'helmeted thief') is a genus of oviraptorid dinosaur from the late Maastrichtian Nanxiong Formation of South China.

Oviraptorids may have predominantly inhabited arid environments and ate xerophytic (drought-resistant) plants, nuts, and seeds.

The holotype, JPM-2015-001, is a nearly complete skeleton of an individual at least seven or eight years old, lacking distal caudal vertebrae but including the skull and lower jaw (JPM-2015-001).

It was not in a typical death pose, and the neck was in a circular curl much like the type specimen for the contemporary oviraptorid Heyuannia.

The species name jacobsi honors American vertebrate paleontologist Louis L. Jacobs who mentored three of the authors while they were getting their PhD's at Southern Methodist University, Dallas, Texas.

[1] Corythoraptor bore a tall crest on its head similar to that of the modern cassowary, with a 2 mm (0.079 in) thick perhaps keratinous bony shell casing.

The lower part of the premaxillae (at the tip of the snout) features several irregularly distributed pits, which probably represent foramina which allowed blood vessels to flow, indicating a keratinous sheath (rhamphotheca) over a beak similar to ornithomimids.

The ventral side (underside) of the premaxillae is highly broken up, which could indicate the bone was lightweight, perhaps being pneumatized.

The ulna is slightly shorter than the humerus and makes up 26% of the entire arm length including the hand, and features a poorly developed olecranon (which also forms the elbow joint).

The tibia is 19% longer than the femur, and features a pronounced cnemial crest running along half of its length.

Below is a family tree of Oviraptoridae based on Lü et al., 2017 (bolded species inhabited South China):[1] Nankangia jiangxiensis Yulong mini Nomingia gobiensis Oviraptor philoceratops Rinchenia mongoliensis Zamyn Khondt oviraptorid Citipati osmolskae Corythoraptor jacobsi Huanansaurus ganzhouensis Tongtianlong limosus Wulatelong gobiensis Banji long Shixinggia oblita Khaan mckennai Conchoraptor gracilis Machairasaurus leptonychus Jiangxisaurus ganzhouensis Ganzhousaurus nankangensis Nemegtomaia barsboldi "Ingenia" yanshini Heyuannia huangi The validity of Corythoraptor was called into question by Cau (2024), who considered it to be a junior synonym of the contemporary Banji due to them both sharing unique characteristics of the skull.

[1] Based on histological analysis on a portion of the fibula and radius, the growth marks indicate the holotype was older than 6 or 7 years when it died.

Because growth restarted near the edge of the bone, the specimen probably died at the beginning of a new growing season and therefore was still a young adult which had not yet reached its maximum size.

If the crest did serve as a mating display, this would suggest Corythoraptor was sexually active before it finished growing, and that growth continued for more than 8 years.

The cassowary uses its casque to dissipate heat from the brain cavity, and as an resonator to aid in the detection or gauge the point of origin of low frequency signals across a greater distance.

In Corythoraptor, the latter may have been used to hear predators or prey items, or possibly to pick up low frequency mating calls as modern cassowaries do.

[1] Other dinosaurs include the therizinosaurid Nanshiungosaurus, the tyrannosaurid Qianzhousaurus, the sauropods Gannansaurus, and Jiangxititan, and the hadrosaurid Microhadrosaurus.

[4] However, fossil trackways from the nearby Yangmeikeng area indicate an assemblage of predominantly ornithopods (hadrosaurids), but also nodosaurids, therizinosaurids, tyrannosaurids, oviraptorids, coelurosaurians, deinonychosaurians, the bird Wupus, sauropods (perhaps Gannansaurus), pterosaurs (Pteraichnus), and turtles (perhaps Jiangxichelys).