page_title: Timeline of ceratopsian research
section_title: 1900s
hierarchical_section_title: Timeline of ceratopsian research / 20th century / 1900s
caption_attribution_description: Centrosaurus apertus specimen ROM 767. Exhibit in the Royal Ontario Museum, Toronto, Ontario, Canada. This exhibit is old enough so that it is in the public domain, and photography was permitted in the museum. I took this photograph and release it into the public domain.
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: 1901
  William Temple Hornaday discovered some Triceratops fossils in Montana. These were the first Triceratops fossils to ever be discovered in the Hell Creek Formation.
  1902
  Lawrence Lambe described the new species Monoclonius dawsoni.
  Lambe described the new species Monoclonius belli.
  Lambe described the new species Monoclonius canadensis.
  Barnum Brown and Richard Swann Lull set out to excavate the Triceratops discovered by Hornaday.
  1904
  Lambe described the new genus and species Centrosaurus apertus.
  A skeletal mount for Triceratops was designed for the United States National Museum of Natural History. This was the first skeletal mounts of any ceratopsid constructed for a museum.
  1905
  Richard Swann Lull described the new genus and species Diceratops hatcheri.
  John Bell Hatcher described the new species Triceratops brevicornus.
  1907
  Hatcher and others published a monograph on ceratopsids. This publication has been regarded as the first comprehensive study on ceratopsids and was still regarded as "the most valuable single reference on ceratopsid anatomy" nearly a century later. The researchers classified ceratopsids into two main groups. One consisted of Monoclonius, Triceratops, and their relatives and the other consisted of Ceratops, Torosaurus and their relatives.
  1908
  Lull interpreted ceratopsid frills as sites for the attachment of enlarged jaw muscles.
caption: Centrosaurus apertus specimen ROM 767 on exhibit in the Royal Ontario Museum, Toronto, Canada
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