Tyrannosaurus is a genus of large theropod dinosaur. The type species Tyrannosaurus rex, often shortened to 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 latest Campanian-Maastrichtian ages of the late Cretaceous period, 72.7 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 fifteen 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.
Timeline of paleontology
Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.5 and 75 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.
Hylaeosaurus is a herbivorous ankylosaurian dinosaur that lived about 136 million years ago, in the late Valanginian stage of the early Cretaceous period of England. It was found in the Grinstead Clay Formation.
In osteology, the osteon or haversian system is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically between 0.25 mm and 0.35 mm in diameter. Their length is often hard to define, but estimates vary from several millimeters to around 1 centimeter. They are present in many bones of most mammals and some bird, reptile, and amphibian species.
Ornithopsis is a genus of sauropod dinosaur, from the Early Cretaceous of England and possibly Germany. The type species, which is the only species seen as valid today, is O. hulkei, which is only known from fragmentary remains.
The physiology of dinosaurs has historically been a controversial subject, particularly their thermoregulation. Recently, many new lines of evidence have been brought to bear on dinosaur physiology generally, including not only metabolic systems and thermoregulation, but on respiratory and cardiovascular systems as well.
Charles Whitney Gilmore was an American paleontologist who gained renown in the early 20th century for his work on vertebrate fossils during his career at the United States National Museum. Gilmore named many dinosaurs in North America and Mongolia, including the Cretaceous sauropod Alamosaurus, Alectrosaurus, Archaeornithomimus, Bactrosaurus, Brachyceratops, Chirostenotes, Mongolosaurus, Parrosaurus, Pinacosaurus, Styracosaurus ovatus and Thescelosaurus.
Short bones are designated as those bones that are more or less equal in length, width, and thickness. They include the tarsals in the ankle and the carpals in the wrist. They are one of five types of bones: short, long, flat, irregular and sesamoid. Most short bones are named according to their shape as they exhibit a variety of complex morphological features
Mary Higby Schweitzer is an American paleontologist at North Carolina State University, who led the groups that discovered the remains of blood cells in dinosaur fossils and later discovered soft tissue remains in the Tyrannosaurus rex specimen MOR 1125, as well as evidence that the specimen was a pregnant female when she died.
Mary Ann Mantell was a British fossil collector and the wife of the British paleontologist Gideon Mantell. She is credited – although this is disputed – with the discovery of the first fossils of Iguanodon and provided several pen and ink sketches of the fossils for her husband's scientific description of the Iguanodon.
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 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.
Kevin Padian is an American paleontologist. He is Professor of Integrative Biology at the University of California, Berkeley, Curator of Paleontology, University of California Museum of Paleontology, and was President of the National Center for Science Education from 2007 to 2008. Padian's area of interest is in vertebrate evolution, especially the origins of flight and the evolution of birds from theropod dinosaurs. He served as an expert witness for the plaintiffs in the Kitzmiller v. Dover Area School District trial, and his testimony was repeatedly cited in the court's decision.
Age determination in dinosaurs is mainly used to determine the approximate age of a dinosaur when the animal died.
Armand de Ricqlès is a French paleontologist best known for his work in bone histology and its implications for the growth of dinosaurs (e.g.).
Anusuya Chinsamy-Turan is a South African vertebrate paleontologist known for her expertise and developments in the study of the microstructure of fossil teeth and bones of extinct and extant vertebrates. She was the head of the Department of Biological Sciences, at the University of Cape Town from 2012 to 2015.
Osteoderms are dermal bone structures that support the upper layer of skin and serve as protection against the elements in a large variety of extinct and extant organisms, especially reptiles. This structure is commonly called "dermal armor" and serves to protect the organism, while also helping with temperature regulation. Osteoderms represent hard tissue components of the integument, making them easy to identify in fossil examination. This dermal armor is found prominently in many lizards. Some early amphibians have this armor, but it is lost in modern species with the exception a ventral plate, called the gastralia.
Dinosaur teeth have been studied since 1822 when Mary Ann Mantell (1795-1869) and her husband Dr Gideon Algernon Mantell (1790-1852) discovered an Iguanodon tooth in Sussex in England. Unlike mammal teeth, individual dinosaur teeth are generally not considered by paleontologists to be diagnostic to the genus or species level for unknown taxa, due morphological convergence and variability between teeth. and many historically named tooth taxa like Paronychodon and Richardoestesia are today considered nomina dubia, and are used as form taxa to refer to isolated teeth from other localities displaced considerably in time and space from the type specimens. However, it is possible to refer isolated teeth to known taxa provided that the tooth morphology is known and the teeth originate from a similar time and place.
Holly Woodward Ballard is an American paleontologist and paleohistologist.
