page_title: Timeline of therizinosaur research
section_title: 2000s
hierarchical_section_title: Timeline of therizinosaur research / 21st century / 2000s
caption_attribution_description: English: Falcarius skeletal cast, detail of chest region, on display at the Natural History Museum of Utah, Salt Lake City.
context_page_description: The timeline of therizinosaur research is a chronological listing of events in the history of paleontology focused on therizinosaurs. They were unusually long-necked, pot-bellied, and large-clawed herbivorous theropods most closely related to birds. The early history of therizinosaur research occurred in three phases. The first phase was the discovery of scanty and puzzling fossils in Asia by the Central Asiatic Expeditions of the 1920s and Soviet-backed research in the 1950s. This phase resulted in the discovery of the Therizinosaurus cheloniformis type specimen. Soviet paleontologist Evgeny Maleev interpreted these unusual remains as belonging to some kind of gigantic turtle.
  The second major phase of therizinosaur research followed the discovery of better preserved remains in the 1970s by collaborative research between the Soviets and Mongolians. These finds revealed the true nature of therizinosaurs as bizarre dinosaurs. However, the exact nature and classification of therizinosaurs within Dinosauria was controversial as was their paleobiology.
context_section_description: 2000
  Manning and others observed that the embryos identified by Currie in 1996 as therizinosaurian had "an unusual pattern of tooth replacement in which a slender, elongate tooth is replaced by a symmetrical, denticulate tooth". Contrary to Carpenter's claim in 1999, Manning and his colleagues reported the embryos premaxillae as toothless.
  2001
  Xu, Zhao, and Clark described the new genus and species Eshanosaurus deguchiianus based on the Early Jurassic dentary. This species was the probably oldest known therizinosaur.
  Kirkland and Wolfe described the new genus and species Nothronychus mckinleyi. This was the first definitive therizinosaurid discovered outside of Asia. They also found that Eshanosaurus had a similar dentition to prosauropods.
  Zhang and others described the new genus and species Neimongosaurus yangi.
  2002
  Xu and others described the new genus and species Erliansaurus bellamanus.
  2004
  Kirkland and colleagues briefly reported and described primitive remains of therizinosaurs found in Utah.
  The same team made comparisons with braincases found among the remains and that of Nothronychus mckinleyi.
  Lindsay Zanno continue with these short descriptions but this time focused on forelimb elements.
  Zanno discussed in more detail these elements in her Ph.D.
  2005
  Kirkland and others described the primitive new genus and species Falcarius utahensis based on the multiple remains previously described.
  2006
  Zanno and Erickson briefly discussed the growth of Falcarius which was represented by adult and juvenile specimens.
  Zanno formally published and described the pectoral anatomy of Falcarius.
  Bursh reported the inferred range of motion in the therizinosaurids Neimongosaurus, which was very pronounced and circular.
  Sennikov re-examined Macropodosaurus and concluded that a therizinosaurid-grade dinosaur made those tracks, suggesting a possible plantigrade stance. He also considered these tracks to be more associated with therizinosaurids.
  2007
  Li and others described the new genus and species Suzhousaurus megatherioides.
  Kundrát with colleagues described in detail the embryos from the Nanchao Formation.
  2008
  A new specimen of Suzhousaurus was described by Li and colleagues.
  Lee and colleagues reported new therizinosaurid specimens composed of partially complete skeletons collected from the Nemegt Formation.
  2009
  Zanno and colleagues described the newer N. graffami, a second and more complete species of the genus Nothronychus.
  Barrett considered that the controversial Eshanosaurus was a therizinosaur taxon.
caption: Pectoral girdle of Falcarius
exif: {"Image ImageDescription": "", "Image Make": "SONY", "Image Model": "DSC-RX100M2", "Image Orientation": "Horizontal (normal)", "Image XResolution": "350", "Image YResolution": "350", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "DSC-RX100M2 v1.00", "Image DateTime": "2015:10:25 20:32:36", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "290", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 2, 0, 2, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail ImageDescription": "", "Thumbnail Make": "SONY", "Thumbnail Model": "DSC-RX100M2", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail Software": "DSC-RX100M2 v1.00", "Thumbnail DateTime": "2015:10:25 20:32:36", "Thumbnail JPEGInterchangeFormat": "26860", "Thumbnail JPEGInterchangeFormatLength": "9931", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/15", "EXIF FNumber": "9/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "800", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "800", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2015:10:25 20:32:36", "EXIF DateTimeDigitized": "2015:10:25 20:32:36", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "2", "EXIF BrightnessValue": "-577/320", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "217/128", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "52/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "5472", "EXIF ExifImageLength": "3648", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "26564", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "28", "EXIF SceneCaptureType": "Standard", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF LensSpecification": "[52/5, 371/10, 9/5, 49/10]"}