page_title: Timeline of ceratopsian research
section_title: 2000s
hierarchical_section_title: Timeline of ceratopsian research / 21st century / 2000s
caption_attribution_description: Liaoceratops yanzigouensis, a ceratopsian from the Early Cretaceous of China, pencil drawing, digital coloring
context_page_description: This timeline of ceratopsian research is a chronological listing of events in the history of paleontology focused on the ceratopsians, a group of herbivorous marginocephalian dinosaurs that evolved parrot-like beaks, bony frills, and, later, spectacular horns. The first scientifically documented ceratopsian fossils were described by Edward Drinker Cope starting in the 1870s; however, the remains were poorly preserved and their true nature was not recognized. Over the next several decades, Cope named several such genera and species. Cope's hated rival, Othniel Charles Marsh, also described ceratopsian remains. In 1887, Marsh mistook a Triceratops horn for one belonging to a new species of prehistoric Bison. Marsh also named the eponymous genus Ceratops in 1888. The next year, he named the most famous ceratopsian, Triceratops horridus. It was the discovery of Triceratops that illuminated the ceratopsian body plan, and he formally named the Ceratopsia in 1890.
  The early 20th century was a fruitful time for ceratopsian research. In 1907, Hatcher and others published a monograph on ceratopsid anatomy that is still considered the single most significant publication on the topic to date.
context_section_description: 2000
  Paul and Christiansen studied ceratopsid forelimbs and concluded that in life the animal probably stood with its elbows slightly everted but with its forelimbs otherwise erect. They also concluded that ceratopsians had faster running speeds than modern elephants and were able to gallop.
  Sereno described the new genus and species Graciliceratops mongoliensis.
  Lambert and others described the new species Protoceratops hellenikorhinus.
  Shuvalov reported Psittacosaurus fossils from near the Berriasian-Valanginian boundary in the Sangiin Dala Nuur depression. Most Psittacosaurus fossils date to an age closer to the Barremian-Aptian boundary.
  Erickson and Tumanova reported Psittacosaurus mongoliensis fossils from Khamaryn Us in Mongolia that ranged from 0.9 kg juveniles to 19.9 kg adults. They found that it took 9 years for a Psittacosaurus to become fully grown. To reach that size in that time frame it must have grown at a rate of 12.5 grams per day. This is four times faster than modern reptiles and 25% faster than modern marsupials. However it is only three to twenty times as slow as modern eutherian mammals and birds.
  Weishampel and others reported the presence of fifteen Protoceratops hatchlings from a single nest in an Aeolian sandstone deposit in the central Gobi Desert.
  2001
  Tang and others dated Psittacosaurus mazongshanensis to near the Barremian-Aptian boundary based on fossil pollen and spores.
  Witmer studied the nasal passages of ceratopsids. He found that the nasal vestibule of cerastopsids is complex and may have helped regulate the animal's body temperature through its effect on inhaled air.
  Tereshchenko reported that Protoceratops andrewsi had sexual dimorphism in its body in addition to its head.
  Lambert and others reported sexual dimorphism in Protoceratops hellenikorhinus.
  Holmes and others found that the two Chasmosaurus species argued to be valid by Godfrey and Holmes are found at different positions within the stratigraphic column of the Dinosaur Park Formation. This finding bolstered the idea that these species were distinct after all. They also described a new species, Chasmosaurus irvinensis, which was discovered in Dinosaur Park Formation rocks deposited more recently than either previously described Chasmosaurus species.
  Peter J. Makovicky formally described the braincase attributed to the small ceratopsian dinosaur Montanoceratops cerorhynchus. This specimen is currently cataloged as AMNH 5244. Makovicky found that it shares anatomical features with Leptoceratops gracilis. The shared features between the two taxa's braincases contradicts previous phylogenetic studies which had suggested that they were not closeley related. M. cerorhynchus had been previously known from the contemporary St. Mary River Formation and Makovicky's referral of AMNH 5224 to the species expanded its known paleobiogeographic range. Makovicky performed a phylogenetic analysis to clarify the relationship between ceratopsian in the light of the new braincase data. Makovicky concluded from his analysis that at least three dispersal events from Asia to North America are required to explain the paleobiogeography of neoceratopsians. The patterns of distribution and dispersal are similar to those found in other contemporary taxa like oviraptorosaurs, troodonts, and multituberculate mammals.
  2002
  Swisher and others dated the Psittacosaurus fossils of the Yixian Formation to near the Barremian-Aptian boundary based on Argon-Argon radiometric dating.
  Xu and others described the new genus and species Liaoceratops yangzigouensis.
  Makovicky re-examined the type specimen of Turanoceratops. Nessov had claimed that this genus was a ceratopsid because it had horns and teeth with two roots, but Makovicky found that the teeth were single rooted after all and the supposed eye-horn may actually have come from and armored dinosaur. Since it had no good distinguishing traits, Makovicky regarded the genus as dubious.
  2003
  Tereschenko and Alifanov described the new genus and species Bainoceratops efremovi.
  Alifanov described the new genus and s
caption: Artistic restoration of Liaoceratops
exif: {}