page_title: Dilophosaurus
section_title: Formerly assigned species
hierarchical_section_title: Dilophosaurus / History of discovery / Formerly assigned species
caption_attribution_description: Italiano: Fossil of Sinosaurus, an extinct reptile- Took the picture at Muse (Trento)
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: In 1984, Welles suggested that the 1964 specimen (UCMP 77270) did not belong to Dilophosaurus, but to a new genus, based on differences in the skull, vertebrae, and femora. He maintained that both genera bore crests, but that the exact shape of these was unknown in Dilophosaurus. Welles died in 1997, before he could name this supposed new dinosaur, but the idea that the two were separate genera has generally been ignored or forgotten since. In 1999, amateur paleontologist Stephan Pickering privately published the new name Dilophosaurus "breedorum" based on the 1964 specimen, named in honor of Breed, who had assisted in collecting it. This name is considered a nomen nudum, an invalidly published name, and Gay pointed out in 2005 that no significant differences exist between D. "breedorum" and other D. wetherilli specimens. In 2012, Carrano and colleagues found differences between the 1964 specimen and the holotype specimen, but attributed them to variation between individuals rather than species. Paleontologists Christophe Hendrickx and Octávio Mateus suggested in 2014 that the known specimens might represent two species of Dilophosaurus based on different skull features and stratigraphic separation, pending thorough description of assigned specimens. Marsh and Rowe concluded in 2020 that there was only one taxon among known Dilophosaurus specimens, and that differences between them were due to their different degree of maturity and preservation. They did not find considerable stratigraphic separation between the specimens either.
  A nearly complete theropod skeleton (KMV 8701) was discovered in the Lufeng Formation, in Yunnan Province, China, in 1987. It is similar to Dilophosaurus, with a pair of crests and a gap separating the premaxilla from the maxilla, but differs in some details. The paleontologist Shaojin Hu named it as a new species of Dilophosaurus in 1993, D. sinensis (from Greek Sinai, referring to China). In 1998, the paleontologist Matthew C. Lamanna and colleagues found D. sinensis to be identical to Sinosaurus triassicus, a theropod from the same formation, named in 1940. This conclusion was confirmed by Chinese paleontologist Lida Xing and colleagues in 2013, and though  Chinese paleontologist Guo-Fu Wang and colleagues agreed the species belonged in Sinosaurus in 2017, they suggested it may be a separate species, S. sinensis.
caption: Reconstructed skeleton of Sinosaurus sinensis, which was originally described as a species of Dilophosaurus, Museo delle Scienze
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