Editing Protoceratops (section)

{{Short description|Genus of reptiles (fossil)}}
{{Use dmy dates|date=October 2024}}
{{Automatic taxobox
| fossil_range = [[Late Cretaceous]], ([[Campanian]]) ~{{fossil range|75|71}}
| image = Protoceratops-skeleton.jpg
| image_caption = Mounted ''P. andrewsi'' skeleton, [[Wyoming Dinosaur Center]]
| display_parents = 2
| taxon = Protoceratops
| authority = [[Walter W. Granger|Granger]] & [[W.K. Gregory|Gregory]], 1923
| type_species = {{extinct}}'''''Protoceratops andrewsi'''''
| type_species_authority = Granger & Gregory, 1923
| subdivision_ranks = Other species
| subdivision = 
* {{extinct}}'''''P. hellenikorhinus''''' <br><small>Lambert ''et al.'', 2001</small>
}}

'''''Protoceratops''''' ({{IPAc-en|ˌ|p|r|əʊ|t|oʊ|ˈ|s|ɛr|ə|t|ɒ|p|s}}; {{lit|first horned face}})<ref>{{cite book |last1=Colbert |first1=Edwin H. (Edwin Harris) |last2=Knight |first2=Charles Robert |title=The dinosaur book: the ruling reptiles and their relatives |date=1951 |publisher=McGraw-Hill |location=New York |page=153 |url=https://archive.org/details/bookruli00colb/page/152/mode/2up}}</ref> is a [[genus]] of small [[protoceratopsid]] dinosaurs that lived in Asia during the [[Late Cretaceous]], around 75 to 71 million years ago. The genus ''Protoceratops'' includes two species: '''''P. andrewsi''''' and the larger '''''P. hellenikorhinus'''''. The former was described in 1923 with fossils from the Mongolian [[Djadokhta Formation]], and the latter in 2001 with fossils from the Chinese [[Bayan Mandahu Formation]]. ''Protoceratops'' was initially believed to be an ancestor of [[ankylosauria]]ns and larger ceratopsians, such as ''[[Triceratops]]'' and relatives, until the discoveries of other protoceratopsids. Populations of ''P. andrewsi'' may have [[evolved]] into ''[[Bagaceratops rozhdestvenskyi]]'' through [[anagenesis]].

''Protoceratops'' were small ceratopsians, up to {{convert|2|-|2.5|m|ft|abbr=on}} long and around {{convert|62|-|104|kg|lb|abbr=on}} in body mass. While adults were largely [[quadrupedal]], juveniles had the capacity to walk around [[Facultative bipedalism|bipedally if necessary]]. They were characterized by a proportionally large [[skull]], short and stiff neck, and [[neck frill]]. The frill was likely used for [[Display (zoology)|display]] or [[intraspecific combat]], as well as [[protection]] of the neck and anchoring of jaw muscles. A horn-like structure was present over the nose, which varied from a single structure in ''P. andrewsi'' to a double, paired structure in ''P. hellenikorhinus''. The "horn" and frill were highly variable in shape and size across individuals of the same species, but there is no evidence of [[sexual dimorphism]]. They had a prominent parrot-like beak at the tip of the jaws. ''P. andrewsi'' had a pair of cylindrical, blunt [[teeth]] near the tip of the upper jaw. The forelimbs had five [[Digit (anatomy)|fingers]] of which only the first three bore wide and flat [[ungual]]s. The [[Pes (anatomy)|feet]] were wide and had four toes with flattened, shovel-like unguals, which would have been useful for [[Fossorial|digging]] through the sand. The hindlimbs were longer than the forelimbs. The tail was long and had an enigmatic [[Neural spine sail|sail]]-like structure, which may have been used for display, [[Aquatic locomotion|swimming]], or [[metabolic]] reasons.

''Protoceratops'', like many other ceratopsians, were [[herbivore]]s equipped with prominent jaws and teeth suited for chopping [[foliage]] and other plant material. They are thought to have lived in highly [[social behavior|sociable]] groups of mixed ages. They appear to have [[parental care|cared for their young]]. They laid soft-shelled [[egg]]s, a rare occurrence in dinosaurs. During maturation, the skull and neck frill underwent rapid growth. ''Protoceratops'' were hunted by ''[[Velociraptor]]'', and one particularly famous specimen (the [[Fighting Dinosaurs]]) preserves a pair of them locked in combat. ''Protoceratops'' used to be characterized as [[nocturnal]] because of the large [[sclerotic ring]] around the eye, but they are now thought to have been [[cathemeral]] (active at dawn and dusk).