. Bulletin. Natural history; Natuurlijke historie. ang 0 1 2. FIG. 2L Right prearticular (reversed) of Deinonychus antirrhopus, YPM 5210, in lateral (A) and medial (B) views. Abbreviations: ang—^suture for angular; ar—articulation with articular; sa— articulation with surangular; sp—area of contact with splenial. groove and a very narrow medial one. The lateral groove gradually fades out anteriorly, but the medial groove expands and persists nearly to the anterior extremity of the inferior margin. These features correspond to the posterior part of the ventro-medial margin of the angular (descr
. Bulletin. Natural history; Natuurlijke historie. ang 0 1 2. FIG. 2L Right prearticular (reversed) of Deinonychus antirrhopus, YPM 5210, in lateral (A) and medial (B) views. Abbreviations: ang—^suture for angular; ar—articulation with articular; sa— articulation with surangular; sp—area of contact with splenial. groove and a very narrow medial one. The lateral groove gradually fades out anteriorly, but the medial groove expands and persists nearly to the anterior extremity of the inferior margin. These features correspond to the posterior part of the ventro-medial margin of the angular (described above) and are interpreted as the sutural surfaces that joined these two bones. The dorsal margin of the prearticular forms a broad sweeping curve, which defines the lower margin of the adductor fossa. In general form, the prearticular appears to most closely resemble that of Velociraptor. It is relatively longer and higher (anteriorly) and much more deli- cate than that of Allosaurus. ARTICULAR The articular is a massive, triangular element (Fig. 22) with a short but broad retroarticular process bearing a robust, ventro-medially directed, hook-like ex- tremity and a longitudinally oriented, rectangular, blade-like flange projecting dorsally. The former might be the insertion site of the M. depressor mandibulae, but I suspect it is also related to the pterygoideous musculature. The ascending flange, which is situated directly behind (7 mm) the glenoid and is oriented per- pendicular to the long axis of the glenoid, is the other most probable point of at- tachment for the depressor muscles. Colbert and Russell (1969) described a very similar, but much more prominent, dorsally directed process in almost the same position on the retroarticular process. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.
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Keywords: ., bookcentury1900, bookcollectionbiodiv, booksubjectnaturalhistory
