- The Paleontological Society
Ossified clavicles, either as paired elements or as a median furcula, have been recorded in all major clades of dinosaurs, including ornithischians, sauropodomorphs, and theropods (Bryant and Russell, 1993). Nearly all but the most basal theropods, Eoraptor lunensis and Herrerasaurus ischigualastensis, have an ossified furcula including coelophysids (Downs, 2000; Tykoski et al., 2002; Carrano et al., 2005), allosauroids (Chure and Madsen, 1996), tyrannosaurids (Makovicky and Currie, 1998; Larson and Donnan, 2002; Brochu, 2003; Lipkin and Sereno, 2004; Larson and Rigby, 2005), therizinosaurids (Xu et al., 1999a; Zhang et al., 2001), oviraptorids (Barsbold, 1983; Clark et al., 1999, 2001; Hwang et al., 2002; Osmólska et al., 2004), troodontids (Xu and Norell, 2004), and dromaeosaurids (Norell et al., 1997; Norell and Makovicky, 1999; Xu et al., 1999b; Burnham et al., 2000; Hwang et al., 2002). No ossification of any element beyond the coracoid has been found in the pectoral girdle of the well-preserved primitive theropods, Eoraptor lunensis and Herrerasaurus ischigualastensis.
Although the furcula in tyrannosaurids has been described in several genera (Makovicky and Currie, 1998), the bone has never been found in articulation in any species, and controversy has surrounded the form of the furcula in Tyrannosaurus rex (Larson and Donnan, 2002; Brochu, 2003). We describe the furcula in the spinosaurid, Suchomimus tenerensis, which aids in establishing the basal condition of this bone for tetanuran theropods. We then describe furculae in Tyrannosaurus rex, one of which is preserved in articulation and others of which highlight important variation.
The specimens in this study are housed in the Children's Museum of Indianapolis (CMI), Field Museum (FMNH), Musée National du Niger (MNN), Museum of the Rockies (MOR), and the University of Chicago Research Collection …