the brain would have projected into the area surrounded by the semicircular canals, just like in other non-avian theropods, birds, and pterosaurs. [56]
Few postcranial elements are confidently known from Carcharodontosaurus, though many isolated bones from the Sahara have been referred to the genus without detailed study. [9] [23] [32] [10] Like other carcharodontosaurids, it was robust with small forelimbs, an elongated tail, and short neck. The most complete specimen was IPHG 1922 X46, but it was destroyed. This specimen preserved 3 cervical vertebrae, which were weathered severely. One is an axis and the other two are articulating anterior cervicals which are longer and wider than the axis. The cervical vertebrae of Carcharodontosaurus are stout and opisthocoelus (concave posterior ends). [57] [52] Cervical vertebrae in this genus, as in Giganotosaurus, are topped by low neural spines joined with sturdy transverse processes which hung over the pleurocoels (shallow depressions on the sides of centra), which would contain pneumatic air sacs to lighten the vertebrae. The centra of these vertebrae are adorned by keels along their ventral sides. An anterior caudal vertebra was also known, which was platycoelous (flat anterior and posterior ends) and short. This caudal was incomplete, missing much of the neural spine, but had diapophyses that would conjugate with the chevrons. The sides of its centrum were pleurocoelus as well. Two blade-like chevrons were preserved in this individual as well. [13]
The pelvis was incomplete, containing both pubes and the left ischium, though complete pelves are known in related genera. The ischium pointed backwards whereas the pubes pointed forwards, a diagnostic trait of saurischians. The pubes were likely nearly 1 metre (3.3 ft) when fully preserved, with shafts that were thin but were transversely expanded at the anterior ends where they connected, creating a V-shape in anterior view. Both femora in addition to the left fibula were recovered, the former element being one of the largest recorded from a theropod at 1.26 metres (4.1 ft) in length. Its femora lacked strong curvature and are mostly straight except for the anterior and posterior ends. The greater trochanter is small but has a notable protrusion, which would attach to the m. caudofemoralis longus muscle of the tail. Its fibula was only 88 centimetres (35 in) long, around 1/3rd the length of the femora. The anterior end was triangular in lateral view with bulging condyles whereas the posterior end is rounded. [13]
Carcharodontosaurus is the type genus of the family Carcharodontosauridae and subfamily Carcharodontosaurinae. This subfamily contains Carcharodontosaurus itself as well as the other carcharodontosaurines Giganotosaurus, Mapusaurus, Meraxes, and Tyrannotitan; however, these genera make up an independent tribe: Giganotosaurini. Carcharodontosauridae was a clade created by Stromer for Carcharodontosaurus and Bahariasaurus, though the name remained unused until the recognition of other members of the group in the late 20th century. He noted the likeness of Carcharodontosaurus bones to the American theropods Allosaurus and Tyrannosaurus, leading him to consider the family part of Theropoda. [58] [13]
Paul Sereno's description of Carcharodontosaurus fossils in 1996 led to the realization of a transcontinental clade of carcharodontosaurids. As more carcharodontosaurids were discovered, their interrelationships became even clearer. The group was defined as all allosauroids closer to Carcharodontosaurus than Allosaurus or Sinraptor by the paleontologist Thomas R. Holtz and colleagues in 2004. [59] Carcharodontosaurus is more poorly known than most other carcharodontosaurids, with Meraxes and Giganotosaurus represented by nearly complete skeletons. [60] [61] Members of the family have been recognized from the Late Jurassic to Middle Cretaceous of every continent except Oceania and Antarctica. [49] [62] [7]
Canale et al. (2022) recovered Carcharodontosaurus as the earliest diverging member of Carcharodontosaurinae. The cladogram results of their phylogenetic analyses are displayed in the cladogram below: [60]
Rodolfo Coria and Leonardo Salgado suggested that the convergent evolution of gigantism in theropods could have been linked to common conditions in their environments or ecosystems. [61] Sereno and colleagues found that the presence of carcharodontosaurids in Africa (Carcharodontosaurus), North America (Acrocanthosaurus), and South America (Giganotosaurus), showed the group had a transcontinental distribution by the Early Cretaceous period. Dispersal routes between the northern and southern continents appear to have been severed by ocean barriers in the Late Cretaceous, which led to more distinct, provincial faunas, by preventing exchange. [63] [7] Previously, it was thought that the Cretaceous world was biogeographically separated, with the northern continents being dominated by tyrannosaurids, South America by abelisaurids, and Africa by carcharodontosaurids. [64] The subfamily Carcharodontosaurinae, in which Carcharodontosaurus belongs, appears to have been restricted to the southern continent of Gondwana (formed by South America and Africa), where they were probably the apex predators. [59] The South American tribe Giganotosaurini may have been separated from their African relatives through vicariance, when Gondwana broke up during the Aptian–Albian ages of the Early Cretaceous. [65]
A biomechanical analysis of Carcharodontosaurus' lifting capabilities was conducted by paleontologist Donald Henderson and paleoartist Robert Nicholls in 2015. The authors used 3D models of the animal as well as a subadult sauropod Limaysaurus , which although not found alongside Carcharodontosaurus, is similar to the rebbachisaurids of the Kem Kem Beds. The models included the size of the lungs and other pneumatic structures of the two, fostering an accurate weight simulation of the scenario. Henderson & Nicholls' study found that an adult C. saharicus could hold a maximum of 424 kg (935 lb), half the weight of an adult Limaysaurus. However, two C. saharicus adults could together lift as much as 850 kilograms (1,870 lb). [46]
The dentition of allosauroids is distinct, with carcharodontosaurid teeth bearing distinctly thin and blade-like teeth. However, these teeth are thin and likely could not sustain impact against hard surfaces like bone without potentially bending and snapping. This danger is exacerbated by the straight edges, slightly recurved tips, and sinusoidal shapes observed in their dentition. Despite these traits, the teeth are still much more robust than those of smaller theropods and due to their overall size could take more pressure. Carcharodontosaurus also had a high tooth replacement rate meaning that damaged teeth could be replaced easily in contrast to extant bone-crushing mammals who spend much of their energy maintaining their teeth. [66] [67] Evidence of bone-crunching bites is observed in Allosaurus, which would engage in ritual face-biting with other individuals and bite into the pelves of Stegosaurus as shown by bite marks. [68] [69] [70]
Bite forces of Carcharodontosaurus as well as other giant theropods including Acrocanthosaurus and Tyrannosaurus have been analyzed. Studies reported that carcharodontosaurids had much lower bite forces than Tyrannosaurus despite being in the same size class. The anterior bite force of C. saharicus was estimated in a 2022 paper to be 11,312 newtons while the posterior bite force was 25,449 newtons. This is much lower than that of Tyrannosaurus, implying that it did not eat bones. [71] [72] Finite element accounts of the skulls of theropods have also been taken, which further supported the idea that Carcharodontosaurus ate softer food than tyrannosaurids. Great amounts of stress were recovered in the posterior part of the cranium near the quadrate in Carcharodontosaurus, Spinosaurus, and Acrocanthosaurus. The skulls of these theropods had higher relative stress quantities in opposition to that of smaller genera. This indicates that the crania of giant taxa (ex. Carcharodontosaurus) were unstable due to having large pneumatic structures to save weight instead of creating a firm build. However, Spinosaurus and Suchomimus experienced even greater values of stress meaning that they could only consume light, small prey instead of larger items, which the stronger skull of Carcharodontosaurus could bite while sustaining the stress. [73]
Isotopic analyses of the teeth of C. saharicus have found δ18O values that are higher than that of the contemporary Spinosaurus, suggesting the latter pursued semi-aquatic habits whereas Carcharodontosaurus was more terrestrial. [74] This is further supported by the taphonomy of C. saharicus teeth, which are more often found in land terrains than aquatic ones. [53] Carcharodontosaurus was also a homeotherm with an endotherm-like thermophysiology as inferred by these isotopes meaning that most of its oxygen was accumulated by drinking water rather than being in it. [75] [76]
Theropods such as Carcharodontosaurus, Allosaurus, and Acrocanthosaurus have enlarged lacrimal crests, whose purpose is unknown. Paleontologist Daniel Chure hypothesized that these crests were used for "head-butting" between individuals, but how durable they are has not been studied. [77]
A 2006 study by biologist Kent Stevens analyzed the binocular vision capabilities of the allosauroids Carcharodontosaurus and Allosaurus as well as several coelurosaurs including Tyrannosaurus and Stenonychosaurus . By applying modified perimetry to models of these dinosaurs' heads, Stevens deduced that the binocular vision of Carcharodontosaurus was limited, a side effect of its large, elongated rostrum. Its greatest degree of binocular vision was at higher elevations, suggesting that Carcharodontosaurus may have habitually held its head at a downward 40° angle with its eyes facing up accordingly to achieve maximum binocular vision. The range of vision seen in these allosauroids is comparable to that of crocodiles, suggesting that they were ambush predators. They likely sensed prey via motion parallax between prey and background, with a narrow binocular field of vision helping predators judge prey distances and time attacks. [78]
The neotype skull of C. saharicus is one of many allosauroid individuals to preserve pathologies, with signs of biting, infection, and breaks observed in Allosaurus and Acrocanthosaurus among others. [79] [80] This skull bears a circular puncture wound in the nasal and "an abnormal projection of bone on the antorbital rim". [80] A later study theorized that this was the result of craniofacial bites. [81]
Fossils of Carcharodontosaurus are known from several Cretaceous-age sites across North Africa, similar to the ranges of Spinosaurus and Deltadromeus . [20] [7] North Africa during this period bordered the Tethys Sea, which transformed the region into a mangrove-dominated coastal environment filled with vast tidal flats and waterways. [82] [83] [84] Isotopes from Carcharodontosaurus and Spinosaurus fossils suggest that the Kem Kem Beds witnessed a temporary monsoon season rather than constant rainfall, similar to modern conditions present in sub-tropical and tropical environments in Southeast Asia and Sub-Saharan Africa. [74] [85] These riverine deposits bore large fishes, including the sawskate Onchopristis , coelacanth Mawsonia , and bichir Bawitius . [86] This led to an abundance of piscivorous crocodyliformes evolving in response, such as the giant stomatosuchid Stomatosuchus in Egypt and the genera Elosuchus, Laganosuchus, and Aegisuchus from Morocco. [87] [88] Morocco also bore an abundance of pterosaurs like Siroccopteryx and Nicorhynchus . [89] [90]
The composition of the dinosaur fauna of these sites is an anomaly, as there are fewer herbivorous dinosaur species relative to carnivorous dinosaurs than usual. This indicates that there was niche partitioning between the different theropod clades, with spinosaurids consuming fish while other groups hunted herbivorous dinosaurs. [91] Isotopic evidence supports this, which found greater quantities of sizable, terrestrial animals in the diets of carcharodontosaurids and ceratosaurs from both the Kem Kem Beds and Elrhaz Formation. [92] [10] Some sauropods are known from the Bahariya Formation such as Paralititan and Aegyptosaurus, [93] while Rebbachisaurus is found in the Kem Kem Beds. [94] Carcharodontosaurids are represented by C. saharicus and Sauroniops in the Kem Kem Beds, Eocarcharia and potentially Carcharodontosaurus in the Elrhaz Formation, and C. iguidensis in the Echkar Formation. [9]
Spinosaurus is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian to upper Turonian stages of the Late Cretaceous period, about 99 to 93.5 million years ago. The genus was known first from Egyptian remains discovered in 1912 and described by German palaeontologist Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material came to light in the early 21st century. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The best known species is S. aegyptiacus from Egypt, although a potential second species, S. maroccanus, has been recovered from Morocco. The contemporary spinosaurid genus Sigilmassasaurus has also been synonymized by some authors with S. aegyptiacus, though other researchers propose it to be a distinct taxon. Another possible junior synonym is Oxalaia from the Alcântara Formation in Brazil.
Irritator is a genus of spinosaurid dinosaur that lived in what is now Brazil during the Albian stage of the Early Cretaceous Period, about 113 to 110 million years ago. It is known from a nearly complete skull found in the Romualdo Formation of the Araripe Basin. Fossil dealers had acquired this skull and sold it to the State Museum of Natural History Stuttgart. In 1996, the specimen became the holotype of the type species Irritator challengeri. The genus name comes from the word "irritation", reflecting the feelings of paleontologists who found the skull had been heavily damaged and altered by the collectors. The species name is a homage to the fictional character Professor Challenger from Arthur Conan Doyle's novels.
Giganotosaurus is a genus of theropod dinosaur that lived in what is now Argentina, during the early Cenomanian age of the Late Cretaceous period, approximately 99.6 to 95 million years ago. The holotype specimen was discovered in the Candeleros Formation of Patagonia in 1993 and is almost 70% complete. The animal was named Giganotosaurus carolinii in 1995; the genus name translates to "giant southern lizard", and the specific name honors the discoverer, Ruben Carolini. A dentary bone, a tooth, and some tracks, discovered before the holotype, were later assigned to this animal. The genus attracted much interest and became part of a scientific debate about the maximum sizes of theropod dinosaurs.
Acrocanthosaurus is a genus of carcharodontosaurid dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous, from 113 to 110 million years ago. Like most dinosaur genera, Acrocanthosaurus contains only a single species, A. atokensis. It had a continent-wide range, with fossil remains known from the U.S. states of Oklahoma, Texas, and Wyoming in the west, and Maryland in the east.
Suchomimus is a species of spinosaur dinosaur that lived between 125 and 112 million years ago in what is now Niger, north Africa, during the Aptian to early Albian stages of the Early Cretaceous period. It was named and described by paleontologist Paul Sereno and colleagues in 1998, based on a partial skeleton from the Elrhaz Formation. Suchomimus's long and shallow skull, similar to that of a crocodile, earns it its generic name, while the specific name Suchomimus tenerensis alludes to the locality of its first remains, the Ténéré Dese.
Ernst Freiherr Stromer von Reichenbach was a German paleontologist best remembered for his expedition to Egypt, during which the discovery of the first known remains of Spinosaurus was made.
Tyrannotitan is a genus of large bipedal carnivorous dinosaur of the carcharodontosaurid family from the Aptian stage of the early Cretaceous period, discovered in Argentina. It is closely related to other giant predators like Carcharodontosaurus and especially Giganotosaurus as well as Mapusaurus.
Spinosauridae is a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. Spinosaurid fossils have been recovered worldwide, including Africa, Europe, South America and Asia. Their remains have generally been attributed to the Early to Mid Cretaceous.
Carcharodontosauridae is a group of carnivorous theropod dinosaurs. In 1931, Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids include some of the largest land predators ever known: Giganotosaurus, Mapusaurus, Carcharodontosaurus, and Tyrannotitan all rivaled Tyrannosaurus in size. Estimates give a maximum weight of 8–10 metric tons for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have weighed at least 500 kilograms (1,100 lb).
Rugops is a monospecific genus of basal abelisaurid theropod dinosaur from Niger that lived during the Late Cretaceous period in what is now the Echkar Formation. The type and only species, Rugops primus, is known only from a partial skull. It was named and described in 2004 by Paul Sereno, Jeffery Wilson and Jack Conrad. Rugops has an estimated length of 4.4–5.3 metres and weight of 410 kilograms. The top of its skull bears several pits which correlates with overlaying scale and the front of the snout would have had an armour-like dermis.
Bahariasaurus is an enigmatic genus of large theropod dinosaur. Bahariasaurus is known to have included at least 1 species, Bahariasaurus ingens, which was found in North African rock layers dating to the Cenomanian and Turonian ages of the Late Cretaceous. The only fossils confidently assigned to Bahariasaurus were found in the Bahariya Formation of the Bahariya oasis in Egypt by Ernst Stromer but were destroyed during a World War II bombing raid with the same raid taking out the holotype of Spinosaurus and Aegyptosaurus among other animals found in the Bahariya Formation. While there have been more fossils assigned to the genus such as some from the Farak Formation of Niger, these remains are referred to with much less certainty. Bahariasaurus is, by most estimations, one of the largest theropods, approaching the height and length of other large bodied theropods such as Tyrannosaurus rex and the contemporaneous Carcharodontosaurus. The aforementioned estimations tend to put it at around 11–12.2 metres in length and 4-4.8 tonnes in overall weight.
Deltadromeus is a genus of theropod dinosaur from the Aoufous Formation of Morocco.
Rebbachisaurus is a genus of sauropod dinosaur of the superfamily Diplodocoidea, that lived during the Late Cretaceous period in Africa and possibly also South America about 99-97 million years ago. Remains attributed to Rebbachisaurus have been found in Morocco, Niger, Algeria, Tunisia and possibly also Argentina, although only the Moroccan remains can be referred to the genus without doubt. The discovery of Rayososaurus, a South American sauropod nearly identical to Rebbachisaurus which may have actually have been the same animal as Rebbachisaurus, supports the theory that there was still a land connection between Africa and South America during the Early Cretaceous, long after it was commonly thought the two continents had separated.
Cristatusaurus is a genus of theropod dinosaur that lived during the Early Cretaceous Period of what is now Niger, 112 million years ago. It was a baryonychine member of the Spinosauridae, a group of large bipedal carnivores with well-built forelimbs and elongated, crocodile-like skulls. The type species Cristatusaurus lapparenti was named in 1998 by scientists Philippe Taquet and Dale Russell, on the basis of jaw bones and some vertebrae. Two claw fossils were also later assigned to Cristatusaurus. The animal's generic name, which means "crested reptile", alludes to a sagittal crest on top of its snout; while the specific name is in honor of the French paleontologist Albert-Félix de Lapparent. Cristatusaurus is known from the Albian to Aptian Elrhaz Formation, where it would have coexisted with sauropod and iguanodontian dinosaurs, other theropods, and various crocodylomorphs.
Mapusaurus was a giant carcharodontosaurid carnosaurian dinosaur from the early Late Cretaceous, approximately 93.9 to 89.6 million years ago, of what is now Argentina.
Sigilmassasaurus is a controversial genus of spinosaurid dinosaur that lived approximately 100 to 94 million years ago during the Late Cretaceous Period in what is now northern Africa. Named in 1996 by Canadian paleontologist Dale Russell, it contains a single species, Sigilmassasaurus brevicollis. The identity of the genus has been debated by scientists, with some considering its fossils to represent material from the closely related species Spinosaurus aegyptiacus, while others have classified it as a separate taxon, forming the clade Spinosaurini with Spinosaurus as its sister taxon.
Eocarcharia is a genus of carcharodontosaurid theropod dinosaur from the Early Cretaceous Elrhaz Formation that lived in the Sahara 112 million years ago, in what today is the country of Niger. It was discovered in 2000 on an expedition led by University of Chicago paleontologist Paul Sereno. The type and only species is Eocarcharia dinops. Its teeth were shaped like blades and were used for disabling live prey and ripping apart body parts. Eocarcharia’s brow is swollen into a massive band of bone, giving it a menacing glare. It may have reached lengths of 6–8 m (19.7–26.2 ft).
The Kem Kem Group is a geological group in the Kem Kem region of eastern Morocco, whose strata date back to the Cenomanian stage of the Late Cretaceous. Its strata are subdivided into two geological formations, with the lower Ifezouane Formation and the upper Aoufous Formation, with the Gara Sbaa Formation and Douira Formation used in the southern Tafilalt region. It is exposed on an escarpment along the Algeria–Morocco border.
Oxalaia is a genus of spinosaurid dinosaur that lived in what is now the Northeast Region of Brazil during the Cenomanian stage of the Late Cretaceous period, sometime between 100.5 and 93.9 million years ago. Its only known fossils were found in 1999 on Cajual Island in the rocks of the Alcântara Formation, which is known for its abundance of fragmentary, isolated fossil specimens. The remains of Oxalaia were described in 2011 by Brazilian palaeontologist Alexander Kellner and colleagues, who assigned the specimens to a new genus containing one species, Oxalaia quilombensis. The species name refers to the Brazilian quilombo settlements. Oxalaia quilombensis is the eighth officially named theropod species from Brazil and the largest carnivorous dinosaur discovered there. It is closely related to the African genus Spinosaurus, and/or may be a junior synonym of this taxon.
Sauroniops is a controversial genus of carnivorous basal carcharodontosaurid theropod dinosaur known from the Late Cretaceous Gara Sbaa Formation, and possibly also the Kem Kem Formation, both of Morocco. The type, and currently only, species is S. platytholus.