Dilophosaurus wetherelli ( Welles, 1954 )

Nesbitt, Sterling J., 2011, The Early Evolution Of Archosaurs: Relationships And The Origin Of Major Clades, Bulletin of the American Museum of Natural History 2011 (352), pp. 1-292 : 56

Dilophosaurus wetherelli ( Welles, 1954) , sensu Welles, 1970 5 Megalosaurus wetherelli Welles, 1954

AGE: Simmurian, Early Jurassic ( Peterson and Pipiringos, 1979).

OCCURRENCE: Lower portion of the silty facies of the Kayenta Formation, Moenkopi Wash, northern Arizona ( Welles, 1984).

HOLOTYPE: UCMP 37302, nearly complete skeleton.

REFERRED MATERIAL: UCMP 37303, premaxilla, maxilla, mandibles, vertebrae, articulated manus; TMM material figured by Tykoski (2005a).

REMARKS: Dilophosaurus is one of the best-known early theropods and is known from a variety of material housed at UCMP, TMM, and MNA. All material referable to the taxon originated from the silty facies of the Kayenta Formation on Ward’s Terrace. Basal theropod phylogenies placed Dilophosaurus as either the basalmost coelophysoid ( Gauthier, 1986; Rowe, 1989; Rowe and Gauthier, 1990; Tykoski and Rowe, 2004) or closer to the tetanurans than to coelophysoids ( Rauhut, 2003; Smith et al., 2007; Yates, 2007) in a clade containing Dracovenator , Zupaysaurus , and ‘‘ Dilophosaurus ’’ sinensis.

Rauhut (2003) listed the following autapomorphies for Dilophosaurus : lacrimal with thickened dorsoposterior rim; cervical neural spines with distinct central ‘‘cap’’; an anterior and posterior ‘‘shoulder’’; scapular blade with squared distal margin.

KEY REFERENCES: Welles, 1954, 1970, 1984; Rauhut, 2003.