Proceratosaurus bradleyi (S/F)

Proceratosaurus, meaning “before Ceratosaurus,” was discovered in 1910 in the Forest Marble Formation of Gloucestershire, England, and was described by Arthur Smith Woodward in 1926 and later by Friedrich von Huene in the 1930s. Proceratosaurus lived during the Middle Jurassic period some 168 to 165 million years ago, during the Bathonian age. The only known species is Proceratosaurus bradleyi. It was originally believed to be an ancestor of Ceratosaurus due to a possible nasal horn on Proceratosaurus. However, revisions in the early 21st century by Thomas R. Holtz, Jr. including a phylogenetic study in 2004 and a later major review in 2010 reclassified it. Today, it is known to be a primitive tyrannosauroid, meaning it is more closely related to Tyrannosaurus than Ceratosaurus. Along with the relatively well-known Guanlong and several more obscure genera, it is now classified in the family Proceratosauridae. The dinosaur is known only from its skull, which was found at Minchinhampton, England during the excavation of a reservoir.

InGen recovered and successfully identified DNA of Proceratosaurus sometime prior to 1993, but was unable to clone any specimens before the incident. During the evacuation of Isla Sorna prior to Hurricane Clarissa, InGen personnel lost all Proceratosaurus samples. No DNA of this species has been recovered since, as samples left on Isla Nublar were lost due to sabotage and water damage.


This animal is known only from a single fossil skull, and no specimens have ever been cloned. As a result, details about its anatomy are mostly unknown. Some paleontologists believe that it grew to three meters (ten feet) in length, though other estimates suggest that it was significantly smaller. It may have weighed 45 kilograms (100 pounds), but this is also speculative. If it was similar in build to its close relatives, it would have been a lithe bipedal animal with a long, tapering tail, strong arms with three fingers on each hand, and long legs with three toes on each foot.

It was initially believed to have a nasal horn similar to that of Ceratosaurus, and this depiction is used on InGen‘s Jurassic Park brochures and non-canon merchandise produced in 2018 or later. However, later analysis suggests that it is more likely a saggital crest similar to that found on other early tyrannosauroids such as its close relative Guanlong wucaii.

Speculative depiction of a Proceratosaurus from the Jurassic Park Institute.

Because all genetic samples were lost, the coloration of Proceratosaurus is unknown. It is depicted on the Jurassic Park Institute as being beige in color with a yellow dorsal side and orange patterning on its flanks. The first toy representation of the animal depicts it as being dull brown with a bright red nasal horn, which would presumably be a display feature; the second toy depiction presents it as a mottled brown with a lighter-colored nasal horn. The mobile game Jurassic World Alive represents it as being covered with primitive gray-green feathers, but with bare scales on its hands, feet, and face. The tail in this depiction ends with a large brush of longer feathers. The scaly parts appear bright yellow, particularly on the face. The nasal horn is depicted as red again, and a vertical black stripe decorates ether side of the face passing over the eye. In real life, the Proceratosaurus would most likely have had feathers as depicted in Jurassic World Alive, but its crest would probably not have resembled a horn as in all of the franchise depictions so far.


While its later descendants’ growth process is fairly well documented, this animal’s physiology is known from a single incomplete fossil skull, the exact growth stage of which is not known.

Sexual Dimorphism

While sexual dimorphism is well-documented in this animal’s later descendants, its physiology is only known from a single incomplete fossil skull. The sex of the fossil animal has not been determined.

Preferred Habitat

In real life, the only known Proceratosaurus fossil was recovered from the Forest Marble Formation, which is a mostly-marine environment but is believed to have supported a forested region as well.

Isla Nublar

Despite its incomplete status, InGen did have plans to exhibit Proceratosaurus in Jurassic Park. It would have inhabited a small sub-paddock in the central part of the island. It would have bordered the secondary herbivore paddock (containing Brachiosaurus and Parasaurolophus) to the south and west, separated from them by a service road. To the north, it would have bordered the primary Dilophosaurus paddock, separated from it by the twenty-four-foot electric fence which divided up the regions of the Park. To the east, the main tour road would have separated them from an unused portion of paddock area.

Last known image of Proceratosaurus specimen on Isla Nublar, 6/11/1993. All specimens following this were lost due to sabotage, environmental damage, and eventually unknown circumstances on Site B.

Proceratosaurus embryos were even incubating on Isla Nublar as of June 11, 1993. However, there is no evidence that they were viable. On June 11, the power to the secondary backup generator in the embryo cold storage units was shut down due to sabotage. The insulated pipes which transferred liquid nitrogen to the cold storage units were severed during the sabotage as well, which caused a rise in temperature that led to irreparable damage to the embryos. Additionally, the pipe which fed the artificial lake outside the Visitors’ Center burst sometime after the incident; the 1994 investigation found that minor tectonic activity was a possible cause. The investigation found that the building’s foundations were severely damaged by the flooding, and water damage also affected both embryo storage units. One of the units had buckled due to the damage, resulting in specimens being washed away by floodwater. As the stolen embryos were destroyed during the incident, no recoverable DNA from Proceratosaurus remained on Isla Nublar.

Planned (orange) range for P. bradleyi on Isla Nublar, as of June 11, 1993
Isla Sorna

During the evacuation in preparation for Hurricane Clarissa sometime after the incident on Isla Nublar during mid-June of 1993, InGen personnel removed DNA samples from Site B for safekeeping. However, for unknown reasons, all Proceratosaurus samples were lost during the evacuation. As a result, all known Proceratosaurus DNA has been irretrievably lost.

Behavior and Ecology
Daily Activity

The activity patterns of Proceratosaurus are unknown due to a lack of specimens.

Diet and Feeding Behavior

Proceratosaurus was a carnivore. Its dietary habits are unknown due to a lack of specimens.

Social Behavior

Any details about social structure among Proceratosaurus remain unknown due to a lack of specimens.


All dinosaurs lay eggs, and Proceratosaurus would have been no exception. Its much later and more derived relative Tyrannosaurus rex is portrayed with a cloaca in Jurassic Park: The Game, so it can be hypothesized that Proceratosaurus would also have a cloaca. Any other details about its reproductive cycle are unknown due to a lack of specimens.


Due to a lack of specimens, any vocalizations made by Proceratosaurus are unknown.

Ecological Interactions

As a carnivore, Proceratosaurus would have preyed on other animals. Its paleoenvironment in real life is known for an abundant variety of small reptiles, amphibians, and early relatives of mammals. Presumably, it would have been vulnerable to larger predators than itself. Its exact relationships to other animals are unknown due to a lack of specimens.

Interactions with Humans

Despite attempts to create this animal and plans to exhibit it to the public, InGen never succeeded in cloning Proceratosaurus before the unfortunate loss of all known DNA samples. Therefore, it has never lived at the same time as humans, and has never interacted with them.

Proceratosaurus, meaning “before Ceratosaurus“, was discovered in 1910 in the Forest Marble Formation of Gloucestershire, England, and was described by Friedrich von Huene in 1926. Proceratosaurus lived during the Middle Jurassic period some 168-165 million years ago, during the Bathonian age. They may have been 3m (10ft) long, 1.5m (5ft) tall, and weighed 45kg (100lbs). In spite of its name, Proceratosaurus was not a member of Ceratosauria, nor was it related to the ceratosaurs; instead, it belongs to the group Proceratosauridae in the superfamily Tyrannosauroidea. It is thought that Proceratosaurus had a small horn on its nasal bone, though this may have been a malformation caused during fossilization, as some of the upper parts of its skull were not preserved. Proceratosaurus probably had a coating of primitive feathers, much like Dilong. The dinosaur is known only from its skull, which was found near a highway construction site.

Proceratosaurus can be found on Isla Nublar, though was never seen on the tour. However, its name is listed on the Jurassic Park Brochure Map in the Ford Explorers on the tour, and on the embryo cold storage unit. They may exist on Isla Sorna, as this is where InGen originally cloned its dinosaurs, but there is currently no evidence proving that it still or ever existed there.