141-716: Carcharodontosaurus ( / ˌ k ɑːr k ər oʊ ˌ d ɒ n t oʊ ˈ s ɔːr ə s / ; lit. ' jagged toothed lizard ' ) is a genus of carnivorous theropod dinosaur that lived in North Africa from about 100 to 94 million years ago during the Cenomanian age 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
282-652: A facultative carnivore from an omnivore . Obligate or "true" carnivores are those whose diet requires nutrients found only in animal flesh in the wild. While obligate carnivores might be able to ingest small amounts of plant matter, they lack the necessary physiology required to fully digest it. Some obligate carnivorous mammals will ingest vegetation as an emetic , a food that upsets their stomachs, to self-induce vomiting. Obligate carnivores are diverse. The amphibian axolotl consumes mainly worms and larvae in its environment, but if necessary will consume algae. All wild felids , including feral domestic cats , require
423-720: A monophyletic clade. The results of his phylogenetic analyses are shown in the cladogram below: Neovenator Sauroniops Veterupristisaurus Lusovenator Eocarcharia (type skull roof) Concavenator Carcharodontosaurus iguidensis (holotype maxilla) Acrocanthosaurus Eocarcharia (referred maxilla) Meraxes Carcharodontosaurus iguidensis (referred cranial material) Lajasvenator Labocania Shaochilong Carcharodontosaurus saharicus (neotype) Carcharodontosaurus saharicus (described by Stromer in 1931) Tyrannotitan Mapusaurus Giganotosaurus Rodolfo Coria and Leonardo Salgado suggested that
564-476: 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
705-529: 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 . 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
846-549: 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, reaching 10–12.5 m (33–41 ft) in length and approximately 4–7 metric tons (4.4–7.7 short tons) in body mass. It had
987-426: A consequence, the weather tends to be sunny, dry and stable with a minimal chance of rainfall. Subsiding, diverging, dry air masses associated with subtropical high-pressure systems are extremely unfavorable for the development of convectional showers. The subtropical ridge is the predominant factor that explains the hot desert climate ( Köppen climate classification BWh ) of this vast region. The descending airflow
1128-534: A diet of primarily animal flesh and organs. Specifically, cats have high protein requirements and their metabolisms appear unable to synthesize essential nutrients such as retinol , arginine , taurine , and arachidonic acid ; thus, in nature, they must consume flesh to supply these nutrients. Characteristics commonly associated with carnivores include strength, speed, and keen senses for hunting, as well as teeth and claws for capturing and tearing prey. However, some carnivores do not hunt and are scavengers , lacking
1269-421: A diprodontan dentition completely unlike that of any other mammal; and eutriconodonts like gobiconodontids and Jugulator , with a three-cusp anatomy which nevertheless functioned similarly to carnassials. Sahara The Sahara ( / s ə ˈ h ɑːr ə / , / s ə ˈ h ær ə / ) is a desert spanning across North Africa . With an area of 9,200,000 square kilometres (3,600,000 sq mi), it
1410-511: A form of endosymbiosis , might have led to symbiogenesis that gave rise to eukaryotes and eukaryotic autotrophs such as green and red algae . The earliest predators were microorganisms , which engulfed and "swallowed" other smaller cells (i.e. phagocytosis ) and digested them internally . Because the earliest fossil record is poor, these first predators could date back anywhere between 1 and over 2.7 bya (billion years ago). The rise of eukaryotic cells at around 2.7 bya,
1551-634: A great diversity of eutherian carnivores in the northern continents and Africa . In South America , sparassodonts were dominant, while Australia saw the presence of several marsupial predators, such as the dasyuromorphs and thylacoleonids . From the Miocene to the present, the dominant carnivorous mammals have been carnivoramorphs . Most carnivorous mammals, from dogs to deltatheridiums , share several dental adaptations, such as carnassialiforme teeth, long canines and even similar tooth replacement patterns. Most aberrant are thylacoleonids , with
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#17330922396961692-515: A healthy adult. The Saharan silver ant is unique in that due to the extreme high temperatures of their habitat, and the threat of predators, the ants are active outside their nest for only about ten minutes per day. Dromedary camels and goats are the domesticated animals most commonly found in the Sahara. Because of its qualities of endurance and speed, the dromedary is the favourite animal used by nomads . Human activities are more likely to affect
1833-419: 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 (genus Carcharodon ), 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
1974-486: A non- carcharodontosaurine , and therefore chose to limit C. iguidensis to the holotype pending future research. Another carcharodontosaurid from the Kem Kem Beds, Sauroniops pachytholus , was dubbed in 2012 based on a single frontal. This species has been proposed to be synonymous with C. saharicus , though this has seen resistance and the validity maintained in most literature. The South American genus Giganotosaurus
2115-558: A summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae ), or northern limit of Cenchrus biflorus , a grass typical of the Sahel. According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (this
2256-542: A surface feature of Earth, with near-current technology. The Sahara is mainly rocky hamada (stone plateaus); ergs (sand seas – large areas covered with sand dunes ) form only a minor part, contrary to common misconception , but many of the sand dunes are over 180 metres (590 ft) high. Wind or rare rainfall shape the desert features: sand dunes, dune fields, sand seas, stone plateaus, gravel plains ( reg ), dry valleys ( wadi ), dry lakes ( oued ), and salt flats ( shatt or chott ). Unusual landforms include
2397-639: Is a long-term average, since precipitation varies annually). Important cities located in the Sahara include Nouakchott , the capital of Mauritania; Tamanrasset , Ouargla , Béchar , Hassi Messaoud , Ghardaïa , and El Oued in Algeria; Timbuktu in Mali; Agadez in Niger; Ghat in Libya; and Faya-Largeau in Chad. The Sahara is the world's largest hot desert . It is located in
2538-422: Is a north African gazelle that can also go for a long time without water. Other notable gazelles include the rhim gazelle and dama gazelle . The Saharan cheetah ( northwest African cheetah ) lives in Algeria, Togo , Niger, Mali, Benin , and Burkina Faso . There remain fewer than 250 mature cheetahs, which are very cautious, fleeing any human presence. The cheetah avoids the sun from April to October, seeking
2679-609: Is a prehistoric industry, or domain, that existed between 10,000 and 8,000 years ago in the Sahara, during the Neolithic Subpluvial . Human remains from this culture were found in 2000 at a site known as Gobero , located in Niger in the Ténéré Desert . The site is known as the largest and earliest grave of Stone Age people in the Sahara. The Kiffians were skilled hunters . Bones of many large savannah animals that were discovered in
2820-428: 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. Chiarenza and Cau (2016) identified the referred material of C. iguidensis as belonging to Sigilmassasaurus (later referred to Spinosaurus sp.) and
2961-460: Is associated with high rates of wind-blown mineral dust, and these dust levels are found as expected in marine cores from the north tropical Atlantic. But around 12,500 BCE the amount of dust in the cores in the Bølling / Allerød phase suddenly plummets and shows a period of much wetter conditions in the Sahara, indicating a Dansgaard-Oeschger (DO) event (a sudden warming followed by a slower cooling of
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#17330922396963102-456: 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. The most distinctive trait of Carcharodontosaurus ' skull is the sculpted exterior of the maxillae, which
3243-403: Is estimated to include five hundred species of plants, which is extremely low considering the huge extent of the area. Plants such as acacia trees, palms, succulents, spiny shrubs, and grasses have adapted to the arid conditions, by growing lower to avoid water loss by strong winds, by storing water in their thick stems to use it in dry periods, by having long roots that travel horizontally to reach
3384-507: 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. Evidence of bone-crunching bites
3525-414: 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. The jugals are broad and triangle-shaped. The lower jaw articulation
3666-459: 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. 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
3807-401: 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
3948-937: Is termed an apex predator , regardless of whether it is an obligate or facultative carnivore. In captivity or domestic settings, obligate carnivores like cats and crocodiles can, in principle, get all their required nutrients from processed food made from plant and synthetic sources. Outside the animal kingdom, there are several genera containing carnivorous plants (predominantly insectivores) and several phyla containing carnivorous fungi (preying mostly on microscopic invertebrates , such as nematodes , amoebae , and springtails ). Carnivores are sometimes characterized by their type of prey . For example, animals that eat mainly insects and similar terrestrial arthropods are called insectivores , while those that eat mainly soft-bodied invertebrates are called vermivores . Those that eat mainly fish are called piscivores . Carnivores may alternatively be classified according to
4089-407: Is the largest hot desert in the world and the third-largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic . The name "Sahara" is derived from Arabic : صَحَارَى , romanized : ṣaḥārā /sˤaħaːraː/ , a broken plural form of ṣaḥrā' ( صَحْرَاء /sˤaħraːʔ/ ), meaning "desert". The desert covers much of North Africa , excluding
4230-643: Is the strongest and the most effective over the eastern part of the Great Desert, in the Libyan Desert: this is the sunniest, driest and the most nearly "rainless" place on the planet, rivaling the Atacama Desert , lying in Chile and Peru . The rainfall inhibition and the dissipation of cloud cover are most accentuated over the eastern section of the Sahara rather than the western. The prevailing air mass lying above
4371-423: 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. The maxilla of IPHG 1922 X46 would have been 70 centimetres (28 in) long when complete, whereas the neotype's complete maxilla
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4512-422: Is very unreliable and erratic in the Sahara as it may vary considerably year by year. In full contrast to the negligible annual rainfall amounts, the annual rates of potential evaporation are extraordinarily high, roughly ranging from 2,500 millimetres (100 in) per year to more than 6,000 millimetres (240 in) per year in the whole desert. Nowhere else on Earth has air been found as dry and evaporative as in
4653-535: The Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in Borkou , northern Chad. Due to lack of cloud cover and very low humidity, the desert usually has high diurnal temperature variations between days and nights. However, it is a myth that the nights are especially cold after extremely hot days in the Sahara. On average, nighttime temperatures tend to be 13–20 °C (23–36 °F) cooler than in
4794-481: The Algerian Desert called Bou Bernous , at an elevation of 378 metres (1,240 ft) above sea level, and only Death Valley, California rivals it. Other hot spots in Algeria such as Adrar , Timimoun , In Salah , Ouallene , Aoulef , Reggane with an elevation between 200 and 400 metres (660 and 1,310 ft) above sea level get slightly lower summer average highs, around 46 °C (114.8 °F) during
4935-604: The Cambrian substrate revolution led to increased active predation among animals, likely triggering various evolutionary arms races that contributed to the rapid diversification during the Cambrian explosion . Radiodont arthropods , which produced the first apex predators such as Anomalocaris , quickly became the dominant carnivores of the Cambrian sea. After their decline due to the Cambrian-Ordovician extinction event ,
5076-487: The Cenomanian -aged Bahariya Formation , one of many Cretaceous-aged sites of North Africa . 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
5217-540: The Cretaceous -aged Continental intercalaire Formation . 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
5358-742: The Late Pleistocene Iberomaurusians , early Holocene Capsians , and mid-Holocene Mechta groups, whereas the Tenerian crania are more like those of Mediterranean groups. Graves show that the Tenerians observed spiritual traditions, as they were buried with artifacts such as jewelry made of hippo tusks and clay pots. The most interesting find is a triple burial, dated to 5300 years ago, of an adult female and two children, estimated through their teeth as being five and eight years old, hugging each other. Pollen residue indicates they were buried on
5499-726: The Niger River valley and the Sudan region of sub-Saharan Africa . The Sahara can be divided into several regions, including the western Sahara, the central Ahaggar Mountains , the Tibesti Mountains , the Aïr Mountains , the Ténéré desert, and the Libyan Desert . For several hundred thousand years, the Sahara has alternated between desert and savanna grassland in a 20,000-year cycle caused by
5640-668: The Richat Structure in Mauritania. Several deeply dissected mountains, many volcanic, rise from the desert, including the Aïr Mountains , Ahaggar Mountains , Saharan Atlas , Tibesti Mountains , Adrar des Iforas , and the Red Sea Hills . The highest peak in the Sahara is Emi Koussi , a shield volcano in the Tibesti range of northern Chad. The central Sahara is hyperarid , with sparse vegetation. The northern and southern reaches of
5781-778: 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. The taxonomy of Carcharodontosaurus
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5922-468: 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
6063-456: 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 , but it is likely from a ceratosaur . Due to political tensions between the German Empire and then British-owned Egypt , the Carcharodontosaurus skeleton took years to get to Germany. It
6204-500: The chevrons . The sides of its centrum were pleurocoelus as well. Two blade-like chevrons were preserved in this individual as well. 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
6345-537: The convergent evolution of gigantism in theropods could have been linked to common conditions in their environments or ecosystems . 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
6486-414: 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
6627-474: The horse latitudes under the subtropical ridge , a significant belt of semi-permanent subtropical warm-core high pressure where the air from the upper troposphere usually descends, warming and drying the lower troposphere and preventing cloud formation. The permanent absence of clouds allows unhindered light and thermal radiation. The stability of the atmosphere above the desert prevents any convective overturning, thus making rainfall virtually non-existent. As
6768-423: The lobe-finned fish , became the dominant carnivores of freshwater wetlands formed by early land plants . Some of these fish became better adapted for breathing air and eventually giving rise to amphibian tetrapods . These early tetrapods were large semi-aquatic piscivores and riparian ambush predators that hunt terrestrial arthropods (mainly arachnids and myriopods ), and one group in particular,
6909-434: 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. Carcharodontosaurus is the type genus of the family Carcharodontosauridae and subfamily Carcharodontosaurinae . This subfamily contains Carcharodontosaurus itself as well as
7050-437: The order Carnivora is carnivoran , and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the large and small cats ( Felidae ) are obligate carnivores (see below). Other classes of carnivore are highly variable. The ursids , for example: while
7191-431: 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
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#17330922396967332-504: The precession of Earth's axis (about 26,000 years) as it rotates around the Sun, which changes the location of the North African monsoon . The Sahara covers large parts of Algeria , Chad , Egypt , Libya , Mali , Mauritania , Niger , Western Sahara and Sudan , and parts of southern Morocco and Tunisia . It covers 9 million square kilometres (3,500,000 sq mi), 31% of
7473-524: The temnospondyls , became terrestrial apex predators that hunt other tetrapods. The dominance of temnospondyls around the wetland habitats throughout the Carboniferous forced other amphibians to evolve into amniotes that had adaptations that allowed them to live farther away from water bodies. These amniotes began to evolve both carnivory, which was a natural transition from insectivory requiring minimal adaptation; and herbivory , which took advantage of
7614-423: The triconodontid Jugulator , the deltatheroidans and Cimolestes . Many of these, such as Repenomamus , Jugulator and Cimolestes , were among the largest mammals in their faunal assemblages, capable of attacking dinosaurs. In the early-to-mid-Cenozoic, the dominant predator forms were mammals: hyaenodonts , oxyaenids , entelodonts , ptolemaiidans , arctocyonids and mesonychians , representing
7755-499: The African continent. If all areas with a mean annual precipitation of less than 250 mm (9.8 in) were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division . The Sahara is so large and bright that, in theory, it could be detected from other stars as
7896-417: The African humid period. At its largest extent, sometime before 5000 BCE, Lake Mega-Chad was the largest of four Saharan paleolakes, and is estimated to have covered an area of 350,000 km . The Sahara pump theory describes this cycle. During periods of a wet or " Green Sahara ", the Sahara becomes a savanna grassland and various flora and fauna become more common. Following inter-pluvial arid periods,
8037-510: The American theropods Allosaurus and Tyrannosaurus , leading him to consider the family part of Theropoda. 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
8178-497: The Arctic polar bear eats meat almost exclusively (more than 90% of its diet is meat), almost all other bear species are omnivorous , and one species, the giant panda , is nearly exclusively herbivorous . Dietary carnivory is not a distinguishing trait of the order . Many mammals with highly carnivorous diets are not members of the order Carnivora . Cetaceans , for example, all eat other animals, but are paradoxically members of
8319-412: The Great Desert the hottest large region in the world, and the hottest place on Earth during summer in some spots. The average high temperature exceeds 38 to 40 °C (100.4 to 104.0 °F) during the hottest month nearly everywhere in the desert except at very high altitudes. The world's highest officially recorded average daily high temperature was 47 °C (116.6 °F) in a remote desert town in
8460-474: The Intertropical Convergence Zone from the south and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Timbuktu, Mali and Agadez , Niger are found in this zone. The vast central hyper-arid core of the desert is virtually never affected by northerly or southerly atmospheric disturbances and permanently remains under the influence of
8601-541: The Kem Kem Beds, such as dentary fragments, a cervical vertebra, and many teeth. 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. Later research proved otherwise, with the vertebrae being placed in Spinosaurus aegyptiacus by Ibrahim et al. (2020). French paleontologist René Lavocat
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#17330922396968742-513: The Kiffian culture do not exist after 8,000 years ago, as the Sahara went through a dry period for the next thousand years. After this time, the Tenerian culture colonized the area. Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno , which sought dinosaur remains. Two distinct prehistoric cultures were discovered at the site: the early Holocene Kiffian culture, and
8883-455: The Sahara (birds in particular) such as African silverbill and black-faced firefinch , among others. There are also small desert crocodiles in Mauritania and the Ennedi Plateau of Chad. The deathstalker scorpion can be 10 cm (3.9 in) long. Its venom contains large amounts of agitoxin and scyllatoxin and is very dangerous; however, a sting from this scorpion rarely kills
9024-518: The Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains , southwards into West Africa , or eastwards into the Nile Valley . This separates populations of some of the species in areas with different climates , forcing them to adapt , possibly giving rise to allopatric speciation . It is also proposed that humans accelerated
9165-514: The Sahara is strongly influenced by the North Atlantic Oscillation (NAO), with warmer winter temperatures during negative NAO events and cooler winters with more frosts when the NAO is positive. This is because the weaker clockwise flow around the eastern side of the subtropical anticyclone during negative NAO winters, although too dry to produce more than negligible precipitation, does reduce
9306-497: The Sahara is the continental tropical (cT) air mass, which is hot and dry. Hot, dry air masses primarily form over the North-African desert from the heating of the vast continental land area, and it affects the whole desert during most of the year. Because of this extreme heating process, a thermal low is usually noticed near the surface, and is the strongest and the most developed during the summertime. The Sahara High represents
9447-616: The Sahara region. However, at least two instances of snowfall have been recorded in Sahara, in February 1979 and December 2016, both in the town of Ain Sefra . One theory for the formation of the Sahara is that the monsoon in Northern Africa was weakened because of glaciation during the Quaternary period, starting two or three million years ago. Another theory is that the monsoon was weakened when
9588-698: The Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs , including Afrovenator , Jobaria and Ouranosaurus , have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases , and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. Shifts in Earth's axis increased temperatures and decreased precipitation, which caused an abrupt beginning of North Africa desertification about 5,400 years ago. The Kiffian culture
9729-452: The abundance of coal forest foliage but in contrast required a complex set of adaptations that was necessary for digesting on the cellulose - and lignin -rich plant materials. After the Carboniferous rainforest collapse , both synapsid and sauropsid amniotes quickly gained dominance as the top terrestrial animals during the subsequent Permian period. Some scientists assert that sphenacodontoid synapsids such as Dimetrodon "were
9870-444: The almost exclusively plant-eating hooved mammals . Animals that depend solely on animal flesh for their nutrient requirements in nature are called hypercarnivores or obligate carnivores , whilst those that also consume non-animal food are called mesocarnivores , or facultative carnivores , or omnivores (there are no clear distinctions). A carnivore at the top of the food chain (adults not preyed upon by other animals)
10011-576: The amount of rainfall received – the Northern (Mediterranean), Central and Southern Zones. There are two transitional zones – the Mediterranean-Sahara transition and the Sahel transition zone. The Saharan flora comprises around 2800 species of vascular plants . Approximately a quarter of these are endemic . About half of these species are common to the flora of the Arabian deserts. The central Sahara
10152-536: The ancient Tethys Sea dried up during the Tortonian period around 7 million years ago. The climate of the Sahara has undergone enormous variations between wet and dry over the last few hundred thousand years, believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon – usually southward. The cycle is caused by a 41,000-year cycle in which
10293-442: 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
10434-433: 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
10575-421: The atmospheric circulation itself, the desert is made even drier by its geographical configuration and location. Indeed, the extreme aridity of the Sahara is not only explained by the subtropical high pressure: the Atlas Mountains of Algeria, Morocco and Tunisia also help to enhance the aridity of the northern part of the desert. These major mountain ranges act as a barrier, causing a strong rain shadow effect on
10716-600: The climate). The moister Saharan conditions had begun about 12,500 BCE, with the extension of the ITCZ northward in the northern hemisphere summer, bringing moist wet conditions and a savanna climate to the Sahara, which (apart from a short dry spell associated with the Younger Dryas ) peaked during the Holocene thermal maximum climatic phase at 4000 BCE when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in
10857-402: The crowns. These wrinkles curve towards the marginal serrations, composing a band-shape along the ends. 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
10998-474: The daytime. The smallest variations are found along the coastal regions due to high humidity and are often even lower than a 10 °C (18 °F) difference, while the largest variations are found in inland desert areas where the humidity is the lowest, mainly in the southern Sahara. Still, it is true that winter nights can be cold, as it can drop to the freezing point and even below, especially in high-elevation areas. The frequency of subfreezing winter nights in
11139-469: The desert experiences around three to five months when the average high strictly exceeds 40 °C (104 °F); while in the southern central part of the desert, there are up to six or seven months when the average high temperature strictly exceeds 40 °C (104 °F). Some examples of this are Bilma , Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds 20 °C (68 °F) everywhere and can approach 30 °C (86 °F) in
11280-516: The desert, along with the highlands, have areas of sparse grassland and desert shrub , with trees and taller shrubs in wadis , where moisture collects. In the central, hyperarid region, there are many subdivisions of the great desert: Tanezrouft , the Ténéré , the Libyan Desert , the Eastern Desert , the Nubian Desert and others. These extremely arid areas often receive no rain for years. To
11421-526: The drying-out period from 6000 to 2500 BCE by pastoralists overgrazing available grassland. The growth of speleothems (which requires rainwater) was detected in Hol-Zakh, Ashalim , Even-Sid, Ma'ale-ha-Meyshar, Ktora Cracks, Nagev Tzavoa Cave, and elsewhere, and has allowed tracking of prehistoric rainfall. The Red Sea coastal route was extremely arid before 140 and after 115 kya (thousands of years ago). Slightly wetter conditions appear at 90–87 kya, but it still
11562-431: The earliest diverging member of Carcharodontosaurinae. The cladogram results of their phylogenetic analyses are displayed in the cladogram below: Concavenator [REDACTED] Lajasvenator Lusovenator Carcharodontosaurus spp. [REDACTED] Tyrannotitan [REDACTED] In his 2024 review of theropod relationships, Cau did not recover all of the tested Carcharodontosaurus specimens in
11703-646: The eastern continental extension of the Azores High , centered over the North Atlantic Ocean . The subsidence of the Sahara High nearly reaches the ground during the coolest part of the year, while it is confined to the upper troposphere during the hottest periods. The effects of local surface low pressure are extremely limited because upper-level subsidence still continues to block any form of air ascent. Also, to be protected against rain-bearing weather systems by
11844-600: The edge of the desert thousands of years ago, since the end of the last glacial period . In the Central Sahara, engraved and painted rock art were created perhaps as early as 10,000 years ago, spanning the Bubaline Period , Kel Essuf Period , Round Head Period , Pastoral Period , Caballine Period , and Cameline Period . The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in
11985-782: The fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb , and the Nile Valley in Egypt and the Sudan . It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south it is bounded by the Sahel , a belt of semi-arid tropical savanna around
12126-463: The first terrestrial vertebrate to develop the curved, serrated teeth that enable a predator to eat prey much larger than itself". In the Mesozoic , some theropod dinosaurs such as Tyrannosaurus rex are thought probably to have been obligate carnivores. Though the theropods were the larger carnivores, several carnivorous mammal groups were already present. Most notable are the gobiconodontids ,
12267-476: The flow of dry, cold air from higher latitudes of Eurasia into the Sahara significantly. The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along
12408-699: The habitat in areas of permanent water (oases) or where water comes close to the surface. Here, the local pressure on natural resources can be intense. The remaining populations of large mammals have been greatly reduced by hunting for food and recreation. In recent years development projects have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers. These schemes often lead to soil degradation and salinization . Researchers from Hacettepe University have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. People lived on
12549-405: The highest recorded worldwide. The sky is usually clear above the desert, and the sunshine duration is extremely high everywhere in the Sahara. Most of the desert has more than 3,600 hours of bright sunshine per year (over 82% of daylight hours), and a wide area in the eastern part has over 4,000 hours of bright sunshine per year (over 91% of daylight hours). The highest values are very close to
12690-543: The hottest months of the year. Salah, well known in Algeria for its extreme heat, has average high temperatures of 43.8 °C (110.8 °F), 46.4 °C (115.5 °F), 45.5 °C (113.9 °F) and 41.9 °C (107.4 °F) in June, July, August and September respectively. There are even hotter spots in the Sahara, but they are located in extremely remote areas, especially in the Azalai , lying in northern Mali. The major part of
12831-485: The hottest regions year-round. However, most of the desert has a value in excess of 25 °C (77 °F). Sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high: it can easily reach 80 °C (176 °F) or more. A sand temperature of 83.5 °C (182.3 °F) has been recorded in Port Sudan . Ground temperatures of 72 °C (161.6 °F) have been recorded in
12972-406: The last glacial period , the Sahara was much larger than it is today, extending south beyond its current boundaries. The end of the glacial period brought more rain to the Sahara, from about 8000 BCE to 6000 BCE, perhaps because of low pressure areas over the collapsing ice sheets to the north. Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend
13113-458: The late nineteenth century, The hypothesis was later formally proposed and tested by the meteorologist John Kutzbach in 1981. Kutzbach's ideas about the impacts of insolation on global monsoonal patterns have become widely accepted today as the underlying driver of long-term monsoonal cycles. Kutzbach never formally named his hypothesis and as such it is referred to here as the " Orbital Monsoon Hypothesis " as suggested by Ruddiman in 2001. During
13254-612: 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. This makes Carcharodontosaurus saharicus one of the largest known theropod dinosaurs and terrestrial carnivores known, being the 2nd biggest carcharodontosaurid and 3rd largest theropod overall according to most estimates. C. iguidensis was much smaller, only reaching 10 metres (33 ft) in length and 4 metric tons (4.4 short tons) in body mass. The largest and most complete skull of C. saharicus would measure 1.6 metres (5.2 ft) when complete, around
13395-518: The leeward side by dropping much of the humidity brought by atmospheric disturbances along the polar front which affects the surrounding Mediterranean climates. The primary source of rain in the Sahara is the Intertropical Convergence Zone , a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular rainy season to the Sahel and southern Sahara. Rainfall in this giant desert has to overcome
13536-419: The maximum area of water and to find any surface moisture, and by having small thick leaves or needles to prevent water loss by evapotranspiration . Plant leaves may dry out totally and then recover. Several species of fox live in the Sahara including: the fennec fox , pale fox and Rüppell's fox . The addax , a large white antelope , can go nearly a year in the desert without drinking. The dorcas gazelle
13677-437: The middle Holocene Tenerian culture . The post-Kiffian desiccation lasted until around 4600 BCE, when the earliest artefacts associated with the Tenerians have been dated to. Some 200 skeletons have been discovered at Gobero. The Tenerians were considerably shorter in height and less robust than the earlier Kiffians. Craniometric analysis also indicates that they were osteologically distinct. The Kiffian skulls are akin to those of
13818-585: The niches of large carnivores were taken over by nautiloid cephalopods such as Cameroceras and later eurypterids such as Jaekelopterus during the Ordovician and Silurian periods. The first vertebrate carnivores appeared after the evolution of jawed fish , especially armored placoderms such as the massive Dunkleosteus . The dominance of placoderms in the Devonian ocean forced other fish to venture into other niches, and one clade of bony fish ,
13959-563: The north, the Sahara skirts the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Maghreb , the Sahara borders the Mediterranean forest, woodland, and scrub eco-regions of northern Africa, all of which have a Mediterranean climate characterized by hot summers and cool and rainy winters. According to the botanical criteria of Frank White and geographer Robert Capot-Rey,
14100-621: 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. 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. The subfamily Carcharodontosaurinae, in which Carcharodontosaurus belongs, appears to have been restricted to
14241-472: The northern limit of the Sahara corresponds to the northern limit of date palm cultivation and the southern limit of the range of esparto , a grass typical of the Mediterranean climate portion of the Maghreb and Iberia . The northern limit also corresponds to the 100 mm (3.9 in) isohyet of annual precipitation. To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with
14382-455: The opposite is true, with decreased annual precipitation and less vegetation resulting in a phase of the Sahara climate cycle known as the "desert Sahara". The idea that changes in insolation (solar heating) caused by long-term changes in Earth's orbit are a controlling factor for the long-term variations in the strength of monsoon patterns across the globe was first suggested by Rudolf Spitaler in
14523-427: 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
14664-471: The paleontologist Thomas R. Holtz and colleagues in 2004. Carcharodontosaurus is more poorly known than most other carcharodontosaurids, with Meraxes and Giganotosaurus represented by nearly complete skeletons. Members of the family have been recognized from the Late Jurassic to Middle Cretaceous of every continent except Oceania and Antarctica. Canale et al. (2022) recovered Carcharodontosaurus as
14805-468: The percentage of meat in their diet. The diet of a hypercarnivore consists of more than 70% meat, that of a mesocarnivore 30–70%, and that of a hypocarnivore less than 30%, with the balance consisting of non-animal foods, such as fruits , other plant material, or fungi . Omnivores also consume both animal and non-animal food, and apart from their more general definition, there is no clearly defined ratio of plant vs. animal material that distinguishes
14946-419: The physical and atmospheric barriers that normally prevent the production of precipitation. The harsh climate of the Sahara is characterized by: extremely low, unreliable, highly erratic rainfall; extremely high sunshine duration values; high temperatures year-round; negligible rates of relative humidity ; a significant diurnal temperature variation ; and extremely high levels of potential evaporation which are
15087-555: The physical characteristics to bring down prey; in addition, most hunting carnivores will scavenge when the opportunity arises. Carnivores have comparatively short digestive systems, as they are not required to break down the tough cellulose found in plants. Many hunting animals have evolved eyes facing forward, enabling depth perception. This is almost universal among mammalian predators, while most reptile and amphibian predators have eyes facing sideways. Predation (the eating of one living organism by another for nutrition ) predates
15228-416: 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. Few postcranial elements are confidently known from Carcharodontosaurus, though many isolated bones from the Sahara have been referred to the genus without detailed study. Like other carcharodontosaurids, it
15369-401: The polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Biskra , Algeria, and Ouarzazate , Morocco, are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of
15510-570: 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
15651-518: The recent past. Analysis of Nile River deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile , suggesting higher rainfall also in the Ethiopian Highlands . This was caused principally by a stronger monsoonal circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. Lake Victoria only recently became
15792-514: The region. The name saharicus refers to the Sahara Desert where the teeth had been found. The genus Megalosaurus was a wastebasket taxon , with many new species referred to it without justification, including M. saharicus . It was later considered to be a species of Dryptosaurus in 1927, though this is unjustified. By accident, another species of Megalosaurus, M. africanus , was named by German paleontologist Friedrich von Huene based on
15933-402: The rise of commonly recognized carnivores by hundreds of millions (perhaps billions) of years. It began with single-celled organisms that phagocytozed and digested other cells, and later evolved into multicellular organisms with specialized cells that were dedicated to breaking down other organisms. Incomplete digestion of the prey organisms, some of which survived inside the predators in
16074-663: The rise of multicellular organisms at about 2 bya, and the rise of motile predators (around 600 Mya – 2 bya, probably around 1 bya) have all been attributed to early predatory behavior, and many very early remains show evidence of boreholes or other markings attributed to small predator species. The sudden disappearance of the precambrian Ediacaran biota at the end-Ediacaran extinction , who were mostly bottom-dwelling filter feeders and grazers , has been hypothetized to be partly caused by increased predation by newer animals with hardened skeleton and mouthparts. The degradation of seafloor microbial mats due to
16215-587: The same area suggest that they lived on the shores of a lake that was present during the Holocene Wet Phase, a period when the Sahara was verdant and wet. The Kiffian people were tall, standing over six feet in height. Craniometric analysis indicates that this early Holocene population was closely related to the Late Pleistocene Iberomaurusians and early Holocene Capsians of the Maghreb, as well as mid-Holocene Mechta groups. Traces of
16356-409: 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
16497-461: 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. 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
16638-459: The scale of the Nile floods between 2700 and 2100 BCE. The Sahara comprises several distinct ecoregions . With their variations in temperature, rainfall, elevation, and soil, these regions harbor distinct communities of plants and animals. The flora of the Sahara is highly diversified based on the bio-geographical characteristics of this vast desert. Floristically , the Sahara has three zones based on
16779-521: The shelter of shrubs such as balanites and acacias. They are unusually pale. The other cheetah subspecies ( northeast African cheetah ) lives in Chad, Sudan and the eastern region of Niger. However, it is currently extinct in the wild in Egypt and Libya. There are approximately 2000 mature individuals left in the wild. Other animals include the monitor lizards , hyrax , sand vipers , and small populations of African wild dog , in perhaps only 14 countries and red-necked ostrich . Other animals exist in
16920-573: The source of the White Nile and dried out almost completely around 15 kya. The sudden subsequent movement of the ITCZ southwards with a Heinrich event (a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation cycle, led to a rapid drying out of the Saharan and Arabian regions, which quickly became desert. This is linked to a marked decline in
17061-624: The southern continent of Gondwana (formed by South America and Africa), where they were probably the apex predators . 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. 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
17202-527: The stronger skull of Carcharodontosaurus could bite while sustaining the stress. Carnivore A carnivore / ˈ k ɑːr n ɪ v ɔːr / , or meat-eater ( Latin , caro , genitive carnis , meaning meat or "flesh" and vorare meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly muscle , fat and other soft tissues ) as food , whether through predation or scavenging . The technical term for mammals in
17343-561: The strongest anticyclonic weather regime, and the annual average rainfall can drop to less than 1 millimetre (0.04 in). In fact, most of the Sahara receives less than 20 millimetres (0.8 in). Of the 9,000,000 square kilometres (3,500,000 sq mi) of desert land in the Sahara, an area of about 2,800,000 square kilometres (1,100,000 sq mi) (about 31% of the total area) receives an annual average rainfall amount of 10 millimetres (0.4 in) or less, while some 1,500,000 square kilometres (580,000 sq mi) (about 17% of
17484-530: The teeth of the great white shark ( Carcharodon carcharias ). 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. An endocast was made and survived the war, being the only remaining relic of the specimen. Few discoveries of Carcharodontosaurus material were made until 1995, when American paleontologist Paul Sereno found an incomplete skull during an expedition embarked on by
17625-869: The teeth. It is therefore considered a junior synonym of M. saharicus . 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 . 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 , though some of these fossils might belong to other genera. Later authors have mentioned finds of teeth and isolated fossils from other provinces of Algeria. 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
17766-549: The theoretical maximum value. A value of 4300 hours (98%) of the time would be recorded in Upper Egypt ( Aswan , Luxor ) and in the Nubian Desert ( Wadi Halfa ). The annual average direct solar irradiation is around 2,800 kWh/(m year) in the Great Desert. The Sahara has a huge potential for solar energy production. The high position of the Sun, the extremely low relative humidity, and the lack of vegetation and rainfall make
17907-465: The tilt of the earth changes between 22° and 24.5°. At present, it is in a dry period, but it is expected that the Sahara will become green again in 15,000 years. When the North African monsoon is at its strongest, annual precipitation and subsequent vegetation in the Sahara region increase, resulting in conditions commonly referred to as the " green Sahara ". For a relatively weak North African monsoon,
18048-408: 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. 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. However, they are extremely thin, with most being under
18189-478: The total area) receives an average of 5 millimetres (0.2 in) or less. The annual average rainfall is virtually zero over a wide area of some 1,000,000 square kilometres (390,000 sq mi) in the eastern Sahara comprising deserts of: Libya, Egypt and Sudan ( Tazirbu , Kufra , Dakhla , Kharga , Farafra , Siwa , Asyut , Sohag , Luxor, Aswan, Abu Simbel , Wadi Halfa) where the long-term mean approximates 0.5 millimetres (0.02 in) per year. Rainfall
18330-408: The weight of an adult Limaysaurus . However, two C. saharicus adults could together lift as much as 850 kilograms (1,870 lb). 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
18471-545: 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
18612-433: Was discussed by Chiarenza and Cau (2016), 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. Several other fossils of C. saharicus have been unearthed from
18753-403: Was initially counteracted by the monsoon , which brought rain further north than it does today. By around 4200 BCE, however, the monsoon retreated south to approximately where it is today, leading to the gradual desertification of the Sahara. The Sahara is now as dry as it was about 13,000 years ago. Lake Chad is the remnant of a former inland sea, paleolake Mega-Chad, which existed during
18894-461: Was just one tenth the rainfall around 125 kya. In the southern Negev Desert speleothems did not grow between 185 and 140 kya ( MIS 6), 110–90 (MIS 5.4–5.2), nor after 85 kya nor during most of the interglacial period (MIS 5.1), the glacial period and Holocene . This suggests that the southern Negev was arid-to-hyper-arid in these periods. During the Last Glacial Maximum (LGM) the Sahara
19035-556: Was more extensive than it is now with the extent of the tropical forests being greatly reduced, and the lower temperatures reduced the strength of the Hadley Cell . This is a climate cell which causes rising tropical air of the Inter-Tropical Convergence Zone (ITCZ) to bring rain to the tropics, while dry descending air, at about 20 degrees north , flows back to the equator and brings desert conditions to this region. It
19176-450: Was not until 1922 that they were transported overseas to Munich where they were described by Stromer in 1931. 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
19317-433: Was placed farther back behind the occipital condyle (where the neck is attached to the skull) compared to other theropods. 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. If like Tyrannotitan and Giganotosaurus , the dentary would have 16 alveoli (tooth sockets). Estimations of
19458-639: 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). Cervical vertebrae in this genus, as in Giganotosaurus , are topped by low neural spines joined with sturdy transverse processes which hung over
19599-404: Was synonymized with Carcharodontosaurus by Figueiredo (1998) and Paul (2010), however no authors have since followed this assessment. 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,
19740-483: Was the first to note the possible presence of Carcharodontosaurus in Morocco as early as 1954. 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
19881-472: Was typical for a non-avian reptile. Carcharodontosaurus also had a large optic nerve . 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
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