Suchomimus tenerensis

Christine Lipkin, Paul C. Sereno & John R. Horner, 2007, The furcula in Suchomimus tenerensis and Tyrannosaurus rex (Dinosauria: Theropoda: Tetanurae), Journal of Paleontology 81, No. 6, pp. 1523-1527 : 1523

Suchomimus tenerensis .—A furcula was recovered in a partially articulated skeleton (MNN GAD513) of the spinosaurid Suchomimus tenerensis ( Sereno et al., 1998). The presacral vertebral column was preserved in articulation, whereas the furcula, ribs, gastralia, girdles, and limbs were disarticulated but in close association. The furcula is V-shaped in anterior view with an intrafurcular angle of 111 ° ( Fig. 1 ; Table 1). A dorsoventrally-flattened, tongue-shaped hypocleideum projects ventrally in the midline ( Fig. 2.1 ). In anterior view, the hypocleideum is gently concave and displaced somewhat to the left of the midline. The absence of articular rugosities on the hypocleideum suggests that it did not contact other elements of the pectoral girdle. The central ramus has a D-shape in cross-section; anterior and posterior surfaces are convex and nearly flat, respectively ( Figs. 1 , 2 ).

The proximal half of each clavicular ramus tapers in dorsoventral width at mid length before expanding as a tongue-shaped epicleideal process ( Fig. 1 ). With the central body held vertically, the epicleideal processes arch gently posteriorly and are marked by striations both anteriorly and posteriorly. The dorsal two-thirds of the epicleideal process is thin; the ventral one-third is thickened posteriorly to form an articular platform for the edge of the acromion. This portion of the process is more strongly fluted for ligament attachment ( Fig. 2.2 ).

Figures

FIGURE 1—Stereopairs and line drawings of the furcula in Suchomimus tenerensis (MNN GAD513). 1, anterior view and cross-sectional views; 2, posterior view. Cross-hatching indicates broken bone or a cross-sectional surface. Dashed lines indicate missing portions. Abbreviations: cb, central body; ep, epicleideum; hc, hypocleideum; la, ligament attachment scars. Scale bar equals 10 cm in Stereopairs; 5 cm in line drawings.

FIGURE 2—Photographs and line drawings of the furcula in Suchomimus tenerensis (MNN GAD513). 1, hypocleideum in anterior view; 2, epicleideal process in posterior view. Dashed lines indicate missing bone. Abbreviations: ep, epicleideum; hc, hypocleideum; la, ligament attachment scars. Scale bar equals 5 cm.