Lawrence M. Witmer (born October 10, 1959, at Rochester, New York) [1] is an American paleontologist and paleobiologist. He is a Professor of Anatomy and a Chang Ying-Chien Professor of Paleontology at the Department of Biomedical Sciences at the Heritage College of Osteopathic Medicine in Ohio University. Witmer is considered to be one of the world's foremost experts on soft-tissue anatomy of the skull in extinct animals such as dinosaurs and pterosaurs.[ citation needed ] One of Witmer's largest contributions to vertebrate paleontology was the creation of the Extant Phylogenetic Bracket approach to ancestral character state reconstruction. [2] This methodology incorporates extensive comparative anatomy using physical and digital dissections of extant (not extinct) animals. [3]
He appeared in TV shows such as the Triumph of the Beasts featurette for Walking with Beasts , Jurassic Fight Club (History Channel, 2008), Clash of the Dinosaurs (Discovery Channel, 2009), and Bizarre Dinosaurs (National Geographic Channel, 2009), among others. [3]
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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.
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.
Vertebrate paleontology is the subfield of paleontology that seeks to discover, through the study of fossilized remains, the behavior, reproduction and appearance of extinct vertebrates. It also tries to connect, by using the evolutionary timeline, the animals of the past and their modern-day relatives.
The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans, the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over eighty species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs.
The class Osteostraci is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian.
Erlikosaurus is a genus of therizinosaurid that lived in Asia during the Late Cretaceous period. The fossils, a skull and some post-cranial fragments, were found in the Bayan Shireh Formation of Mongolia in 1972, dating to around 96 million and 89 million years ago. These remains were later described by Altangerel Perle and Rinchen Barsbold in 1980, naming the new genus and species Erlikosaurus andrewsi. It represents the second therizinosaur taxon from this formation with the most complete skull among members of this peculiar family of dinosaurs.
Jacques Armand Gauthier is an American vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology.
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.
David Bruce Norman is a British paleontologist, currently the main curator of vertebrate paleontology at the Sedgwick Museum, Cambridge University. From 1991 to 2011, Norman has also been the Sedgwick Museum's director.
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.
Eoalulavis is a monotypic genus of enantiornithean bird that lived during the Barremian, in the Lower Cretaceous around 125 million years ago. The only known species is Eoalulavis hoyasi.
Matthew Bonnan is an American paleobiologist, a Professor of Biological Sciences at Stockton University, and as of 2021 a singer/songwriter. His research combines traditional descriptive and anatomical study with computer-aided morphometric analysis and modeling of vertebrate skeletons, and he is the co-discoverer of three new species of dinosaurs. He is the author of the book The Bare Bones: An Unconventional Evolutionary History of the Skeleton, designed to introduce undergraduates and curious lay readers to the anatomy and evolution of the vertebrate skeleton. Bonnan has a music/art outreach project, Once Upon Deep Time, a pop/rock song cycle about the evolution of hearing and our connection to the tree of life.
Paleoart is any original artistic work that attempts to depict prehistoric life according to scientific evidence. Works of paleoart may be representations of fossil remains or imagined depictions of the living creatures and their ecosystems. While paleoart is typically defined as being scientifically informed, it is often the basis of depictions of prehistoric animals in popular culture, which in turn influences public perception of and fuels interest in these organisms. The word paleoart is also used in an informal sense as a name for prehistoric art, most often cave paintings.
Scott Donald Sampson is a Canadian paleontologist and science communicator. Sampson is currently the Executive Director of California Academy of Sciences in San Francisco, California. He was previously Vice President of Research & Collections and Chief Curator at the Denver Museum of Nature & Science,. Sampson is notable for his work on the carnivorous theropod dinosaurs Majungasaurus and Masiakasaurus and his extensive research into the Late Cretaceous Period, particularly in Madagascar. He is also known as the presenter of the PBS Kids show Dinosaur Train.
Edwin Harris "Ned" Colbert was a distinguished American vertebrate paleontologist and prolific researcher and author.
The following outline is provided as an overview of and topical guide to dinosaurs:
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.
Lindsay E. Zanno is an American vertebrate paleontologist and a leading expert on theropod dinosaurs and Cretaceous paleoecosystems. She is the Head of Paleontology at the North Carolina Museum of Natural Sciences and an Associate Research Professor in the Department of Biological Sciences at North Carolina State University.
The timeline of therizinosaur research is a chronological listing of events in the history of paleontology focused on therizinosaurs. They were unusually long-necked, pot-bellied, and large-clawed herbivorous theropods most closely related to birds. The early history of therizinosaur research occurred in three phases. The first phase was the discovery of scanty and puzzling fossils in Asia by the Central Asiatic Expeditions of the 1920s and Soviet-backed research in the 1950s. This phase resulted in the discovery of the Therizinosaurus cheloniformis type specimen. Soviet paleontologist Evgeny Maleev interpreted these unusual remains as belonging to some kind of gigantic turtle.
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.