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.
The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.
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.
Robert Thomas Bakker is an American paleontologist who helped reshape modern theories about dinosaurs, particularly by adding support to the theory that some dinosaurs were endothermic (warm-blooded). Along with his mentor John Ostrom, Bakker was responsible for initiating the ongoing "dinosaur renaissance" in paleontological studies, beginning with Bakker's article "Dinosaur Renaissance" in the April 1975 issue of Scientific American. His specialty is the ecological context and behavior of dinosaurs.
Gregory Scott Paul is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal. Professionally investigating and restoring dinosaurs for three decades, Paul received an on-screen credit as dinosaur specialist on Jurassic Park and Discovery Channel's When Dinosaurs Roamed America and Dinosaur Planet. He is the author and illustrator of Predatory Dinosaurs of the World (1988), The Complete Illustrated Guide to Dinosaur Skeletons (1996), Dinosaurs of the Air (2001), three editions of The Princeton Field Guide to Dinosaurs, Gregory S. Paul's Dinosaur Coffee Table Book (2010), The Princeton Field Guide to Pterosaurs (2022), The Princeton Field Guide to Mesozoic Sea Reptiles (2022) and editor of The Scientific American Book of Dinosaurs (2000).
Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with Ceratosaurus than with birds. The oldest known ceratosaur, Saltriovenator, dates to the earliest part of the Jurassic, around 199 million years ago. Ceratosauria includes three major clades: Ceratosauridae, Noasauridae, and Abelisauridae, found primarily in the Southern Hemisphere. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea and Dilophosauridae, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group with other ceratosaurs, and are excluded from this group.
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 Ma and 145.0 ± 4 Ma. It is preceded by the Kimmeridgian and followed by the Berriasian.
The New Dinosaurs: An Alternative Evolution is a 1988 speculative evolution book written by Scottish geologist and palaeontologist Dougal Dixon and illustrated by several illustrators including Amanda Barlow, Peter Barrett, John Butler, Jeane Colville, Anthony Duke, Andy Farmer, Lee Gibbons, Steve Holden, Philip Hood, Martin Knowelden, Sean Milne, Denys Ovenden and Joyce Tuhill. The book also features a foreword by Desmond Morris. The New Dinosaurs explores a hypothetical alternate Earth, complete with animals and ecosystems, where the Cretaceous-Paleogene extinction event never occurred, leaving non-avian dinosaurs and other Mesozoic animals an additional 65 million years to evolve and adapt over the course of the Cenozoic to the present day.
Carcharodontosauridae is a group of carnivorous theropod dinosaurs. In 1931, Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids include some of the largest land predators ever known: Giganotosaurus, Mapusaurus, Carcharodontosaurus, and Tyrannotitan all rivaled Tyrannosaurus in size. Estimates give a maximum weight of 8–10 metric tons for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have weighed at least 500 kilograms (1,100 lb).
Stokesosaurus is a genus of small, carnivorous early tyrannosauroid theropod dinosaurs from the late Jurassic period of Utah, United States and Guimarota, Portugal.
The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation is the major source rock for North Sea oil. The fossil fauna of the Kimmeridge Clay includes turtles, crocodiles, sauropods, plesiosaurs, pliosaurs and ichthyosaurs, as well as a number of invertebrate species.
Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Despite Pseudosuchia meaning "false crocodiles", the name is a misnomer as true crocodilians are now defined as a subset of the group.
Xu Xing is a Chinese paleontologist who has named more dinosaurs than any other living paleontologist. Such dinosaurs include the Jurassic ceratopsian Yinlong, the Jurassic tyrannosauroid Guanlong, the large oviraptorosaur Gigantoraptor, and the troodontid Mei.
Stephen Louis "Steve" Brusatte FRSE is an American paleontologist, author, and evolutionary biologist who specializes in the anatomy and evolution of dinosaurs. He was educated at the University of Chicago for his Bachelor's degree, at the University of Bristol for his Master's of Science on a Marshall Scholarship, and finally at the Columbia University for Master's in Philosophy and Doctorate. He is currently Professor of Palaeontology and Evolution at the University of Edinburgh. In April 2024, Brusatte was elected to fellowship of the Royal Society of Edinburgh.
Edwin Harris "Ned" Colbert was a distinguished American vertebrate paleontologist and prolific researcher and author.
The Princeton Field Guide to Dinosaurs is a reference work on dinosaurs written by the paleontologist and paleoartist Gregory S. Paul. It was first published by Princeton University Press in 2010. In the United Kingdom it was published by A & C Black under the title Dinosaurs: A Field Guide. An updated second edition was released in 2016. A third edition was released in 2024.
Aurornis is an extinct genus of anchiornithid theropod dinosaurs from the Jurassic period of China. The genus Aurornis contains a single known species, Aurornis xui. Aurornis xui may be the most basal ("primitive") avialan dinosaur known to date, and it is one of the earliest avialans found to date. The fossil evidence for the animal pre-dates that of Archaeopteryx lithographica, often considered the earliest bird species, by about 10 million years.
How to Build a Dinosaur: Extinction Doesn't Have to Be Forever is a 2009 book by paleontologist Jack Horner and James Gorman. The book outlines Horner's theory for being able to resurrect a maniraptoran dinosaur by altering the genes of a chicken embryo. In 2010, a paperback version was published under the title How to Build a Dinosaur: The New Science of Reverse Evolution.
Anchiornithidae is a family of small paravian dinosaurs. Anchiornithids have been classified at varying positions in the paravian tree, with some scientists classifying them as a distinct family, a basal subfamily of Troodontidae, members of Archaeopterygidae, or an assemblage of dinosaurs that are an evolutionary grade within Avialae or Paraves.
The biogeography of Paravian dinosaurs is the study of the global distribution of Paraves through geological history. Paraves is a clade that includes all of the Theropoda that are more closely related to birds than to oviraptorosaurs. These include Dromaeosauridae and Troodontidae and Avialae. The distribution of paraves is closely related to the evolution of the clade. Understanding the changes in their distributions may shed light on problems like how and why paraves evolve, eventually gaining the ability to fly.
