page_title: Ichthyosaur
section_title: Twentieth century
hierarchical_section_title: Ichthyosaur / History of discoveries / Twentieth century
caption_attribution_description: English: Precious opal replacing Ichthyosaur backbone; display specimen, South Australian Museum. Original filename = P2211104.JPG
context_page_description: Ichthyosaurs are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia. Ichthyosaurs lived during the time of the dinosaurs, but formed a separate group from the dinosaurs and may not have been closely related to them.
  Ichthyosaurs thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago and at least one species survived until about 90 million years ago, into the Late Cretaceous. During the early Triassic period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea, in a development similar to how the mammalian land-dwelling ancestors of modern-day dolphins and whales returned to the sea millions of years later, which they gradually came to resemble in a case of convergent evolution. Ichthyosaurs were particularly abundant in the later Triassic and early Jurassic periods, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous periods. In the Late Cretaceous, ichthyosaurs were hard hit by the Cenomanian-Turonian anoxic event.
context_section_description: In the early 20th century, ichthyosaur research was dominated by the German paleontologist Friedrich von Huene, who wrote an extensive series of articles, taking advantage of an easy access to the many specimens found in his country. The amount of anatomical data was hereby vastly increased. Von Huene also travelled widely abroad, describing many fossils from locations outside of Europe. During the 20th century, North America became an important source of new fossils. In 1905, the Saurian Expedition led by John Campbell Merriam of the University of California and financed by Annie Montague Alexander, found 25 specimens in central Nevada, which were under a shallow ocean during the Triassic. Several of these are now in the collection of the University of California Museum of Paleontology. Other specimens are embedded in the rock and visible at Berlin–Ichthyosaur State Park in Nye County. In 1977, the Triassic ichthyosaur Shonisaurus became the state fossil of Nevada. Nevada is the only state to possess a skeleton of this 17-metre-long (56 ft) extinct marine reptile. In 1992, Canadian ichthyologist Dr. Elizabeth Nicholls (curator of marine reptiles at the Royal Tyrrell Museum) uncovered the largest known specimen, a 23-metre-long (75 ft) example, though this larger specimen was later reclassified as the related Shastasaurus.
  After a slack during the middle of the century, with no new genera being named between the 1930s and the 1970s, the rate of discoveries picked up towards its end. About half of the ichthyosaur genera today seen as valid were described after 1990. The new finds have allowed a gradual improvement in knowledge about the anatomy and physiology of what had already been seen as rather advanced "Mesozoic dolphins". Christopher McGowan published a larger number of articles and also brought the group to the attention of the general public. The new method of cladistics provided a means to exactly calculate the relationships between groups of animals, and in 1999, Ryosuke Motani published the first extensive study on ichthyosaur phylogenetics. In 2003, McGowan and Motani published the first modern textbook on the Ichthyosauria and their closest relatives.
  In June 2020, an article was accepted about a new species of Hauffiopteryx from the southwest German basin. It is a valid genus, defined by a set of synapomorphies from both the skull and postcranium.
caption: Precious opal replacing ichthyosaur backbone, display specimen, South Australian Museum
exif: {"Image ImageDescription": "OLYMPUS DIGITAL CAMERA", "Image Make": "OLYMPUS IMAGING CORP.", "Image Model": "E-P3", "Image Orientation": "Horizontal (normal)", "Image XResolution": "314", "Image YResolution": "314", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Version 1.3", "Image DateTime": "2014:02:21 15:02:13", "Image Artist": "", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "218", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 37, 0, 1, 0, 20, 0, ... ]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "314", "Thumbnail YResolution": "314", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "13588", "Thumbnail JPEGInterchangeFormatLength": "3274", "EXIF ExposureTime": "1/60", "EXIF FNumber": "7/2", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2014:02:21 15:02:13", "EXIF DateTimeDigitized": "2014:02:21 15:02:13", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "925/256", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash fired, auto mode", "EXIF FocalLength": "14", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "4032", "EXIF ExifImageLength": "3024", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "686", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal"}