page_title: Dilophosaurus
section_title: Ichnology
hierarchical_section_title: Dilophosaurus / Ichnology
caption_attribution_description: Français&#160;: Traces de Dilophosaurus relevées sur le site de Glen Canyon National Recreation Area. Arizona, USA English: Dilophosaurus footprint in Glen Canyon National Recreation Area. Arizona, USA
context_page_description: Dilophosaurus is a genus of theropod dinosaurs that lived in what is now North America during the Early Jurassic, about 193 million years ago. Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942. The most complete specimen became the holotype of a new species in the genus Megalosaurus, named M. wetherilli by Samuel P. Welles in 1954. Welles found a larger skeleton belonging to the same species in 1964. Realizing it bore crests on its skull, he assigned the species to the new genus Dilophosaurus in 1970, as Dilophosaurus wetherilli. The genus name means "two-crested lizard", and the species name honors John Wetherill, a Navajo councilor. Further specimens have since been found, including an infant. Footprints have also been attributed to the animal, including resting traces. Another species, Dilophosaurus sinensis from China, was named in 1993, but was later found to belong to the genus Sinosaurus.
  At about 7 m in length, with a weight of about 400 kg, Dilophosaurus was one of the earliest large predatory dinosaurs and the largest known land-animal in North America at the time.
context_section_description: Various ichnotaxa (taxa based on trace fossils) have been attributed to Dilophosaurus or similar theropods. In 1971, Welles reported dinosaur footprints from the Kayenta Formation of northern Arizona, on two levels 14 m (45 ft) and 112 m (367 ft) below where the original Dilophosaurus specimens were found. The lower footprints were tridactyl (three-toed), and could have been made by Dilophosaurus; Welles created the new ichnogenus and species Dilophosauripus williamsi based on them, in honor of Williams, the discoverer of the first Dilophosaurus skeletons. The type specimen is a cast of a large footprint catalogued as UCMP 79690-4, with casts of three other prints included in the hypodigm. In 1984, Welles conceded that  no way had been found to prove or disprove that the footprints belonged to Dilophosaurus. In 1996, the paleontologists Michael Morales and Scott Bulkey reported a trackway of the ichnogenus Eubrontes from the Kayenta Formation made by a very large theropod. They noted it could have been made by a very large Dilophosaurus individual, but found that unlikely, as they estimated the trackmaker would have been 2.83–2.99 m (9 ft 3 ¹⁄₂ in–9 ft 9 ³⁄₄ in) tall at the hips, compared to the 1.50–1.75 m (4 ft 11 in–5 ft 9 in) of Dilophosaurus.
   
  The paleontologist Gerard Gierliński examined tridactyl footprints from the Holy Cross Mountains in Poland and concluded in 1991 that they belonged to a theropod like Dilophosaurus. He named the new ichnospecies Grallator (Eubrontes) soltykovensis based on them, with a cast of footprint MGIW 1560.11.12 as the holotype. In 1994 Gierliński also assigned footprints from the Höganäs Formation in Sweden discovered in 1974 to G. (E.) soltykovensis. In 1996, Gierliński attributed track AC 1/7 from the Turners Falls Formation of Massachusetts, a resting trace he believed to show feather impressions, to a theropod similar to Dilophosaurus and Liliensternus, and assigned it to the ichnotaxon Grallator minisculus. The paleontologist Martin Kundrát agreed that the track showed feather impressions in 2004, but this interpretation was disputed by the paleontologist Martin Lockley and colleagues in 2003 and the paleontologist Anthony J. Martin and colleagues in 2004, who considered them as sedimentological artifacts. Martin and colleagues also reassigned the track to the ichnotaxon Fulicopus lyellii.
  The paleontologist Robert E. Weems proposed in 2003 that Eubrontes tracks were not produced by a theropod, but by a sauropodomorph similar to Plateosaurus, excluding Dilophosaurus as a possible trackmaker. Instead, Weems proposed Kayentapus hopii, another ichnotaxon named by Welles in 1971, as the best match for Dilophosaurus. The attribution to Dilophosaurus was primarily based on the wide angle between digit impressions three and four shown by these tracks, and the observation that the foot of the holotype specimen shows a similarly splayed-out fourth digit. Also in 2003,  American paleontologist Emma Rainforth argued that the splay in the holotype foot was merely the result of distortion, and that Eubrontes would indeed be a good match for Dilophosaurus. The paleontologist Spencer G. Lucas and colleagues stated in 2006 that  virtually universal agreement existed that Eubrontes tracks were made by a theropod like Dilophosaurus, and that they and other researchers dismissed Weems' claims.
  In 2006, Weems defended his 2003 assessment of Eubrontes, and proposed an animal like Dilophosaurus as the  possible trackmaker of numerous Kayentapus trackways of the Culpeper Quarry in Virginia. Weems suggested rounded impressions associated with some of these trackways to represent hand impressions lacking digit traces, which he interpreted as a trace of quadrupedal movement. In 2009, the paleontologists Andrew R. C. Milner and colleagues used the new combination Kayentapus soltykovensis, and suggested that Dilophosauripus may not be distinct from Eubrontes and Kayentapus. They suggested that the long claw marks that were used to distinguish Dilophosauripus may be an artifact of dragging. They found that G
caption: Attributed footprints in Glen Canyon National Recreation Area, Arizona
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