Protoceratops

*Protoceratops andrewsi*

* Jurassic Park Institute Artwork
* Robert F Walters Artwork

***Protoceratops (pro·to·cer·a·tops)*** (/ˌproʊtoʊˈsɛrətɒps/; from Greek ***proto-/πρωτο-*** "first", ***cerat-/κερατ-*** "horn" and ***-ops/-ωψ*** "face", meaning "First Horned Face") is a genus of sheep-sized (1.8 m long) herbivorous ceratopsian dinosaur, from the Upper Cretaceous Period (Campanian stage) of what is now Mongolia. It was a member of the Protoceratopsidae, a group of early horned dinosaurs. Unlike later ceratopsians, however, it was a much smaller creature that lacked well-developed horns and retained some primitive traits not seen in later genera.

Protoceratops had a large neck frill which was likely used as a display site to impress other members of the species. Other hypotheses about its function include protection of the neck and anchoring of jaw muscles, but the fragility of the frill and the poor leverage offered by possible attachment sites here makes these ideas implausible. Described by Walter W. Granger and W.K. Gregory in 1923, Protoceratops was initially believed to be an ancestor of the North American ceratopsians. Researchers currently distinguish two species of Protoceratops (*P. andrewsi* and *P. hellenikorhinus*), based in part by their respective sizes.

In the 1920s, Roy Chapman Andrews discovered fossilized eggs in Mongolia that were interpreted as belonging to this dinosaur, but which turned out to be those of *Oviraptor*.

## Description

*Protoceratops* was a quadrupedal dinosaur that was partially characterized by its distinctive neck frill at the back of its skull. The frill itself contained two large parietal fenestrae (holes in the frill), while its cheeks had large jugal bones. The exact size and shape of the neck frill varied by individual; some specimens had short, compact frills, while others had frills nearly half the length of the skull. The frill consists mostly of the parietal bone and partially of the squamosal. Some researchers, including Peter Dodson attribute the different sizes and shapes of these bones to sexual dimorphism, as well as the age of the specimen, at the time of death.

*Protoceratops* was approximately 1.8 meters (5.9 ft) in length and 0.6 meters (2 ft) high at the shoulder. A fully grown adult would have weighed about 82.7 kilograms (182 lb). Smaller specimens are estimated at 23.7 kilograms (52 lb). The large numbers of specimens found in high concentration suggest that *Protoceratops* lived in herds.
Restoration of *P. andrewsi*
*Protoceratops* was a relatively small dinosaur with a proportionately large skull. *Protoceratops* appears to have had muscular jaws capable of a powerful bite. These jaws were packed with dozens of teeth, well suited for chewing tough vegetation. Based on other relatives, and a specimen that was found in a collapsed tunnel, protoceratops was likely a burrower, dwelling underground and digging holes to live in. The skull consisted of a massive frontal beak, and four pairs of fenestrae (skull openings). The foremost hole, the naris, was considerably smaller than the nostrils seen in later genera. *Protoceratops* had large orbits (the holes for its eyes), which measured around 50 millimeters in diameter. Behind the eye was a slightly smaller fenestra, known as the "infratemporal fenestra."

## Discovery and species

Photographer James Blaine Shackelford discovered the first specimen of *Protoceratops* in the Gobi desert, (Gansu, Inner Mongolia), as part of a 1922 American expedition looking for human ancestors. No early human fossils were found, but the expedition, led by Roy Chapman Andrews, collected many specimens of the genus *Protoceratops*, along with fossil skeletons of theropods *Velociraptor*, *Oviraptor*, and ceratopsian *Psittacosaurus*.

Walter Granger and W. K. Gregory formally described the type species, *P. andrewsi* in 1923, the specific name in honor of Andrews. The fossils hail from the Djadochta Formation and date from the Campanian stage of the Upper Cretaceous (dating to between 75 and 71 million years ago). Researchers immediately noted the importance of the *Protoceratops* finds, and the genus was hailed as the "long-sought ancestor of *Triceratops*". The fossils were in an excellent state of preservation, with even the sclerotic rings (delicate ocular bones) preserved in some specimens.
*P. hellenikorhinus* skull
In 1971, a fossil was found that captured a *Velociraptor mongoliensis* clutched around a *Protoceratops andrewsi* in Mongolia. It is believed that they died simultaneously, while fighting, when they were either surprised by a sand storm or buried when a sand dune collapsed on top of them.

In 1975, Polish paleontologists Teresa Maryanska and Halszka Osmólska described a second species of *Protoceratops*, also from the Campanian stage of Mongolia, which they named *P. kozlowskii*. However, the fossils consisted of incomplete juvenile remains, and are now considered synonymous with *Bagaceratops rozhdestvenskyi*.

In 2001, a second valid species, *P. hellenikorhinus*, was named from the Bayan Mandahu Formation in Inner Mongolia, China and also dates from the Campanian stage of the Upper Cretaceous. It was notably larger than *P. andrewsi*, had a slightly different frill, and had more robust jugal horns. The arch of bone over its nostrils had two small nasal horns, and there were no teeth at the front of the snout.

In 2011, a specimen of *Protoceratops* first uncovered in 1965 was found to be preserved with its own footprint. It is the first example of a dinosaur to be preserved with footprints.

## Paleobiology

### Reproduction

The cast of the *Protoceratops sp*. egg at the Wrexham Museum, Wales

*P. andrewsi* hatchling at the American Museum of Natural History in New York City

In the 1920s, Roy Chapman Andrews discovered the first known fossilized dinosaur eggs, in the Gobi Desert of Mongolia. Each egg was about 8 inches long, and newborn hatchlings estimated to have been about a foot in length. Due to the proximity and abundance of *Protoceratops*, these eggs were believed at the time to belong to this genus.

The contemporary theropod *Oviraptor* was thought to consume *Protoceratops* eggs due to the discovery of an *Oviraptor* skeleton present at a nest. The skull was crushed, and it was speculated that the injury was received by a *Protoceratops* mother defending her nest from the predator. However, in 1993 Norrell *et al.* discovered an embryo inside a supposed *Protoceratops* egg. This embryo, upon close examination, turned out be an *Oviraptor*; the original find represented *Oviraptor* brooding behavior rather than a failed attempt at oophagy.

The oogenus *Protoceratopsidovum* (meaning "*Protoceratops* egg") was also originally misidentified as belonging to *Protoceratops*; it is now known to be the eggs of a derived theropod.
*P. andrewsi* growth series
In 2011, a nest of 15 young *Protoceratops andrewsi* was discovered in Mongolia. Stated as being the first *Protoceratops* nest discovered to date, the discovery suggests that *Protoceratops* parents might have cared for their young at nests during at least the early stages of childhood. As *Protoceratops* is a relatively basal member of the ceratopsians, the finding also suggests that other ceratopsians provided care for their young as well. Studies of lines of growth (i.e. lines of von Ebner) of the teeth in embryonic *P. andrewsi* suggests plesiomorphically long incubation times, with a minimum incubation time of 83.16 days for *P. andrewsi*.

### Daily activity patterns

The large eyes of *Protoceratops* has been suggested as evidence for a nocturnal lifestyle. However, subsequent comparisons between the scleral rings of *Protoceratops* and modern birds and reptiles have indicated a more cathemeral lifestyle, being active throughout the day during short intervals. This suggests that the fight between *Protoceratops* and the primarily nocturnal *Velociraptor* indicated by the fighting specimens may have occurred at twilight or under low-light conditions.

## Classification

*Protoceratops* was the first named protoceratopsian and hence gives its name to the family Protoceratopsidae, a group of herbivorous dinosaurs more derived than psittacosaurids, but less derived than ceratopsids. The group is characterized by their similarities to the Ceratopsidae but with more cursorial limb proportions, generally smaller frills, and lack of large horns.

In 1998, Paul Sereno defined Protoceratopsidae as the branch-based clade including "all coronosaurs closer to *Protoceratops* than to *Triceratops*." Some studies placed *Bagaceratops*, *Breviceratops*, *Graciliceratops*, *Magnirostris*, *Platyceratops*, and *Serendipaceratops* within Protoceratopsidae, but in 2006, Makovicky and Norell published a new phylogeny which removed several genera from Protoceratopsidae; several other phylogenies also exist. *Bainoceratops* may be synonymous with *Protoceratops*.

## Cultural significance

### Origin of griffin myths

Folklorist and historian of science Adrienne Mayor of Stanford University has suggested that the exquisitely preserved fossil skeletons of *Protoceratops* and other beaked dinosaurs, found by ancient Scythian nomads who mined gold in the Tian Shan and Altai Mountains of Central Asia, may have been at the root of the image of the mythical creature known as the griffin. Griffins were described as lion-sized quadrupeds with large claws and a raptor-bird-like beak; they laid their eggs in nests on the ground.

Greek writers began describing the griffin around 675 B.C., at the same time the Greeks first made contact with Scythian nomads. Griffins were described as guarding the gold deposits in the arid hills and red sandstone formations of the wilderness. The region of Mongolia and China where many *Protoceratops* fossils are found is rich in gold runoff from the neighboring mountains, lending some credence to the theory that these fossils were the basis of griffin myths.

In 2016 this hypothesis was contested by Mark Witton, as it ignores pre-Greek griffin art and accounts. Witton goes on to point out that the wings of traditional griffins are positioned above the shoulder blades, not behind the neck as the frills of *Protoceratops*, that the bodies of griffins much more closely resemble the bodies of modern big cats than they do those of *Protoceratops*, and that the gold deposits of central Asia occur hundreds of kilometers from the known *Protoceratops* fossil remains, among many other inconsistencies. It is simpler, he argues, to understand the griffin as a mythical combination of well-known extant animal species than as an ancient misunderstanding of fossilized collections of bones.

## Predators

*Protoceratops* had predators like *Velociraptor* to keep its numbers down. A famous fossil shows a lone *Velociraptor* take down a lone *Protoceratops*. The *Velociraptor* slashed the herbivore's throat while the *Protoceratops* bit the Dromaeosaurid's arm and broke it. Both are claimed to have been killed by a sandstorm right when they were about kill each other. This was a very famous fossil preserved until 1971 where it was unearthed by paleontologists.

## JPInstitute.com Description

This is the first ancestor of the famous ceratopsian family to look like the later, more famous members such as Triceratops. It was much smaller that its more famous relatives, but it was a very successful design that lasted many millions of years. Protoceratops didn't have horns to protect itself, just its sharp beak to bite with.

It is a fairly common fossil, one of the few dinosaurs for which a complete growth history can be seen in fossils ranging from infant to adult. Like other ceratopsian family members each individual shows a difference in the size and shape of its frill. Protoceratops frills were not solid and did not grow overly large. Some scientists believe that the frills may have been brightly colored for display, either to intimidate attackers or for courtship. There are some of this species that show a small horn on the snout. This is thought to be a gender differentiation.

One of the most famous fossils ever found is of a Velociraptor and a Protoceratops locked in battle. They were both killed in the midst of a fight. It is interesting to note that the species name, andrewsii, is for Roy Chapman Andrews. Mr. Andrews was a very adventurous fossil hunter; the movie character Indiana Jones is based on Andrews exploits.

## Links

http://web.archive.org/web/20040214165730fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_protoc.html#