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Allosaurus is an extinct genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch. The name "Allosaurus" means "different lizard" alluding to its unique concave vertebrae. It is derived from the Greek ἄλλος and σαῦρος. The first fossil remains that could definitively be ascribed to this genus were described in 1877 by paleontologist Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles.
Albertosaurus is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago. The type species, A. sarcophagus, was apparently restricted in range to the modern-day Canadian province of Alberta, after which the genus is named, although an indeterminate species has been discovered in the Corral de Enmedio and Packard Formations in Mexico. Scientists disagree on the content of the genus and some recognize Gorgosaurus libratus as a second species.
Tyrannosaurus is a genus of large theropod dinosaur. The species Tyrannosaurus rex, often called T. rex or colloquially T-Rex, is one of the best represented theropods. It lived throughout what is now western North America, on what was then an island continent known as Laramidia. Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the Upper Cretaceous period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event.
Tyrannosauridae is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to thirteen genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three. All of these animals lived near the end of the Cretaceous Period and their fossils have been found only in North America and Asia.
Tarbosaurus is a genus of tyrannosaurine theropod dinosaur that lived in Asia about 70 million years ago, during the Maastrichtian age at the end of the Late Cretaceous period, considered to contain a single known species: Tarbosaurus bataar. Fossils have been recovered from the Nemegt Formation of Mongolia, with more fragmentary remains found further afield in the Subashi Formation of China.
Daspletosaurus is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 75 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains three species. Fossils of the earlier type species, D. torosus, have been found in Alberta, and fossils of a later second species, D. horneri, and third species, D. wilsoni, have been found only in Montana. A possible fourth species, also from Alberta, awaits formal identification. The taxon Thanatotheristes has been suggested to represent a species of Daspletosaurus, D. degrootorum, but this has not been widely supported. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex. Like most tyrannosaurids, Daspletosaurus was a multi-tonne bipedal predator equipped with dozens of large, sharp teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera.
Deinonychus is a genus of dromaeosaurid theropod dinosaur with one described species, Deinonychus antirrhopus. This species, which could grow up to 3.4 meters (11 ft) long, lived during the early Cretaceous Period, about 115–108 million years ago. Fossils have been recovered from the U.S. states of Montana, Utah, Wyoming, and Oklahoma, in rocks of the Cloverly Formation and Antlers Formation, though teeth that may belong to Deinonychus have been found much farther east in Maryland.
Theropoda, whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago (Ma) and included all the large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species.
Dilophosaurus is a genus of theropod dinosaurs that lived in what is now North America during the Early Jurassic, about 193 million years ago. Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942. The most complete specimen became the holotype of a new species in the genus Megalosaurus, named M. wetherilli by Samuel P. Welles in 1954. Welles found a larger skeleton belonging to the same species in 1964. Realizing it bore crests on its skull, he assigned the species to the new genus Dilophosaurus in 1970, as Dilophosaurus wetherilli. The genus name means "two-crested lizard", and the species name honors John Wetherill, a Navajo councilor. Further specimens have since been found, including an infant. Footprints have also been attributed to the animal, including resting traces. Another species, Dilophosaurus sinensis from China, was named in 1993, but was later found to belong to the genus Sinosaurus.
Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding behavior. Scavengers play an important role in the ecosystem by consuming dead animal and plant material. Decomposers and detritivores complete this process, by consuming the remains left by scavengers.
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, Rubén D. 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.
Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Canadian province of Alberta and the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus.
Baryonyx is a genus of theropod dinosaur which lived in the Barremian stage of the Early Cretaceous period, about 130–125 million years ago. The first skeleton was discovered in 1983 in the Smokejack Clay Pit, of Surrey, England, in sediments of the Weald Clay Formation, and became the holotype specimen of Baryonyx walkeri, named by palaeontologists Alan J. Charig and Angela C. Milner in 1986. The generic name, Baryonyx, means "heavy claw" and alludes to the animal's very large claw on the first finger; the specific name, walkeri, refers to its discoverer, amateur fossil collector William J. Walker. The holotype specimen is one of the most complete theropod skeletons from the UK, and its discovery attracted media attention. Specimens later discovered in other parts of the United Kingdom and Iberia have also been assigned to the genus, though many have since been moved to new genera.
Ceratosaurus was a carnivorous theropod dinosaur in the Late Jurassic period. The genus was first described in 1884 by American paleontologist Othniel Charles Marsh based on a nearly complete skeleton discovered in Garden Park, Colorado, in rocks belonging to the Morrison Formation. The type species is Ceratosaurus nasicornis.
Neovenator is a genus of carcharodontosaurian theropod dinosaur. It is known from several skeletons found in the Early Cretaceous Wessex Formation on the south coast of the Isle of Wight, southern England. It is one of the best known theropod dinosaurs from the Early Cretaceous of Europe.
The Spinosauridae are 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.
Tyrannosaurus is one of the most iconic dinosaurs and is known from numerous specimens, some of which have individually acquired notability due to their scientific significance and media coverage.
Theropod paleopathology is the study of injury and disease in theropod dinosaurs. In 2001, Ralph E. Molnar published a survey of pathologies in theropod dinosaur bone that uncovered pathological features in 21 genera from 10 theropod families. Pathologies have been seen on most theropod body parts, with the most common sites of preserved injury and disease being the ribs and tail vertebrae. The least common sites of preserved pathology are the weight-bearing bones like the tibia, femur and sacrum. Most pathologies preserved in theropod fossils are the remains of injuries, but infections and congenital deformities have also been documented. Pathologies are less frequently documented in small theropods, although this may simply be because the larger bones of correspondingly larger animals would be more likely to fossilize in the first place.
The feeding behaviour of Tyrannosaurus rex has been studied extensively. The well known attributes of T. rex are often interpreted to be indicative of either a predatory or scavenging lifestyle, and as such the biomechanics, feeding strategies and diet of Tyrannosaurus have been subject to much research and debate.
This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally. Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, and Delaware stories about smoking the bones of ancient monsters to have wishes granted.
References
- ↑ Locke R, 2001, "Killing a Legend: New Evidence Paints T. Rex as a Nasty Scavenger, Not a Vicious Hunter", dsc.discovery.com, read July 11, 2012.
- 1 2 Holtz T.R.jr. "A critical re-appraisal of the obligate scavenging hypothesis for Tyrannosaurus rex and other tyrant dinosaurs", in Tanke D.H., Carpenter K & Skrepnick M.W. Mesozoic Vertebrate Life (Indiana University Press, 2001), p. 370-396.
- ↑ Holekamp, K. E.; Smale, L.; Berg, R.; Cooper, S. M. (March 24, 2009). "Hunting rates and hunting success in the spotted hyena (Crocuta crocuta)". Journal of Zoology . 242 (1): 1–15. doi:10.1111/j.1469-7998.1997.tb02925.x . Retrieved March 19, 2023.
- ↑ http://www.cmnh.org/dinoarch/2001Sep/msg00522.html .
- ↑ Larson P.L., "Variation and Sexual Dimorphism in Tyrannosaurus rex", in Larson P.L. & Carpenter K, Tyrannosaurus rex, the Tyrant King (Indiana University Press, 2008), p. 103-130.
- ↑ Horner J.R. & Padian K. (2004), "Age and growth dynamics of Tyrannosaurus rex", Proceedings of the Royal Society of London B 271(1551): p. 1875-1880.
- ↑ Stevens K.A. (2006), "Binocular vision in theropod dinosaurs" Archived March 23, 2012, at the Wayback Machine , Journal of Vertebrate Paleontology26(2): p. 321-330.
- ↑ Carpenter, Kenneth (1998). "Evidence of predatory behavior by theropod dinosaurs" (PDF). Gaia. 15: 135–144.
- ↑ Happ, John; Carpenter, Kenneth (2008). "An analysis of predator-prey behavior in a head-to-head encounter between Tyrannosaurus rex and Triceratops". In Carpenter, Kenneth; Larson, Peter E. (eds.). Tyrannosaurus rex, the Tyrant King (Life of the Past). Bloomington: Indiana University Press. pp. 355–368. ISBN 978-0-253-35087-9.