page_title: 20th century in ichnology
section_title: 1990s
hierarchical_section_title: 20th century in ichnology / 1990s
caption_attribution_description: Physico-geographical regionalization of Poland Mezoregion 342.34-5 Holy Cross Mountains Regionalizacja fizycznogeograficzna Polski Mezoregion 342.34-5 Góry Świętokrzyskie
context_page_description: The 20th century in ichnology refers to advances made between the years 1900 and 1999 in the scientific study of trace fossils, the preserved record of the behavior and physiological processes of ancient life forms, especially fossil footprints. Significant fossil trackway discoveries began almost immediately after the start of the 20th century with the 1900 discovery at Ipolytarnoc, Hungary of a wide variety of bird and mammal footprints left behind during the early Miocene. Not long after, fossil Iguanodon footprints were discovered in Sussex, England, a discovery that probably served as the inspiration for Sir Arthur Conan Doyle's The Lost World.
  Several enduring mysteries from the 19th century continued to vex ichnologists, like the identity of the Chirotherium trackmaker. Renowned paleontologist Franz von Nopcsa attributed the ichnogenus to the prosauropod dinosaur Plateosaurus, despite an apparent mismatch between its number of toes and the preserved digit traces of Chirotherium. Von Nopcsa explained the discrepancy by arguing that one of the impressions in the Chirotherium tracks was left by a soft tissue structure that did not fossilize.
context_section_description: 1990
  Ryszard Fuglewicz and others reported fossil trackways from the Holy Cross Mountains of Poland that may be the oldest Triassic trackways in Europe. They reported tracksites at six different positions within a stratigraphic series in several distinct paleoenvironments including river channels and floodplains. The ichnogenera they identified in these tracksites included Brachychirotherium, Capitosauroides, Isochirotherium, Rhynchosauroides, and Synaptichnium.
  Demathieu reported the presence of dinosaur tracks at Saint-Leons and Saint-Laurent de Tives in the Causses region of France.
  Lockley disputed claims that some sauropod tracks were left underwater by swimming trackmakers.
  1991
  A track site containing more than 250 fossil bird footprints was discovered ear Villar del Rio, Spain.
  Robison reported shorebird footprints in the Cretaceous Mesa Verde Group of Utah. He also reported the presence of the oldest known frog tracks.
  Lockley argued that the supposed sauropod tracks reported by Ensom from the Purbeck Beds of Dorset, England were actually made by ankylosaurs.
  Lockley described the Moab megatracksite.
  1992
  C. Lancis and A. Estevez reported the presence of early Pliocene tracks preserved near Alicante, Spain. Among the mammals who left their mark here were members of the horse family and bears.
  Farlow observed that sauropod trackways could be categorized as either being "narrow-gauge" or "wide-gauge".
  Mid November: Lockley and Hunt's research group at the University of Colorado undertook one of the few major dinosaur footprint excavations in history in order to expand the exposed track-bearing surface at Dinosaur Ridge for an outdoor interpretive center.
  May 3rd: The Seattle Times reported the discovery of a potential Diatryma track in the Eocene Puget Group of Flaming Geyser State Park, Washington.
  Lockley and Madsen published ichnological evidence for the predation of large reptiles on smaller animals during the Permian period.
  1993
  Lockley and dos Santos described the Kimmeridgian-aged Avelino quarry tracksite near Lisbon, Portugal, the first scientifically documented sauropod dinosaur tracksite in Europe to contain well-preserved tracks of the animals' front feet. All of the trackmakers seem to have been juveniles.
  Meyer reported the first scientifically documented Late Jurassic dinosaur footprints from Switzerland. These tracks were discovered near the town of Lommiswil.
  Claude Guerin and George Demathieu described the new ichnospecies Dicerotichnus laetoliensis. This ichnospecies was left behind by a late Pliocene rhinoceros of fairly modern build, possibly from the genus Diceros. Its tracks are preserved at the same site known for its ancient hominid tracks.
  A non-technical article in the Spanish magazine Blanco y Negro discussed the wide variety of Miocene tracks preserved at Salinas de Anana, Spain.
  Lockley and Hunt introduced the idea of ichnofacies to the scientific literature. They described and named the Brontopodus ichnofacies based on sauropod tracksites in Texas.~NA210~
  A new tracksite was discovered in Toadstool Park area of Nebraska's Oglala National Grassland. Eleven different trackmakers have been documented here, including camels, carnivorans, ducks, rhinoceroses, and shorebirds.
  Late: An expansive Late Triassic dinosaur tracksite was discovered at the Pennsylvania State Correctional Institution in Graterford.
  1994
  Lockley and others argued that Deltapodus was probably not left by a sauropod because the hind prints had only three toes and the tracks themselves were preserved in an environment where sauropod tracks are not generally found.~135~ Instead they concluded it was more likely to be the tracks of a thyreophoran, possibly a stegosaur.
  A cave enthusiast near Fatima, Portugal looked down on a quarry from a high ridge and noticed that its floor was covered in sauropod footprints. The site included the longest known dinosaur trails at the time. The individual tracks are the largest sauropod prints known from the Middle Jurassic and include the largest foreprints of any known sauropod track 
caption: Location of the Holy Cross Mountains in Poland
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