Corythoraptor

## CorythoraptorHelmeted Thief

* **Crest Thickness** of 2 millimeters (0.08 inches), likely covered in keratin
* Took at least eight years to grow

 **Main** Segments

MainSegments

***“ Having clever, caring parents can give youngsters an excellent start. And here in the badlands of Asia, there are few more dedicated dinosaur parents than these. A colony of nesting Corythoraptors. ”***

― **David Attenborough**, *Badlands*
***Corythoraptor*** (Helmeted Thief) is a genus of oviraptorid dinosaur that lived in the Nanxiong Formation, Guangdong Province, Southern China, 67 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.

## Description

### Physique

As an oviraptorid, *Corythoraptor* is likely to have been covered in a coat of feathers, with longer ones lining the arms and the tail to form a pygostyle (tail fan). Like many oviraptorids, *Corythoraptor* also has a tall head crest (likely covered in a shell of keratin) resembling that of a cassowary, possibly serving as a means of display, a radiator to dissipate heat from the head, and a resonator to pick up low-frequency signals from long distances and pinpoint their origin.

*Corythoraptor* also has other standard oviraptorid traits, namely, a skeleton made lightweight by several air pockets, a long neck, sharp claws, and a powerful beak, believed to be fit for crushing nuts and seeds, as well as other plant matter. These beaks were also proposed to be meant for shelled prey or eggs, though given how oviraptorids are believed to dwell in arid environments, they were unlikely to have come across shelled prey, while the long-held stereotype of oviraptorids raiding and crushing eggs has long since fallen out of favor. Even so, eggs being a part of their diet is still plausible, but are unlikely to have been their regular source of food.

### Growth

Microanalysis of the bones show that *Corythoraptor* was subject to seasonal growth spurts. With this, the *Corythoraptor* type specimen is estimated to be a six or seven year-old individual that grew 1.6 meters (5 feet, 3 inches), just as it was about to start growing again, indicating that it hasn't reached its full size yet when it died. Conversely, if the crest serves as a mating display, this would indicate that, even as a young adult, *Corythoraptor* would have taken part in courtship, competitive mating, and other such activities even though it is yet to fully grow.

### Prehistoric Planet's Depiction

*Main: *Corythoraptor* on Prehistoric Planet*

Main: *Corythoraptor* on Prehistoric Planet

On Prehistoric Planet, only male *Corythoraptors* are seen, covered in vivid blue feathers with an underside of white feathers, and sporting a crest crest in shades of red and bright orange. While these traits imply that its portrayal was inspired by cassowaries (fitting since it is believed that the species lived a cassowary-esque lifestyle), according to Dr. Darren Naish, Prehistoric Planet's lead consultant, *Corythoraptor* was not originally intended to be blue.

*Corythoraptor* first appears in the fourth segment of Forests, with a flock of them feasting on fallen gingko nuts during autumn while they themselves get hunted by a female *Qianzhousaurus*. *Corythoraptor* is next featured in the third segment of Badlands, with males brooding over their eggs under the hot desert sun, only leaving during the night to feed while some remain behind to guard the nests, which provides an opportunity for a *Kuru kulla* to eat some eggs and steal one for her chicks to practice on. Footage of *Corythoraptor* in Badlands is also used for the Uncovered segment "Were Dinosaurs Good Parents?", which tackles the different ways in which dinosaurs took care off their eggs, from the costly brooding of the *Corythoraptors* to the reliance of *Isisaurus* on the heat of volcanic areas to incubate their eggs for them.

## Habitat

*Main: Nanxiong Formation*

Main: Nanxiong Formation

***“ This is east Asia. In these mountain forests, autumn arrives early. This is when many trees produce their fruit, and amongst the most highly-prized are the nuts of the gingko tree. ”***

― **David Attenborough**, *Forests*
*Corythoraptor* lived 67 - 66 million years ago in the Nanxiong Formation, Guangdong Province, South China, which is depicted on Prehistoric Planet as a series of temperate, deciduous mountain forests. *Corythoraptor* lived alongside six other oviraptorosaurs in this area (*Banji*, *Ganzhousaurus*, *Huanansaurus*, *Jiangxisaurus*, *Nankangia*, and *Shixinggia*). All seven oviraptorosaurs of the Nanxiong Formation likely had different food preferences, forming separate niches and preventing competition. While the plant life of Late Cretaceous China is poorly known, it is believed that the oviraptorosaurs actually lived in arid environments, and thus fed on xerophytic (drought-resistant) plants, indicating that the Nanxiong Formation had an arid or semi-arid climate.

While not explicitly found in a desert environment, *Corythoraptor* appears to have been depicted in the Badlands episode as living in the Barun Goyot Formation (where *Kuru kulla*, the other dinosaur it shares that specific segment with, hails from), perhaps due to speculation that the animal had a greater range than the fossil records show, or, in order to conserve budget and avoid making another dinosaur model, *Corythoraptor* was simply reused to serve as a stand-in for an oviraptorid species in the Barun Goyot Formation (which has three oviraptorids, *Conchoraptor*, *Heyuannia*, and *Nemegtomaia*).

## Behavior

### Flocking Behavior

***“ These have found a particularly abundant fall of fruit, but such gatherings can attract unwelcome attention. ”***

― **David Attenborough**, *Forests*
*Corythoraptors* are shown to congregate together to feed on an abundance of food. This unfortunately attracts the attention of a hungry *Qianzhousaurus*, which manages to sneak up quite close to them before being detected (and by that point, its very individual for themselves, with the oviraptorans running off like ostriches). The second time around, the gloom and the howling of the winds rustling up more leaves causes the *Corythoraptors* to be even less aware of incoming threats, leading one to get grabbed by the *Qianzhousaurus*.

### Parental Habits

***“ A few days ago, females laid eggs on these circular mounds. But the job of brooding them falls to the males. And that is not easy. Exposed to the midday sun, the eggs would soon cook. But the fathers use their broad tail and fallen feathers to keep the nest shaded... and pay a heavy price, enduring hour after hour in the searing heat. ”***

― **David Attenborough**, *Badlands*
*Corythoraptors* are oviraptorosaurs, a family of theropod dinosaurs that were mistakenly named "egg thieves" because the type species, *Oviraptor philoceratops*, was found atop what was assumed to be a *Protoceratops* nest, only for the eggs to turn out to be its own, showing that the animal was not a thief, but rather, a brooding parent that died (likely buried alive by a sandstorm because it refused to abandon its nest. Following this, discoveries of several nests in Asia showed that oviraptorosaurs laid their eggs two at a time in a circle and covered them all evenly with their feathered arms and the rest of their body. And based off of geochemical analysis, it appears that oviraptorosaurs incubated their eggs within the same temperature range as modern birds, around 35 - 40 degrees Celsius (95 - 104 degrees Fahrenheit). Prehistoric Planet portrays the task of brooding being solely done by the males, though, much like modern birds, it is possible that the parents took turns during the day, or that the exact strategy varies between oviraptorosaur species.

***“ At last, in the cool of the evening, the males can step away in search of food. This is where nesting in a colony brings benefits. Instead of all leaving at once, the Corythoraptors take turns, so there's always a neighbor keeping an eye out for danger. But even this neighborhood watch can't guarantee their safety. ”***

― **David Attenborough**, *Badlands*
In a further ironic twist, while the oviraptorosaurs are attentive parents as opposed to being the regular egg stealers popular culture stereotypically portrays them as (though they may have eaten eggs occasionally, it's unlikely their standard food), oviraptorosaurs themselves are known to be victims of true nest raiders, as indicated by the remains of the alvarezsaurid *Qiupanykus* being found with some oviraptorid eggshells. Prehistoric Planet depicts this irony in the second segment of Badlands. During the night, when the sun no longer threatens the eggs, the male *Corythoraptors* can get off their nests, though, once again showing their grouping behavior and its advantages, they do not leave all at once, relying on a few of them staying behind to keep watch over the rest of the nests, and alert the others when an intruder, like the velociraptorine dromaeosaur *Kuru kulla*, is discovered, prompting the rest of the flock to run the intruder down and attack with their powerful crushing beaks and sharp claws. This means little, however, when the nest raider takes advantage of the *Corythoraptors'* poorer night vision and overall poorer senses to feed on a few eggs undetected, and is fast enough to get away with one last egg.

## References

### General

1. ↑ 1.0 1.1 High diversity of the Ganzhou Oviraptorid Fauna increased by a new “cassowary-like” crested species
2. ↑ A new oviraptorid (Dinosauria: Theropoda) from the Upper Cretaceous of Bayan Mandahu, Inner Mongolia
3. ↑ A Pair of Shelled Eggs Inside A Female Dinosaur
4. ↑ δ18O-derived incubation temperatures of oviraptorosaur eggs
5. ↑ A new alvarezsaurid dinosaur from the Late Cretaceous Qiupa Formation of Luanchuan, Henan Province, central China

### Dr. Darren Naish

1. ↑ The point of the fourth segment of Forests was to show the featured animals in a deciduous "autumnal" setting. The *Corythoraptors* were never meant to be bright blue, however.