Alectrosaurus was a very fast running tyrannosauroid as indicated by the elongated hindlimbs that likely filled the niche of a pursuit predator, a trait that seems to be lost by the advanced and robust tyrannosaurids.
The skull had a pair of horns above and in front of the eyes. The horns were probably covered in a keratin sheath and may have had a variety of functions, including acting as sunshades for the eye, being used for display, and being used in combat against other members of the same species.
Some paleontologists have postulated that this dinosaur may have actually had a sail that grew out of its back. If it did, then it would have been used to make the dinosaur look better, for regulation of body temperature or maybe even used for mating rituals.
An extinct species of large wild cattle that inhabited Asia, Europe, and North Africa. It is the ancestor of domestic cattle. The species survived in Europe until 1627, when the last recorded aurochs died in the Jaktorów Forest, Poland.
It was an early relative of Lambeosaurus, and shows a number of iguanodont-like features, including three stacked teeth for each visible tooth, small maxillary teeth, and an unusually powerful build for a hadrosaur.
Early meat-eating dinosaurs like Coelophysis relied on their speed and agility to catch a variety of animals like insects and small reptiles. The sharp teeth and grasping claws of Coelophysis would have helped them to hold and kill their food.
It had a pair of longitudinal, plate-shaped crests on its skull, similar to a cassowary with two crests. The function of the crests is unknown; they were too weak for battle, but may have been used in visual display, such as species recognition and sexual selection.
Dimorphodon means "two-form tooth", derived from the Greek δι (di) meaning "two", μορφη (morphe) meaning "shape" and οδων (odon) meaning "tooth", referring to the fact that it had two distinct types of teeth in its jaws – which is comparatively rare among reptiles.
Elasmotherium is thought to have had a keratinous horn, indicated by a circular dome on the forehead. There was likely a large hump of muscle on the back, which is generally thought to have supported a heavy horn.
Primitive characters for Tyrannosauroidea are the elongate neck vertebrae and the long, well-developed arms forelimbs along with the undecorated dorsal surface of the skull, unlike the more advanced tyrannosaurids.
Like most small dinosaurs, Hypsilophodon was bipedal: it ran on two legs. Its entire body was built for running. A light-weight, minimized skeleton, low, aerodynamic posture, long legs and stiff tail, immobilised by ossified tendons, for balance: all would have allowed it to travel remarkably fast for its size.
Macrauchenia had a somewhat camel-like body, with sturdy legs, a long neck and a relatively small head. Its feet, however, more closely resembled those of a modern rhinoceros, with one central toe and two side toes on each foot.
The skull of Majungasaurus is exceptionally well-known compared to most theropods and generally similar to that of other abelisaurids. Like other abelisaurid skulls, its length was proportionally short for its height, although not as short as in Carnotaurus.
It is thought that without a club on its tail, Nodosaurus would have been left without much in terms of active defenses. When threatened, it probably dropped to the ground so that only its armored back and sides were exposed, much like modern-day hedgehogs.