Потребителски вход

Запомни ме | Регистрация
02.01.2016 16:23 - Encyclopedia Largest prehistoric animals Vol.1 Vertebrates part3 Dinosaurs ch.1 Theropods- Carcharodontosaurids from Africa
Автор: valentint Категория: Забавление   
Прочетен: 3561 Коментари: 0 Гласове:

Последна промяна: 02.06.2019 19:56

Some other notable giant theropods is Carcharodontosaurus.It is currently known to include two species:
and C.iguidensis

Carcharodontosaurus /ˌkɑrkərɵˌdɒntɵˈsɔrəs/ is a genus of carnivorous carcharodontosaurid dinosaurs that existed between 100 and 93 million years ago, during the late Albian to early Cenomanian stages of the mid-CretaceousPeriod. It is currently known to include two species, C.saharicus and C.iguidensis, which were among the larger theropods, as large as or slightly bigger than Tyrannosaurus and possibly slightly larger than Giganotosaurus, but not quite as large as Spinosaurus.

The genus Carcharodontosaurus is named after the shark genus Carcharodon (itself named from the Greek καρχαρο (karcharo) meaning "jagged" or "sharp" and οδοντο (odonto) meaning "teeth")), and σαυρος (sauros), meaning "lizard".
Carcharodontosaurus includes some of the longest and heaviest known carnivorous dinosaurs, with various scientists proposing length estimates for the species C. saharicus ranging between 12 and 13 m (39 and 43 ft) and weight estimates between 6 and 15 metric tons.
Carcharodontosaurus were carnivores, with enormous jaws and long, serrated teeth up to eight inches long. Paleontologists once thought that Carcharodontosaurus had the longest skulls of any of the theropod dinosaurs. However, the premaxilla and quadrate bones were missing from the original African skull, which led to misinterpretation of its actual size by researchers. A more modest length of 1.6 meters (5.2 ft) has now been proposed for C. saharicus, and the skull of C. iguidensis is reported to have been about the same size. Currently, the largest known theropod skull belongs to another huge carcharodontosaurid dinosaur, the closely related Giganotosaurus (with skull length estimates up to 1.95 m) (6.3 ft).Gregory S. Paul estimates Carcharodontosaurus iguidensis at 10 m (33 ft) and 4 t (4.4 short tons). 
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 hind brain, 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.
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, turtles, but not in birds.The semi-"circular" canals themselves were actually 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.
SGM-Din 1, a Carcharodontosaurus saharicus skull, has a circular puncture wound in the nasal and "an abnormal projection of bone on the antorbital rim".
In 1924, two teeth were found in the Continental intercalaire of Algeria, showing what were at the time unique characteristics, this teeth were described by Depйret and Savornin (1925) as representing a new taxon, which they named Megalosaurus saharicusand later referred by the same authors to the subgenus Dryptosaurus. Some years later, paleontologist Ernst Stromer described the remains of a partial skull and skeleton from Cenomanian aged rocks in the Bahariya Formation of Egypt (Stromer, 1931),originally excavated in 1914, the remains consisted on a partial skull, teeth, vertebrae, claw bones and assorted hip and leg bones.The teeth in this new finding matched the characteristic of those described by Depйret and Savornin which lead Stromer to conserve the species name saharicus but found necessary to erect a new genus for this species, Carcharodontosaurus, for their strong resemblance to the teeth of Carcharodon (Great white shark).
The fossils described by Stromer were destroyed in 1944 during World War II but a new more complete skull was found in the Kem Kem Formation of Morocco during an expedition lead by paleontologist Paul Sereno in 1995, not too far from the Algerian border and the locality where the teeth described by Depйret and Savornin (1925) were found, the teeth found with this new skull matched those described by Depйret and Savornin (1925) and Stromer (1931), the rest of the skull also matched that described by Stromer. This new skull was designated as the neotype by Brusatte and Sereno (2007) who also described a second species of Carcharodontosaurus, C. iguidensis from the Echkar Formation of Niger, differing from C. saharicus in aspects of the maxilla and braincase.

Bahariasaurus ingens
1.Bahariasaurus ingens 2.Deltadromeus agilis 3.Ceratosaurus nasicornis 4.Limusaurus inextricabilis

Bahariasaurus (meaning "Bahariya lizard") is a genus of large theropod dinosaur found in the Bahariya Formation in El-Waha el-Bahariya or Bahariya ( meaning the "northern oasis") oasis in Egypt and Kem Kem Beds of North Africa, which date to the late Cretaceous Period, (Cenomanian age), about 95 million years ago. It was a huge theropod, in the same size range as Tyrannosaurus and the contemporary genus Carcharodontosaurus.
The type species, B. ingens, was described by Ernst Stromer in 1934, though the type specimen was destroyed during World War II. The exact placement of Bahariasaurus is uncertain, although it has been variously assigned to several theropod groups, including Carcharodontosauridae (by Rauhut in 1995) and Tyrannosauroidea (by Chure in 2000). It is potentially synonymous with Deltadromeus, another theropod from the early Late Cretaceous of North Africa, this would possibly make it the largest ceratosaur.More specimens would be needed to more accurately classify it, and to determine its relationship to Deltadromeus.

Veterupristisaurus is an extinct genus of carcharodontosaurid theropod dinosaur known from the Jurassic of Tendaguru, southeastern Tanzania.
Veterupristisaurus is known from the holotype specimen MB R 1938, an isolated middle caudal vertebra. Two partially fused posterior middle caudal vertebrae, MB R 2166, from the same locality as the holotype, are referred to this genus and most probably came from the same individual. The anterior caudal vertebra, MB R 1940, may also represent this genus. The holotype was collected in the St (EH) locality of the Tendaguru in German East Africa, from the Middle Dinosaur Member of the Tendaguru Formation, dating to the late Kimmeridgian to earliest Tithonian faunal stage of the Late Jurassic, about 154-150 million years ago. It was originally referred to Ceratosaurus? roechlingi by Werner Janensch.
Veterupristisaurus was a large bipedal animal. The length of the holotype vertebra is about 123 mm (4.8 in), thus Veterupristisaurus has been estimated to have been about 8.5 m (28 ft) -10 m (33 ft) in length, based on the more complete and closely related Acrocanthosaurus. Whether the individual represented by the holotype represents an adult individual cannot be determined based on the available material. It is diagnosed by a spinoprezygapophyseal lamina in the middle caudal vertebrae extending anteriorly to the midwidth of the base of the prezygapophysis and being flanked laterally by a short, parallel lamina extending from the lateral margin of the prezygapophysis posteriorly. Thus, Rauhut considered a sister-group relationship between Veterupristisaurus and Acrocanthosaurus within the Carcharodontosauridae.

Sauroniops is a genus of predatory basal carcharodontosaurid theropoddinosaur known from the Late Cretaceous (Cenomanian stage) of Morocco.
In the early twenty-first century a collector donated a dinosaur skull bone to the Italian Museo Paleontologico di Montevarchi. He had acquired the specimen from a Moroccan fossil dealer, who again had bought the piece from local fossil hunters near Taouz. Its exact provenance is therefore uncertain. Later research showed that it presented a new species that was in 2012 reported and described by Andrea Cau, Marco Dalla Vecchia and Matteo Fabbri.
The same year, 2012, the specimen was by the same authors formally named in a subsequent publication as the type species Sauroniops pachytholus. The generic name has the intended meaning of "Eye of Sauron", a demonic entity from the Lord of the Ringsfantasy novel by J.R.R. Tolkien, combining its name with a Classical Greek ops, "eye". Like in the novels the corporeal presence of Sauron had largely been limited to a single searching eye, Sauroniops is only known from a single bone above the eye socket. The specific name is derived from Greek παχύς, pachys, "thick", and θόλος, tholos, "round building with conical roof", in reference to the thick vaulted skull roof.
The holotype, specimen MPM 2594, had probably been recovered from the Kem Kem Beds dating from the Cenomanian. It consists of a left frontal bone.
Sauroniops was a large bipedal predator. The describers established several unique traits, differentiating Sauroniops from its relatives, such as Carcharodontosaurus which is found in the same layers. The nasal bone has an area of contact with the frontal bone over 40% of the latter"s length. The frontal has in the left front corner a thick vaulted area. On the front upper rim the frontal has a trapezoid facet to contact the prefrontal, which is no part of the upper rim of the eye socket, and is separated from the facet for the lacrimal bone by a thin vertical ridge. The contact area with the lacrimal is D-shaped, extremely large and has four times the height of the facet with the postorbital bone. On the rear inner side of the frontal an elevated rim is present that is joint to the front vaulted area by a saddle-shaped depression and more towards the front midline of the skull continues in a series of rugosities.
The frontal has a preserved length of 186 millimetres. Near the contact with the lacrimal the bone is extremely thickened to a height of seventy-three millimetres and vaulted; a second thick area is present at the rear separated from the first by a hollow surface. Such a thickening of the skull roof is more typical of the Abelisauridae in which group however, it is the postorbital that shows the phenomenon. The authors explained the thickening as an adaptation for display or to strengthen the skull for intraspecific head-butting.
The holotype of Sauroniops was originally interpreted as belonging to a derived member of the Carcharodontosauridae. A more extensive cladistic analysis in the naming paper showed a more basal position in the same group as a sister species of Eocarcharia. The similarities to the abelisaurids would then be convergences.


Няма коментари

За този блог
Автор: valentint
Категория: Политика
Прочетен: 1088628
Постинги: 250
Коментари: 22
Гласове: 23
«  Юли, 2021