Predatory dinosaurs have been gone for 650,000 centuries, but that does not stop us from painting such pictures of how they made a living-how they hunted, how they spent their spare time, their social behavior, reproduction, and the like.1 We are able to do so by making deductions based on what we know about their structure and on the fossil records. In describing the life-styles of the predatory dinosaurs, I am going to work from a basic assumption that the dinosaurs were fully warm-blooded in the way birds and mammals are. As I explain in Chapter 7, I do not think the alternative physiologies are viable ones.Let us begin with the one feature that made most predatory dinosaurs what they were-killers-and that is their teeth. . Most typical theropods had long rows of sharp teeth* This tells us that they were predators-for herbivores simply do not have such teeth. The fact that they were predators in turn tells us something less obvious: that theropods enjoyed much more leisure time than do most humans, and spent most of it asleep. This is typical of medium sized and big predators-lions and even house cats for that matter spend up to twenty hours a day napping. Predators, especially those that kill big game, go out and kill something, eat it in one quick sitting, and then sleep it off until they are hungry again. As detailed in Appendix A, big predators can go for days or, in the case of giants, even weeks between meals. This is quite unlike herbivores, which must spend long hours nipping at and chewing large quantities of fodder* In fact, sleeping when there is nothing else to do has an important advantage. Bedding down helps keep an animal out of sight and out of trouble. This is especially true for small species and the juveniles of big ones, for big predators are very happy to attack and consume smaller predators.
But whatever amount of time they spent lazing about, predatory dinosaurs were built for those briefer but much more intense and interesting times-when they went off to kill and eat other animals. Killing big animals requires firepower, and in animals such power can only come from muscles. Mammalian carnivores of today have oversized neck muscles which give them tremendous biting power, something our household pets can demonstrate. Feel the neck muscles of a big dog and compare them to your own. Likewise, the heads of most predaceous dinosaurs were packed with powerful jaw-closing muscles (animatronic dinosaur), and their neck muscles were well developed, further increasing the available killing power.
With its long neck and its paddle-like limbs, Anshunsaurus was thought to be some sort of ichthyosaur-like reptile when its fossils were first found. However, further study of the fragmentary remains showed that it was a thalattosaur. This came as a surprise as previously animals from this order were known only from Europe and North America. animatronic dinosaur
Scientists currently place it within the Askeptosauridac family, though it is ackowledged that the relationships between the three families within the thalattosaur order are not entirely clear. Only one specimen of Anshunsaurus has been found, so scientists have as yet described only one species. Like other animals that returned to a life in the ocean, Anshunsaurus is adapted to its marine environment hut retains features that are similar in appearance to its land-living ancestors.
Features As in the other thalattosaurs. Anshunsaurus has a neck and body that are long and slim. The tail is extremely long and ribbon-like, propelling the animal along with a sinuous side- to-side action. The broad webbed feet would have been used for steering and manoeuvring. These reptiles must have come on to land to lay eggs, but their movements would have been clumsy there.
Another problematic group of early marine reptiles are the pachypleurosaurs – the lizards with thick ribs, fhey were once thought to have been a part of the nothosaur group but arc currently believed to be separate from them, and more primitive. The heads were short and the necks were long.
Dactylosaurus was the smallest of this group of small reptiles.
Features: The distinctive feature of Dactylosaurus is the shape of the humerus, indicating that the muscle attachment would mean a different swimming action from its contemporaries. There is a reduced number of bones in the flippers, showing a specialization to a swimming mode of life. However the primitive nature of the rest of the skeleton indicates that it was at best semaquatic. Like the other pachy pleurosaurs. the ribs are thick (hence the name of the group), to help to control the buoyancy while submerged.
Originally thought to have been a pachypleurosaur Corosaurus is now regarded as the most advanced nothosaur so far known. It lived in quiet waters, as shown by the presence of stromatolites (mineral mounds built up by algae and bacteria) in the same shallow marine strata. It is possible that these mounds may have made suitable nesting areas for these reptiles.
Features: The shoulder and hip girdles of Corosaurus are very similar to those of the early plesiosaurs. The paddles are also highly adapted, although not quite in the plesiosaur manner.
They would have been ideal for paddling through quiet waters, but less suited for clambering about on land.
Nevertheless, Corosaurus probably spent some time on land, basking or laying eggs.
Nothosaurs and the plesiosaur connection
The plesiosaurs were far better adapted for aquatic life than their relatives the nothosaurs. Their bodies were flat and rigid, and they were powered by paddles that worked with a flying action, rather like modern turtles. In Triassic times there were many that seem to be transitional between the two groups.
The pistosaurs seem to have been intermediate between the nothosaurs and the true plesiosaurs. Their remains are known from both sides of the Atlantic, Pistosaurus was found in Germany, while its relative Augustasaurus was found in America. It is not known whether they swam like crocodiles as nothosaurs did, or like turtles like plesiosaurs.
Features: Theintermediate nature of this animal is shown by the nothosaur-like body and the plesiosaur-like head. The plesiosaur skull still had the palate of a nothosaur, while the largely nothosaur body had the stiff backbone that usually denotes a plesiosaur. The teeth are similar to both, and the animal was obviously an active fish- hunter as both groups were. Hence there is an ongoing discussion among scientists of the actual classification of this animal.
Lariosaurus: It appears that at least this genus of nothosaur was viviparous (able to bear live young). Several skeletons have been found associated with embryos indicating that they carried their young to maturity in their bodies. In one specimen two juvenile placodonts of the genus Cyatnodus have been found in the stomach area, a clue to the diet of this nothosaur. Much of our modern knowledge of nothosaurs comes from the work of Dr Olivier Ricppel of the Field Museum in Chicago, the present day specialist in these uniquely Triassic marine reptiles.
Features: The primitive features of this small nothosaur include the short neck and toes. The back legs are five-toed with claws, and slightly webbed. The front legs are adapted into paddles. Both pairs of legs are quite short and do not give the impression of powerful swimming structures.
The front legs are stronger than the hind, suggestingthat they were the main swimming organs, unlikein the pachypleurosaurs. Fangs at the front ofthe broad head interlock as the jawsare closed, forming a vicioustrap for catching fishand other aquaticanimals.
Henodus: We can imagine Henndus like some kind of reptilian ray, paddling its broad flat body across the bed of a shallow lagoon, foraging in the rippled sand with its broad mouth.
Its plate-like body would have made it better adapted to searching along flat sea beds than to the shellfish-encrusted reefs frequented by its relatives. Its weak limbs suggest that it did not spend much time on land.
Features: This is the placodont that most resembles the turtles. There is a carapace over the whole of the body that stretches out well beyond the span of the limbs, and as in the other cyamodonts this is matched by a plastron, a lower shell, which covers the undersurface. Both carapace and plastron are made up of a geometric array of individual plates. The head is squared off at the front and is shortened in front of the eyes.
Placodus: Aquatic animals adopt several methods of dealing with buoyancy. The placodonts used what is known as pachystasis: the development of particularly thick and heavy bones to keep the body submerged. Voluminous lungs allowed them to adjust their buoyancy. Thistechnique is often used by animals that feed whilewalking along the sea bed, such as modern dugongs and sca-ottcrs.(animatronic dinosaur)
Features: Like Paraplacodus. Placodus has protruding teeth at the front. However they are shorter, thicker and more spoorvshaped. The crushing teeth are not confined to the edges of the mouth but form a broad pavement across the palate, and the skull is particularly strong to withstand the stresses of crushing seashells. A row of bony scutes forms a jagged ridge along the back. A gap at the top of the skull may have held a light-sensitive organ.
The laws of Paraplacodus are uniquely adapted to picking up shellfish, with three pairs of protruding teeth in the top and two in the bottom. The teeth project from the front of the mouth. They have a senes of rounded crushing teeth in the upper and lower jaws. The thick ribs produce a distinctly box-like body with an almost square cross-section, a strong set of belly ribs forming the flat floor of the body – a heavy design that kept it close to the seabed.
The word dinosaur comes from the Greek for “terrible lizard”,but despite their name, dinosaurs are not really lizards at all. Rather, they are members of the animal group called archosaurs. Living archosaurs are crocodilians and birds. The extinct flying “reptiles” or pterosaurs, which flew on batlike wings, are also in this bunch. All archosaurs descended from the earliest archosaur group, the rather crocodile-like thecodonts of the Triassic Period. Usually, archosaurs are considered reptiles, but some of us progressive types think they are too different from reptiles to be called that. Hence, the reader will find that I never refer to dinosaurs as reptiles, but as archosaurs. lifelike dinosaur costume
Predatory dinosaurs came in three basic types-paleodinosaurs, herreravians, and theropods. The first two, which were four-toed, were limited in success. The theropods, which had three toes, were much more numerous and longer lasting; among the better known genera are Tyrannosaurus, Allosaurus, Coe/ophysis, Velociraptor, and Ornithomimus. Sporting a birdlike extraordinary that when one looks at a jewel hummingbird, hov¬ering as it sips nectar, one is seeing a true relative of Tyranno¬saurus rex. It is a wonderful thing, and a superb example of what random genetic mutations guided by selective forces can do. animatronic dinosaur factory
The relationship between theropods and birds is so close that birds can be considered flying theropods, and theropods can in turn be thought of as early terrestrial birdsThis may be true in the formal, literal sense. A good argument can be made that birds should be classified as dinosaurs, just as the flying bats are considered mammals. So if someone points to a sparrow and says, “oh, what a nice little dinosaur,” they are quite in line with the latest thinking.
GORGONOPSIANS AND OTHER MEAT-EATING THERAPSIDS
A rough description of the appearance of a gorgonopsiart would be a cross between a crocodile and a sabre toothed tiger. They were hunters by nature and had light agile skeletons, with long legs well adapted for rumiing. They were typical of the fauna of late Permian South Africa.(walking dinosaur costume)
Lycaenops: The long canine teeth of Lycaeftops were evidently adapted for stabbing, and would have inflicted deep bleeding wounds in the flanks of larger prey. Rather than going for the quick kill it would have waited for its prey to bleed to death. It is possible that Lycaenops hunted in packs, although no evidence of this hasbeen found.(animatronic dinosaur)
Features: The skull is long, low and slender. The canine teeth are very long, in both jaws. The blades are serrated, and the roots are deep, running well into the bone, accounting for the deep skull. There are few teeth in the back of the mouth, and those show little wear, suggesting that Lycaenops bolted down food without chewing. There is a zygomatic arch – a curved structure in thecheek bone under which the jaw muscle passed – a feature that mammals have. Not only did Lycaenops have mammal-like teeth but also mammal-like jaw muscles. The leg articulation shows that it could have both sprawled and walked with a high stance.
The head ornament of Styracocepbalus meant that it could be recognized from a distance. The crest stuck upwards and backwards, but there is some variation in its shape, and this suggests that it changed throughout life and that it was different between the male and the female. Styracocepbalus was a large herbivore that may have been fully terrestrial or partly aquatic like the modern hippopotamus, which resembles it in shape and size. It may have evolved from the estemmenosuchid group. Its remains are known from South Africa but it probably had a wider distribution. realsitic dinosaur costume
Features: The distinction of Styracocephalus lies in the ornamentation of the head and the size and arrangement of the teeth. The front teeth and the canines are conical and quite small, and there is a large number of back teeth, as well as a set of crushing teeth on the palate. This is a very primitive arrangement later forms had prominent interlocking incisor teeth at the front and reduced and palate teeth.
The front teeth of the dinocephalians tended to differ from genus to genus, but the back teeth were usually of the same pattern. The back teeth were much smaller than those of the front. Each tooth was the same shape as the next in each jaw, and the same in the opposing jaw. It consisted of a curved crown with a rounded blunt tip. and a ledge near the root. When the jaws closed the curved crowns interiaced and the tips fitted into sockets on the ledges of the opposite set. As a result the teeth meshed perfectly, allowing no gaps for the escape of food and making the chopping and crushing action very efficient.