This text is about dinosaurs. Dinosaurs are a grouping of animals tiny to large, bipedal or quadrupedal, eating plants, meat, or both, but always land-based note . More precisely, this text is about non-avialian dinosaurs, i.e. definite birds are excluded. All dinosaurs of this kind (and many early bird genera) lived in the Mesozoic Era, nicknamed "The Age of Dinosaurs," 250-66 million years ago (mya). The era is divided by geologists and palaeontologists into three periods: from the most ancient to the most recent one, they are the Triassic, Jurassic, and Cretaceous. You'll note that most stock dinosaurs come from North America during either the Late Jurassic or the Late Cretaceous. Note that
Dinosaurs and other extinct animals are divided here into four categories:
A brief history of popular depictions of dinosaursSee here for a more detailed article. 1850s: The Crystal Palace dinosaur sculptures in London introduced dinosaurs to the public. The image they provide is of scaly bulky doglike dragons (quite undinosaurian critters to our modern view). Introducing: Iguanodon and Megalosaurus. The park also introduced some non-dinosaur reptiles: the flying Pterodactylus and the swimming Mosasaurus, Ichthyosaurus, and Plesiosaurus. In 1864 novel Journey to the Center of the Earth portrayed the latest two as the first "antediluvian reptiles" ever in literature. Late 1800s: The excitement of the U.S. Bone Wars made dinosaurs interesting to the readership of the newspapers and magazines that recounted the exploits and discoveries of Marsh and Cope. Stock dinosaurs found: Brontosaurus (Apatosaurus, though at the moment said synonymy is kind of rocky), Diplodocus, Allosaurus, Ceratosaurus, Stegosaurus, Triceratops, and Trachodon (indeterminate hadrosaur). Non-dinosaurs: Pteranodon, Elasmosaurus, Tylosaurus, and Dimetrodon. Early 1900s: Updated depictions of dinosaurs were brought to the general public by early paleoartists (beginning with Charles R. Knight), by distribution of skeleton castings which made life-sized and fairly life-like museum exhibits possible, and by dinosaurs being introduced to films. From this time on, dinosaurs and movie special effects were tightly coupled. Based on the finds during and since the Bone Wars dinosaurs are now seen as a more varied bunch, with larger and... less large forms, bipedal or quadrupedal. They are still sluggish brutes destined for complete extinction, though. In year 1940 Disney's Fantasia reached a large audience, but didn't change the media image much. Introducing: the aforementioned dinosaurs and non-dinosaurs from the Bone Wars plus Tyrannosaurus rex, Brachiosaurus (now split into Brachiosaurus altithorax and Giraffatitan brancai; the latter of which is infinitely more represented under the B. moniker), Styracosaurus, Ankylosaurus, Parasaurolophus, Corythosaurus, Plateosaurus, Ornithomimus/Struthiomimus, Protoceratops, and the non-dinosaur Rhamphorhynchus. 1970s: The Dinosaur Renaissance changed the image of dinosaurs to more active, more intelligent, more caring to their offspring, and well adapted to their environment (and surviving extinction through bird descendants). Introducing: Deinonychus, and to some extent, Archaeopteryx (as a proper dinosaur: it's been well-known since the 19th century but usually believed a non-dinosaur before the "renaissance"). 1980s/1990s/2000s: The Land Before Time and other works made at the end of the 1980s started popularizing the image of dinosaurs as set up by the Dinosaur Renaissance. Since the 1990s, scientifically up-to-date writing in the books and computer-based animation in the films / shows (especially in the Jurassic Park and Walking with Dinosaurs franchises) have definitively completed the job. Introducing:
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Meat-eaters (usually)Most dinosaurs were herbivorous or omnivorous: the Theropod group contains all the carnivorous dinosaurs. Some of them were very small, while the biggest weighed like an elephant or a bit more, although taller and much longer. Their legs were birdlike in structure; their feet had three main toes and usually a smaller reversed forth toe. All of them were bipedal; some had only tiny remains of the forelimbs. Theropods are the only group of dinosaurs that has living members today, since they included the common ancestor of birds. Some close-to-bird theropods became omnivores and sometimes herbivores; the group includes the only toothless non-bird-dinosaurs. Many theropods are now known to have been feathered, but in films they are usually shown with lizard-like scales — while documentaries tend to be a bit wonky on the coverings of their theropods.
The King of the Cretaceous: Tyrannosaurus rex ***
Lived in western North America 67—65 mya at the very end of the Age of Dinosaurs. Other tyrannosaurs lived in Asia in the same period, and other members of the tyrannosaurid family lived slightly earlier (still within the Late Cretaceous Period) in North America. note Together with Triceratops (and few others) Tyrannosaurus was one of the rare dinosaurs that was directly led to extinction by the asteroid/comet collision at the end of the Mesozoic Era. T. rex was discovered by Barnum Brown slightly before the start of the XX century, and described by Henry Fairfield Osborn in 1905. Since then, it has been a hit with the audience and possibly the most famous dinosaur for almost a century. During this time T. rex has changed from the heavy, fat-bellied giant with goose-like gait and flexible tail seen in Fantasia to the slender, running beast seen in Jurassic Park. We are still waiting to see it and/or its chicks depicted with downy covering, though (Thank you Dinosaur Revolution). Despite only living for a couple of million years in a small part of the world, every visit to a dinosaur-populated time or place will have at least one T. rex appearing. This is for reasons better explained on the animal's own trope page. Yes, that's how big it is in media.
Sickle-feet: Deinonychus, Velociraptor & Utahraptor, aka the "Raptors" ***
Raptors, or more formally dromaeosaurids, were bipedal carnivorous dinosaurs of the Cretaceous Period. They were small with long, thin tails and compact bodies. They were closely related to birds: their skeletal structure was bird-like, and since the late 1990s it has been proven they were also covered with pennaceous feathers. The most distinctive feature was the large, retractable "sickle claw" on their second toe. How it was used is being still debated. For decades, dromaeosaurids were depicted as hunting and attacking herbivores much bigger than itself, e.g. the classical Deinonychus hunting Tenontosaurus or even the five-ton Iguanodon. Like a pack of wolves, dromaeosaurids would track down and attack their prey, using their powerful claws to rend and to climb atop the herbivore; Since around 2000 dromaeosaurids have instead been suggested to have been mostly solitary small prey hunters (see Prehistoric Life). In the early 20th century, two small dinosaurs were discovered and described as generic small predators. Both were from the Late Cretaceous. While the finds were incomplete and difficult to interpret, we now know the animals were about 6.5 ft / 2 m long and weighed about 33 lb / 15 kg. Dromaeosaurus ("running lizard") lived in the Alberta region, while Velociraptor ("swift robber") lived in Mongolia and China 75—71 mya. For half a century, they were sorted away and largely ignored. Then... Deinonychus note ("terrible claw") was (re)discovered in 1964. It lived 115—108 mya in Early Cretaceous North America and was at the same time one of the largest and one of the earliest raptors, 11 ft / 3.4 m long and weighing 160 lb / 73 kg. Even though some illustrations showed it as tall as an adult man it could actually only reach his hips if alive today. Some years later, more complete remains of Velociraptor were found, showing that it was similar to Deinonychus but even smaller (the bulk of a turkey or an ocelot). Deinonychus was described by John Ostrom in 1969 in an influential monograph that kicked off the Dinosaur Renaissance. After that, paleontologists, especially Ostrom's pupil Bob Bakker, began to debate if the traits ascribed to Deinonychus (agility, smartness, warm-bloodedness, social behavior) should be extended to all dromaeosaurids, or possibly to all theropods, or even to all dinosaurs. In the 1980s, one paleontologist (Gregory Paul) claimed that Deinonychus and Velociraptor were actually the same taxon and that the species Deinonychus antirrhopus should be renamed "Velociraptor antirrhopus"; author Michael Crichton picked up this idea, showing both Deinonychus and Velociraptor proper in his Jurassic Park novel as distinct species within one single genus, "Velociraptor". note Works from before the 1970s never represent dromaeosaurids, simply because they were too obscure at the time. Significantly, between 1970 and the Jurassic Park mania in the 1990s, the most represented "raptor" (though not yet known as such) in popular culture was the biggest known at the time, Deinonychus, while the less-impressive Velociraptor was totally unknown to laymen (not counting the antecedent dino-fans). For instance, see Dino Riders, Dinosaurs Attack!, the RuneQuest Borderlands tabletop RPG adventure, or even the Dutch metal-band named Deinonychus It was Jurassic Park that apparently caused Velociraptor to displace Deinonychus as the stock sickle-clawed dino, and started the usage of "raptor" for dromaeosaurid in the mind of the public. (Prior to this, "raptor" was used only to indicate birds of prey.) Without Jurassic Park, Velociraptor would have almost-surely remained in the Non-Stock realm forever. There are several issues with the depiction of raptors in the film. At the same time that the name Velociraptor became popular, a new dromaeosaurid was discovered in Utah. This animal was even larger and slightly older than Deinonychus, living 128—105 mya and being 23 ft / 7 m long and as tall as a human. It was named Utahraptor, beginning an awesome case of science culture Ascended Fanon — before Jurassic Park, no genus of dromaeosaurids except Velociraptor had the -raptor suffix to its name. Since the film, paleontologists started to use it for naming most new dromaeosaurids. The discovery of Utahraptor was much reported in media as it incidentally matched the size of the oversized JP raptors (or rather, was even longer than they were). Many then reported the Utahraptors as "the most fearsome killing-machines of all times", capable to kill, in packs, the biggest sauropods and even to destroy entire dinosaur species. However, Walking with Dinosaurs was not so extreme, showing Utahraptor hunting the relatively smaller Iguanodon — not in Utah but in Europe for some reason.
Post-rex stock theropods
Since the eighties/nineties a handful of large theropods have started to filter into pop-consciousness, often after a single remarkable apparition in Movieland: Spinosaurus (Jurassic Park 3), Giganotosaurus, Carnotaurus (Disney's Dinosaur), and Baryonyx (Ice Age 3). Even though bearing some cool traits (crests, horns, claws, or sheer size), none of them has managed to replace T. rex as the "King Dinosaur" — at least for now. Though relatively small, Dilophosaurus (popularized by the 1st Jurassic Park film) is here for comparison.
Spiny back: Spinosaurus **
Lived in Northern Africa from 112 to 97 million years ago, during the Cretaceous Period. At present, this is the biggest theropod; no other matches it in bulk and length. Spinosaurus is one of the most recognizable theropods with its 5ft / 1.5 m tall spines on its back. In the most common interpretation the spines form a "sail" similar to that of the non-dinosaur Dimetrodon. Some suggest that they instead supported a slim hump, while others thought they came from another dinosaur altogether. A sail could have been useful as a thermoregulating device and/or a display tool, and a hump could have been for display, making the animal seem larger, as well as storing extra energy gained from the giant fish and other prey that Spinosaurus fed on. Spinosaurus was first described in 1915 by a German paleontologist, but its remains are very scanty: its skull is incomplete, and we have no limb bones. The spinosaur's best record was stored in a German museum, but got destroyed by aerial bombing during World War II. In older drawings Spinosaurus had a head like a generic "carnosaur"; today it is generally accepted that it was crocodile-headed. Due to the fragmentary nature of its remains, the actual overall size is in debate; once thought the same length of an average Tyrannosaurus (40 ft / 12 m), many paleontologists wanted to set the length at 50ft / 15 m. Lack of real evidence for this left T. rex with the official record until the discovery of Giganotosaurus in the middle 1990s. Meanwhile, the spinosaur remained an only-known-among-dino-lovers dinosaur. Then, in the year 2001... ...Jurassic Park III (which fans don’t really like to talk about but was nonetheless popular) changed this situation in a blink. This film introduced the spinosaur to the audience as "bigger and badder" than a Tyrannosaurus rex, and easily capable to defeat the latter in a fight. Many dino-fans complained that the JP spinosaur was oversized and altered to make it a sort of Pseudo-Rex thing. Then, new discoveries told us Spielberg wasn't totally wrong: Spinosaurus really was bigger than Tyrannosaurus rex. Not only that, it was indeed the biggest of the lot, and is still considered to be so. There is some controversy regarding Spinosaurus’ diet and way-of-life: did it prey on fish like its smaller cousin Baryonyx (see later), or on giant herbivores like Tyrannosaurus? Experts tended to prefer the first option at the time Jurassic Park III was produced, and this fostered even more criticism about the film portrayal as the Ultimate Superpredator. Today Spinosaurus is generally believed a middle-way between these two extremes: an opportunist like a prehistoric grizzly, attacking other smaller dinosaurs when given the opportunity, as well as eating fish (even freshwater sharks), and using its size to steal kills from other predators. We're unsure about the latter, though: if it did have a fragile sail, it might break in a fight against other giant predators such as Carcharodontosaurus, likely causing the spinosaur to bleed to death.
Giant of the south: Giganotosaurus *
Giganotosaurus (NOT "Gigantosaurus"; that name was used for an invalid sauropod) lived in late Cretaceous South America 97 million years ago. A close Allosaurus relative, it had a bigger head (6 ft / 1.80 m long, even longer than a Tyrannosaur's) and a stockier build: its looks seems rather like a cross between an allosaur and a tyrannosaur — incidentally, making the classic hybrid allo/tyranno so often seen in classic films (Fantasia, One Million BC… ) a sort of Truth in Television. Discovered in 1993 and officially described two years later, Giganotosaurus was celebrated as "the biggest predatory dinosaur ever," surpassing Tyrannosaurus, of whom the largest specimen known (the famous Sue) was discovered a few years before. The "giga" remained the record-holder until new Spinosaurus fossils were discovered in the 2000s, and the re-examination of the descriptions of older finds, reminded us that the latter was even larger, something already postulated but ignored for 80 years. At the same time, re-examination of Giganotosaurus remains show an animal not much larger that Tyrannosaurus; the only advantage in length is due to a longer snout, and had the two animals been placed side to side, they'd seem to be the same size. Its close relative Carcharodontosaurus (known since the first half of the 20th century in the form of teeth, but rediscovered in 1996), got the same treatment in the 1990s, ultimately lost the struggle for widespread recognition; and both ended up overshadowed in popular culture by Spinosaurus. Giganotosaurus remains one of the most powerful meat-eaters that ever lived; and it's just starting to gain popularity. The fact that it could have possibly hunted some of the largest sauropods — related with the utterly vast Argentinosaurus — means that it may become very popular in the future. If that doesn't sound cool enough, then consider that to do so, it would have had to be a pack hunter. Walking with Dinosaurs did a special on just how Bad Ass such a hunt would be (even though in the show the Argentinosaurus that became prey was a juvenile). Though there isn't any evidence for pack behavior in Giganotosaurus, there might be for its relative, the recently-discovered Mapusaurus, which was the same length but had a more slender frame.
Meat-loving bull: Carnotaurus *
Another South American theropod like the former, Carnotaurus lived in the late Cretaceous in a younger age, 70 million years ago. Discovered only in 1985, it is known from a single specimen, but this was one of these things every paleontologist wishes to find: one of very few big theropods so far found with evident skin impressions. As these prints are from the whole right side of its body, Carnotaurus is one of the only large dinosaurs whose external look is known with a reasonable degree of sureness, together with the so-called "hadrosaur mummies" (see "Hadrosaurs"). We don't know what was the coloration of the living animal, however. But this is not all: our carnotaur has revealed to be one of the strangest-looking dinosaurs known. Forelimbs even tinier than those of T. rex, a sort of useless stubs with no true fingers (though three clawed fingers appear in many portrayals, and sometimes even a small Iguanodon-like thumbclaw for each hand) that contrast vividly with the long legs apt for high-speed runs note . Unusually shortened head (some compare it to a bulldog's). Above all, a couple of unique bull-like horns above the eyes which no other known theropod had (Carnotaurus means "meat-eating bull"). Finally, its skin was covered by rows of horny tubercles. The horns and the skin make Carnotaurus a quite dragon-looking dinosaur. Ironically, with its slender body, tiny forearms, and fragile lower jaws, it's hard to imagine how it could kill large prey in Real Life, esecially if you think it doesn't come close to rivalling Tyrannosaurus in size (it was only about 22 ft / 7 m or so in length, while a big rex would be about 43 ft / 13 m). However, Carnotaurus has become somewhat popular in the last decades, thanks to its striking look. It was portrayed as an oversized, pseudo-rexing villain in the 2000 Disney’s Dinosaur. Here, the biggest carnotaur appears even greater than a spinosaur, able to lift an Iguanodon with its jaws, and flings it to death against a rock. In Real Life the 1-ton Carnotaurus was much smaller and weaker than he 5-tons Iguanodon, and lived several million years after the latter. Before that, it also showed up in Michael Crichton's second Jurassic Park book, where its size was portrayed more accurately, but to up the threat level, it was given (quite implausible) chameleon-style stealth abilities. Note that neither modern birds nor crocodilians can change their colors like chameleons do. Carnotaurus may be the responsible for the recent decline of the classic carnivore Ceratosaurus in media, as both dinosaurs had a similarly horned/tubercled look and the two dinos might be confused with each other, even though their look was rather different (see also Ceratosaurus in another section). But also note a bit of resemblance both in shape and in name between the Carnotaur and a mythical critter, the Minotaur. This association may have at least subconsciously led to it becoming a go-to bad guy dinosaur.
Heavy claws: Baryonyx *
A cousin of Spinosaurus that lived in Europe in the Early Cretaceous, 130—125 mya, alongside Iguanodon. Discovered in 1983 in Southern England and named in 1986, its find got massive media coverage at the time (especially the British media); in part because, being 30 ft / 9 m long, Baryonyx was the largest and most complete European giant theropod, but mostly because it was very different to other dinosaurs known at the time, with its crocodile-like jaws lined with an incredible 96 teeth note (Spinosaurus was still portrayed with a token-theropod head in the 1980s), and very special forelimbs. Baryonyx means "heavy claw" and the animal has been nicknamed "Claws" because of its 10 inch / 25 cm long, hook-like thumb-claws, bigger than the other two fingers on each hand. We don't know if Spinosaurus had these hook hands as well. The baryonyx's forelimbs were longer and stronger than in most other theropods, but the structure of the forefeet seems to preclude quadrupedal walking (contrary to what is sometimes shown in illustrations); it is speculated, however, that Baryonyx might have fed by resting on its front legs on a riverbank and swept large fish such as the carp-like Lepidotes from the river with its powerful claw, a bit like grizzly bears do with salmon. We know for sure fish were included in its diet: scales of Lepidotes were found inside the ribcage of the only well-known Baryonyx specimen. Baryonyx was the first discovered fish-eater among dinosaurs, and several traits scientists today assign to Spinosaurus were initially based on Baryonyx. Together, these dinosaurs (plus Suchomimus and few others) form the spinosaurid family. However, Baryonyx was quite different from Spinosaurus: it had no sail on its back,note and was considerably smaller (10 m long and weighing 2 tons, like an Allosaurus). Its head was thinner with a small bump on its top, and gharial-like jaws with twice the teeth than most other theropods. Baryonyx was probably more aquatic than Spinosaurus: fish might have made a greater part of its diet, possibly with occasional carrion and small land animals as a supplement. Its short hindlegs show it was not an expecially-fast runner; moreover, its blunt croc-like teeth and weak thin jaws probably prevented the "bary" to kill preys the size of a fully-grown Iguanodon in spite of the former's huge thumbclaws (incidentally, Iguanodon too had oversized thumbnails, but they were almost-straight and not curved like the carnivore's ones). Since the 1980s, "Claws" has been one of the most frequently-portrayed large theropods in popular dino-books. On the other hand, it has long been ignored in Fictionland or even most TV documentaries. It came into the spotlight only in 2009 thanks to the Ice Age 3: Dawn Of The Dinosaurs film. Here an oversized Baryonyx called Rudy is the Pseudo-Rexing Big Bad who is even bigger than the JP3 Spinosaur or the real life one. The baryonyx is unnamed however (some dino-fans wrongly think he's a Suchomimus), and also quite inaccurate, with a head shaped like a literal crocodile's and hands lacking the distinctive thumbclaws. Rudy is an albino; unlike chameleon-like carnotaurs, albino dinosaurs were possible in Real Life but certainly very rare.
Double crest: Dilophosaurus **Dilophosaurus lived 197 million years ago in Early Jurassic North America and maybe China. It was one of the first theropods to have exceeded human size (20 ft / 6 m long and weighing 500 kg). Smaller and more slender than the other carnivores listed above, it was a fairly close relative of the dog-sized Coelophysis. Its most easily recognizable trait is the two parallel crests on its skull (perhaps only in males), probably used for display. These fragile and vulnerable structures indicate that it was no Bad Ass dinosaur. Its head was long and narrow with weak jaws and teeth, and each upper half-jaw also show a deep pit between the frontal and back-teeth, making the whole structure even weaker. note Scientists have usually said the dilophosaur was a mere scavenger or a small prey hunter, even though some had initially described it as the "the first giant killer dinosaur". It was indeed one of the biggest terrestrian carnivores of its time (some docu-portrayals show it as a rather unlikely powerful super-predator); however, really-powerful meat-eating dinosaurs appeared only in the following Middle Jurassic, for example Megalosaurus. note Dilophosaurus was first described in 1954 in Arizona from scant remains lacking the head, and was initially thought to be another species of the "wastebasket taxon" Megalosaurus. The first head complete with double-crest was found only several years later; in 1970, the animal received the name Dilophosaurus, "double-crested lizard." Several footprints found in Early Jurassic terrains of the USA might have been made by dilophosaurs, but the exact identity of dinosaurian tracks cannot be told with sureness. One of these tracks was made by a swimming animal which barely touched the bottom with the tip of its feet. It's unlikely that many people outside the dino-fandom had ever heard of Dilophosaurus before the novel Jurassic Park was published in 1990. Here it was depicted as capable of spitting venom like some species of cobra, which it probably couldn't do in Real Life: venomous saliva is unknown among modern birds and crocodiles. Two years later, the JP movie made the dilophosaur even more popular and even more incorrect. Its size was greatly decreased note , but above all, Spielberg added a totally improbable Frilled Lizard -like cowl on its neck. It certainly did not have this frill; it would require a lot of specific musculature on the neck, and the imprint of this would be visible on the skeleton (it isn't). Still, all later popular depictions have represented Dilophosaurus with this thing. Just like Velociraptor, Dilophosaurus became a household name after the film, commonly known as the Spitting Dinosaur. Even though it has not appeared in any of the sequels, the JP portrayal has remained in pop-consciousness, coincidentally preventing the Real Life animal from become more widely-known. Today, the ever-increasing public interest in dinosaurs (mainly started thanks to Jurassic Park) is making Spielberg’s Mix-and-Match Critter more and more of a Lost Subtrope.
Pre-rex stock theropods
It's interesting to note that some large meat-eaters entered in pop-culture before T. rex: Allosaurus, Ceratosaurus, and Megalosaurus. But they have become less portrayed just since T. rex was discovered.
The King of the Jurassic: Allosaurus **
Allosaurus lived 155 to 150 million years ago in North America, with some fossils found in Europe and maybe Africa. Along with Tyrannosaurus, it has traditionally been the large carnivorous dinosaur. Allosaurus is the scientifically most well-known large theropod: dozens of specimens have been found so far in Western USA, including a veritable "graveyard" in Utah.note Many young individuals are also known to science. First discovered in 1877 during the Bone Wars, Allosaurus literally means "other lizard" or "strange lizard", but Othniel Charles Marsh's article naming it gives no reason for the bland choice. The most well-known species is Allosaurus fragilis ("the other fragile lizard"); some fragmentary remains of unusually large size are often classified in separate genera (see Prehistoric Life). Some scanty fossils from Early Cretaceous Australia used to be classified as a small-sized late-surviving Allosaurus species, but were reclassified in 2009 as a totally different theropod, Australovenator. Even scantier remains were found in the USA before Allosaurus was officially described in 1877; they were labeled Antrodemus, but possibly belong to Allosaurus as well. If true, the former might become the valid name for this dinosaur. note Allosaurus was the top predator in the Late Jurassic, sometimes referred as "The Tyrannosaur of the Jurassic". Its hunting behavior is still uncertain: we're not sure if it was mainly a pack-hunter or a solitary ambush-predator. In documentaries and pop-books it usually appears as a pack-hunter capable of bringing down the biggest sauropods like Diplodocus (like in the memorable The Ballad Of Big Al), Apatosaurus, or even Brachiosaurus. Alternatively, it is shown in a battle against the armored Stegosaurus (the Jurassic equivalent of the tyrannosaur-vs-triceratops Cretaceous one). All this might be Truth in Television since all these animals lived together in North America in the same period; but more probably Allosaurus more often hunted easier prey such as young sauropods, young stegosaurs, and ornithopods like Camptosaurus. Allosaurus entered pop culture before Tyrannosaurus. After its description, was briefly considered the "biggest land carnivore ever" together with Megalosaurus. In Conan Doyle’s The Lost World (1912) the two scientists encounter a giant carnivore, and argue about whether it is an Allosaurus or a Megalosaurus (maybe a reference to the recent "bone wars.") Soon later, both dinosaurs got overshadowed by the more impressive (and much cooler-named) Tyrannosaurus rex in pop-media, especially cinema. Allosaurus has somehow managed to survive the supremacy of the rex... automatically becoming its Poor Man's Substitute, as the two animals tend to be easily confused with each other in the public mind. Actually, Allosaurus is rather easy to distinguish from T. rex. It was generally smaller (the classic species was slightly shorter and about one half of the weight of a T. rex), had shorter legs, longer tail, slimmer body and neck, narrower head, weaker lower-jaw, smaller teeth, and a pair of "bosses" in front of their eyes (maybe covered in keratin in Real Life, making them like small "horns"). Above all, it had longer front arms with three clawed fingers rather than two. Sadly, all these differences tend to be glossed over in popular media. The fact that T. rex itself has often been depicted with long arms with three functional digits (e.g. in Disney's Fantasia) doesn't help, either. Among the official Allosaurus appearances in cinema, the Ray Harryhausen ones are the most remembered. The allosaur is the go-to Big Bad of his movies, appearing in One Million Years BC and playing the role of Gwangi in The Valley of Gwangi. Ray's critters looked just like that of Fantasia, with the same mishmash of allosaur and tyrannosaur features (and with the same outdated erect-body / serpentine-tail / goose-gait); the only difference is that Harryhausen's theropods have Evil Eyebrows (this may be forgivable for some, considering the aforementioned eye bosses).
Horned rex, or just underdog?: Ceratosaurus *Ceratosaurus lived in the same place as Allosaurus in the late Jurassic, 153-148 mya. Usually 17-23 ft / 5-7 m long, it was smaller than most other Stock Theropods above, but still a powerful animal. Its look was that of an undersized allosaur, with the same eye-bosses and long forelimbs. Its name, "horned lizard," underlines its more distinctive anatomical feature: a laterally-flat crest on its nose, classically described as a "nasal horn." note It was also the only known theropod to have armor in the form of bony plates along the middle of its back. While the "horn" is a constant in Ceratosaurus portraits (don't exclude to see it shaped like a rhino's), the armor can be left out altogether, or alternatively, modified to make the animal similar to a dragon. Despite the appearences, Ceratosaurus was actually more archaic than Allosaurus. Allosaurus belongs to the Tetanuran branch of theropods, while Ceratosaurus is the namesake of its own branch, Ceratosaurs. The latter can be told apart from Tetanurans by the primitive shape of their pelvis, more flexible tails, and a remnant forth finger in each hand (tetanuran theropods always bear no more than three fingers). Most of the other theropods discussed here are Tetanurans, except fellow ceratosaur Carnotaurus, and the more primitive Dilophosaurus and Coelophysis. Ceratosaurus was first found during the "bone wars" like Allosaurus, but is much rarer in the fossil record than the latter: many palaeontologists suspect it was more solitary than allosaurs. In paleo-art and documentaries Ceratosaurus is usually shown either as a scavenger or an underdog predator, but can also be shown as a pack-hunter of big game occasionally. While the allosaur is seen as the "lion" of its time, the ceratosaur might be considered the "hyena"; with its smaller size, longer teeth and stronger jaws, the comparison works. Since Real Life spotted hyenas are not lions' underdogs (as seen in The Lion King) with both co-dominating the top-predator niche, its possible that ceratosaurs and allosaurs had a similar relationship. The horn on its nose and the armor make Ceratosaurus the most "dragon-looking" of the theropods known at the start of the 20th century. It's not a big surprise that it appeared in so many classic dino-films, from simple cameos (like Fantasia) up to being the main dino-actor (like the film by Ray Harryhausen Animal World, in which two ceratosaurs get into a fight and fall off a cliff). Ceratosaurus holds the record of being the first dinosaur ever shown in non-animated cinema —the 1914 film Brute Force pitted cavemen vs dinosaurs and started the Dinosaurs Are Dragons trope. In the following fiction Ceratosaurus received the same treatment of Allosaurus, acting as a T. rex substitute for the Big Bad part. With its distinctive look, the ceratosaur has lower chances than the allosaur to be confused with the tyrannosaur; on the other hand, its size was often exaggerated to make it more of a "horned tyrannosaur." Ceratosaurus is quite rare in films these days: the only relevant example is a short cameo in Jurassic Park III, in which it's not even named (but at least is correct-sized). Even modern documentaries rarely represent it – the Walking with Dinosaurs series didn't show it at all. The recent Ceratosaurus decline is probably due to the occurrence of other, newly-discovered theropods since the seventies: Carnotaurus in particular, being similar yet even more Bad Ass looking.
The first named non-bird dinosaur: Megalosaurus *
We've already mentioned Megalosaurus more than once. Why? Well, both because it was the first giant theropod known to science, and because shows neatly how Science Marches On is normal stuff in dino-science. Its first remain, the extremity of a leg-bone found in 1676 in England near Oxford, was mistaken by Robert Plot for the remain of an ancient giant man (others named this remain "Scrotum humanum" because of its shape), but this fossil has been lost today. Later, a half lower jaw with a single tooth left was found in 1824 in Southern England; its discoverer, reverend and geologist William Buckland, described it as belonging to a "big lizard" (the meaning of its name, which started the tradition of "saurus" in dinosaur names). Buckland didn’t realize to have named the very first non-avian dinosaur. At the time, the Dinosaur category didn't even exist in scientific literature. The scientific and popular view of what a megalosaur was has gone through several drastic changes. The first attempt at reconstruction, the life-size sculpture in Crystal Palace Park constructed in the 1850s, made the Megalosaurus a dragon-like animal walking on all fours. Next to the Megalosaurus was an Iguanodon sculpture (also quadrupedal), and for several decades this was the stock image of the world of dinosaurs: one herbivorous dragon facing a carnivorous dragon in combat◊. From this time is Charles Dickens' novel Bleak House (1853) where Megalosaurus is mentioned, described as an "elephantine lizard." New genera of large carnivores were described during the Bone Wars, such as Allosaurus and Ceratosaurus, whose better remains showed clearly bipedal animals. Since then, Megalosaurus has been reconstructed bipedal as well. Even with their correct shapes, the "Megalosaurus vs Iguanodon" battle has remained a classic in non-fictional portrayals (a bit like "Tyrannosaurus vs Triceratops"), even though in Real Life the megalosaur was a middle Jurassic animal (166 mya), while the iguanodont lived 40 million years after in the Early Cretaceous. The tendence to classify theropod fossils of every kind as Megalosaurus started soon after its first description. After the Bone Wars, Megalosaurus still remained a "Wastebasket taxon" to which all finds that were too incomplete or too ambiguous were assigned. Megalosauruses cropped up everywhere from North America to Africa and from Early Jurassic to Late Cretaceous. Finally, scientists sorted out outsiders into more than 20 genera (Carcharodontosaurus, Dilophosaurus, Eustreptospondylus, Majungasaurus, and Proceratosaurus among them). This clean-up has yet to be definitively finished. The only-valid Megalosaurus is a fairly generic theropod some 30 ft / 9 m in length, similar to an elongated allosaur but smaller and more primitive. Even though its historical relevance makes it a common sight in classic and modern dino-books, the "big lizard" didn't go a long way in popular works after the two important mentions in early literature (Bleak House and Lost World). In the 20th century it heavily suffered the competition with Tyrannosaurus and Allosaurus; even the resolution of the "wastebasket" issue didn't help much. Apart from some occasional documentary, you've got low chances to see any "megalosaur" both in cinema and in TV media —- just as an example, Walking with Dinosaurs chose to portray the contemporary close-relative Eustreptospondylus in the Jurassic-Europe episode. There is, however, the curious case of the TV show Dinosaurs, which has one "megalosaur" in the form of Bob Sinclair: but he doesn't look particularly like any dinosaur at all.
Other large theropodsSorry, these ones aren't here. If you're looking for Tarbosaurus, Albertosaurus, Megaraptor, Suchomimus, Majungasaurus, and others, see here.
Bird-like / small theropods
Here is a list of several bird-like and/or small theropods that make some appearance in media, although less commonly than the iconic "raptors."
Dino-like bird or bird-like dino?: Archaeopteryx **
Archaeopteryx note lived around 150-148 million years ago in Late Jurassic Europe. Its name means "ancient wing" or "ancient feather"; another obsolete synonym very common in old textbooks was Archaeornis, "ancient bird." Both terms are very meaningful about its historical relevance. It is sometimes known as the "Urvogel," which is German for "original bird." Archaeopteryx was discovered 1861 in the famed Solnhofen deposit in Germany, whose rocks have preserved fossils so well that even soft parts of animals are visible. Because of this, most specimens of Archaeopteryx found later in Germany were found with impressions of feathers. Charles Darwin had published On the Origin of Species two years earlier, and in the following debate this "half-reptile" / "half-bird" became a key piece of evidence, as the perfect example of a "missing link" between two animal classes. A century later, Archaeopteryx was again used as crucial evidence, this time in John Ostrom's theory that modern birds had evolved within the theropod group. Before that, most scientists considered Archaeopteryx and its bird-descendants only distant dinosaur-relatives, in part because in traditional zoology Feathers = Bird, and no other dinosaur was known with prints of feathers. Even though one scientist (Darwin's pupil T. H. Huxley) already recognized the dinosaurian origins of birds as early as the late 19th century (by studying the skeletal features), this was largely accepted only after the "Dinosaur Renaissance" note and definitively proven only in the 1990s after the find of the feathered "Liaoning theropods". Archaeopteryx has had a somewhat unique role among stock prehistoric animals: just like the Dodo is the icon of Extinction, Archaeopteryx has been that of Evolution. Within the long-lasting debate between scientists and creationists, the latter went so far to claim Archaeopteryx fossils are just fake. According to modern knowledge Archaeopteryx is just another feathered theropod — possibly a bird, possibly a deinonychosaur, possibly more primitive than either. Highlighting its theropodian nature, one archaeopterygid skeleton with no signs of feathers was long classified in another theropod genus, Compsognathus (see later). The size of a chicken, Archaeopteryx had a long bony tail (modern birds have always stubby tails), three claws on its forelimbs, running feet with an enlarged second toe claw (this was discovered only in the 2000s), jaws with small, pointed teeth, and feathers. The main difference is that its feathers aren't just skin-covering down; it has flight feathers of very modern-looking shape in its wings and tail. It probably could glide but it is unlikely that it could flap its wings for powered flight —- it had not the modern birds' keeled breastbone for poweful wing-muscles attachment, but the usual "ventral ribs" seen in non-bird theropods. Maybe it simply used its claws to climb up trees and then glided to the next tree. Its diet was probably made only of insects and small vertebrates. Its classic status as "the first bird" is merely traditional at this point, and the start of the "bird lineage" within the theropod branch depends on the chosen criteria to define what’s a bird and its exact position. Still, it remains one of the most ancient known dinosaurs found with prints of feathers. In media, Archaeopteryx is fairly established as the "first bird." It will fly like a bird, and perch like a bird, neither of which was possible for the real-life Archaeopteryx. Media archeopteryges will lack the sickle claws on their feet, and possibly also their wing-fingers and teeth. Expect also to see them with a naked head, making them resembling "feathered lizards." Actually, their head would have been almost totally feathered like deinonychosaurs and most modern birds (see Raptor Attack).
Lighter and softer: Ornithomimus, Struthiomimus & Gallimimus, aka the "Ostrich-dinosaurs" **
Ornithomimus was a small, agile animal (the antithesis to the classical Mighty Glacier dinosaur) that lived in North America between 75—65 million years ago, in the Late Cretaceous. It was 12 feet / 3.5 meters long and weighed around 220—330 lbs / 100—150 kg. Its shape was similar to a long-tailed ostrich. It had a long neck with a birdlike skull and a toothless beak. The brain and eyes were large, possibly an adaptation to support quick movement. Its tail was very long, balancing the animal when running. The legs were similar to modern running birds, with short muscular femurs, elongated tibias / shins, and three toes each. With this anatomy it may have been the fastest non-avian dinosaur, easily capable to escape the bigger and clumsier Tyrannosaurus rex. Ultimately confirmed to be feathered, which was already suspected for some time. It turned out that not only it had down-covering, but the adult specimens also had shafted feathers (similar to covert feathers of birds) on their forelimbs that most likely formed a wing-like structures called pennibrachia (though obviously not used for aerial locomotion). note Ornithomimus ("bird-mimic") is the prototype of the Ornithomimids, often nicknamed "Ostrich-dinosaurs". This family also includes Struthiomimus and Gallimimus among the others. The former ("ostrich-mimic") was almost identical to the namesake of the family (it had only longer forelimbs), lived in North America in the same period, and the two were actually considered the same animal at the time ornithomimids first entered pop-media (1940). They were definitively recognized distinct only in the 1970s. The genus Dromiceiomimus ("emu-mimic") was briefly separated from Ornithomimus in the same decade, but has since been merged back in the 2000s. This means the character Dromiceiomimus in Dinosaur Comics is actually an Ornithomimus. As their names suggest, Ornithomimus and Struthiomimus have been recognized as birdlike dinosaurs since their very first discovery. Ornithomimus was the first described (USA, "Bone-Wars", 1890), while Struthiomimus was named later (Alberta, 1917). The first US remains were fragmentary though, and complete ornithomimids came to light only in the early 20th century. They were described as fast-moving and graceful even before the Dinosaur Renaissance, and usually portrayed with erect tail and horizontal body (unlike the giant bipedal dinos with their upright body / dragged tail). Unusually for dinosaurs, media have never shown ornithomimids as scary killers dangerous to humans. This can be due to their lacking of teeth that make them look harmless. Their actual diet is still uncertain, as no stomach remains are known for now. Their large numbers, among other things, seems to indicate that they were mainly herbivorous with insects, eggs, and small animals as a supplement. In popular media they have often been depicted as plant-eaters and/or insect-eaters (very rarely as meat-eaters). But the most common pop-portrayal has shown them as egg-stealers outwitting larger dinosaurs, like in the Land Before Time (possibly due to confusion with Oviraptor). Even though they could have eaten some eggs, there is no evidence this was a major part of their diet. Furthermore, being not "maniraptorans" ("robbing hands"), they probably couldn't grasp things so easily as the latter did. Today, the "robbing" role is more often attributed to actual maniraptoran theropods, especially oviraptorosaurs (see further). Finally, in the early 2000s it was suggested ornithomimids were filter-feeders like flamingos (as seen in Prehistoric Park), but now this hypothesis is disproved. Discovered in the 1970s, Gallimimus ("rooster-mimic") was one of the largest ornithomimids — 20 ft / 6 m long, with some reports of sizes up to 8 meters long, as long as several giant predatory theropods. It lived in Mongolia in the late Cretaceous, 70 mya. Apart from its longer, blunter snout and slightly shorter legs, its appearance was that of an enlarged Ornithomimus. With its large fossil record Gallimimus has become a common sight in dino-books since the eighties, but has entered the pop-consciousness only after Jurassic Park — the film, not the novel, which has the hadrosaur Maiasaura in the stampede scene. Like Velociraptor and Dilophosaurus, Gallimimus became one of the Stock Dinosaurs immediately after the movie, but has replaced Ornithomimus and Struthiomimus in pop-culture only partially. Fictional works from after 1993 can still add Ornitho- or Struthio- (or even "Dromiceio-") to their -mimuses, instead of Galli-.
Cannibal, or hero? Coelophysis *
One of the first true dinosaurs to appear on Earth, Coelophysis lived in Late Triassic North America 216 to 203 million years ago, although fragmentary material suggests a near worldwide distribution lasting up to 188 million years ago. Described during the Bone Wars from some pieces of bone, today it is by far the most abundant early theropod in fossil record. In the 1940s, a whole graveyard with hundreds of specimens was found in New Mexico; traditionally said to have died all together in a flood, this could be untrue however. Coelophysis was a slim, fast-running dinosaur growing up to 10 ft / 3 m, and weighed about 30 kg. Coelophysis looks like a fragile animal, with a narrow head, weak jaws with small pointed teeth, a long, stork-like neck (sometimes improperly described as "snake-like"), and an elongated, thin body. As an early theropod, Coelophysis was not very closely related to birds. For example, it had still a remnant of the forth digits on each hand, and the presence of feathers is uncertain. It it had them, they were surely "proto-feathers" or down-like structures, not the modern-looking feathers. note Still, it had bird-like features showing how far back in time the dinosaur—bird link goes. Its skull and hindlegs were similar to the more evolved theropods; its bones were hollow and had airsacs within them (its name just means "hollow frame"); and it even had a wishbone, a typical bird trait. Coelophysis probably hunted down small prey, which it swallowed whole: lizards, dinosaur nestlings, fish, insects, proto-mammals, and whatnot. In the Triassic the top-predator roles was played by non-dinosaur archosaurs like Postosuchus or Rutiodon, or even larger theropods like Gojirasaurus. Coelophysis is often described as an "successful underdog" which finally managed to outcompete non-dino-archosaurs, anticipating the following domination of the dinosaurs in the Jurassic world. It is usually portrayed as a gregarious animal that lived and sometimes hunted in packs; even though the pack-behavior was possible, the pack-hunt is unlikely. In many works it's said adult Coelophysises ate younger members of their own kind (or even their own young) during famines. This because bones found in the stomachs of adult specimens from the aforementioned "graveyard" were reported to belong to young Coelophysis, leading the dinosaur to be described as cannibalistic. Later studies have determined that the bones in question were animals of other species. This doesn't exclude Coelophysis occasionally devoured conspecifics (crocodiles and eagle-nestlings do this after all); only, there isn't any fossil proof anymore. Together with the large herbivorous Plateosaurus, Coelophysis is the dinosaur you've more chances to see in those documentary works portraying the Triassic Period, to show how the earliest dinosaurs looked (even though in Real Life there were many other dinos in the Triassic, some even more primitive than the latter: Staurikosaurus and Thecodontosaurus as just two examples). In these works, the smaller Coelophysis is used to represent the very start of the dinosaur evolution, while the bigger Plateosaurus representing a more advanced-enlarged stage. An excellent example of all this is the first episode of the TV documentary Walking with Dinosaurs, in which the two animals are shown living together in North America (in Real Life only the coelophysis was North American, the plateosaur was found in Europe). On the other hand, Coelophysis has been far less common in fiction or other more popular media, since it is too humble-looking and generic to be interesting; the most known appearance may be "Spot" from the 1974 children's television series Land of the Lost.
Dinosaurs as pets: Compsognathus *
Compsognathus was native to Europe 150 million years ago and lived alongside the famed "first bird" Archaeopteryx, in the same habitat made of small islands. Like the "urvogel", it was one of the first dinosaurs described, in the same years of the latter. The first Compsognathus specimen was found in Germany in the Solnhofen site (like Archaeopteryx). The second known specimen was found later in Southern France. Both skeletons are nearly-complete and still-articulated (again like Archaeopteryx), but haven't preserved prints of skin. Even though is little-known, Compsognathus could have been the first non-bird dinosaur ever found from an almost-complete skeleton. Only 4 ft long and weighing few kilograms, Compsognathus is the smallest Stock Dinosaur, not counting Archaeopteryx and Microraptor (which could be considered stock by some at this point). Like Coelophysis above, its frame was that of a generic small theropod with no sickle-claws on its feet. Compsognathus was more evolved and bird-like than Coelophysis however, with a shorter head and neck, a more compact body, and only three fingers on each hand. Old portraits in popular dino-books have typically depicted the "compy" with two-fingered T. rex-like hands, and sometimes even with fin-like hands: these errors were due to the incompleteness of the two known specimen's hands. If you hear about it in documentary media, it will likely be for two things: its former record of "the smallest dinosaur" (classically described as chicken-sized because its first-found skeleton was only 2 ft long, but was from a subadult), and its former status as "the closest relative of Archaeopteryx" (despite similarities, it was possibly less close to birds than tyrannosaurs). Another compsognathid, Sinosauropteryx from Early Cretaceous China, shows downy covering around its skeleton but not pennaceous feathers; this was probably the same for Compsognathus, too. Compsognathus has been a common sight in dino-books, in which is usually shown as a solitary hunter of insects, small vertebrates, and sometimes archaeopteryges (the latter is unlikely though).note Even though its tiny size doesn't make the "compy" particularly menacing for humans, popular media have equally managed to transform it in a "miniature terror". In 1997, The Lost World: Jurassic Park made it a deceptively cute critter which attacks in huge packs and kills humans with a paralytic bite. While Compsognathus may have been cute (its name means "dainty-jaw"), in Real Life there is no indication of social behavior, and its jaws and teeth were strictly adapted to catch small prey. The fact that the original specimen's stomach cavity contained only a small lizard would tend to support this.
Oviraptor lived in Late Cretaceous Asia 75 million years ago. This dinosaur is another demonstration about how Science Marches On is a crucial factor in popular dino-portraits. First discovered in Mongolia in 1924 together with Protoceratops and Velociraptor, this toothless theropod was originally thought to be an ornithomimid. Since the 1970s it is classified into its own family, even closer related to birds. Oviraptor was distinct from ornithomimids by having a rounder, stockier beak, a shorter tail, and the small forth reversed toe on each foot present in most theropods (birds included), which got lost in ornithomimids. Unlike the latter, it was a "maniraptoran" theropod: its forelimbs were bird-like, and is considered to have had a very bird-like covering of feathers, with feathered wings and a feathered tail fan. It was given the name Oviraptor, meaning "egg-thief," because its first remains (a crushed skull) was found next to a clutch of eggs which were thought to belong to the small ceratopsian Protoceratops. In the 1990s the eggs were found to contain oviraptor chicks: the specimen was brooding its eggs. This was further confirmed few years later, when an oviraptorid skeleton was found just above a nest full of the same kind of eggs. Before the middle 1990s scientists used to describe Oviraptors as a specialist nest-robbers, and documentary works have typically shown them frequenting the nesting ground of herbivorous dinosaurs (especially those of Protoceratops), grasping the eggs with their prehensile hands, and fleeing away from the angry mothers when they're discovered. As said above, the "robbing" behavior has often been attributed to ornithomimids as well, but Oviraptor was considered specifically adapted just to eat eggs and no other kind of food, with its robust bill that was just thought a specialization for breaking eggshells. Today, the actual diet of oviraptorids is a matter of speculation – they could have been fruit-eaters, predators, or both; they could even have fed on eggs if given the chance, however. Since the first discovery the oviraptor has also notably changed its look: paleo-artistic works from before the 1990s usually depicted it featherless (like every other non-bird theropod), and with a strange protruding palate with a pair of teeth at the tip. In works made in this period you can see the animal with two different head-shapes: the one with a small bony bump on its nose (inaccurate), and the most familiar today, with a square bony flat crest. (see also Prehistoric Life). However, since the 2000s the most complete Oviraptor skeletons have been reclassified in a brand new genus, Citipati: the familiar square-crested image probably belongs to this new genus. Note that this is not a "Brontosaurus"/Apatosaurus case: the genus Oviraptor is still valid, it's just that many specimens that used to be considered to belong to the genus are now considered Citipati, and that the actual Oviraptor is very unlike its depictions, lacking any known crest and being far smaller that its emu-sized relative. Unlike ornithomimids, oviraptorids have attracted the attention of dino-writers only since the 2000s: after the apparition of the feathered, non-egg-stealing scientific depiction. And yet, expect to see them in the older inaccurate way nonetheless (and you could also see oviraptorids and ornithomimids mixed up with each other). E.g. in the 2000 Disney movie Dinosaur, a featherless "Oviraptor" steals Aladar's egg, but loses it before it has a chance to eat the contents. More recently, an "Oviraptor" appeared in The Land Before Time TV series: feathered and not egg-stealing. Both portrayals show the oviraptors with a Citipati-like tall crest on their head. Dinotopia lampshades the animal's Science Marches On story showing it in two variations; the featherless "Oviraptor" and the feathered "Ovinutrix" ("egg-nurse").
The big brain: Troodon and the "Dinosauroid" *
This has been another complex case of Science Marches On as well, but also an astounding example about how imagination can be a very influential factor even for people studying dinosaurs seriously. Living in North America some 75—65 million years ago alongside giant tyrannosaurs, Troodon was a small dinosaur only around 7.9 ft / 2.4 m in length and weighing some 110 lb / 50 kg. It was still the largest member of the troodontid family, a sibling family to Dromaeosauridae and among the closest relatives to birds. Troodontids looked a lot like dromaeosaurids, including having feather covering. Specifically, Troodon was rather similar in shape to the Real Life Velociraptor; you can tell apart the two by observing the troodont's shorter head, smaller teeth, eyes pointing forwards note , shorter tail, longer legs, and less formidable sickle-claws on their second toe. Since the 1980s Troodon has attracted the scientist's attention because it shows several very specialized anatomical traits. For example, it had larger eyes and ears than most dinosaurs, perhaps indicating nocturnal habits; its brain was relatively large for a non-bird dinosaur as well. Its forwards-pointing eyes show binocular vision similar to modern owls; many old portraits showed it with bulbous eyes with cat-like or even gecko-like pupils, almost resembling humanoid aliens (remember the latest detail, we'll return on it at the end). More realistically, it had bird-like eyes with round pupils. It used also to be imagined with opposable thumbs making its hands like an eagle's foot to better-grasp its preys, but this is controversial. The troodont's actual diet is still debated: with its small, relatively blunt teeth, it was likely a mostly-carnivorous omnivore, though it used to be portrayed as a specialist small-prey hunter (mammals, dinosaur nestlings). Some have even hypothized it was herbivore, but this is now mostly discarded. At the other extreme, some depictions attribute to it dromaeosaurian traits such as pack-behavior or the ability to kill large preys, which weren't possible in Real Life. Troodon 's toothed jaws and sickle-claws were too weak to tear meat of big-sized living animals. Its first remain was a single tooth (hence the name Troodon, "wounding tooth"), one of the very first north-american dinosaurs found (1856), but initially believed a lizard, then a pachycephalosaurian. Meanwhile, a small theropod, Stenonychosaurus, was described in the 1920s, and classified as a generic "coelurosaur." In the 1980s, one scientist (Phil Currie) found the two animals being one and the same, and Stenonychosaurus fell in disuse in favor to Troodon. If you read popular dino-books written before the 1990s, you'll probably find the same "Stenonychosaurus" more often. note In the same years, scientists found the troodont’s brain being the biggest respect-to-the-size among all dinosaurs: this gave to it the reputation of "the smartest dinosaur" in popular books note — despite this, its brain was still smaller than most modern birds. Despite an emergent tend to feature it in documentaries the troodont’s presence in fiction has been only occasional, and not related to the actual animal but to that could be called its "altmode." In 1982 note , Canadian paleontologist Dale Russel conjectured a possible way that descendants of Troodon could have evolved had it not gone extinct along with the rest of the dinosaurs. If its brain had kept increasing in size, today it would have been comparable to a human's. Combined with further evolution of its bipedal movement, binocular vision, and semi-manipulative hands, the resulting "Dinosauroid" was proposed to be a blend of (featherless) dinosaurian and humanoid features. The Dinosauroid has made a few appearances in novels and TV series; its Real Life dino-ancestor usually gets mentioned. It's worth noting that the Dinosauroid model resembles the Sleestaks of Land of the Lost (1974—1977), possibly a case of Ascended Fanon.
Other small or birdlike theropodsSorry, these ones aren't here. If you're looking for Dromaeosaurus, Ornitholestes, Therizinosaurus, Mononykus, Deinocheirus, the Liaoning feathered dinosaurs, and others, see here. Or here.
Long-necked plant-eatersThe Sauropodomorphs ("sauropod-shaped") include dinosaurs with long necks. Most of them pertain to the Sauropods subgroup, while all the other members are traditionally called Prosauropods.
Sauropods are the (mostly) gigantic quadrupedal plant-eating dinosaurs with long necks and tails. Some of them were the largest land animals that ever lived, but not quite as massive as they seem: the weight was brought down significantly by a system of air sacs in hollow bones, similar to theropod (and hence, bird) skeletons. Since sauropods are rather similar to each other in size and appearance, only a few of them will usually be identified / identifiable in Fictionland: "Brontosaurus", Brachiosaurus, and Diplodocus. Their iconic status is due to several factors: the earliness of their discovery, the relative completeness of their remains, and for having held some "record" in the past — Diplodocus has long been the "longest" land animal ever, the brachiosaur the "tallest" and "heaviest" one; while "Brontosaurus", being the very first mounted sauropod in a museum, was the first one that became popular. Today scientists recognized more than one hundred sauropod genuses,but pop-culture usually ignore them. All stock sauropods are from Late Jurassic North America (even though the most known "brachiosaur" species was found in Africa), but in Real Life sauropods lived worldwide from Early Jurassic up to the end of the Dinosaur Age. However, in recent years some other sauropods have received some attention in media, but only because were said to be "Longer!-Taller!-Heavier!" than the traditional record-holders. Some really were, but other weren't even real animals. You can find them here classified as "little-stock".
Common inaccuracies in sauropod portraitsIf a writer relies on pre-"Renaissance" science, a featured sauropod is up to its armpits in water and living in swamps while lazily munching some swamp weed. Before The Seventies, the dominant but wrong hypothesis said they needed to spend most of their time in water to support their massive bulk and to escape the (allegedly) non-swimming theropods. Modern science says sauropods were terrestrial (though able to swim in an elephant style if needed); note if they were really swamp-specialists, they would have had higher chances to slip in the mud with fatal consequences. If lucky enough to survive the fall, they'd starve to death from lack of nutritious food. note If submerged,their ribcage wouldn't even be capable to expand due to water pressure, suffocating them. And the alleged weakness of their teeth and the high placement of their nasal openings are not real proof for an amphibious, swampweed-eating lifestyle.note Finally, footprints show carnivorous dinosaur were capable to swim using their hindlegs (as shown by the aforementioned alleged Dilophosaurus footprints), making the sauropods' fleeing in water to escape them potentially useless. Another common mistake when portraying sauropods is to show them with elephant-like nails or hooves, falling straight in Most Writers Are Mammals. Actually, sauropods had true claws. They usually had a thumb-claw on each forefoot (which was narrower than in modern elephants) and three claws on each hindfoot (which was broader and more elephant-like than the forefoot). Even so, in most portraits that do show clawed sauropods, they usually have four or five claws on each foot. More related with Reptiles Are Abhorrent is the way to depict sauropods' necks as serpentine: you'd even find brontosaurs using them like snakes when attack their prey. Actually, their neck had relatively few vertebrae like a giraffe's and were relatively stiff (expecially if compared with their flexible tails which had often more than 50-70 bones).
Deceptive dinosaur: Apatosaurus, aka "Brontosaurus" ***Lived in the Late Jurassic (154 to 150 million years ago) in what is now the USA. It was large, 75 ft / 23 m long and weighing at least 23 metric tons (equal to roughly four elephants). The neck added up to about 1/4 of its total length, the tail about 2/4. The Apatosaurus overall size is often exaggerated in popular writing, for instance by claiming that it was the largest dinosaur, or that it weighed as much as 10 elephants. The head was small and slender; the teeth were peg-like and only in the jaw-tips. The neck had more than 10 vertebrae, was of average length but wider than in other sauropods. The body was stocky and deep; the hips were taller than the shoulders. The legs were robust (even more so than in most sauropods), the hindlimbs longer than the forelimbs. The tail was very long (about 80 vertebrae), thin and whiplike near the end. Apatosaurus is one of the few sauropod kinds already known to science when the first modern pop-cultural portraits of dinosaurs came to light in the 1900s. Marsh described the first species in 1877, in full "Bone Wars" context, but its first remains were incomplete. Just two years later Marsh described a second Apatosaurus species as a distinct animal, "Brontosaurus". It was the latter that became the iconic image of a sauropod for most the 1900. Apatosaurus and Tyrannosaurus were the ultimate stock dinosaurs in their respective roles as herbivore and carnivore, and contenders for the title of overall iconic dinosaur. In classic dino-stories the "brontosaur"'s designated role is the Gentle Giant (while T. rex is the Big Bad and Triceratops the Bad Ass)... unless Everything Trying to Kill You, of course. In the classical version of King Kong, brontosaurs are meat eaters. Why is Apatosaurus the correct name for this dinosaur? Because scientific rules say if one animal is called with two names only the first one is valid, and "Apatosaurus" was created two years before "Brontosaurus". The latter means "thunder lizard" (probably a reference to the booming sounds sauropods could have made when walking), while the former means "deceptive lizard" — a much less cool name but, stunningly, the most apt one. And then, why has just "Brontosaurus" been the traditionally most popular sauropod, in spite of being smaller than Brachiosaurus and shorter than Diplodocus? Probably because the first ever mounted display of a sauropod skeleton (erected at the American Museum of Natural History in 1905) was based on a mostly complete Apatosaurus skeleton, with missing parts borrowed from other sauropod specimens, which also gave the display skeleton a short, boxy head and blunt tail, both incorrect. However, the Museum chose to label the display "Brontosaurus." Other museums followed suit with similar "Brontosaurus" displays. Popular writing and dino-art kept spreading the incorrect name, and the ghost of "Brontosaurus" still haunts Apatosaurus, as does the image of the short, round head. Peter Jackson's King Kong Re Make referenced this situation by having a newly-discovered dinosaur on Kong Island be named Brontosaurus in the special features on the DVD. A nice homage, but in reality, once a name is used, even if it's invalidated, it can never be used again for a new animal, lest later researchers be left with no idea which Brontosaurus you're talking about. Winsor McCay's famous 1914 Gertie the Dinosaur made "Brontosaurus" the very first dinosaur in cinema. Interestingly, she's shown as a land-animal, anticipating a largely-discarded theory for more than half a century. Gertie has also the correct head-shape of an apatosaur. However, since the "brontosaur" head was considered round at the time, some hypothize she's actually a stocky Diplodocus.
The "longest": Diplodocus **
Living in western North America during the Late Jurassic Period (154—150 million years ago), Diplodocus was a neighbor of Apatosaurus. Both dinosaurs belonged to the same family, Diplodocidae, and many features of Apatosaurus (the whip-like tail, the skull-shape, and the longer hindlimbs) are shared by Diplodocus as well. Unlike Apatosaurus, Diplodocus' portraits have always had a narrow-ended tail and the long head with a flattened snout typical of diplodocids (the Diplodocus' skull and tail-end are known since the first discoveries). This means the two animals can be easily distinguished from each other in older media (unless the artists didn't know better or knew but didn't care). note In more updated depictions, their overall profile is the main key to tell Diplodocus apart from Apatosaurus. note The diplodocuses were longer than the apatosaurs, from about 80 ft / 24 m to 115 ft / 35 m, but weighed only about half as much (10-16 metric tons). The Diplodocus shape was more slender and elegant than the robust Apatosaurus, with a longer, slimmer neck: these differences allowed the two animals to live side by side and to avoid competition by browsing different kind of vegetation. Diplodocus has classically been qualified as "the longest dinosaur," but this record is now contended by other diplodocids, like Supersaurus. All diplodocid sauropods had long tails, but Diplodocus took this to an extreme. Its tail was 14 m long, longer than a whole T. rex! note It has been speculated that the thin end of the diplodocids' tail could have been used as a whip directly against threats, or indirectly by making whip-cracking sounds. The tail vertebrae also had double beams (hence the name Diplodocus: "double beam") that may have protected the blood vessels inside the tail when the tail pressed against the ground. Diplodocid sauropods could have been using their tail as a support together with their hindlimbs, lifting their forequarters to reach higher vegetation. Found during the Bone-Wars like Apatosaurus, Diplodocus was introduced to the public courtesy of Andrew Carnegie some decades later. He sponsored an expedition that discovered a new Diplodocus species (which was named Diplodocus carnegii), and had the remains mounted in his museum in Pittsburgh. He then donated replicas of it to museums all over the world; as a result, in some European nations (especially Britain) Diplodocus became the iconic sauropod, rather than "Brontosaurus" as in the USA. In recent years, the British Speculative Documentary Walking with Dinosaurs has made popular some recent theories about Diplodocus and sauropods in general: the straight, horizontal neck posture and the iguana-like spiky back. The first is due to analysis of the neck vertebrae using computer models; note the second arose from a discovery made in the 1990s of a diplo with prints of horny spikes near its back. Both theories are now disputed: both the base and the end of the sauropods' necks were more flexible, and maybe the animals could fold their neck and lift it like most modern long-necked animals. The spikes were dermic structures not related with the skeleton; being dinosaurs closer to birds than to lizards, they might be spread over the animal's back like theropod feathers, instead of one a single line like an iguana's. We don't know if other sauropods did have spikes, but spiky longnecks are now a common sight in books and art — at it seems, dino-artists have hard work to get rid of the "Dinosaurs are Lizards" idea still today.
The "tallest": Brachiosaurus in the former sense **
This is the third member of the iconic sauropod Power Trio and lived along Apatosaurus and Diplodocus in Late Jurassic North America, 154-153 mya, but also (allegedly) in Africa in the same period. This detail was mentioned as a concrete proof about the Pangea hypothesis, as brachiosaurs weren't able to cross oceans to migrate from one landmass to another. (continents were still not completely separated from each other in the Jurassic). Since its first description at the start of the 20th century, Brachiosaurus was considered "The biggest land animal ever!" until really or allegedly new sauropod kinds were described since the 1970s (see further). Generally thought to weigh between 30 and 50 tons, Brachiosaurus has often been oversized in popular books, so far as to triple its size up to 130 tons, which would make it heavier than any animal alive today, except for the blue whale. Brachiosaurs are visually distinct from diplodocids in several ways. First, their necks were noticeably longer than their tails, and their back sloped backwards instead of forwards. Going to more detail, their tail had a thicker end lacking any "whip"; their neck was stronger, had more vertebrae and was held more vertically like a giraffe; their teeth bordered most of their jaws and were chisel-like; their nasal openings were unfused, placed more forwardly, and much wider than diplodocids (the brachiosaur subgroup of sauropods, "Macronarians", just means "large nostrils").note Finally, brachiosaurs are nearly the only non-bird dinosaurs with forelimbs longer than hindlimbs ("Brachiosaurus" means "arm lizards"). Sometimes these difference get glossed over in popular media, which may show brachiosaurs with diplodocid heads, necks, bodies, legs, and tails. In these cases, they might be recognizable as brachiosaurs only thanks to a more upright body-shape. As with other sauropods, it was associated with water in older reconstructions. To accommodate its upright shape, Brachiosaurus was often shown totally submerged in lakes, with only their head and, sometimes, only their nostrils above the water level, making its neck like a giant snorkel. Needless to say, this is quite unrealistic. In modern portrayals, Brachiosaurus has often been described as a "prehistoric giraffe" capable of browsing the highest vegetation that other sauropods were not capable to reach – unless diplodocids were able to stand upright on their hindlegs. Brachiosaurs probably weren’t capable of the latter having their center of gravity much farther forward, and their shorter tails didn't provide support (it would only bring a little bit of extra reach anyway). Moreover, as their greater size could have automatically protected adults even against the biggest predators, they didn't need to lift their forebody and use the front-legs to fight an Allosaurus, nor didn't they need to use their short tail to hit it to death (Diplodocus and Apatosaurus probably did all this). However, in fictional (and sometimes even documentary) media, brachiosaurs show unusual athletic skills: in Jurassic Park, a brachiosaur is rearing up its hindlegs to reach a tiny branch. In Disney's Dinosaur, the brachiosaur Baylene is able to remain in a fully erect position for 30 seconds to break the wall of a cave with her forefeet. Also in Jurassic Park, a brachiosaur is shown with an oversized head with fleshy lips, chewing vegetation like a cow. Sauropods didn't chew: their teeth were more suited to cutting plant material (in the case of the brachiosaur), or to raking it like a comb (like the diplodocids). Before the '90s Brachiosaurus was less common in cinema than "Brontosaurus" and Diplodocus despite its record-size. Then, in 1993, Spielberg made a brachiosaur the solemn show-opener of his first film (Crichton's eponymous novel had Apatosaurus in this role). Thanks to this (and possibly to its cooler look), the brachiosaur has perhaps become the most frequent longneck in popular works since then, and many "young" dino-fans now consider it THE iconic sauropod in pop-culture, while pre-JP dino-fans still tend to think "Brontosaurus" (in the USA) or Diplodocus (in Britain) in this role. Here we put the brachiosaur and the diplodocus as "middle-stock" because of the greater historical mediatic relevance of Apatosaurus in most nations. note Sadly, Brachiosaurus recently also went through some naming troubles, but its situation isn't as severe as the Apatosaurus-Brontosaurus deal – the name Brachiosaurus remains valid, however its best-known species, B. brancai, had to be placed in a different genus, named Giraffatitan. note Giraffatitan ("titanic giraffe") was found in Africa in the Tendaguru site two decades after the US brachiosaur, and is known from complete remains with show a distinctive "domed" skull. An impressive, 12 m tall Giraffatitan skeleton was mounted in the Berlin museum in the 1930s: this has been the biggest mounted dino-skeleton until two decades ago, and the model of the popular image of the brachiosaur. On the other hand, the valid Brachiosaurus has long been known only by fragments, and its skull was described only few years ago. This skull, which had a smaller "dome" than Giraffatitan's, was long classified as another kind of sauropod, Camarasaurus; ironically, it was just this skull that was put in the original "Brontosaurus" skeleton. The popular "brontosaur" is just a Mix-and-Match Critter made of Apatosaurus and Brachiosaurus.
The "heaviest": Argentinosaurus *Argentinosaurus was discovered Argentina in 1993. It lived in the Early Cretaceous, 95 mya, unlike the more famous sauropods, the diplodocids and brachiosaurids, which lived earlier during the Jurassic. Argentinosaurus belonged to a group of sauropods called Titanosaurs, which evolved within the Titanosauriformes (which included Brachiosaurus) and replaced the earlier sauropods worldwide in the Cretaceous. Titanosaurs are based on the genus Titanosaurus which was first described in 1877 and used as a "wastebin taxon" since then. The classification of titanosaur genera is still in debate and many (including Argentinosaurus) are based on fragmentary remains note . New finds and further cladistic research may still change the descriptions of these animals. Titanosaurs seem to have been more compact than earlier sauropods, with shorter necks and tails, solid bones, and wider frames. At least some titanosaurs had crocodile-like skin armor; in one case (Saltasaurus) this was fully developed as bony plates similar to Ankylosaurus. On the other hand, Argentinosaurus probably didn't develop an armored skin. Length and weight estimations of Argentinosaurus are necessarily speculative, but the consensus seems to put the length at 98 ft / 30 m (like Diplodocus) and the weight at about 73 metric tons (about twice a Brachiosaurus). Few people know, however, that another South American titanosaur, Antarctosaurus, has left some possible remains almost the same size of the argentinosaur, which were found several decades before. Being very scant and dubious, they have been largely ignored. Other sauropods were previously extimated even heavier than 73 tons (see in the following section) but these valuations appear positively exaggerated. Such heavy land-animals would haven't even able to survive, and the Blue Whale still remains the official record-holder of all times (only other sea-creatures could have overweighed it in the past). In 2002, a Walking with Dinosaurs special (Chased by Dinosaurs) featured a herd of Argentinosaurus. In a memorable scene, Nigel Marven hurries to place weight sensors in front of the herd as it approaches, walking straight towards the camera and messing with the viewer's perspective: a very effective demonstration of the immense size of these animals. It’s strange, unlike its (portrayed, though not in reality) predator Giganotosaurus, Argentinosaurus has not received much attention in fiction since that. Maybe because, size-related impressiveness apart, the Argentinosaurus here do nothing sensational — the adults continue to walk apparently unmoved after the Giganotosaurus bring down one of their young. On the other hand, Argentinosaurus became popular among dino-fans for being described as "the biggest ever dinosaur" in the show. But this is not an isolated case, however. Several other sauropods have been at one point described the same way since the very first sauropod discoveries. One of the first ones was Atlantosaurus "Atlas lizard". Many others followed since then, with scientists seemingly competing with each other for who coined the most awesome name - it's just Argentinosaurus one of the rare exceptions, meaning simply "lizard from Argentina".
Size matters *Let's face it—paleontologists are people too. While they carefully excavate fossils in some dusty badlands location, or sort through boxes of collected fossils in chilly museum basements, they can't help but secretly hope to be the one that discovers or describes Badassosaurus mynamii. Sometimes they do strike gold. Most of the time, they report an unremarkable animal and get the satisfaction of a job well done but very little glory. Then, there are cases like these...
Other sauropods:Sorry, these ones aren't here. If you're looking for Camarasaurus, Mamenchisaurus, Saltasaurus, Cetiosaurus, Barosaurus, and others, see here.
Prosauropod means "before the sauropods." Living in the Triassic or Early Jurassic periods, prosauropods were among the very first dinosaurs to appear, and the first dinosaurs to reach elephant size. Some of them may have been the ancestors of the sauropods. The name Prosauropoda isn't formally used nowadays (members of the group are now being referred to as basal sauropodomorphs). Plateosaurus has been considered the prototypical "sauropod predecessor," is the most common in fossil record and one of the largest as well.
The first giant: Plateosaurus *
Lived 216-199 million years ago, in the Triassic Period. Plateosaurus is one of the scientifically better-known dinosaurs, and also the most abundant dinosaur in European fossil record. More than 100 specimens are known, and even a "graveyard," in Southern Germany. Plateosaurus was also one of the first dinosaur described, even before the word "dinosaur" was invented, but Owen didn’t include Plateosaurus in his new group (its first remains were very fragmentary). When the genus was being classified into Dinosauria, it was first placed in the theropod branch and thought carnivorous; later, was moved to the prosauropod group. Its adult size was astonishingly variable, from 16 ft / 4.8 m up to 33 ft / 10 m, and its weight ranged from 600 kg to 4 metric tons. At a first glance, Plateosaurus looks like a cross between a diplodocid and a theropod. The general body-shape was sauropod-like, with a small head, long neck, sturdy body, and long flexible tail (and also the typical thumb-claws). The limbs and stance were theropod-like; it was bipedal, walking on hind legs that were slightly folded, rather than pillar-like. The hindfeet had distinct digits with a claw on each. The head was rather theropod-shaped too, but their teeth were small and blunt, apt to grabbing vegetation instead of tearing meat. The closer relationship with sauropods is betrayed by one detail: the hands and feet of the prosauropods had five digits each like sauropods, while true theropods lost the fifth digit both in their hands and their feet (except for the most primitive controversial theropods, like Herrerasaurus and its relatives, which had five digits on their hands/feet). Science Marches On has been a strong factor within Plateosaurus portraits. When believed a theropod it was depicted with a tripodal stance like all large bipedal dinosaurs; one example could be in Fantasia. After being classified as a sauropod relative, the plateosaur has usually appeared as a slow quadruped but able to rear up its hindlegs like diplodocids, either to reach higher foliage or for defensive purpose (like in Walking with Dinosaurs). The exclusively bipedal portrait re-emerged only very recently, and today scientists believe Plateosaurus was capable of rapid runs if necessary. It may have defended itself with its thumbclaws. The plateosaur' large size could have been obtained to avoid predation by the carnivorous dinosaurs (which were still small and gracile at the time); the only predators that were possibly able to defeat the adults were basal archosaurs such as the contemporaneous Teratosaurus. The two stock Triassic dinosaurs, Plateosaurus and Coelophysis, are among the most abundant in fossil record but among the least common in pop-culture. Plateosaurus appearances in fiction are very rare; in documentaries, it is usually shown only to emphasize the rise to power of the dinosaurs — like in the aforementioned Walking with Dinosaurs. Even though some Plateosaurus-looking dinosaurs occasionally crop up in TV (like Dino), they are more likely humanized sauropods or Mix-and-Match Critter things.
Other sauropod predecessorsSorry, these ones aren't here. If you're looking for Massospondylus, Anchisaurus, and others, see here.
Armor-bodied plant-eatersThe Thyreophorans ("shield bearers"), were a group of dinosaurs notable for their body armor made of bony plates covered with horny sheaths. Many also developed weapons on the tips of their tails. All but the most primitive forms were massive quadrupedal animals belonging to one of these two groups: stegosaurians and ankylosaurians.
Stegosaurians were small-headed, mostly Jurassic herbivores that developed large bony plates along their backbone for uncertain purposes, and had pairs of spikes on their tail and sometimes on their hips or shoulders as well. Stegosaurus is the namesake of the group as well as one of the largest known members.
Too dumb to live?: Stegosaurus ***
Lived in Late Jurassic North America, 155 to 150 million years ago, and was discovered during the Bone Wars like several other Stock Dinosaurs (Allosaurus, Diplodocus, Apatosaurus etc.) note One of the most easily recognizable dinosaurs thanks to its bony plates, spike-tail and distinctive silhouette, Stegosaurus has always been one of the most iconic dinosaurs of all, along with T. rex, Triceratops, and a token sauropod. It is regularly portrayed both in films and in cartoons, though usually with a less important role in respect to sauropods and carnivores. The several Stegosaurus species were from 24 ft / 7.5 m up to 30 ft / 9 m long, and weighed from 1.5 up to 5 metric tons. Its plates and deep body made it looking bigger than it was when watched from the side: actually, the stegosaur’s body was laterally-flattened, and not so heavy as it seems. Its limbs were pillar-like; the front-legs were much shorter than hindlegs, and the neck was set low above the ground (but not the same degree as in old portraits). Despite its overall size, Stegosaurus had a remarkably small head, with room for only 2.8 oz / 80 g of brain (often stated as "walnut-sized") note . This has made it the most iconic dinosaur within the "Dinosaurs Are Dumb" subtrope (even though sauropods are not far away). The small brain does not mean that stegosaurs and sauropods were witless, though. And they didn't have a secondary brain in their hip region as is often stated; the extra space there probably accommodated the nerves for the hindquarters. The back plates were the most distinctive stegosaurian feature, but it isn't entirely clear what their purpose was. We don't even know if the plates were covered in horn or in skin (though the former seems more likely, since the plates are the same type of osteoderm possessed by other thyreophoreans). Defense, thermoregulation, and display (mating or threat) are the classic hyps, but we haven’t definitive proof for any. The early defense-theory is the most unlikely: the plates were dermic structures not attached to the skeleton, and were rich in blood-vessels (if wounded, they’d have bled a lot, bringing the animal to death). The "solar panel/radiator" theory was the most followed until recent years: it could explain the vessels, and also the singular arrangement of these plates—they were asymmetrically-placed, giving more surface to solar rays. Walking with Dinosaurs popularized the third theory, showing a Stegosaurus reddening its plates and scaring an Allosaurus away. However, if used for display, they might also have had the function to make the animal look larger or communicating with others of its kind. Even the configuration of these plates was until recently debated. Even though Stegosaurus has left dozens of specimens, they are usually found with misplaced plates, making them a sort of puzzle to rebuilt. All combinations were proposed, from a single line to two paired lines. One early theory was they were flat on the back like tiles: this gave to the dinosaur the odd name Stegosaurus, "roof-lizard." The first still-articulated stegosaur skeleton was found only in the 1990s, and shows alternated plates. Stegosaurus' tail was muscular and flexible, and could have been put on the ground to lift the animal on its hindlegs and reach higher vegetation (this is not sure however). When swung from side to side, this tail made a powerful weapon against enemies. Near the tip of the tail was a group of four long spikes known as the thagomizer, a term that originates from a Far Side cartoon, later adopted by the paleontological community (you can find it used in serious scientific publications) in an even more awesome case of Ascended Fanon than "raptors". One last curiosity, though, is rarely mentioned: Stegosaurus had small scutes on its hips and tiny osteoderms under its throat. If you see Stegosaurus in popular media, don't be surprised to see inaccuracies. To this day, it could have paired plates or even plates in a single line, instead of zigzagging in two lines — and they could be wrongly round or triangular instead of pentagonal. And it could have none, two, three, five, six, or even eight spikes. These spikes may be shown much shorter than in reality note . In some cases the neck is unrealistically long, like Dinny in Alley Oop, making it resemble a cross between a stegosaurian and a sauropod. The body may be shown as very low-slung and fat (even when faced in the front), and the legs are often stubby. Stegosaurus may often be depicted with a turtle-like face instead of a horse-shaped one like in real life. Occasionally, it is shown with a beak full of teeth or even worse, no beak. In many old films, Stegosaurus is shown as a sorta "predestined loser" against big meat-eaters like Allosaurus, Ceratosaurus or Tyrannosaurus, being too slow to defend itself effectively. Later in modern portraits, Stegosaurus took a level in badass and more often wins fights with the aforementioned carnivores, like in The Lost World: Jurassic Park or Walking with Dinosaurs, as it is now considered to be agile and flexible in spite of its slow running speed and heavy body.
Other stegosauriansSorry, these ones aren't here. If you're looking for Kentrosaurus, Tuojiangosaurus, and others, see here.
These are the most well-armored among all the dinosaurs (sometimes called the armored dinosaurs), with low frames, quadrupedal stance, strong short legs and armor consisting of bony plates covering the upper part of their body. They were herbivorous and mostly lived during the Cretaceous. They aren't as common as stegosaurians in works, but still crop up semi-regularly both in fiction and in documentaries. Ankylosaurians were once divided in only two families: ankylosaurids (clubbed) and nodosaurids (club-less). Ankylosaurids had a broad head, their armor plates formed a keratin-covered shell with short spikes in many directions, and they had a tail club except for the most primitive forms; proper nodosaurids had a narrow head, rows of osteoderms on their backs and flanks, and longer spikes jutting out sideways. In recent years a third subgroup has been recognized distinct from nodosaurids: the polacanthids, variably classified as either closer to ankylosaurids or to nodosaurids.
An (un-)well-known critter: Ankylosaurus **Lived in North America around 66-65 million years ago alongside Tyrannosaurus and Triceratops at the end of the Dinosaur Age. Discovered in 1908 in Alberta, its actual size is uncertain, extimated from about 20 ft (6 m) long up to 9-10 m, but the latter is more likely: if so, it's the biggest known ankylosaurian, possibly weighing up to 6 metric tons (like a male african elephant), in the same weight-range of Triceratops and the biggest Stegosauruses. Despite its size, its remains are quite scant, with no complete skeletons still found, and other relatives (for example Scolosaurus) are more common in fossils. The Ankylosaurus iconic status among ankylosaurians could be explained by its sheer size and because its own dinosaurian group is called with its name. Ankylosaurus was also one of the most strongly-armored ankylosaurians –- several sources have described it as a "living tank." Ankylosaurus has become famous since the 1940s as the Up to Eleven example of an armored dinosaur. In both fictional and documentary media it is often portrayed in a battle against T. rex (similarly to Triceratops). In these struggles the ankylosaur is seen defending itself by sheltering under its impenetrable bony armor, and using its tail-club as a medieval mace, breaking the legs of its opponent and making it fall down. This could be Truth in Television, even though tyrannosaurs certainly didn't prey upon adult ankylosaurians so frequently (hadrosaurs were much more abundants and armor-less). Despite their heavy built and short legs, they perhaps were even able to charge the carnivore like a rhino. Like stegosaurs, ankylosaurs tend today to be portrayed more agile and active in fight than once: in Walking with Dinosaurs it easily wins the struggle (despite being shown a very slow-walking animal), delivering to the carnivore a fatal blow with its tail-mace. When the tyrannosaur is shown winning the battle, it's seen "overturning" the ankylosaur to expone the soft vulnerable underbelly and delivering there the fatal bite. Most herbivorous-omnivorous dinosaurs are often depicted in media as gregarious animals: scenes involving herd-living sauropods/ceratopsians/stegosaurs/hadrosaurs/iguanodonts/ornithomimids are a very common sight. On the other hand, adult ankylosaurians are always depicted as loners. This is realistic though, because their fossils are more rare than those of other large herbivores and almost always found isolated. One rare exception is a group of about 8 juvenile Pinacosaurus found together, probably dead in the same moment during a sand-storm. Ankylosaurus probably detains the sad record of the worst-known Stock Dinosaur. Even in documentary works, its size, shape, and composition tend to be pictured incorrectly, often with traits from other ankylosaurian species. The incompleteness of the remains justify only partially this. One common mistake is to leave out the tail club, or to have it shaped incorrectly — for example, adding spike to it. When based on Real Life fossils, the club usually appears two-lobed like that of an Euoplocephalus (a close relative commonly depicted in popular dino-books), instead of elliptical. The bony covering on its back should be a snugly fitting mix of large and small plates and be interspersed with short spikes. Many classic portraits, on the other hand, show long spikes only on the sides, in a similar way of the related Nodosaurids. Other portraits go even further showing totally spikeless Ankylosauruses (see the aforementioned finale of Walking with Dinosaurs). Finally, the broad head should have four horns behind the eyes and the ends of the mouth. Ironically, one of the few correctly-shaped ankylosaurs in cinema is the dog-like Url from Disney's Dinosaurs (he was strongly undersized, but this may be justified if he was a young). Many other inaccuracies seen in ankylosaur portraits are substantially the same of the stegosaurs, so see above. Being related to each other, stegosaurs and ankylosaurs shared many features even in Real Life. They had the typical ornithischian jaws, with teeth only on the back and a toothless beak on the tip. However, their beak/teeth were weaker than other ornithischians (ceratopsians, ornithopods); maybe they chewed only soft plant material near the ground-level, and/or swallowed small stones to aid digestion, like sauropods. Even though were much smaller-sized, stegosaurians and ankylosaurians tend to be shown as slow-moving as the sauropods: ex. the aforementioned Url which has the slowest pace among all the dinosaurs of its herd (just as slow as its companion brachiosaur Baylene). Pre-"renaissance" depictions used to portray ankylosaurians and other four-legged dinosaurs with splayed legs and dragged tails. Actually quadrupedal dinos had erect limbs (among them only sauropods had true claws), and footprints show they usually kept their tails above the ground when walking around. Of course, expect to see splayed-limbed ankylosaurs even in relatively recent works — Rooter of The Land Before Time, which appears even slower than the sauropods of the same film (the latter have correct upright limbs, though).
Other ankylosauriansSorry, these ones aren't here. If you're looking for Euoplocephalus, Pinacosaurus, Polacanthus, Hylaeosaurus, Scelidosaurus, and others, see here.
Armor-headed plant-eatersThe most recent group of ornithischian dinosaurs, marginocephalians have been usually discovered in Late Cretaceous terrains. They were closer to ornithopods (see further) than to thyreophorans (see previous), and are divided in two very different subgroups: ceratopsians and pachycephalosaurs, unified by their armored head.
The ceratopsians were a group of dinosaurs characterized by a bony "frill" at the back of the neck. Starting as small bipedal animals like all the main dinosaur groups, they evolved towards a heavy quadrupedal body plan, while lengthening the frill and growing horns on their eyebrows and nose. Even though ceratopsians had erect limbs like every other quadrupedal dinosaur, several portraits have shown them with splayed frontal legs. Moreover, their legs tend to be shown stockier and more "elephantine" than in Real Life. The ceratopsid family contains all the largest members of the group. Apart from the frill-shape and number/length of the horns, ceratopsids shared the same basic look. They are classically divided in two subgroups: those with long frontal horns, short nasal horn and (usually) long frills; and those with short frill, no frontal horns, and (usually) a long nasal horn. Triceratops is a short-frilled member of the first subgroup, while Styracosaurus is a good example of the second one. Finally, Protoceratops has been the prototypical ancestral ceratopsian.
Mr. Three-Horn: Triceratops ***
Lived 68 to 65 million years ago in Late Cretaceous North America. It was one of the last discoveries from the Bone Wars. note Its name means "three-horned face" and is due to its most prominent feature. It was about 26—29.5 ft / 7.9—9 m long and weighing about 6—12 metric tons, and was one of the biggest ornithischian dinosaurs (only some hadrosaurs were larger). Hundreds of skulls are known so far, but (oddly) not a complete skeleton. Two main species are recognized today: Triceratops horridus and Triceratops prorsus, even though up to 15 species were described at one point due to the great variability of the skull. Triceratops has traditionally been considered the largest ceratopsian; its size and abundance in the fossil record have contributed to making it the most popular one. It has always been beloved by dino-fans. Maybe because with its short tail, big head, and rhino-like body, it is the least reptilian-looking among the Stock Dinos (even in older depictions); or maybe, because of its historical reputation as "the only plant-eater able to defeat the Big Bad Tyrannosaurus rex" (even though ankylosaurs and maybe even the biggest hadrosaurs could also have been able to defeat the tyrannosaur in a fight). Its portrayal in Jurassic Park consolidated Triceratops' popularity even more: the touching scene of the sick triceratops with the caring humans around has remained in public consciousness. And how could we forget the strong temper of Cera in the Land Before Time film? Compared to other stock dinosaurs, Triceratops and his relatives have been portrayed fairly accurately. The ceratopsids in the original movie The Lost World (the Trope Maker, from year 1925) are nearly as realistic as those seen in the 1999 docu Walking with Dinosaurs (which are actually Torosaurusnote ). Thanks to their evident resemblance with rhinos, media triceratopses have been usually portrayed agile and active like a modern ungulate mammal; basically, the only mistake in older depictions (other than the aforementioned issue regarding the legs) is the wide lizard-like mouth without the typical ornithischian cheeks (see also Iguanodon). Science Marches On even for "Mr. Three-Horn" however, and a third element (the completely scaly hide) has revealed to be an inaccuracy as well. Extremely recent finds indicate that Triceratops was covered in bristles. Today, many scientists believe every dinosaur was at least partially covered in filamentous structures (just like modern mammals). Triceratops and T. rex have been shown fighting in modern works from the first dino-movies and through the whole paleoartistic tradition (including one especially iconic painting). In these battles, the percentages of victories between the tyrannosaur and the triceratops appears to about 50%. Though all this may even be Truth in Television, it's likely that the tyrannosaur preferred younger and more vulnerable prey than an adult Triceratops. Often considered the Bad Ass guy par excellence among plant-eating dinos, writers can’t resist the urge to make Triceratopses acting like rhinos or even bulls. They’ll be ill-tempered, will charge everything, and could even moo like bovines. The ceratopsids’ horn structure was more like cattle’s than to a rhino’s: that is, bony protrusions covered with a horny sheath. Their function is still debated: maybe ceratopsian horns were simply display devices. The frequently-seen "Triceratops goring to death a big carnivore" scene could not be realistic, and some think the frontal horns were too fragile and not pointed enough to go through flesh. Another classic hypothesis is that triceratopses locked their horns like deer in head-vs-head combats, based on possible "wounds" found in ceratopsian skulls. However, only some Triceratops specimens show curved frontal horns apt for that, others had straight horns. The frill was variable, too: some individuals had tubercles on its edges, while others had smooth shields. Generally, most media Triceratopses have tubercled frills. The parrot-like jaws are rarely mentioned, to the point that some authors omit the shape from their models to make Triceratops more like a rhino or a bull. Some have gone even further, showing ceratopsians with sharp carnivorous teeth even in their jaw-tips (especially common in some rubber toys collections). In Real Life, the ceratopsians' jaws were the strongest among all plant-eating dinosaurs, filled with sharp cutting teeth behind the parrot bill, but were arguably adapted to eat fibrous plants, not tearing meat (or at least this was not the main function, see further). Some thought the powerful maxillary muscles were anchored to the frill, but this is not proven. Even less mentioned are the pair of bony knobs near the cheeks; they maybe were for protecting the head furthermorly, but they've been only for display.
Mr. Multi-Horn: Styracosaurus **
Several genera of horned dinosaurs other than Triceratops existed in Late Cretaceous North America, but only some of them have made appearances in pop-culture, and Styracosaurus is the only one to do so with regularity, sometimes as substitute for Triceratops, other times together with it. Being more spectacular but less common in fossil record than other ceratopsids, this makes the usual Rule of Cool example. Styracosaurus lived in North America 76—75 million years ago, slightly earlier than Triceratops. It was discovered in 1913 during the second great North American "dino-rush." note About half as long as a triceratops (only 18 ft / 5.5 m, weighing nearly 3 tons), the styracosaur was actually even more rhino-like. It had much longer horn above the nose but only hints of horns above its eyes. It had a round, short frill, but this headgear was one to match: several pairs of long spikes protruding from the end of the frill in a rayed manner, and shorter protuberances in the anterior edge. This sort of Horned Hairdo incidentally makes its head resemble the Statue of Liberty. No other known dinosaur had such an ornamentation: other relatives had one isolated pair of spikes at the most, for example Centrosaurus. Styracosaurus had also jaws shorter and stronger than those of Triceratops; some speculate styracosaurs were more sociable than triceratopses and lived in more numerous herds. Styracosaurus spikes were not true horns as commonly said, but only an Up to Eleven version of those protuberances seen in almost all ceratopsid species. Even though the most common portrayal has six spikes, it seems most specimens had only four. But don’t exclude to see styracosaurs with eight spikes or more in popular works, or even with no frill and the spikes protruding directly from the back of the neck. Why do ceratopsids have their frill? The bony core has a pair of large holes that make it less heavy but also less useful as protection (Triceratops was almost the only ceratopsid that didn’t have those holes). The frill could have been raised for threat display. Another hypothesis is that it was a thermoregulating device (like Stegosaurus plates, Triceratops shield seems rich in blood-vessels). Maybe the frill was for making the several ceratopsid species more distinctive (like the hadrosaur crests, see further). It is also possible that frills show sexual dimorphism. The styracosaur has appeared in several works since the first portrayal in 1933 (in Son Of Kong), and is also a common feature in toys and popular books. On the other hand, recent documentaries haven’t represented it so frequently. Maybe because in Real Life Styracosaurus could not battle Tyrannosaurus rex as Triceratops did, but only smaller carnivores like Daspletosaurus.
Mr. No-Horn: Protoceratops *
Protoceratops lived 83—70 million years ago in Late Cretaceous Asia, unlike the giant ceratopsids, which were mostly North American in distribution. It was around 6 ft / 1.8 m in length and weighed no more than 400 lbs / 180 kg. Protoceratopsids are generally smaller and more primitive than ceratopsids, and were once considered the ancestors of the latter group (hence the name, meaning "first horned face"). At a first glance, Protoceratops resembled a miniaturized Triceratops — four-legged, with the same robust body, short tail, and unmistakeably ceratopsian head. However, it differed from ceratopsids mainly in having no true horns. Other differences include: a simpler frill lacking protuberances; bigger cheek-spikes; stronger parrot-jaws; and legs more adapted to running. The genders could have been sexually dimorphic (larger skulls with a nasal bump and a couple of upper "canine teeth" probably belonged to males). First discovered in Mongolia in 1922, Protoceratops is one of the most abundant Asian dinosaurs in fossil record, with hundreds of specimens discovered so far — earning it the nickname "the sheep of the Cretaceous" (given the large numbers of animals found together, they probably lived in herds). Many juveniles have also been found, and its growth pattern is one of the best understood among dinosaurs. It was the most famous Asian dinosaur until Jurassic Park made Velociraptor famous. The discoverer of Protoceratops, Roy Chapman Andrews, note attributed to it some elongated eggs which now are known to belong to Oviraptor. These were the very first dinosaurian eggs ever identified. The original crushed Oviraptor skull was found nearby (see "Oviraptor" above). A classic in paleo-art is showing Protoceratops hatching its eggs and chasing or even trampling an egg-robbing Oviraptor. However, several nests complete with eggs were found later in Asia, which were actually laid by protoceratopses. One especially spectacular find (from 1971) consists of a Protoceratops and a Velociraptor clutched together: they were probably fighting each other when they were buried by a sudden sandstorm or a collapsing sand dune. It still remains the best evidence of a "dinosaur battle" between a vegetarian and a carnivore. The Protoceratops appears biting the Velociraptor with its parrot-jaws, while the "raptor" is holding the protoceratops' head with its forelimbs and has one of its sickle-claws near the herbivore's throat. The real cause of the battle is uncertain however: probably the protoceratops was defending itself and/or its offspring from the carnivore. note Despite its scientific relevance, because of its relatively modest appearence Protoceratops is less portrayed in pop-media than Triceratops and Styracosaurus. Maybe the most well-known protoceratops is B.J., that yellow guy seen in Barney & Friends. In the much more beloved book series Dinotopia, the talking dino-character who befriends humans is also a Protoceratops.
Other ceratopsiansSorry, these ones aren't here. If you're looking for Torosaurus, Centrosaurus, Chasmosaurus, Pentaceratops, Psittacosaurus, and others, see here. Or here.
Unlike ceratopsians, pachycephalosaurians kept the original bipedal body plan, but evolved a thick skull roof and bony knobs on their head for uncertain purpose. Like ceratopsians, there is the possibility that were omnivores. Needless to say, the iconic member of the group is also the biggest one, Pachycephalosaurus.
Hard-headed ram or clever monk?: Pachycephalosaurus *
Lived during the Late Cretaceous 70—65 million years ago in North America like many well known dinosaurs. It usually shows up when an author feels like showing an "exotic" dinosaur. Its relationship with other dinosaurs has long been uncertain: originally classified as an ornithopod note , its affinity with ceratopsians was demonstrated only in the 1980s. Pachycephalosaurusnote ("thick-headed lizard") is by far the biggest known pachycephalosaur. Its actual length is uncertain: popular books often set its size at up to 30 ft / 9 m; a length of 15—18 ft / 4.6—5.5 m is more likely (the other relatives were not longer than 10 ft). Described in 1931 from a single skull, it was initially identified as Troodonnote , and renamed Pachycephalosaurus only in 1943. No other parts of the body have been found since then: reconstructions are typically based on a smaller, less famous pachycephalosaurian, Stegoceras. Pachycephalosaurus is distinguished by its dome-like head which makes it look very intelligent. However, the height of the dome was almost entirely made of one foot thick bone, and its brain wasn't larger than other dinosaurs'. Its nickname "The Bone-headed Dino" is quite understandable. A number of bony knobs and blunt spikes around the base of the dome and on its nose contrasted with the smoothness of the dome to create a look of partial baldness or of a monk's tonsurenote ; hence the epithet "Friar Tuck -osaurus" in The Lost World: Jurassic Park film. Being totally bipedal, pachycephalosaurians were superficially similar to theropods: however, their jaws and grinding posterior teeth were typically ornithischians (and thus plant-eating). However, Pachycephalosaurus had weaker jaws than ceratopsians or hadrosaurs and still retained small pointed teeth on its jaw-tips which were lost in the most evolved bird-hipped dinosaurs: this would indicate the pachy had a mixed diet based on plant material with insect and small vertebrates as a supplement. Its relative Stegoceras shows small five-fingered forelimbs, slender body, long tail, and running legs note . The body of Pachycephalosaurus probably was similar to Stegoceras, but being the former larger than the latter, its body might have had an overall stockier frame. As one of the most recent groups of herbivores/omnivores in formal dinosaur classification, pachys never appear in the oldest works. The ur-example was perhaps the 1988 The Land Before Time film where the pachy shows up as a predatory villain trying to kill one of the protagonists with headbutts. The headbutting is a standard trait when pachycephalosaurs appear in works. Since the "dinosaur renaissance", it used to be that males were shown trying to impress females by ramming their heads into each other: Pachycephalosaurus is traditionally depicted so in classic dino-books and documentaries. note However, scientists found in the 2000s that the smooth domes would have slipped if put against each other, and proposed that pachycephalosaurians bashed each others' flanks instead. But even this has been disputed: recent studies seem to show their necks were weaker than traditionaly thought, maybe not even able to withstand such an impact. Now many scientists think pachycephalosaurs simply used their dome heads to display maturity like an over-sized toucan bill. The pachycephalosaurs' real lifestyle and diet will probably remain a mystery for long, until more complete remains will be found. The large Pachycephalosaurus was once the only bonehead portrayed in fiction. This changed in the 2000s when two smaller relatives, Stygimoloch and Dracorex hogwartsia (the latter discovered as recently as 2006) started making occasional appearances as well, thanks to their even spikier heads. A very recent theory (2009) suggests that these two horned pachys were just juvenile Pachycephalosaurus; if so, the latter will remain the only pop-cultural bonehead.
Other pachycephalosauriansSorry, these ones aren't here. If you're looking for Stegoceras, Homalocephale, and others, see here.
Bipedal plant-eatersThe Ornithopod group contains several ornithischian dinosaurs of different size, from Middle Jurassic to Late Cretaceous. The smallest ones were slender and completely bipedal, and probably omnivorous. The most evolved ones became bigger and returned to a partial quadrupedality, becoming strict herbivores. The largest were among the most massive non-sauropod dinosaurs. "Ornithopod" means "bird-foot": they had limbs and feet similar but (ironically) less bird-like than those of theropods. Unlike the latter, they had small mouth openings and blunt teeth for grinding plant matter. Ornithopods are the most abundant dinosaurs in fossil record; even though they lacked the thick defenses of the ornithischians above mentioned, they made up from that either with speed or sheer bulk.
Hadrosaurs are nicknamed "duck-billed dinosaurs" because of their wide, flat beak especially evident in some species, less in others. They all lived at the end of the Cretaceous. The biggest and most evolved Ornithopods, their grinding maxillary mechanism was the most efficient of all reptiles ever, and they also developed complex prominences above their skull with social function. Hadrosaurs have an unusually high number of kinds portrayed in popular media, but four have received the greatest attention: Parasaurolophus and Corythosaurus thanks to their evident headgears; Edmontosaurus (called Trachodon or Anatosaurus in old media), because is the most duck-billed duckbill, and one of the first described too; and Maiasaura, which has heavily contributed to the "dino-renaissance." Breaking the usual rule, none of them is the biggest known hadrosaur.
Noisy Nature: Parasaurolophus **
Lived 76 to 73 million years ago in Late Cretaceous North America. 25 ft / 8 m long and weighing 4/5 metric tons (like an elephant), Parasaurolophus was a typical hadrosaur, with longer and stronger hindlimbs than forelimbs, three-toed feet ending with blunt nails, a long powerful tail, a small "hump" on its shoulders, a flexible neck, and the classic "duck-billed" head (although the "bill" was not as wide as other relatives). Its long, backwards-pointing protrusion made its skull a bit longer than a human’s height. Even though is often called a "horn," it was actually an extension of the nasal cavities, and ended with a blunt point. note . Its unique crest makes Parasaurolophus one of the most popular hadrosaurs (if the most popular). Significatively, parasaurolophus' remains are rarer than other duckbills. The hadrosaurs' lacking of specific weapons has made them nicknamed "the Cretaceous antelopes." They are usually shown in dino-books and documentaries as "chosen preys" for tyrannosaurs, "raptors" and even giant crocodiles, uncapable to offer resistence and obliged to flee away from them. This could be Truth in Television, but in Real Life "duckbills" were not exactly gazelle-like things. Adult hadrosaurs were strong and heavily-built: in a high-speed collision against a tyrannosaur, the hadrosaur had less chances to fall down (and more chances to rise again thanks to its longer forefeet). It's easier to imagine tyrannosaurs hunted young hadrosaurs more often than adults. Like the sauropods, hadrosaurs used to be associated with water in pre-"Renaissance" times. The early discover of some mummified hadrosaurs whose skin on their hands was believed to be remnants of webbing, made scientists believe they were semi-aquatic creatures with literally duck-like webbed "hands." We know now this skin bound the fingers together into a single, toughened "hoof" apt for walking on dry soil. Also, when on land, hadrosaurs were once shown assuming the same upright posture of an old-fashioned theropod. After the "renaissance," scientists described hadrosaurs as terrestrial animals, similar to modern ungulates but capable to shift from a quadrupedal to a bipedal pose. Needless to say, amphibious hadrosaurs with webbed hands and upright stance still appear in recent media (see The Land Before Time). Specifically about Parasaurolophus, countless hypotheses have been made about the function of its "horn": among them, a tool to thread its way through the dense forest foliage, or even a snorkel when swimming underwater. The latter just plain doesn't work; there aren't any holes on its tip. The most commonly accepted scientific theory is that the complex series of tubes found within were used for amplifying calls. Scientists have even turned out to reproduce these calls, which quite resemble a brass instrument. note It's highly probable the headgear had also a display function: it might be brightly colored to attract attention, and could have had a flap of skin stretched from it to the neck, but both hyps are unproved. This dinosaur has a rather strange destiny in fiction: it has appeared in almost every dino-film, but almost always with minor roles – basically with the only purpose to increase the variety of the "dinosaur world." And don’t expect to hear its name, too. note A good example is in the Jurassic Park films. Some Parasaurolophuses are visible behing the Brachiosaurus in the famous "Welcome to Jurassic Park!" scene; some are seen in both sequels, too. But all these were simple cameos, and the animal is never named. note Other unnamed apparitions are in Disney’s Fantasia and Dinosaurs. One rare example of a major-character Parasaurolophus is seen in The Land Before Time... at least, Ducky and her parents are officially labeled so: they’re actually another hadrosaur, Saurolophus.
The literal duckbill has many names: the Edmontosaurus / Trachodon / Anatosaurus / Anatotitan case **
No other stock dinosaurs has had such a Mind Screw story than the Edmontosaurines (The Brontosaurus/Apatosaurus is nothing in comparison). Here, Science Marches On is to a Up to Eleven degree, coupled with a huge Taxonomic Term Confusion and I Have Many Names. Edmontosaurines roamed North America at the very end of the Cretaceous, 73-65 mya. Two genera were then recognized, Anatotitan and Edmontosaurus, but they were reunited into one in 2011. Some claim this makes Edmontosaurus the only valid name for this dinosaur, while others support the separation of Anatosaurus. By any name, these creatures included both normal-sized species (10 m) but also some of the biggest hadrosaurian species, reaching 12/13 m long — as long as T. rex and a bit heavier than it. Despite this, their size didn't preclude them to be among the rex's favorite prey. note . Edmontosaurus (if it includes Anatosaurus) is one of the most scientifically known dinosaurs. More than 10,000 known specimens (more than most other dinosaur) show every evidence about its life, even diseases. The most striking ones are the "petrified mummies," which have preserved not only skin prints, but also hardened muscles. If you don't believe us, see here. The second find is very recent, and shows an unexpected thing: hadrosaurs had a much more massive tail than traditionally thought. If this’d be true for all dinosaurs, then many classic studies about dinosaur biomechanics should be reviewed. For example, hadrosaurs and Iguanodon are often thought mainly quadrupedal, but a heavier tail would made their center of gravity just under their hips, perfectly balancing their body on two legs. Maybe hadrosaurs mainly walked on two feet and stayed on all fours only when grazing or resting, like kangaroos. note Anatosaurus deserves the "duck-billed dinosaur" title more than any other hadrosaur, with its flat head and spatula-like beak. Edmontosaurus had a stockier head and a an undulating-edged upper bill, but was still more duckish than most relatives. Their Donald Duck-like face made these dinosaurs unusually nice-looking. In popular work, their "duckness" may be strongly exaggerated, rendering its flat bill literally identical to a duck's, without any teeth or cheeks. In Real Life, hadrosaurs were not exactly toothless. Behind their bill they had up to a thousand teeth closely packed together in "batteries" and capable to grind the toughest vegetation—fossil pine needles have been found in the aforementioned mummies. Edmontosaurines hadn't got any crest on their head; maybe they had a flap of inflatable skin on their nose to amplify their calls, but this is only a supposition. Here’s a brief summary of the edmontosaurines’ awesome taxonomic tangle: Their first remains, isolated teeth found in USA, were named Trachodon mirabilis ("admirable rough-tooth") in 1856 — among the very first dino-remains described in North America. During the following Bone Wars, two skeletons were discovered and named Trachodon copei. Soon later, two spectacular hadrosaur "mummies" (Claosaurus annectens) were popularly referred as the "Trachodon mummies." In 1917, a gigantic hadrosaur was discovered in Alberta near Edmonton, and named Edmontosaurus regalis. In year 1942, one scientist found that Trachodon must be only used for the original teeth, and coined a brand new name, Anatosaurus ("Duck lizard"), for both the Bone Wars skeletons (Anatosaurus copei) and the mummies (Anatosaurus annectens). Before the year 1990 two well-known genera were thus recognized, Edmontosaurus and Anatosaurus, and described as two distinct hadrosaurs in dino-books and documentaries. However, in that year, new studies showed A. copei being much more different than A. annectens and E. regalis put together, and scientists changed Anatosaurus annectens in Edmontosaurus annectens. At this point the copei was the only remained Anatosaurus, but... taxonomic rules say "Anatosaurus" should indicate only the annectens. This meant it should be renamed, too. Being scientists often very nostalgic, they decided to recall it with a similar name: Anatotitan ("giant duck"). And now Anatotitan should probably be sunk into Edmontosaurus, while Anatosaurus could return valid again.Quite clear, isn’t it? Trachodon first appeared in pop-media in 1925 (The Lost World film adaptation), in which is portrayed as a prey for a giant carnivore. Since then, it became THE duckbill in public consciousness, to the point "trachodont" was also used as a popular synonym of "hadrosaur." Since the "renaissance" times, Anatosaurus has become the most widely-used name. After 1990, Trachodon rapidly disappeared in pop-consciousness -– even though its ghost is still seen sometimes, like the "brontosaur" one. As it seems, the name Edmontosaurus hasn’t gone a long way in non-docu media: when an edmontosaurine appears, is simply known as "duckbill," and the crested Parasaurolophus has become the most portrayed hadrosaur today. Compensating this, edmontosaurines remain still quite common in documentary media, being the only hadrosaurs which could have met Tyrannosaurus rex in Real Life. Current dino-books usually show them with the name Edmontosaurus, while "Anatotitan" became popularized by Walking with Dinosaurs, and has also appeared in Primeval. According to the most recent researches, its proper name is either Edmontosaurus or Anatosaurus.
Greek helmet: Corythosaurus *Hadrosaurs were very diversified in Real Life. Even though they shared the same body-plan, their head was wildly diverse. They are divided in two main lineages: basically, those with hollow crests, and those without. Other than Parasaurolophus, the only hollow-crested duckbill with a significant number of appearances in pop-media is Corythosaurus. Naturally, the latter has been a much rarer sight. In theJurassic Park film series Corythosaurus joins Parasaurolophus only in the third film. Just like Parasaurolophus, good luck if you'll ever hear Corythosaurus named in fictional media. Compensating this, it has been just as common as Parasaurolophus and the Edmontosaurines in documentary works, which regularly show it with its distinctive crested look. Corythosaurus was the same size of Parasaurolophus (8 m long), and lived in Late Cretaceous North America 77-76 mya. A classic error in paleo-art is to depict these two dinosaurs living alongside Tyrannosaurus rex. Since the "rex" was discovered in more recent terrains (68-65 mya), this makes a slight Anachronism Stew case. If the artist did the research these two hadrosaurs will interact with other smaller tyrannosaurids like Albertosaurus. First discovered in 1912 by Barnum Brown note , the "cory," unlike the "para," has one of the richest records among hadrosaurs. Several complete specimens known to science, including many juveniles. The corythosaur’s cranial structure was similar to the parasaurolophus, with expanded nasal bones which formed a crest. However, the Corythosaurus crest was very different than Parasaurolophus: it was laterally-flattened, round-shaped, and put upright above the head. It shape has often been compared to a Greek helmet (Corythosaurus just means "helmet lizard"), but some have (more prosaically) defined it as frisbee-like or dish-like. This crest was hollow like that of Parasaurolophus, but with less complex internal structure. It seems very different-sized and also different-shaped between genders and growth stages: adult males have the biggest, tallest and roundest ones, while those of females and youngsters were smaller and narrower, and the hatchlings were born devoid of it. Issues regarding the possible functions of the corythosaur’s crest are like those regarding Parasaurolophus. Like Corythosaurus, female Parasaurolophus could have had shorter crests than males. Even though some skulls do show some variability, Parasaurolophus fossils are too rare to make a correct comparison — maybe the different-crested specimens are just different species within the genus. Since hadrosaurian crests are so differently-shaped, experts have concluded that they had also the function to distinguish visually the different hadrosaur species/genders/growth stages from each other, just like modern antelopes with their distinctive horns (let’s face it, comparisons with antelopes do work very well when talking about hadrosaurs). Moreover, the different-sized crests made differently-pitched sounds. As trombones emit lower notes than trumpets, adult males’ voices were lower than females, which in turn were lower than youngs. Then, as French horns and bassoons have a different timbre, so would have been for Corythosaurus and Parasaurolophus.
A good mother: Maiasaura *This hadrosaur deserves a special mention. The same size of Parasaurolophus and Corythosaurus and contemporary to them, 74 mya, Maiasaura had no such striking headgear (only a small relief above the eyes), nor did it have such a wide bill like the edmontosaurines. Nonetheless, it has been one of the most important dino-finds ever. Hundreds of Maiasauras were discovered together in Montana in year 1980 by famous paleontologist Jack Horner note , in what is known today as the "Egg Mountain." His mountain showed not only adults, but also many fossilized, 6 ft wide, crater-like nests made of earth and full of hadrosaurian eggs, hatchlings of all ages, and even skeletons of embryos still inside the eggshells! Before the 1980s only few dinosaurian eggs were known to science, and parental caring among dinosaurs was still a very speculative issue. Horner's discovery was a true snapshot of daily dino-life. He noted that the youngest specimens still had incomplete limb-bones: this meant they were incapable of leaving their nests. And yet, their teeth were noticeably worn, as they were already eating tough vegetation. How could they feed on themselves? Here is the proof of parental care: only adult maiasaurs could feed the young to make them surviving until they grew larger and finally could leave their nest alone. Horner gave a Meaningful Name to his caring dinosaur: Maiasaura means "good mother lizard" (note the unusual feminine suffix -saura). It was just his deep study about this dinosaur that has given to Horner his current prestige in the scientific community. Horner and then other scientists made this possible reconstruction of Maiasaura lifestyle. Huge herds of possibly 10,000 individuals used to migrate across Western North America from the northern Canada south to Montana to winter in their island. Here, they mated, built their nests, laid their eggs, and filled their nests with decaying vegetation to keep the precious eggs warm. note After the hatching, adults feed their helpless babies with good food, moved by their cute appearance (the babies’ skulls show large eyes and short muzzles like modern mammal cubs). After having developed their skeleton, the youngsters started to search their food on their own; finally, the whole herd undertook again their migration toward the North, to pass here the Polar summer. In short, an overall behaviour very similar to many modern migrating birds. This reconstruction made the top of the Dinosaur Renaissance, definitively debunking the old "big, stupid, unfeeling, oafs" thing. Some years later, the discover became known among pop-writers, too. Only... Maiasauras inconspicuous appearance was not interesting enough. Even though the "good mother dinosaur" and the whole argument are widely mentioned in the 1st Jurassic Park novel, note this was totally overlooked in Steven Spielberg's following film. Other Hollywoodians resolved the problem in another way: giving Maiasaura's behaviour to other relatives. In The Land Before Time, the hadrosaurs (actually, every herbivorous dinosaur) migrate through the lands and hatch their young in crater-like nests made of earth. This was copied later by Disney's Dinosaurs (this time the duckbills were substituted by Iguanodon). All OK? Obviously, not. We have no proof if other dinosaurs really behaved the same. It's like saying that if sparrows build cup-like nests, then every other bird must build cup-like nests just because is a bird. Mind this: have you ever seen an ostrich or a penguin brooding their eggs in a cup-like nest built on a branch?
Other hadrosaursSorry, these ones aren't here. If you're looking for Hadrosaurus, Kritosaurus, Saurolophus, Lambeosaurus, Tsintaosaurus, and others, see here.
There were many non-hadrosaur ornithopods as well, but only one of them has made significant appearances in fiction, Iguanodon. If you are lucky Hypsilophodon may also show up, but it's almost never named.
A veteran: Iguanodon **
Living 126 to 125 million years ago in Early Cretaceous Europe, this is the most iconic non-avian dinosaur from the "old continent." It’s also one of the most scientifically well-known dinosaurs, and one of the most abundant in fossil record. Iguanodon has had a special role within the stock dino-ensemble. Along with Megalosaurus, it’s the only dinosaur that has covered the whole history of scientific and popular portraits, but unlike the megalosaur, has managed to preserve its fame still today. Although nearly as big as Tyrannosaurus (10 m or more, and up to 4 tons), Iguanodon is perhaps the least striking-looking among stock dinosaurs. Being an earlier relative of hadrosaurs (and possibly their ancestor), its shape resembled one of the latter, with three-toed hindfeet, short but strong forelimbs, long tail stiffened by bony tendons, massive body, hindlimbs much longer than forelimbs. Non-hadrosaurian traits include: the backbone not curved at the shoulder level; grinding teeth much less numerous and put in one single row on each half-jaw; a totally crest-less head; a deep, narrow beak very unlike the duck-billed one. The hands of Iguanodon contain all the "oddities" in its skeleton. The most known is the spike on its hand made of the first digit's phalanxes fused together and encapsulated in a horny sheath, usually shown in books as a weapon against enemies. And it had an opposable "pinkie" finger, maybe to grasp vegetation. Like hadrosaurs, the three central digits were fused together in a hoof-like structure and supported the weight of the dinosaur when on four legs (though incorrect freely-fingered iguanodonts-hadrosaurs often appear in portraits). We don’t know for sure if iguanodonts (and hadrosaurs) were mainly tree-browsers or ground-grazers. However, classic portaits usually show iguanodonts in the usual "tripodal" stance and browsing like a giraffe. Several paleo-works have also added a long extendable giraffe-like tongue to reach tree-foliage, but this is unlikely. Iguanodon is one of the three animals along with Megalosaurus and the obscure ankylosaurian Hylaeosaurus which were called "dinosaurs" for the first time in history (1842), by the English paleontologist Richard Owen. Iguanodon was already identified in 1825, just one year after Megalosaurus, by English doctor and fossil-collector Gideon Mantell (it's the second non-bird dinosaur to have received a official name). It was initially described from its iguana-like teeth and few other incomplete remains: hence its name meaning iguana's tooth. But then, in 1877 about 40 Iguanodon skeletons were discovered within a coalmine in Belgium near the town of Bernissart, the very first "dino graveyard" ever found. Many other remains were later assigned to Iguanodon (often found outside Europe), but many have recently split in other genera (see Prehistoric Life). Most dinosaurs have changed their look at least once: Iguanodon has done this twice. The first attempt of reconstrution showed a huge dragon-like quadruped, and one of its thumbspikes was inaccurately put on its nose—this is justified by the very fragmentary nature of its original remains. note After the discover of the complete skeletons from the "dinosaur mine" in the 1870s, the iguanodon became bipedal and upright, but still reptile-looking, often shown with iguana-spikes running along its back, and with an overall theropod appearance. Finally, studies started in the 1970 and led by English paleontologist David Norman made Iguanodon returning quadrupedal again (though still capable to stay and run on two legs), and with cheeks hiddening the teeth in the living animal. note An excellent example of this new portrait is seen in Disney's Dinosaur, which made Iguanodon the main character in the story — exaggerating its horse-like look with fleshy lips instead of the proper bill. Even though has been extremely common in dino-books and other non-fictional media, Iguanodon has not made significative apparitions in cinema or TV before Disney's Dinosaur and Walking with Dinosaurs were broadcast during the 20th-21st century change. Rule of Cool easily explains why: with its generic look and weak weapons, it don’t bear the comparison with Tyrannosaurus rex jaws, Triceratops horns, Stegosaurus plates, "raptor" claws, or the immense size of sauropods — and some portraits could even leave the beak or the thumbspikes, making it even more generic. However, its historical and scientifical importance won't ever be deleted in dino-fans' consciousness, as no other dinosaur has run the whole two centuries of popular portraits: from Crystal Palace rhinos, to giant two-legged iguanas, up to Disneyan horses.
Other hadrosaur predecessorsSorry, these ones aren't here. If you're looking for Hypsilophodon, Camptosaurus, Ouranosaurus, Tenontosaurus, Dryosaurus, and others, see here.
More primitive dinosaursSorry, these aren't here. If you're looking for Herrerasaurus, Heterodontosaurus, Guaibasaurus, Eocursor, Tianyulong, and others, see here. And here.