It's the perfect beginner's reference book for children aged 7-9 who are curious about all things dinosaurs. Holtz, T.R. Jr.; Brett-Surman, M.K. (1997). "The Taxonomy and Systematics of Dinosaurs". The Complete Dinosaur. Bloomington: Indiana University Press. pp.209–223. ISBN 978-0-253-33349-0. Iggulden, Hal; Iggulden, Conn (2007). "Dinosaurs". The Dangerous Book for Boys. New York: HarperCollins. pp.30–34. ISBN 978-0061243585.

Dinosaurs are united by at least 21 traits in their skulls and skeletons. [12] These common characters (called ' synapomorphies') are the reason palaeontologists are sure dinosaurs had a common origin. Desmond, Adrian J. (1975). The Hot-Blooded Dinosaurs: A Revolution in Palaeontology. London: Blond & Briggs. ISBN 978-0-8037-3755-6. LCCN 76359907. OL 4933052M . Retrieved October 30, 2019.St. Fleur, Nicholas (8 December 2016). "That thing with feathers trapped in amber? It was a dinosaur tail". New York Times . Retrieved 8 December 2016. Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non-avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. [246] Direct fossil evidence of feathers or feather-like structures has been discovered in a diverse array of species in many non-avian dinosaur groups, [70] both among saurischians and ornithischians. Simple, branched, feather-like structures are known from heterodontosaurids, primitive neornithischians, [247] and theropods, [248] and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. [14] [249] Feather-like structures known as pycnofibres have also been found in pterosaurs. [250]

Main-stream palaeontologists have followed this view for small theropods, but not for larger herbivores. [21] Since we know that the size of a Stegosaur's brain was about the size of a walnut, there is good reason to think its intelligence was limited.Ceratosauria (generally elaborately horned carnivores that existed from the Jurassic to Cretaceous periods, originally included Coelophysoidea)

Starrfelt, Jostein; Liow, Lee Hsiang (2016). "How many dinosaur species were there? Fossil bias and true richness estimated using a Poisson sampling model". Philosophical Transactions of the Royal Society B. London: Royal Society. 371 (1691): 20150219. doi: 10.1098/rstb.2015.0219. ISSN 0962-8436. PMC 4810813. PMID 26977060. The largest carnivorous dinosaur was Spinosaurus, reaching a length of 12.6 to 18 meters (41 to 59ft), and weighing 7 to 20.9 metric tons (7.7 to 23.0 short tons). [152] [153] Other large carnivorous theropods included Giganotosaurus, Carcharodontosaurus and Tyrannosaurus. [153] Therizinosaurus and Deinocheirus were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid Shantungosaurus giganteus which measured 16.6 meters (54ft). [154] The largest individuals may have weighed as much as 16 metric tons (18 short tons). [155]Restoration of four ceratopsids: top left – Triceratops, top right – Styracosaurus, bottom left – Anchiceratops, bottom right – Chasmosaurus. While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18m (59ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters (20 inches) in length.