Tyrannosaurus Rex Skull 2
Tyrannosaurus Rex "King of the Tyrant Lizards" Skull at the National Museum of Natural History in Washington, DC on April-9th-2022. TREX Lived in the Maastrichtian Stage of the Late Cretaceous 68MA to 66MA in Western North America.
Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, the forelimbs of Tyrannosaurus were short but unusually powerful for their size, and they had two clawed digits. The most complete specimen measures up to 12.3–12.4 m (40.4–40.7 ft) in length, though T. rex could grow to lengths of over 12.4 m (40.7 ft), up to 3.66–3.96 m (12–13 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, juvenile armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both an active predator and a scavenger.
T. rex was one of the largest land carnivores of all time. One of the largest and the most complete specimens, nicknamed Sue (FMNH PR2081), is located at the Field Museum of Natural History. Sue measured 12.3–12.4 m (40.4–40.7 ft) long,was 3.66–3.96 meters (12–13 ft) tall at the hips,and according to the most recent studies, using a variety of techniques, maximum body masses have been estimated between 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons).A specimen nicknamed Scotty (RSM P2523.8), located at the Royal Saskatchewan Museum, is reported to measure 13 m (43 ft) in length. Using a mass estimation technique that extrapolates from the circumference of the femur, Scotty was estimated as the largest known specimen at 8.8 metric tons (9.7 short tons) in weight.
Not every adult Tyrannosaurus specimen recovered is as big. Historically average adult mass estimates have varied widely over the years, from as low as 4.5 metric tons (5.0 short tons),[38][39] to more than 7.2 metric tons (7.9 short tons),[40] with most modern estimates ranging between 5.4 metric tons (6.0 short tons) and 8.0 metric tons (8.8 short tons).
Restoration showing scaly skin with sparse feathering, and lipped jaws
The largest known T. rex skulls measure up to 1.52 meters (5 ft) in length.[ Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision.The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter. These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids.[47][48][49] The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.[50]
The teeth of T. rex displayed marked heterodonty (differences in shape).The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards. The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled. The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges.Those in the upper jaw, twelve per side in mature individuals, were larger than their counterparts of the lower jaw, except at the rear. The largest found so far is estimated to have been 30.5 centimeters (12 in) long including the root when the animal was alive, making it the largest tooth of any carnivorous dinosaur yet found.[54] The lower jaw was robust. Its front dentary bone bore thirteen teeth. Behind the tooth row, the lower jaw became notably taller.The upper and lower jaws of Tyrannosaurus, like those of many dinosaurs, possessed numerous foramina, or small holes in the bone. Various functions have been proposed for these foramina, such as a crocodile-like sensory system or evidence of extra-oral structures such as scales or potentially lip
Tyrannosaurus lived during what is referred to as the Lancian faunal stage (Maastrichtian age) at the end of the Late Cretaceous. Tyrannosaurus ranged from Canada in the north to at least New Mexico in the south of Laramidia. During this time Triceratops was the major herbivore in the northern portion of its range, while the titanosaurian sauropod Alamosaurus "dominated" its southern range. Tyrannosaurus remains have been discovered in different ecosystems, including inland and coastal subtropical, and semi-arid plains.
Tyrannosaurus and other animals of the Hell Creek Formation
Several notable Tyrannosaurus remains have been found in the Hell Creek Formation. During the Maastrichtian this area was subtropical, with a warm and humid climate. The flora consisted mostly of angiosperms, but also included trees like dawn redwood (Metasequoia) and Araucaria. Tyrannosaurus shared this ecosystem with ceratopsians Leptoceratops, Torosaurus, and Triceratops, the hadrosaurid Edmontosaurus annectens, the parksosaurid Thescelosaurus, the ankylosaurs Ankylosaurus and Denversaurus, the pachycephalosaurs Pachycephalosaurus and Sphaerotholus, and the theropods Ornithomimus, Struthiomimus, Acheroraptor, Dakotaraptor, Pectinodon and Anzu.
Another formation with Tyrannosaurus remains is the Lance Formation of Wyoming. This has been interpreted as a bayou environment similar to today's Gulf Coast. The fauna was very similar to Hell Creek, but with Struthiomimus replacing its relative Ornithomimus. The small ceratopsian Leptoceratops also lived in the area.
In its southern range Tyrannosaurus lived alongside the titanosaur Alamosaurus, the ceratopsians Torosaurus, Bravoceratops and Ojoceratops, hadrosaurs which consisted of a species of Edmontosaurus, Kritosaurus and a possible species of Gryposaurus, the nodosaur Glyptodontopelta, the oviraptorid Ojoraptosaurus, possible species of the theropods Troodon and Richardoestesia, and the pterosaur Quetzalcoatlus.The region is thought to have been dominated by semi-arid inland plains, following the probable retreat of the Western Interior Seaway as global sea levels fell.
Tyrannosaurus Rex Skull 2
Tyrannosaurus Rex "King of the Tyrant Lizards" Skull at the National Museum of Natural History in Washington, DC on April-9th-2022. TREX Lived in the Maastrichtian Stage of the Late Cretaceous 68MA to 66MA in Western North America.
Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, the forelimbs of Tyrannosaurus were short but unusually powerful for their size, and they had two clawed digits. The most complete specimen measures up to 12.3–12.4 m (40.4–40.7 ft) in length, though T. rex could grow to lengths of over 12.4 m (40.7 ft), up to 3.66–3.96 m (12–13 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, juvenile armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both an active predator and a scavenger.
T. rex was one of the largest land carnivores of all time. One of the largest and the most complete specimens, nicknamed Sue (FMNH PR2081), is located at the Field Museum of Natural History. Sue measured 12.3–12.4 m (40.4–40.7 ft) long,was 3.66–3.96 meters (12–13 ft) tall at the hips,and according to the most recent studies, using a variety of techniques, maximum body masses have been estimated between 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons).A specimen nicknamed Scotty (RSM P2523.8), located at the Royal Saskatchewan Museum, is reported to measure 13 m (43 ft) in length. Using a mass estimation technique that extrapolates from the circumference of the femur, Scotty was estimated as the largest known specimen at 8.8 metric tons (9.7 short tons) in weight.
Not every adult Tyrannosaurus specimen recovered is as big. Historically average adult mass estimates have varied widely over the years, from as low as 4.5 metric tons (5.0 short tons),[38][39] to more than 7.2 metric tons (7.9 short tons),[40] with most modern estimates ranging between 5.4 metric tons (6.0 short tons) and 8.0 metric tons (8.8 short tons).
Restoration showing scaly skin with sparse feathering, and lipped jaws
The largest known T. rex skulls measure up to 1.52 meters (5 ft) in length.[ Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision.The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter. These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids.[47][48][49] The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.[50]
The teeth of T. rex displayed marked heterodonty (differences in shape).The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards. The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled. The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges.Those in the upper jaw, twelve per side in mature individuals, were larger than their counterparts of the lower jaw, except at the rear. The largest found so far is estimated to have been 30.5 centimeters (12 in) long including the root when the animal was alive, making it the largest tooth of any carnivorous dinosaur yet found.[54] The lower jaw was robust. Its front dentary bone bore thirteen teeth. Behind the tooth row, the lower jaw became notably taller.The upper and lower jaws of Tyrannosaurus, like those of many dinosaurs, possessed numerous foramina, or small holes in the bone. Various functions have been proposed for these foramina, such as a crocodile-like sensory system or evidence of extra-oral structures such as scales or potentially lip
Tyrannosaurus lived during what is referred to as the Lancian faunal stage (Maastrichtian age) at the end of the Late Cretaceous. Tyrannosaurus ranged from Canada in the north to at least New Mexico in the south of Laramidia. During this time Triceratops was the major herbivore in the northern portion of its range, while the titanosaurian sauropod Alamosaurus "dominated" its southern range. Tyrannosaurus remains have been discovered in different ecosystems, including inland and coastal subtropical, and semi-arid plains.
Tyrannosaurus and other animals of the Hell Creek Formation
Several notable Tyrannosaurus remains have been found in the Hell Creek Formation. During the Maastrichtian this area was subtropical, with a warm and humid climate. The flora consisted mostly of angiosperms, but also included trees like dawn redwood (Metasequoia) and Araucaria. Tyrannosaurus shared this ecosystem with ceratopsians Leptoceratops, Torosaurus, and Triceratops, the hadrosaurid Edmontosaurus annectens, the parksosaurid Thescelosaurus, the ankylosaurs Ankylosaurus and Denversaurus, the pachycephalosaurs Pachycephalosaurus and Sphaerotholus, and the theropods Ornithomimus, Struthiomimus, Acheroraptor, Dakotaraptor, Pectinodon and Anzu.
Another formation with Tyrannosaurus remains is the Lance Formation of Wyoming. This has been interpreted as a bayou environment similar to today's Gulf Coast. The fauna was very similar to Hell Creek, but with Struthiomimus replacing its relative Ornithomimus. The small ceratopsian Leptoceratops also lived in the area.
In its southern range Tyrannosaurus lived alongside the titanosaur Alamosaurus, the ceratopsians Torosaurus, Bravoceratops and Ojoceratops, hadrosaurs which consisted of a species of Edmontosaurus, Kritosaurus and a possible species of Gryposaurus, the nodosaur Glyptodontopelta, the oviraptorid Ojoraptosaurus, possible species of the theropods Troodon and Richardoestesia, and the pterosaur Quetzalcoatlus.The region is thought to have been dominated by semi-arid inland plains, following the probable retreat of the Western Interior Seaway as global sea levels fell.