Cursorex

Cursorex
Cursorolophus rex (King of the Running Ridges)
Clan: Fighting/Stone
Height: 13 ft at shoulder
Length: 5.25 ft
Weight: 1500 lbs
Lifespan: 25-30 years
Diet: Carnivorous
Range: Concept Canyon, Never Mountains (Yonder)
Offense/Defense: Razor-sharp teeth and claws, speed and climbing skills
Status: Extinct on Earth; Common on Yonder
Danger Level: Medium to High - Proceed with Caution

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Division: Archosauria
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
Superfamily: Tyrannosauroidea
Family: Lophocephalidae
Subfamily: Cursorolophidae
Tribe: Cursorolophini
Genus: Cursorolophus
Species: C. rex

On the cliffsides and rock ledges of Concept Canyon, many creatures have to keep their eyes and ears open. One misstep and you'll be plummeting thousands of feet to your inevitable doom. But in the misdt of the sheer drop lurks a different threat: a predator, a hunter that laughs in the face of danger and death...
The Cursorex, or C-rex, is the Concept Canyon's most frequent and famous mid-sized carnivore. Although it is primarily a cursorial creature, it is by no means limited to a level surface. With the prowess of a mountain goat, it can scale sheer rock walls in mere seconds, easily catching up with you and attacking. It takes a skilled mountaineer to take on even one of these creatures, let alone more than one.
Despite resembling the legendary raptors of recent fame, the C-rex is surprisingly more closely related to the tyrannosaurids, a group which also includes T-rex itself. The group which the Cursorex belongs to is the Lophocephalids, or the Ridged Heads, which have similar features to tyrannosaurids: slender legs, robust skulls with small scraping teeth on the front, and fused nasal bones with a slight upward arch. However, they have three fingers on their hands, and they also lack the ridge on the back of the jaw seen in tyrannosaurids, and thus have a less powerful bite than their more infamous cousins. All of them also have head crests, a feature present since their ancestral species, Guanlong wucaii, which is believed to be a common ancestor to the two lineages. The C-rex itself is the eponymous and most well-known member of the Cursorolophid subfamily, which is distinguished from the Lophocephalid subfamily by sporting larger, thicker teeth and more prominent crests, as well as larger arms and hand claws.

C-rexes are famous for their fleetness of foot, and their climbing talent is almost legendary. Few other creatures have evolved to traverse both environments so well. However, horizontal and vertical planes are very different obstacles that the C-rex has to face. To move quickly on land, its long legs are well-designed for speed, with slender, fused metarsals that act as shock absorbers. It can outrun even an automobile for a short distance, racing at up to 45 mph in mad pursuit of prey. Its long tail is mostly stiffened, and aids in counterbalancing when charging, and the arms have evolved wrists that can rotate palm-down like those of humans, so that the creature can tuck its hands into its chest to keep them out of the way. Clambering up a rock wall, however, presents a different challenge. The arms, as well as the legs, are long and muscular, and the hands are equipped with 6-inch curved talons that are used as grapples. Because the foot claws are relatively straighter, to prevent them being damaged while running, it has evolved spicules, scaly ridges on the undersides of its toes, similar to the tire-like gripping pads on rock wallabies; in addition, its ankle joints can rotate such that its feet can rotate into a reversed position, allowing them to grip onto the rock face, and the first toe is opposable and comes with a large curved claw similar to the hand claws as a grasping hook. Again, the tail serves as a balance when climbing at speed, and is especially handy when making dime-turn direction changes. In this way, the C-rex can race up near-vertical walls with little effort, timing the movements of its limbs and claws to exact precision to ensure a proper grip.

Needless to say when considering all tyrannosauroids, the C-rex is carnivorous. It will consume any animal big enough to fit in its mouth, dead or alive. To kill a small animal, it simply crushes it in its jaws; its serrated teeth, which are thicker-set than in other predatory dinosaurs and heavily reinforced, easily do the job for it. A larger quarry, however, is a greater challenge. The most common mid-sized herbivore in the Concept Canyon, the yale, is equipped with lethal swiveling horns that can easily impale a careless C-rex or toss it off the cliff. It is important that the C-rex mortally injures the creature and forces it to fall before it gets hurt itself, so that it inevitably dies before or due to the drop. For this reason, the C-rex is a pack hunter - the Canyon's residents refer to it as the "climbing coyote" in their language. By attacking in numbers, C-rexes can move to attack from all angles, preventing the prey from counterattacking in one specific direction. When it finally succumbs and plummets, the dinosaurs simply scramble down the cliff to feast on the smashed corpse below.
On solid ground, the C-rex also thrives out on the open dry scrub surrounding the Concept Canyon. Although the environment is relatively arid, it does support a moderate amount of scrubland, which in turn feeds grazers such as antelope and ornithomimmids. The C-rex works like an African Wild Dog, relying on stamina, group tactics, and a strong natural arsenal to take down prey. Packs are generally comprised of eight to ten individuals, consisting of an alpha breeding pair, distinguished by their vividly colored crest sails, and three or four subordinate pairs. Most of the time, they need no help in hunting small animals, which is particularly convenient in the dry season. However, in the wet season, when larger animals traverse these lands, the dinosaurs begin cooperating more effectively, and chase down prey as a single united entity. Different packs specialize in different prey, such as ostrich, impala, or Gallimimus. Whatever the case, they are adapted for speed because their prey is too. Faster individuals will run down the food, while others will take alternate paths to cut off any retreat. It is a strategy that works, because these dinosaurs make a kill 4 out of 5 times - the highest success rate of any carnivorous dinosaur.

The Cursorex's genus name, Cursorolophus, is partly derived from its famous head crest. Both sexes have these, the females' being smaller than the males. The crest itself is hollow, similar to that on lambeosaurine hadrosaurs, and the breathing tube within it curves back on itself as it passes down towards the windpipe. This tube is lined with soft tissue to cool the air the creature breathes in, with numerous olfactory bulbs to enhance its sense of smell. However, its most well-known function is display. The crest is brightly colored and is used as a signal, and the sail of skin on the back is also brightly colored, even more so when courting. Using the breathing tube inside as a resonating chamber, the C-rex can create a beautiful noise that sounds a lot like reed pipes. Many residents of the canyons have grown used to this melodious cry, which echoes at dusk across the canyons after a successful hunt.
Being a pack animal, the C-rex has adapted to a very complex social life. Partners are generally monogamous, but if one is killed, the other will return to season and seek a new mate. Each mating pair will lay clutches of 6 to 8 eggs every year at the start of the wet season. The chicks will learn to walk and climb within minutes of birth, so the dinosaurs can afford to brood on the cliffside ledges, for there is little else to serve as a shelter for the nest. By keeping up with their parents, the young exercise their legs intensely, being able to chase down fast-moving lizards and rodents within just three months. Babies are distinguished from their tar-colored parents by the brown feathers all over their bodies, which are gradually shed as they grow older, achieving adolescence in six or seven years and becoming fully grown at the age of 18.
Although it is a formidable predator, the C-rex is vulnerable to predation, being a favorite target for dragons, pterosaurs, coyotes, and humans. However, since it can replenish its numbers easily, its numbers remain stable even while others suffer huge declines during the dry season. The Cursorex can therefore be considered one of the most successful inhabitants of the Concept Canyon, on a par with coyotes and humans. It would take a massive event lasting years or even decades to eliminate this species altogether, for it is very clear indeed that this hardy relative of T-rex can survive a shorter catastrophe.

Aang says: "Although the Cursorex appears specialized for life on the canyons, appearances can be decieving; this creature is amazingly adaptable and can survive almost anywhere, as long as the environment isn't cramped. It comes as a surprise to most that it is becoming increasingly popular as a food source in the desert communities, much to my dismay; I've heard that it's as tender as lamb and divides neatly into joints for serving - not that I've eaten any meat to speak of, of course. One consolation here is that it also makes an interesting pet, although a troublesome one because it will bite almost anything in range - which I should know because I tried owning one myself, only to give it to Sokka because it was much too rowdy. In fact, many C-rexes have been abandoned in the wild because of their wild behavior, which is problematic because they can return to a feral state faster than most other dinosaurs, and with enough food to go around, the population naturally increases. We were considering labeling them as a pest species, but seeing that they stay well away from most cities due to the noise and enclosed spaces, they aren't as common as compies in urban areas, so we eventually decided that adding the C-rex to this category simply wasn't worth the effort."

(After watching DKCR walkthroughs on Youtube for the umpteenth time, I got around to wondering what the Skellyrexes would have looked like in real life... and this was the result. I tried to make it look as much like the original Skellyrex as possible, although most of the design is purely based off my own artistic license! )