. Breviora. 97: CHANARESUCHUS AND GUALOSUCHUS The quadrate bone is well developed. Its posterior end is a thickened articular area, widened transversely and convex at both internal and external ends; it appears that the quadratojugal (as often) takes part to some degree in the lateral condyle. The main shaft of the quadrate extends upward, to terminate in a recess on the under surface of the squamosal at and close to its posterior spur. This ascending ramus of the quadrate is broad ventrally, gradually contracting in width dorsally, and has a concave posterior margin. It faces as much posterio
. Breviora. 97: CHANARESUCHUS AND GUALOSUCHUS The quadrate bone is well developed. Its posterior end is a thickened articular area, widened transversely and convex at both internal and external ends; it appears that the quadratojugal (as often) takes part to some degree in the lateral condyle. The main shaft of the quadrate extends upward, to terminate in a recess on the under surface of the squamosal at and close to its posterior spur. This ascending ramus of the quadrate is broad ventrally, gradually contracting in width dorsally, and has a concave posterior margin. It faces as much posteriorly as later- ally, at an angle to the adjacent areas of the quadratojugal and descending ramus of the squamosal. As generally, a foramen is present on this surface between quadrate and quadratojugal. The ascending ramus presents a broad, forward-slanting, medial sur- face that is covered anteriorly by the quadrate ramus of the pterygoid. In correlation with skull length, the jaw is long and slender anteriorly (Figs. 4, 5). The symphysis is poorly represented in available material but was obviously weak and formed mainly — perhaps entirely — by the dentary. For much of the length of the muzzle the dentary forms almost the entire outer surface of the ramus — a surface that slants markedly inward below, rather than being directed vertically downward. Posteriorly the bone forks, the two branches enclosing between them the anterior end of the long external mandibular fenestra. The upper branch ex- tends along the upper margin of the ramus to the end of the tooth. Figure 4. Cluijuircsiicliiis bonapartei, jaw of type in lateroventral view. X 4/9. row, where it is replaced by the surangular; the lower branch extends backward below the fenestra for some distance, applied to the outer surface of the angular. The splenial is exposed at the lower edge of the external surface. The posterior portion of the external surface is made up almost entirely by the surangular and angular. The
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