Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution

By N. Smith, P. Makovicky, W. R. Hammer, P. Currie. 2007

179 citations recorded by the source corpus.

Department of Biological Sciences, University of Alberta, CW 405 Biological Sciences Centre, Edmonton, Alberta, CanadaReceived March 2005; accepted for publication March 2007Cryolophosaurus ellioti Hammer and Hickerson, 1994, from the Early Jurassic Hanson Formation of the CentralTransantarctic Mountains, represents a theropod dinosaur from a period of time and geographical area that arepoorly sampled with respect to dinosaur taxa. An in-depth morphological description of Cryolophosaurus is pre-sented here, along with a rigorous phylogenetic analysis of theropod relationships consisting of 347 characters and56 taxa, in an attempt to clarify the relationships of Cryolophosaurus and to provide insight into questions sur-rounding early theropod evolution. Cryolophosaurus is characterized by a unique cranial crest, formed primarily bythe lacrimals, a pronounced constriction of the squamosal and jugal bones across the infratemporal fenestra, andextremely elongate cranial processes on the cervical ribs. Several shared characters, including the presence of a slot-shaped foramen at the base of the nasal process of the premaxilla, nasolacrimal crests and erect tab-like dorsal pro-cesses on the articular, suggest afﬁnities between Cryolophosaurus and a clade of medium-bodied Early Jurassictheropods that includes ‘Dilophosaurus’ sinensis, Dracovenator regenti and Dilophosaurus wetherilli. This clade isrecovered as sister-taxon to a Neoceratosauria + Tetanurae clade, rendering both a traditional Coelophysoidea andCeratosauria non-monophyletic. Cryolophosaurus represents the largest known Early Jurassic theropod, and marksthe beginning of theropod occupation of the dominant predator niche in the Mesozoic. © 2007 The Linnean Societyof London, Zoological Journal of the Linnean Society, 2007, 151, 377–421.

Subfields: Nature and Landscape Conservation, Paleontology

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Citations in the corpus

Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs (2012, background): “posteriorly projecting spikes (Welles 1984), while in the remarkable Cryolophosaurus an anteriorly facing, comb-like crest rises from the supraorbital region (Smith et al. 2007).”
Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica (2007, background): “…collected with the sauropodomorph fossils include the relatively complete theropod dinosaur Cryolo− phosaurus ellioti (Hammer and Hickerson 1994; Smith et al. 2007), pelvic material from a possible sauropod dinosaur, a pterosaur humerus, and the tooth of a large tritylodont (Ham− mer and…”
A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic (2016, background): “The stem lineage of Averostra might have included yet another distinct clade, the dilophosaurids (Smith et al., 2007; Ezcurra, 2012; Holtz, 2012; Langer et al., 2014), the monophyly of which is debated (see Brusatte et al.”
A Review of Dromaeosaurid Systematics and Paravian Phylogeny (2012, methodology): “Rauhut (2003) and Smith et al. (2007) found Coelurus as more closely related to compsognathids than to other coelurosaurs, whereas Senter (2007) found Coelurus plus Tanycolagreus topwilsoni (Carpenter et al., 2005) as the sister group to Tyrannosauroidea.”
A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods (2010, methodology): “Smith et al. (2007) recovered Megaraptor in a polytomy with Carcharodontosaurus and Giganotosaurus on the basis of the number and orientation of the cervical pleurocoels, the presence of a marked prezygapophyseal–epipophyseal lamina, the presence of a hyposphene/hypantrum-like articulation in the…”
The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades (2011, methodology): “24) (Rauhut, 1997, 2003; Hwang et al., 2004; Smith et al., 2007).”
Evaluating hypotheses for the early diversification of dinosaurs (2010, background): “A variety of detailed phylogenetic studies have focused on basal dinosaurs, clarifying understanding of the early evolutionary history of these groups (Smith et al. 2007; Yates 2007a, b; Butler et al. 2008; Irmis 2008; Nesbitt et al. 2009b, 2010).”
The phylogeny of Tetanurae (Dinosauria: Theropoda) (2012, methodology): “Allosauridae exists only as Allosaurus + Saurophaganax, the sister lineage to Carcharodontosauria (Carcharodontosauridae + Neovenatoridae).”
Splendid and Seldom Isolated: The Paleobiogeography of Patagonia (2013, background): “Similarly, Piatnitzkysaurus and Condorraptor have been interpreted as basal forms of a rapid global radiation of tetanurans during the Middle Jurassic (Benson 2010, Carrano et al. 2012), but some studies maintain that they form a basal clade restricted to South America (Smith et al. 2007).”
Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida) (2010, unknown): “2004); Dinosauria (Langer & Benton 2006; Butler et al .”
A juvenile specimen of a new coelurosaur (Dinosauria: Theropoda) from the Middle–Late Jurassic Shishugou Formation of Xinjiang, People's Republic of China (2014, background): “2010b) and recent publications on theropod systematics (e.g. Rauhut 2003a; Senter 2007; Smith et al. 2007; Carrano & Sampson 2008; Benson et al. 2010b).”
The origin and early radiation of dinosaurs (2010, background): “The phylogenetic analysis of Smith et al. (2007) recovered a monophyletic “dilophosaurid” clade consisting of several medium-large-bodied Early Jurassic theropods, including Dilophosaurus (Fig.”