page_title: Timeline of stegosaur research
section_title: 1990s
hierarchical_section_title: Timeline of stegosaur research / 20th century / 1990s
caption_attribution_description: Paleo Hall at HMNS
context_page_description: This timeline of stegosaur research is a chronological listing of events in the history of paleontology focused on the stegosaurs, the iconic plate-backed, spike-tailed herbivorous eurypod dinosaurs that predominated during the Jurassic period. The first scientifically documented stegosaur remains were recovered from Early Cretaceous strata in England during the mid-19th century. However, they would not be recognized as a distinct group of dinosaurs until Othniel Charles Marsh described the new genus and species Stegosaurus armatus in 1877, which he regarded as the founding member of the Stegosauria. This new taxon originally included all armored dinosaurs. It was not until 1927 that Alfred Sherwood Romer implemented the modern use of the name Stegosauria as specifically pertaining to the plate-backed and spike-tailed dinosaurs.
  From the time of their earliest description, the chief mystery surrounding stegosaurs was the function of their distinctive back plates. Marsh originally interpreted them as being plates of armor that would protect against predators. In 1910, Richard Swann Lull would agree with this hypothesis.
context_section_description: 1990
  Dong published the new genus and species name Monkonosaurus lawulacus but attributed it to Zhou.
  1991
  Dayton reported possible Early Cretaceous stegosaur footprints from Australia.
  1992
  Boneham and Forsey reported stegosaur armor and vertebrae from the Early Bajocian of England. These are among the oldest known stegosaur bones.
  1993
  Dong described the new species Wuerhosaurus ordosensis.
  1994
  Sara Metcalf and Rachel Walker reported a stegosaur tooth from the early Bajocian of England. It is among the oldest known stegosaur remains.
  1996
  José Fernando Bonaparte reported fragmentary Early Cretaceous stegosaur remains from Argentina.
  Bonaparte reported fragmentary Early Cretaceous stegosaur remains from Argentina.
  Sankar Chatterjee and Dhiraj Kumar Rudra argued that Dravidosaurus was actually a plesiosaur rather than a stegosaur.
  1997
  Chatterjee expanded on his argument that Dravidosaurus was actually a plesiosaur rather than a stegosaur.
  Thulborn reported possible Early Cretaceous stegosaur footprints from Australia.
  Tracy Popowics and Fortelius reported wear facets on stegosaur teeth caused by physical interactions between teeth.
  1998
  Paul Sereno proposed a stem-based definition of Stegosauria that included all taxa more closely related to Stegosaurus than to Ankylosauria.
  Kenneth Carpenter disputed Bakker's reinterpretation of Stegosaurs as high browsers. He argued that the plates along the animal's tail made it too rigid to be used as the third "leg" of the tripodal stance needed to support it in the rearing posture Bakker imagined stegosaurs adopted to reach high foliage. He noted that the first vertebra in the tail had a wedge shape that fit under a backward-facing projection of bone from the top of the last vertebra in the pelvis. This configuration would have held the tail out straight from the animal's body. Its other tail vertebrae show anatomical evidence for ligaments that would have assisted in keeping the tail aloft. Carpenter concluded that while the plates limited the mobility between individual vertebrae, the tail itself had enough range of motion to swing its spiked tip to an angle exceeding ninety degree from a resting position.
  1999
  Sereno continued to use the stem-based definition of Stegosauria he proposed in 1998.
  Jean Le Loeuff and others reported some fossil footprints from France that may have been left behind by stegosaurs. As these tracks date back to the Hettangian, they may represent the oldest known stegosaur fossils.
  Wolf-Dieter Heinrich observed that stegosaur bones were common in Quarry X at Tendaguru, Tanzania. He interpreted the deposit as resulting from the gradual accumulation of remains in a fresh-to-brackish water environment.
  Stephen Czerkas argued that the beak near the front of the jaws of stegosaurs like Chungkingosaurus, Kentrosaurus, and Stegosaurus actually extended along the entire length of the jaw, like in turtles.
  Galton argued that stegosaurs were sexually dimorphic and the females had extra rib in their sacra.
caption: Dravidosaurus may have actually been a plesiosaur.
exif: {"Image Make": "Sony", "Image Model": "C6606", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "10.1.1.B.0.166_3_f600", "Image DateTime": "2013:08:22 15:18:15", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "216", "Image GPSInfo": "628", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "740", "Thumbnail JPEGInterchangeFormatLength": "4718", "EXIF ExposureTime": "1/25", "EXIF FNumber": "12/5", "EXIF ISOSpeedRatings": "1000", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2013:08:22 15:18:15", "EXIF DateTimeDigitized": "2013:08:22 15:18:15", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "116/25", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "CenterWeightedAverage", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "41/10", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3920", "EXIF ExifImageLength": "2204", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "598", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard", "EXIF SubjectDistanceRange": "0"}