A World of Dinosaurs: An Introduction

Recommended Media

1. The Permian Extinction

Approximately 251.9 million years ago, the Permian–Triassic extinction--colloquially known as the Great Dying--forms the boundary between the Permian and Triassic geologic periods, and with them the Paleozoic and Mesozoic eras. It is Earth's most severe known extinction event, with the extinction of over 80 percent of marine species and at least 70 percent of terrestrial vertebrate species. It is also the greatest known mass extinction of insects. The precise causes of the Great Dying remain unknown. The scientific consensus is that the main cause of extinction was massive volcanic eruptions in what is modern-day Siberia which released huge amounts of sulfur dioxide and carbon dioxide into the atmosphere, resulting in oxygen-starved, sulfurous oceans) and elevated global temperatures. Several other contributing factors have been proposed, including the emission of carbon dioxide from the burning of oil and coal deposits ignited by the eruptions and an asteroid impact that created the Araguainha crater (Brasil) and caused the seismic release of methane and the destruction of the ozone layer with increased exposure to solar radiation. While primitive reptiles, amphibians, and proto-mammals existed before the Great Dying, mammals and dinosaurs do not appear until the Triassic period. Thus, the AGE OF DINOSAURS starts after the extinction event. See: https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event

2. What Makes a Dinosaur a Dinosaur?

Dinosaurs stand with their legs positioned directly under their bodies. A hole in the hip socket permits this upright stance. [Other members of the reptile family do not have this feature] This posture allows dinosaurs to run faster and with greater endurance than other reptiles that are the same size. Dinosaurs are a type of reptile known as archosaurs, a group that includes crocodiles, pterosaurs, and birds but excludes snakes and lizards, tuataras, and extinct marine reptiles such as plesiosaurs and mosasaurs.

3. A New Classification?

Excerpt from SCIENCE NEWS© https://www.sciencenews.org/article/anatomy-analysis-suggests-new-dinosaur-family-tree© Rachel Ehrenberg, March 22, 2017For classroom/educational use only
Traditional
After examining more than 400 anatomical traits, scientists have proposed a radical reshuffling of the major dinosaur groups. ...The accepted tree of dinosaur relationships has three dominant branches, each containing critters familiar even to the non–dinosaur obsessed. One branch leads to the “bird-hipped” ornithischians, which include the plant-eating duckbills, stegosaurs, and Triceratops and its bony-frilled kin. Another branch contains the “reptile-hipped” saurischians, which are further divided into two groups: the plant-eating sauropods (typically four-legged, like Brontosaurus) and the meat-eating theropods (typically two-legged, like Tyrannosaurus rex and modern birds). ...Scientists have long divided the dinosaurs into two main groups, the bird-hipped and the reptile-hipped. ...This split between the bird-hipped and reptile-hipped dinos was first proposed in 1887 by British paleontologist Harry Seeley, who had noticed the two strikingly different kinds of pelvic anatomy. That hypothesis of dinosaur relationships was formalized and strengthened in the 1980s and has been accepted since then.
Possible Revision
...A new [family tree] breaks up the reptile-hipped lineage and suggests the bird-hipped group shares recent ancestors with meat-eating theropods. Scientists have been unsure where to put the confusing two-legged, meat-eating herrerasaurids. The new analysis suggests they are close relatives of the sauropods....The new tree yields four groups atop two main branches. The bird-hipped ornithischians, which used to live on their own lone branch, now share a main branch with the reptile-hipped theropods like T. rex. This placement suggests these once-distant cousins are actually closely related. It also underscores existing questions about the bird-hipped dinos, an oddball group with murky origins; they appear late in the dinosaur fossil record and then are everywhere. Some scientists have suggested that they evolved from an existing group of dinosaurs, perhaps similarly herbivorous sauropods. But by placing the bird-hipped dinos next to the theropods, the tree hints that the late-to-the-party vegetarian weirdos could have evolved from their now close relatives, the meat-eating theropods. Sauropods (like Brontosaurus) are no longer next to the theropods but now reside on a branch with the meat-eating herrerasaurids. Herrerasaurids are a confusing group of creatures that some scientists think belong near the other meat eaters, the theropods, while others say the herrerasaurids are not quite dinosaurs at all.

4. The Age of Dinosaurs: What the Earth Looked Like

Pangea, approximately 250 million years ago
150 million years ago
North America, 92 million years ago

5. Saurischian Dinosaurs

OVERVIEW: http://www.ucmp.berkeley.edu/diapsids/saurischia/saurischia.htmlDINOSAUR MORPHOLOGY: http://www.ucmp.berkeley.edu/diapsids/dinomm.htmlSMITHSONIAN: https://www.smithsonianmag.com/science-nature/dinosaur-division-is-all-in-the-hips-20477310/OVERVIEW: https://en.wikipedia.org/wiki/Saurischia
 Saurischian Dinosaurs, like all other tetrapods, had pelves (hips) composed of three elements: the ilium, ischium, and pubis. What distinguishes Saurischians (among other major characteristics; including a grasping hand, asymmetrical fingers, and a long, mobile neck) is the pubis that points downward and forward at an angle to the ischium. The saurischians form two major groups. The Sauropoda were large herbivores such as Apatosaurus and Diplodocus. The Theropoda were bipedal carnivores (meat eaters), ranging from the chicken-sized Compsognathus and the fearsome Deinonychus and Velociraptor to the crested Dilophosaurus and the gigantic Tyrannosaurus. The oldest known dinosaurs, from the middle Triassic of South America, were saurischians. Living birds had common ancestors in the theropod lineage. Oddly, birds are derived from the "lizard-hipped" dinosaurs and not from the "bird-hipped" Ornithischian dinosaurs. The "bird-hipped" condition of a pubis pointing toward the back of the animal occurred twice independently, once in the Ornithischians and once in the lineage leading to birds, an example of convergent evolution. Thus "Ornithischia," taken literally, is a misnomer, since the Ornithischians have Ornithischian-like pelves, not bird-like. Only birds (and their immediate ancestors) have bird-like pelves. [ (c) Wikipedia]

a. Herrerasaurids

Herrerasaurids are among the oldest known dinosaurs, appearing in the fossil record 231.4 million years ago (Late Triassic). These dinosaurs became extinct by the end of the Triassic period. Herrerasaurids were small-sized, not more than 4 meters (13 ft) long, and carnivorous. The best-known representatives of this group are from South America (Brazil, Argentina), where they were first discovered in the 1960s. A nearly complete skeleton of Herrerasaurus ischigulastensis was discovered in the Ischigualasto Formation in San Juan, Argentina, in 1988. Less complete herrerasaurids have been found in North America, and they may have inhabited other continents as well. Herrerasaurid anatomy is unusual and specialized, and they are not considered to be ancestral to any later dinosaur group. They only superficially resemble theropods and often present a mixture of very primitive and derived traits. The acetabulum is only partly open, and there are only two sacral vertebrae, the lowest number among dinosaurs. The pubic bone has a derived structure, being rotated somewhat posteriorly and folded to create a superficially tetanuran-like terminal expansion, especially prominent in H. ischigulastensis. The hand is primitive in having five metacarpals and the third finger longer than the second, but clearly theropod in having only three long fingers, with curved claws. Herrerasaurids also have a hinged mandible, which is also found in theropods. There is also evidence of protofeathers.[(c) Wikipedia]
SEE ALSO: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088398/

b. Sauropods

Sauropods: https://en.wikipedia.org/wiki/SauropodaApatosaurus: https://web.archive.org/web/20240417201420/http://www.prehistoric-wildlife.com/species/a/apatosaurus.htmlApatosaurus: https://www.livescience.com/25093-apatosaurus.htmlBrachiosaurus: https://web.archive.org/web/20240417201419/http://www.prehistoric-wildlife.com/species/b/brachiosaurus.htmlArgentinosaurus: https://web.archive.org/web/20240417201419/http://www.prehistoric-wildlife.com/species/a/argentinosaurus.htmlTITANOSAURIA: https://en.wikipedia.org/wiki/TitanosaurTITANOSAURIA: https://www.thoughtco.com/titanosaurs-the-last-of-the-sauropods-1093762(Video) PATAGOTITAN MAYORUM: https://www.youtube.com/watch?v=dn1BW9tvq-I(AMNH Videos) PATAGOTITAN MAYORUM: https://www.amnh.org/explore/amnh.tv/(category)/131058
 Sauropoda, whose members are known as sauropods, is a clade of saurischian ("lizard-hipped") dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include Brachiosaurus, Diplodocus, Apatosaurus, and Brontosaurus. The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic. Isanosaurus and Antetonitrus were originally described as Triassic sauropods, but their age, and in the case of Antetonitrus also its sauropod status, were subsequently questioned. Sauropod-like sauropodomorph tracks from the Fleming Fjord Formation (Greenland) might, however, indicate the occurrence of the group in the Late Triassic. By the Late Jurassic (150 million years ago), sauropods had become widespread (especially the diplodocids and brachiosaurids). By the Late Cretaceous, one group of sauropods, the titanosaurs, had replaced all others and had a near-global distribution. However, as with all other non-avian dinosaurs alive at the time, the titanosaurs died out in the Cretaceous–Paleogene extinction event. Fossilized remains of sauropods have been found on every continent, including Antarctica. The name Sauropoda was coined by O.C. Marsh in 1878, and is derived from Greek, meaning "lizard foot." Sauropods are one of the most recognizable groups of dinosaurs and have become a fixture in popular culture due to their impressive size. Complete sauropod fossil finds are rare. Many species, especially the largest, are known only from isolated and disarticulated bones. Many near-complete specimens lack heads, tail tips and limbs. (c) Wikipedia

c. Theropods

THEROPOD OVERVIEW: https://en.wikipedia.org/wiki/TheropodaOVERVIEW FROM THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY: http://www.ucmp.berkeley.edu/diapsids/saurischia/theropoda.htmlBIRDS ARE THEROPODS: https://www.scientificamerican.com/article/how-dinosaurs-shrank-and-became-birds/VIDEO OVERVIEW OF SAURISCHIAN DINOSAURS (Benjamin Burger): https://www.youtube.com/watch?v=yse_NNCdzMwCOELOPHYSIS: http://www.prehistoric-wildlife.com/species/c/coelophysis.htmlPOSSIBLE PRESERVED FEATHERS: https://news.nationalgeographic.com/2016/12/feathered-dinosaur-tail-amber-theropod-myanmar-burma-cretaceous/ (Based on the structure of the tail, researchers believe it belongs to a juvenile coelurosaur part of a group of theropod dinosaurs that includes everything from tyrannosaurs to modern birds)ALLOSAURUS: https://en.wikipedia.org/wiki/AllosaurusALLOSAURUS: https://web.archive.org/web/20240417201417/http://www.prehistoric-wildlife.com/species/a/allosaurus.htmlTYRANNOSUARUS: https://web.archive.org/web/20240415015853/http://www.prehistoric-wildlife.com/species/t/tyrannosaurus.htmlTYRANNOSAURUS: https://www.livescience.com/23868-tyrannosaurus-rex-facts.htmlTYRANNOSAURUS AND FEATHERS: https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils-new-discoveries/liaoning-diorama/a-feathered-tyrant/
Theropoda (from Greek meaning "beast feet") is both a suborder of bipedal Saurischian dinosaurs and a clade consisting of that suborder and its descendants (including modern birds). Dinosaurs belonging to the suborder Theropoda were primarily carnivorous, although several theropod groups evolved herbivory, omnivory, and insectivory. Theropods first appeared during the Carnian age of the late Triassic period about 230 million years ago (Ma) and included the sole large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66.038 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by 9,900 living species. Among the features linking theropod dinosaurs to birds are the three-toed foot, a furcula (wishbone), air-filled bones, brooding of the eggs, and (in some cases) feathers. (c) Dinopedia
Tyrannosaurus
Allosaurus

d. Dromaeosaurids and Oviraptosaurids

Dromaeosauridae is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. In informal usage, they are often called raptors (after Velociraptor), a term popularized by the film Jurassic Park; several genera include the term "raptor" directly in their name, and popular culture has come to emphasize their bird-like appearance and speculated bird-like behavior. Dromaeosaurid fossils have been found across the globe in North America, Europe, Africa, Asia, and South America, with some fossils giving credence to the possibility that they inhabited Australia as well. The earliest body fossils are known from the Early Cretaceous (145-140 million years ago), and they survived until the end of the Cretaceous (Maastrichtian stage, 66 ma), existing until the Cretaceous–Paleogene extinction event. The presence of dromaeosaurids as early as the Middle Jurassic has been suggested by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this period. DROMAEOSAURIDS: https://en.wikipedia.org/wiki/DromaeosauridaeDROMAEOSAURIDS: http://www.dinosaur-world.com/feathered_dinosaurs/dromaeosauridae.htmRAPATORS: https://web.archive.org/web/20230413092757/http://www.prehistoric-wildlife.com/species/r/rapator.htmlVELOCIRAPTOR: https://web.archive.org/web/20220921214849/http://www.prehistoric-wildlife.com/species/v/velociraptor.htmlBUSTING SOME VELOCIRAPTOR MYTHS: https://www.thoughtco.com/things-to-know-velociraptor-1093806DEINONYCHUS: https://en.wikipedia.org/wiki/DeinonychusDEINONYCHUS: https://web.archive.org/web/20220922071450/http://www.prehistoric-wildlife.com/species/d/deinonychus.htmlOVIRAPTOROSAURIDS: https://web.archive.org/web/20220724163823/http://www.prehistoric-wildlife.com/species/o/oviraptor.htmlOVIRAPTOROSAURIDS: http://www.dinosaur-world.com/feathered_dinosaurs/oviraptoridae.htmOVIRAPTOR: https://en.wikipedia.org/wiki/Oviraptor
DISSENTING VIEWS: PERHAPS A COMBINATION OF BOTH FEATHERS AND SCALES? An international team of researchers studied skin impressions taken from Tyrannosaurus rex fossils found in Montana. They then compared those impressions to fossilized skin patches of other tyrannosaurs, like the Albertosaurus, Daspletosaurus, Gorgosaurus, and Tarbosaurus. The samples represented parts of the dinosaurs’ stomach, chest, neck, pelvis, and tail, according to Ben Guarino of the Washington Post. And none bore any traces of feathers. These findings indicate “that most (if not all) large-bodied tyrannosaurids were scaly,” the authors of the study write. They add that the Tyrannosaurus rex may have had some feathers, but the plumage was likely limited to the dinosaur’s back. Since there is ample evidence to suggest that earlier tyrannosaurs had feathers, the study’s conclusions would mean that tyrannosaurs evolved a feathery coat, only to eventually lose it. The study’s authors believe that the Tyrannosaurus rex’s size can help explain the evolutionary shift, Bittel reports.
Read more: http://www.smithsonianmag.com/smart-news/t-rex-skin-was-not-covered-feathers-study-says-180963603/
Velociraptor
Velociraptor is one of the dinosaurs that without question had feathers. Evidence for this comes from the quill knobs on the fossil material, particularly the forearms. These are where feathers were anchored in place, and without feathers, there would be no quill knobs (although on the other hand, a lack of quill knobs does not mean a lack of feathers). The feathers on Velociraptor would have provided insulation allowing it to maintain a high metabolism, a vital requirement for a very agile and active hunter. Also, Velociraptors lived in a fairly arid landscape and the feathers would have provided extra protection against the cold nights that are often associated with arid environments. A further idea is that the feathers may have also served a display purpose.

6. The World Of Tyrranosaurs

a. Meet the Tyrant Lizards

When you say the word dinosaur to the average person, she might mention one of those big, lumbering herbivores like Brontosaurus or the slightly smaller Hadrosaurs (a.k.a “Duck-Billed Dinosaurs”). She might even talk about the Triceratops with its prominent horns or the Stegosaurs with their strange spinal “fins.” But ask anyone and the most frequently mentioned name is Tyrannosaurus rex. And with good reason. Thanks in great part to the six films in the Jurassic Park and Jurassic World franchises not to mention the numerous Walking With Dinosaur “documentaries” of the 90s and early 2000s, many hundreds of millions of people across the globe have an image of the fleet-footed, roaring beast that relentlessly hunts its victims--there’s simply no escaping this nine-ton monster with the steak-knife teeth. While much of what we hear and see in the lore about T. rex is based on a certain amount of factual evidence, there’s a great deal that’s either wrong (in the case of the Hollywood movies) or missing (in the BBC and Discovery Channel shows)--including the fact that T. rex sported primitive feathers and had anatomical features that we now associate with birds such as a three-toed foot like a vulture or hawk, “hollow” bones, and a wishbone. Further, this remarkable beast was only one member--and one of the last--of a fairly extended family of Tyrannosaurs (the Tyrannosauroidea) that includes smaller dinosaurs like Guanlong and Dilong who thrived millions of years before T. rex. as well as its nearly contemporary smaller 2-ton cousin Albertosaurus.

b. Barnum Brown and T. rex

  • AMNH VIDEO BIOGRAPHY: https://www.youtube.com/watch?v=SDpVAZEefHY
  • CBS VIDEO BIOGRAPHY: https://www.youtube.com/watch?v=Bkwb_yP39-I
  • BARNUM BROWN NARRATES (2 ½ minute British Pathe newsreel about Stegosaurus dating from 1933): https://www.youtube.com/watch?v=hpkaRQfUGTw
  • THE FOLLOWING BIOGRAPHY IS TAKEN FROM STRANGE SCIENCE: https://www.strangescience.net/brown.htm Retrieved 24 March 2024
  • Born in 1873 to a hard-working farming family, Barnum Brown had to wait several days for a name while his parents and siblings quibbled over what to call him. Consumed with excitement over the traveling circus show, his older brother suggested naming the baby boy after the illustrious P.T. Barnum. The decision proved prophetic. Brown enjoyed a spectacularly successful 66-year career in paleontology, including his post as curator for the American Museum of Natural History, where he was largely responsible for the museum's multi-ton collection of dinosaur fossils.
  • Brown's parents wanted to give their son a good education, and they sent him to high school (not available everywhere) in the nearby town of Carbondale, Kansas. After high school, he attended Kansas University and in 1894, he began hunting fossils under the direction of paleontologist Samuel Wendell Williston. The following year, he worked with Williston again, to retrieve a Triceratops skull from Wyoming. Williston wrote of Brown: Brown has been with me on two expeditions and is the best man in the field that I ever had. He is very energetic, has great powers of endurance, walking thirty miles a day without fatigue, is very methodical in all his habits, and thoroughly honest. He has good ability as a student also and has been a student with me in anatomy, geology and paleontology. He practically relieved me of all care in my last expedition.
  • A recommendation from Williston secured Brown a spot on a fossil dig operated by the American Museum of Natural History. Fine fieldwork for AMNH later earned Brown a job with the museum, and the eager young man left the University of Kansas even before the current academic term was done. The move was vintage Brown; fieldwork always took precedence. In New York, Henry Fairfield Osborn pulled strings to provide Brown with admission and even a scholarship to Columbia University, but Brown's academic abilities didn't match his skills in the field. He didn't last at Columbia and took a decade to complete his undergraduate degree from KU. Decades later, he received an honorary doctorate from Lehigh University, finally enjoying the title of "doctor."
  • In 1897, while working at AMNH, Brown explored Upper Jurassic beds in Wyoming. At first, the quarry looked empty, but he kept looking. The quarry that initially seemed useless eventually yielded 65 tons of fossils. About the same time, Brown and his colleague Henry Fairfield Osborn asked a Wyoming shepherd if he knew of any fossils in the area. He didn't. Then they realized his stone cabin was made of fossils. The whole cabin.
  • Back in New York in December 1898, Brown walked to work through the snow one morning, probably expecting a day like any other. That evening, he was on a ship bound for Patagonia, where he spent roughly 18 months digging fossils and braving blizzards. A few years later, he was again unearthing bones in the western United States.
  • Quarry No. 1 contains the femur, pubes, humerus, three vertebrae and two undetermined bones of a large Carnivorous Dinosaur not described by Marsh. . . . I have never seen anything like it from the Cretaceous. These bones are imbedded in flint-like sandstone concretions and require a great deal of labor to extract. So wrote Brown from Hell Creek, Montana, with an apparent gift for understatement. The "large Carnivorous Dinosaur" was Tyrannosaurus rex, "King of the tyrant lizards." He discovered the first skeleton in 1902 and found a better-preserved skeleton in 1908. Both skeletons were put on display at AMNH. During World War II, Americans feared that the Germans might bomb New York and the T. rex fossil might be lost (not a misplaced fear — many fossils in European museums were blown to bits in the 1940s). The skeleton Brown discovered in 1902 was shipped to the Carnegie Museum in Pittsburgh.
  • Several years after the initial T. rex discovery, while Barnum Brown was still basking in the glow of accomplishment, tragedy struck. His wife Marion — arguably the love of Brown's life — contracted scarlet fever and died. Their baby daughter Frances contracted the illness at the same time, and managed to survive, but the distraught Brown wasn't up to being a single dad. Following common convention of the time, he turned over his toddler daughter to her mother's parents. They wanted to raise the little girl, and Barnum wanted to bury himself in his work. The iconic photograph of Brown in a natty suit and beaverskin coat might suggest a carefree bachelor, but in reality, it shows a widower. Devoted as he had been to his first wife, however, Brown retained an eye for the ladies. Rumors flew for years about his various exploits, but Brown was discreet, and few rumors were ever confirmed.
  • Frances didn't see her father much growing up, in particular during a five-year stretch when he was overseas, working in far-flung locales like Samos, Pakistan, India, Burma and Abyssinia. In the years before air travel, quick visits home were unrealistic. Brown's colleagues at AMNH would hear nothing from him for months, but his long absences were punctuated by the delivery of (literal) tons of fossils. In fact, such gargantuan deliveries sometimes served as the only evidence that the fossil hunter was still alive. Friends and family members in the states had reason to worry. In Mandalay, Brown nearly died of malaria, and he was nursed back from the brink by something else he collected: his second wife, Lilian. Fourteen years Brown's junior, flirtatious Lilian tolerated his occasional dalliances, in part because she indulged in one or two of her own.
  • Brown's extensive overseas fieldwork proved useful in a surprising way years later. During World War II, after he had been required (over his objections) to retire from AMNH, Brown went to work for the war effort in Washington, D.C., providing intelligence on various localities of interest to the U.S. military. His daughter Frances was working in Washington at the same time, so father and daughter lived under the same roof for the first time since she had been tiny. Aside from Frances's fears that her dad was smitten with a Nazi spy, the living arrangement went smoothly.
  • The Great Depression hurt museum budgets as much as anything else, and to keep excavating, Brown had to be creative. On one trip to the field, he and his wife dropped by the Chicago World's Fair, taking in "The World a Million Years Ago." Never mind that the exhibit put prehistoric humans together with dinosaurs that didn't walk the Earth at the same time, it was a fun show. And it was funded by Sinclair Oil. He eventually made a deal with the Sinclair Oil Company: He reviewed dinosaur booklets for them and they paid for his expeditions. So the gas stations with the Diplodocus logo attracted even more customers by giving them the booklets in the 1930s and 1940s. Brown also provided input for the dinosaur sequence in Fantasia.
  • It was also during the Great Depression that Brown took on an assistant: Roland Bird. An excellent fossil hunter in his own right, Bird found some of North America's best dinosaur trackways, including extensive track systems near the Purgatoire River in southeastern Colorado, and the Paluxy River limestone beds near Glen Rose, Texas.
  • Before his career was over, Brown managed to make a remarkable contribution to the field of anthropology, but only after marginal involvement with a gaffe. In the early 1920s, Brown's mentor Osborn was excited by the find of a tooth in Nebraska, later dubbed Hesperopithecus and nicknamed Nebraska Man. The tooth looked like it might belong to a primate. Brown evidently accepted this interpretation at the beginning, but doubts began to gnaw at him. He confided to a colleague that the primate might just as easily be a peccary, which ultimately proved to be the case. But in 1927, Brown reported more welcome news when he confirmed the identification, by Jesse Dade Figgins, of a prehistoric spear point in Folsom, New Mexico. The Folsom point provided evidence that humans were in North America at the end of the Pleistocene Ice Age, and they were hunting big game.
  • After he retired from AMNH in 1942, Brown continued to lead tours there, often describing the dinosaur fossils he had collected as his "children." One of his last assignments was to supervise the construction of Sinclair's life-sized dinosaur models for the 1964 World's Fair. Brown completed his task but didn't live long enough to see the dinosaurs' trip to the fair. About a year after he died, the lovable giants rode on a barge from their construction site in the town of Hudson, floating down the Hudson River. Brown, who had died in February 1963, just a week shy of his 90th birthday, never got to see the looks on Manhattanites' faces.
  • (c) WWW. STRANGE SCIENCE.NET Retrieved 24 March 2024

A Selection of Web Resources

1. TAXONOMY OF TYRANNOSAURUS [The following resources explain the classifications that have been proposed for the Tyrannosaurs.]http://scienceviews.com/dinosaurs/tyrannosaurus.htmlhttps://blog.everythingdinosaur.co.uk/blog/_archives/2008/02/13/3521647.htmlhttp://scienceviews.com/dinosaurs/tyrannosaurus.htmlhttp://tolweb.org/Tyrannosauridae/15896https://www.geol.umd.edu/~tholtz/G104/lectures/104taxon.html
2. TYRANNOSAURUS FACTS:LIVE SCIENCE: https://www.livescience.com/23868-tyrannosaurus-rex-facts.htmlTHOUGHT COMPANY: https://www.thoughtco.com/things-to-know-tyrannosaurus-1093804MENTAL FLOSS: http://mentalfloss.com/article/55390/12-things-you-might-not-know-about-t-rexSMITHSONIAN: https://www.smithsonianmag.com/science-nature/five-things-we-dont-know-about-tyrannosaurus-rex-180951072/
 3. T. REX TEETH AND BITE: NATIONAL GEOGRAPHIC (VIDEO): https://www.youtube.com/watch?v=advXfo646DABITE FORCE OF T. REX AND OTHER THEROPODS (VIDEO): https://www.popularmechanics.com/science/animals/a26546/t-rex-teeth/BITE FORCE: https://www.smithsonianmag.com/science-nature/the-tyrannosaurus-rexs-dangerous-and-deadly-bite-37252918/BITE FORCE: https://sciworthy.com/why-could-tyrannosaurus-rex-bite-so-hard/TEETH (compared to other species) https://www.fossilera.com/pages/dinosaur-teeth
4. THE SOUND OF TYRANNOSAURUS: DISCOVERY CHANNEL: https://www.youtube.com/watch?v=RiikBWDqmsQALASTAIR NEILL (DangerVille): https://www.youtube.com/watch?v=tglIWgG0rak
5. TYRANNOSAURUS INFANTS/GROWTH:HATCHLINGS: https://www.sciencealert.com/baby-tyrannosaurs-could-have-been-fluffy-like-ducklings-and-we-are-just-deadHATCHLINGS: https://www.livescience.com/64936-t-rex-new-look-exhibit.htmlGROWTH: http://www.dinosaur-world.com/tyrannosaurs/tyrannosaur-growth-rate.htmGROWTH (2004 article; Royal Society): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691809/pdf/15347508.pdfGROWTH (2004 article: Nature): https://www.nature.com/news/2004/040809/full/040809-7.htmlSIZE (2011): https://www.livescience.com/16524-rex-dinosaur-weighed.html 6. DISTRIBUTION:https://www.nytimes.com/2021/04/15/science/tyrannosaurus-rex-population.html?referringSource=articleShare 7. SOME RECENT RESEARCH: SIZE (VIDEO): https://www.youtube.com/watch?v=y0medSCkXEQ NEW SPECIES: https://www.nytimes.com/2024/01/11/science/new-tyrannosaur-species-fossil.html NEW SPECIES: https://www.bath.ac.uk/announcements/new-research-shows-juvenile-t-rex-fossils-are-a-distinct-species-of-small-tyrannosaur/

c. Meet the Family <or> "Stay Tuned"

There are over 30 known relatives of T. rex--a number that continues to grow because each year new members of the Tyrannosaur family are described. Below you will find some information about four of those cousins as well as recent lists of known, possible, or disputed family members. It’s important to note that a number of these species lived concurrently, often on the same continent, and just as often separately on different land masses. So, as they used to say on television newscasts, "stay tuned"; what we think we know today about numbers and morphology may be (will be?) upturned tomorrow. As already cited, probably the greatest example of our changing understanding of this lineage was the discovery that all tyrannosaurs bore feathers at some point (or for the entirety) of their lifetimes. When the original Jurassic Park films were released in the early-to-mid-1990s--the same time the remodeled dinosaur halls opened at the American Museum of Natural History--no one knew that. A mere twenty years later, it’s all about the feathers--not to mention the strange headcrests on basal tyrannosaurs. Who knows what the next twenty years will bring?
  • Tyrannosauroidea (meaning ‘tyrant lizard forms’) is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus rex itself. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe, Asia, South America, and Australia. (Paleontology World)

2016 possibilities...

Some confirmed and "disputed" cousins....

A. Tyrannosauroidea (Super Family)
1. Kileskus aristotocus Range 167-164 mya/Russia2. Proceratosaurus bradleyi Range 168-166 mya/EnglandNOTE: The Proceratosauridae are a branch of the Tyrannosauroidea Super Family. They lived from approximately 165 Mya (Jurassic) to 120 Mya (Cretaceous). As you will read and see in the following links, there are differences of opinion regarding exactly where to place some species: https://en.wikipedia.org/wiki/Proceratosauridae https://dinopedia.fandom.com/wiki/Proceratosauridae 3. Guanlong wucaiiRange 163-157 mya/China4. Yutyrannus hualiRange 125-112 mya/China5. Sinotyrannus kazuoensisRange 125-120 mya/China6. Dilong paradoxusRange 130-122 mya/ China7. Stokesosaurus clevelandiRange 156-151 mya/Utah (USA)8. Eotyrannus lengiRange 130-125 mya/Isle of Wight9. Xiongguanglong baimoensisRange 120-90 mya/China10. Dryptosaurus aquilunguisRange 71-67 mya/New Jersey (USA)11. Bistahieversor sealeyiRange 74-72 mya/New Mexico (USA)12. Appalachiosaurus montgomeriensis Range 82-76 mya/ Alabama (USA)
--------------------------------B. Tyrannosauridae (Family)
13. Albertosaurus sarcophagus Range 73-67 mya/North America14. Gorgosaurus libratus Range 80-73 mya/Alberta (Canada)
-------------------------------------C. Tyrannosaurinae (Subfamily)
15. Qianzhousaurus sinensis Range 71-66 mya/ China16. Alioramus altai Range 72-66 mya/Mongolia17. Teratophoneus curriei Range 77-76 mya/ Utah (USA)18. Nanuqsaurus hoglundi Range 78-71 mya/Alaska (USA)19. Nanotyrannus lancensis (disputed) Range 68-66 mya/North America20. Zhuchengtyrannus magnus Range 71-68 mya/China21. Daspletosaurus torosusRange 77-74 mya/Alberta (Canada)22. Tarbosaurus bataarRange 71-68 mya/Mongolia 23. Tyrannosaurus rexRange 68-66 mya/North America

Between 2016 and 2024....(and counting)

Guanlong wucaii

  • Range 163-157 mya/China
  • Named from the Chinese words guan, meaning 'crown', and long, meaning 'dragon,’ in reference to its flashy head-crest, Guanlong is the most elaborate of any known theropod dinosaur. The species name comes from the Chinese word "wucaii" meaning 'five colors' and refers to the multi-hued rocks at Wucaiwan, the badlands where the fossils were found. Guanlong "wucaii" is one of the most primitive tyrannosaurs known. It hunted its prey 95 million years before T. rex lived. According to the Australian Museum, the name is pronounced GWON-long woo-kay-eye.

Sinotyrannus kazuoensis

  • Range 125-120 mya/China
  • Sinotyrannus (meaning "Chinese tyrant") is a genus of large basal proceratosaurid dinosaur, a relative of tyrannosaurids that flourished in North America and Asia during the Jurassic and early Cretaceous periods. Sinotyrannus is known from a single incomplete fossil specimen including a partial skull, from the Early Cretaceous Jiufotang Formation of Liaoning, China. Though it is not much younger than primitive tyrannosauroids such as Dilong, it is similar in size to later forms such as Tyrannosaurus. It was much larger than contemporary tyrannosauroids; reaching a total estimated length of 9–10 m (30–33 ft), it is the largest known theropod from the Jiufotang Formation.

Albertosaurus sarcophagus

  • Range 73-67 mya/North America
  • Albertosaurus ("Alberta lizard") is a genus of tyrannosaurid theropod dinosaurs that lived in western North America during the Late Cretaceous Period, about 70 million years ago. The type species, A. sarcophagus, lived in Western Canada but, according to the San Diego Museum of Natural History, fragmentary fossil remains have been found as far south as Baja California. Scientists disagree on the content of the genus, with some recognizing Gorgosaurus libratus as a second species. As a tyrannosaurid, Albertosaurus was a bipedal predator with tiny, two-fingered hands and a massive head that had dozens of large, sharp teeth. It may have been at the top of the food chain in its local ecosystem. While Albertosaurus was large for a theropod, it was much smaller than its larger and more famous relative Tyrannosaurus rex, growing nine to ten meters long and possibly weighing less than 2 metric tons.

Tarbosaurus bataar

  • Range 71-68 mya/Mongolia
  • Tarbosaurus (meaning "alarming lizard") is a genus of tyrannosaurid theropod dinosaur that flourished in Asia about 70 million years ago, at the end of the Late Cretaceous Period. Fossils have been recovered in Mongolia, with more fragmentary remains found further afield in parts of China. Although many species have been named, modern paleontologists recognize only one, T. bataar, as valid (discovered in 1946). Some experts see this species as an Asian representative of the North American genus Tyrannosaurus; this would make the genus Tarbosaurus redundant. Tarbosaurus and Tyrannosaurus, if not synonymous, are at least closely related genera. Alioramus, also from Mongolia, has previously been thought by some authorities to be the closest relative of Tarbosaurus, though this has since been disproven with the discovery of Qianzhousaurus and the description of the Alioramini. Like most known tyrannosaurids, Tarbosaurus was a large bipedal predator, weighing up to five tons and equipped with about sixty large teeth. It had a unique locking mechanism in its lower jaw and the smallest forelimbs relative to body size of all tyrannosaurids, renowned for their disproportionately tiny, two-fingered forelimbs. Tarbosaurus lived in a humid floodplain crisscrossed by river channels. In this environment, it was an apex predator, probably preying on other large dinosaurs like the hadrosaur Saurolophus or the sauropod Nemegtosaurus. Tarbosaurus is represented by dozens of fossil specimens, including several complete skulls and skeletons. These remains have allowed scientific studies to focus on its phylogeny, skull mechanics, and brain structure.

7. Ornithischians

ORNITHISCHIAN OVERVIEW: https://en.wikipedia.org/wiki/OrnithischiaOVERVIEW FROM THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY: http://www.ucmp.berkeley.edu/diapsids/ornithischia/ornithischia.htmlVIDEO COMPARISON OF SAURISCHIANS AND ORNITHISCHIANS (Benjamin Burger): https://www.youtube.com/watch?v=qYsFVDj-65AVIDEO OVERVIEW ABOUT ORNITHISCHIANS (Benjamin Burger): https://www.youtube.com/watch?v=RObirXm6DDU
What makes an ornithischian dinosaur? All terrestrial animals and even marine animals derived from terrestrial stocks have hip girdles, or pelvises, and all hip girdles are composed of three bones: the ilium, ischium, and pubis. All ornithischians are united by a pubis pointing backward, running parallel with the ischium. The name "Ornithischia" means "bird-hipped," and birds also have pelvises in which the pubis points backward. However, birds are more closely related to the Saurischia, or "lizard-hipped" dinosaurs, than to the ornithischian dinosaurs featured on this page. There were many kinds of ornithischian dinosaurs, dating back to the early Jurassic. The Ornithopoda included the hadrosaurs ("duck-billed dinosaurs"), the iguanodontids, the heterodontosaurs, the hypsilophodontids, and various other dinosaurs. The Ceratopsia included the horned dinosaurs, the Ankylosauria and Stegosauria (now usually grouped in the Thyreophora) included various types of armored dinosaurs, and the Pachycephalosauria, the extremely thick-skulled pachycephalosaurs. Iguanodontids: https://www.britannica.com/animal/Iguanodon Heterodontosaurs: https://en.wikipedia.org/wiki/Heterodontosauridae Hypsilophodontids: https://dinopedia.fandom.com/wiki/Hypsilophodon
Stegosaurus

a. Early Ornithishians & Feathers

The mix of feathers and scales on Kulindadromeus --an early, plant-eating ORNITHISCHIAN DINOSAUR--shows that both epidermal structures could coexist, just as in modern birds--chickens for example have scaly legs, and vultures and turkeys have scaly patches over their necks and heads. Developmental experiments in modern chickens suggest that bird scales are aborted feathers, an idea that explains why birds have scaly legs. Perhaps the molecular mechanisms needed for this switch might have existed already in Kulindadromeus. FURTHER INFORMATION: http://palaeo.gly.bris.ac.uk/melanosomes/Kulindadromeus.html
Tianyulong confuciusi is a feathered ORNITHISCHIAN DINOSAUR that belongs to the same branch of the family tree as Stegosaurus and Triceratops. What makes the discovery important is that it supports the idea that both Theropods AND some Ornithischian dinosaurs had feathers, proto-feathers, "fuzz," or a combination of scaly skin and feathers. In addition to the presence of "hollow" bones in Theropods and some smaller Ornithischian dinosaurs, the presence of feathers (or feather-like structures), gives weight to the idea that both groups of dinosaurs might more properly belong to the proposed group called Ornithoscelida.
FURTHER INFORMATION: https://www.smithsonianmag.com/science-nature/tianyulong-an-unexpectedly-fuzzy-dinosaur-41045210/
Kulindadromeus
Tianyulong confuciusi

Thyreophorans

•Thyreophorans represent the armored dinosaurs and are a clade of (predominantly) quadrupedal ornithischians.•There are characterized by the presence of osteoderms (armor plates) in their skin. Different clades of thyreophorans express these osteoderms in different patterns. •Beyond a few basal taxa, thyreophorans are divided into the plated Stegosauria and the tank-like Ankylosauria.•Armor in thyreophorans seem to have functions beyond simple defense: they served as display structures and (in the case of the stegosaurs and the club-tailed ankylosaurine ankylosaurs) as active weapons.
THYREOPHORA: http://www.ucmp.berkeley.edu/diapsids/ornithischia/thyreophora.htmlTHYREOPHORA: https://www.geol.umd.edu/~tholtz/G104/lectures/104thyreo.htmlANKYLOSAURUS: https://en.wikipedia.org/wiki/AnkylosaurusANKYLOSAURUS: https://web.archive.org/web/20210429062421/http://www.prehistoric-wildlife.com/species/a/ankylosaurus.htmlSTEGOSAURUS: https://en.wikipedia.org/wiki/StegosaurusSTEGOSAURUS: https://web.archive.org/web/20210509125807/https://www.prehistoric-wildlife.com/species/s/stegosaurus.html
Ankylosaurus

c. Marginocephalia

Marginocephalia is a clade of ornithischian dinosaurs that is characterized by a bony shelf or margin at the back of the skull. These fringes were likely used for display. There are two clades included in Marginocephalia: the thick-skulled Pachycephalosauria and the horned Ceratopsia. All members of Marginocephalia were herbivores. They basally used gastroliths to aid in the digestion of tough plant matter until they convergently evolved tooth batteries in Neoceratopsia (or "new Ceratopsia") and Pachycephalosauria. Marginocephalia first evolved in the Jurassic Period and became more common in the Cretaceous. They are basally small facultative quadrupeds while derived members of the group are large obligate quadrupeds. Primitive marginocephalians are found in Asia, but the group migrated upwards into North America.
MARGINOCEPHALIA: https://www.geol.umd.edu/~tholtz/G104/lectures/104margino.htmlMARINOCEPHALIA: http://palaeo.gly.bris.ac.uk/Palaeofiles/Fossilgroups/Dinosauria/Marginocephalia.htmlPACHYCEPHALOSAURIA: https://en.wikipedia.org/wiki/PachycephalosauriaPACHYCEPHALOSUARUS: https://web.archive.org/web/20210510080934/https://www.prehistoric-wildlife.com/species/p/pachycephalosaurus.htmlSTYRACOSAURUS: https://web.archive.org/web/20210513184831/http://www.prehistoric-wildlife.com/species/s/styracosaurus.htmlPROTOCERATOPS: https://web.archive.org/web/20210510082546/https://www.prehistoric-wildlife.com/species/p/protoceratops.htmlPSITTACOSAURUS: https://web.archive.org/web/20210511230305/http://www.prehistoric-wildlife.com/species/p/psittacosaurus.htmlPSITTACOSAURUS: https://en.wikipedia.org/wiki/PsittacosaurusTRICERATOPS: https://web.archive.org/web/20210509135913/https://www.prehistoric-wildlife.com/species/t/triceratops.html

Ornithopods

Ornithopods are a group of ornithischian dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, and dominated the North American landscape. Their major evolutionary advantage was the progressive development of a chewing apparatus that became the most sophisticated ever developed by a non-avian dinosaur, rivaling that of modern mammals such as the domestic cow. They reached their apex in the duck-bills (hadrosaurs), before they were wiped out by the Cretaceous–Paleogene extinction event along with all other non-avian dinosaurs. Members are known from all seven continents, though they are generally rare in the Southern Hemisphere.

Hadrosauridae

OVERVIEW: https://en.wikipedia.org/wiki/HadrosauridaeTHIRTEEN FAMOUS DUCK-BILLS: https://onlydinosaurs.com/types-of-duck-billed-dinosaurs-you-should-know/ NATIONAL PARK SERVICE OVERVIEW: https://www.nps.gov/articles/aps-17-1-3.htmTHOUGHT COMPANY OVERVIEW: https://www.thoughtco.com/duck-billed-dinosaur-4043319
Hadrosaurids or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which includes genera such as Edmontosaurus and Parasaurolophus, was a common group of herbivores during the Late Cretaceous Period. Hadrosaurids are descendants of the Late Jurassic/Early Cretaceous iguanodontian dinosaurs and had a similar body layout. Hadrosaurs were among the most dominant herbivores during the Late Cretaceous in Asia and North America, and during the close of the Cretaceous several lineages dispersed into Europe, Africa, and South America. Like other ornithischians, hadrosaurids had a predentary bone and a pubic bone which was positioned backwards in the pelvis. Unlike more primitive iguanodonts, the teeth of hadrosaurids are stacked into complex structures known as dental batteries, which acted as effective grinding surfaces. Hadrosauridae is divided into two principal subfamilies: the lambeosaurines (Lambeosaurinae), which had hollow cranial crests or tubes; and the saurolophines (Saurolophinae), identified as hadrosaurines (Hadrosaurinae) in most pre-2010 works, which lacked hollow cranial crests (solid crests were present in some forms). Saurolophines tended to be bulkier than lambeosaurines. Lambeosaurines included the aralosaurins, tsintaosaurins, lambeosaurins and parasaurolophins, while saurolophines included the brachylophosaurins, kritosaurins, saurolophins and edmontosaurins. Hadrosaurids were facultative bipeds, with the young of some species walking mostly on two legs and the adults walking mostly on four. © Wikipedia
Parasaurolophus

8. Teeth

1. Tyrannosaurus Rex had a mouth full of serrated teeth, but not all of the dinosaur’s teeth served the same function, according to a 2012 study in the Canadian Journal of Earth Sciences. T-rex’s front teeth gripped and pulled; its side teeth tore flesh and its back teeth diced chunks of meat and forced food into the throat. (More info: www.livescience.com/23868-tyrannosaurus-rex-facts.html)
2. Triceratops teeth were made of five layers of tissue. In contrast, the teeth of plant-eating horses and bison have four layers of tissue. Crocodiles and other reptiles have just two. (More info: www.sci-news.com/paleontology/science-triceratops-teeth-02885.html)
3. All dinosaurs could regrow teeth. Scientists believe plant-eating dinosaurs grew new teeth more frequently to keep their chompers from getting too worn down on all that vegetation. Diplodocus replaced their teeth fairly frequently — growing one new tooth every 35 days — while the Camarasaurus took nearly 62 days to form a new tooth. (More info: www.livescience.com/38249-dinosaurs-teeth-replacement.html)
4. Hadrosaurs had more teeth than any other dinosaur. These duck-billed dinosaurs had nearly 1,000 cheek teeth called grinders, which they used to eat plants. (More info: http://dinosaurs.about.com/od/typesofdinosaurs/a/hadrosaurs.htm)
5. Apatosaurus had teeth but couldn’t chew. According to the American Museum of Natural History, the Apatosaurus had “stripper teeth” that removed leaves from branches. Then, this plant-eater, believed to have weighed 19.8 tons, just swallowed plants whole. They swallowed stones (gastroliths) to help grind vegetation in their enormous stomachs. (More info: www.livescience.com/25093-apatosaurus.html) SEE: http://deltadentalazblog.com/5-fun-facts-about-dinosaur-teeth/
SAURISCHIANS Plant-eating sauropod dinosaurs (Apatosaurus, Diplodocus, Brachiosaurus, Supersaurus and many more) were equipped with peg-like or spoon-shaped teeth they used for stripping leaves off of plants. These teeth were not used for chewing, however, because of their shape. The plant material that these dinosaurs ate was swallowed and digested in their guts, maybe in fermentation chambers where the materials would break down, often with the help of gastroliths, or stones that the dinosaur swallowed to help break up the leaves and twigs in its gut. Meat-eating theropods (Tyrannosaurus rex, Carcharodontosaurus, Allosaurus, Gigantosaurus, Spinosaurus and many more) had sharp, pointed teeth they used to tear flesh and sometimes even crush bones. Recently, a Tyrannosaurus rex coprolite (fossilized feces) was discovered containing bits of crushed bone, which tells scientists that the dinosaur did in fact crush its food with his powerful teeth and strong jaws.
ORNITHISCHIANS Plant-eating Ornithischians, as well as some prosauropods had varying teeth but many had horny beaks and many leaf-like cheek teeth for nipping and chewing through tough foliage. Ankylosaurs (such as Euoplocephalus, Sauropelta and Ankylosaurus) were unable to chew their food so they may have had large fermentation chambers where they were able to digest the tough plant fibers. Ankylosaurs had teeth shaped like a hand with the fingers together. Ornithomimids (like Ansermimus, Gallimimus, Ornithomimus and Struthiomimus) did not have teeth, but they had beaks with which they ate plants and insects and small animals. Stegosaurids (Kentrosaurus and Stegosaurus as well as others) had leaf-shaped teeth that were built for slicing at weeds that grew close to the ground. Hadrosaurs (Edmontosaurus, Maiasaura, Lambeosaurus, Parasaurolophus and many more) were duck-billed dinosaurs and had around 960 self-sharpening cheek teeth; the most teeth of all of the dinosaurs. Iguanodontids (Iguanodon, Probactrosaurus, and Ouranosaurus among others) had teeth that look similiar to today’s iguanas. They were rounded outward, notched on top and curved, indicating that perhaps today’s iguanas originated as iguanodontids. Heterodontosaurus was a small dinosaur that had three different types of teeth in addition to a beak. It had sharp upper teeth which it used with its beak to bite and cheek teeth for grinding its food and two pairs of long canine-type teeth that fit into sockets when Heterodontosaurus closed its mouth. Ceratopsians (Triceratops, Monoclonius, and Styracosaurus belonged to this group) had toothless beaks they used to gather food and lots of flat cheek teeth they used to grind and chew tough plant material.
A DENTAL WEBSITE WITH AN EXCELLENT BREAKDOWN OF DINOSAUR TEETH: https://www.towncaredental.com/dinosaur-dental-discoveries/
Hadrosaur Teeth: Grinding vegetation
Triceratops teeth: slicing vegetation
Sauropod Teeth: Stripping branches
Theropod Teeth: Slicing and cutting flesh

9. K-T Extinction

The K-T boundary separates the age of reptiles and the age of mammals, which was first recognized over one hundred years ago by geologists who realized that there was a dramatic change in the types of fossils deposited on either side of this boundary. This boundary corresponds to one of the greatest mass extinctions in Earth's history. At least 75 percent of the species on our planet, both in the seas and on the continents, were extinguished forever. The most famous of the vanquished are the dinosaurs. However, these giants were only a small fraction of the plants and animals that disappeared. In the oceans, more than 90 percent of the plankton was extinguished, which inevitably led to the collapse of the oceanic food chain. See: https://www.lpi.usra.edu/science/kring/Chicxulub/

10. Modern Birds are Living Dinosaurs

Ask your average paleontologist who is familiar with the phylogeny of vertebrates and they will probably tell you that yes, birds (avians) are dinosaurs. Using proper terminology, birds are avian dinosaurs; other dinosaurs are non-avian dinosaurs, and (strange as it may sound) birds are technically considered reptiles. Overly technical? Just semantics? Perhaps, but still good science. In fact, the evidence is overwhelmingly in favor of birds being the descendants of a maniraptoran dinosaur, probably something similar (but not identical) to a small dromaeosaur. © University of California-Berkeley FULL ARTICLE: https://ucmp.berkeley.edu/diapsids/avians.html
Anchiornis huxleyi
Sinosauropteryx

10a. Interesting Facts About Representative NON-AVIAN and AVIAN DINOSAURS

TRIASSIC:• COELOPHYSIS: https://www.thoughtco.com/things-to-know-coelophysis-1093779 JURASSIC:• KULINDADROMEUS: https://iknowdino.com/kulindadromeus-kulinda-river-running-dinosaur/• ANCHIORNIS: https://kids.nationalgeographic.com/animals/anchiornis-huxleyi/#anchiornis-huxleyi.jpg• ARCHAEOPTERYX (BIRD): http://mentalfloss.com/article/56314/10-facts-about-archaeopteryx CRETACEOUS:• BEIPIAOSAURUS: https://web.archive.org/web/20210513062152/http://www.prehistoric-wildlife.com/species/b/beipiaosaurus.html• SINOSAUROPTERYX: https://web.archive.org/web/20210519024828/https://www.prehistoric-wildlife.com/species/s/sinosauropteryx.html• ZHENYUANLONG: https://www.nationalgeographic.com/science/phenomena/2015/07/16/paleo-profile-zhenyuanlong-suni/• EOCONFUCIUSORNIS (BIRD): http://www.sci-news.com/paleontology/melanosomes-beta-keratin-feathers-bird-eoconfuciusornis-04398.html• DEINONYCHUS: https://www.thoughtco.com/deinonychus-the-terrible-claw-1093783• ORNITHOMIMUS: https://www.thoughtco.com/things-to-know-ornithomimus-1093793• GIGANTORAPTOR https://www.thoughtco.com/things-to-know-gigantoraptor-1093788• OVIRAPTOR: https://www.thoughtco.com/oviraptor-the-egg-thief-dinosaur-1093794• STRUTHIOMIMUS: https://web.archive.org/web/20210511173354/https://www.prehistoric-wildlife.com/species/s/struthiomimus.html• VELOCIRAPTOR: https://www.thoughtco.com/things-to-know-velociraptor-1093806 EOCENE:• GASTORNIS: https://www.newdinosaurs.com/gastornis/ MIOCENE:• ANDALGALORNIS: http://cenozoiclife.blogspot.com/2015/11/steuletts-terror-bird-andalgalornis.html• PELAGORNIS: https://www.newdinosaurs.com/pelagornis/ PLEISTOCENE:• ORNIMEGALONYX: https://web.archive.org/web/20210411224450/http://www.prehistoric-wildlife.com/species/o/ornimegalonyx.html
Struthiomimus
Archaeopteryx and a modern duck dinosaur

10b. Birds are Dinosaurs: Selected Video Resources