Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.
A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record.
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.
John Robert Horner is an American paleontologist most famous for describing Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. In addition to his paleontological discoveries, Horner served as the technical advisor for the first five Jurassic Park films, had a cameo appearance in Jurassic World, and served as a partial inspiration for one of the lead characters of the franchise, Dr. Alan Grant. Horner studied at the University of Montana, although he did not complete his degree due to undiagnosed dyslexia, and was awarded a Doctorate in Science honoris causa. He retired from Montana State University on July 1, 2016, although he claims to have been pushed out of the Museum of the Rockies after having married an undergraduate student and now teaches as a Presidential Fellow at Chapman University.
The scientific question of within which larger group of animals birds evolved has traditionally been called the "origin of birds". The present scientific consensus is that birds are a group of maniraptoran theropod dinosaurs that originated during the Mesozoic Era.
Tyrannosaurinae is one of the two extinct subfamilies of Tyrannosauridae, a family of coelurosaurian theropods that consists of at least three tribes and several genera. All fossils of these genera have been found in the Late Cretaceous deposits of western North America and east Asia. Compared to the related subfamily Albertosaurinae, tyrannosaurines overall are more robust and larger though the alioramins were gracile by comparison. This subfamily also includes the oldest known tyrannosaurid genus Lythronax as well as the youngest and most famous member of the group, Tyrannosaurus rex. There were at least 30 different species of tyrannosaurines.
Sue is the nickname given to FMNH PR 2081, which is one of the largest, most extensive, and best preserved Tyrannosaurus rex specimens ever found, at over 90 percent recovered by bulk. FMNH PR 2081 was discovered on August 12, 1990, by American explorer and fossil collector Sue Hendrickson, and was named after her.
Phylogenetic bracketing is a method of inference used in biological sciences. It is used to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going all the way back to the last universal common ancestor (LUCA). The method is often used for understanding traits that do not fossilize well, such as soft tissue anatomy, physiology and behaviour. By considering the closest and second-closest well-known organisms, traits can be asserted with a fair degree of certainty, though the method is extremely sensitive to problems from convergent evolution.
"Stan", also known by its inventory number BHI 3033, is a Tyrannosaurus rex fossil found in the Hell Creek Formation in South Dakota, just outside of Buffalo in 1987, and excavated in 1992. It is the fifth most complete T. rex fossil discovered to date, at more than 70% bulk. In October 2020, the fossil was sold for $31.8 million at auction, making it the most expensive dinosaur specimen and fossil ever sold. In March 2022 Abu Dhabi's Department of Culture and Tourism stated that they had acquired Stan and were planning on displaying the fossil at a new museum of natural history scheduled to open in 2025.
Tyrannosaurus rex 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.
Dakota is the nickname given to an important Edmontosaurus fossil found in the Hell Creek Formation in North Dakota. It is about 67 million years old, placing it in the Maastrichtian, the last stage of the Cretaceous period. It was about 12 m (40 ft) long and weighed about 7-8 tons.
Dinosaur reproduction was relevant to archosaur physiology, with newborns hatching from eggs. Dinosaurs did not nurture their offspring as mammals typically do, and because dinosaurs did not nurse, it is likely that most dinosaurs were capable of surviving on their own after hatching.
Palaeoimmunology or paleo-immunology is the analysis using histochemical techniques to look at the matrix proteins in historic and pre-historic materials. Modern immunological assays are used to detect the presence of specific antigens in the sample material. Specimens subject to immunoassays have usually been preserved in a way that has prevented biomolecular targets from degrading. This has either been achieved through natural preservative circumstances, such as accelerated fossilization, or through artificial mummification. Regardless of the path taken to achieve this state, preservation has occurred before the denaturing of antigenic targets. The purpose of applying immunological assays to archaeological materials is to better understand the biochemical makeup and composition of these pre-historic samples. Antigenic elements within these materials may reveal information regarding the "life" and "death" of the sample being studied.
Molecular paleontology refers to the recovery and analysis of DNA, proteins, carbohydrates, or lipids, and their diagenetic products from ancient human, animal, and plant remains. The field of molecular paleontology has yielded important insights into evolutionary events, species' diasporas, the discovery and characterization of extinct species. loo In shallow time, advancements in the field of molecular paleontology have allowed scientists to pursue evolutionary questions on a genetic level rather than relying on phenotypic variation alone. By applying molecular analytical techniques to DNA in Recent animal remains, one can quantify the level of relatedness between any two organisms for which DNA has been recovered. Using various biotechnological techniques such as DNA isolation, amplification, and sequencing scientists have been able to gain expanded new insights into the divergence and evolutionary history of countless recently extinct organisms. In February 2021, scientists reported, for the first time, the sequencing of DNA from animal remains, a mammoth in this instance, over a million years old, the oldest DNA sequenced to date.
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.
Wendy Sloboda is a Canadian fossil hunter from Warner, Alberta. She has made fossil discoveries of dinosaurs and other extinct animals on several continents, with finds in Canada, Argentina, Mongolia, France, and Greenland. She is commemorated in name of the horned dinosaur Wendiceratops, remains of which she discovered in 2010, as well as the fossil footprint Barrosopus slobodai which she discovered in 2003.
Ancient proteins are complex mixtures and the term palaeoproteomics is used to characterise the study of proteomes in the past. Ancients proteins have been recovered from a wide range of archaeological materials, including bones, teeth, eggshells, leathers, parchments, ceramics, painting binders and well-preserved soft tissues like gut intestines. These preserved proteins have provided valuable information about taxonomic identification, evolution history (phylogeny), diet, health, disease, technology and social dynamics in the past.
