. Bulletin. Natural history; Natuurlijke historie. FIG. 50. Cervical ribs of Deinonychus antirrhopus (YPM 5210). An anterior cervical rib in lateral (A) and medial (B) views. A posterior rib in lateral (C) and medial (D) views. Abbreviations: ca—capitulum; tu—tuberculura. and tubercular pedicels form a C-shaped structure in transverse section. Its concave inner surface has a single, small, deep pit facing posteriorly at the base of the pedicels. A short, irregular process extends forward approximately 10 mm beyond the tuberculum and the main shaft. A parallel-edged, medially concave blade exte
. Bulletin. Natural history; Natuurlijke historie. FIG. 50. Cervical ribs of Deinonychus antirrhopus (YPM 5210). An anterior cervical rib in lateral (A) and medial (B) views. A posterior rib in lateral (C) and medial (D) views. Abbreviations: ca—capitulum; tu—tuberculura. and tubercular pedicels form a C-shaped structure in transverse section. Its concave inner surface has a single, small, deep pit facing posteriorly at the base of the pedicels. A short, irregular process extends forward approximately 10 mm beyond the tuberculum and the main shaft. A parallel-edged, medially concave blade extends to a posterior termination, rounded and striated, some 33 mm behind the tuberculum. The capitular process is nearly round in section and flares slightly at its extremity. The tubercular process is a compressed oval in section and is not expanded at its termination. Closely associated with these ribs was another pair of quite different cervical ribs (Fig. 50C and D). These are distinctly triangular in shape, rather than elongated blades, with short (5 mm), irregular, anterior processes and longer (18 mm), triangular, posterior extensions. The capitulum and tuberculum are more widely separated (15 mm) and the latter is only about half the size of the former. These features correspond most closely with a cervico-dorsal vertebra, suggesting these are probably posterior cervical ribs, perhaps the eighth or ninth. Again, the capitular surface is strongly rugose, indicating that the entire cervical rib series were immovably united by digitate sutures with the cervical vertebrae. The external rib surface is moderately convex, the inner surface is strongly concave and is sculptured by a number of deep excavations at the base of the tubercular process and across the triangular posterior exten- sion. When articulated with their respective vertebrae, these cervical ribs trended down and backward, parallel and close to the lower lateral surfaces of the centra. Posterior processes ma
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Keywords: ., bookcentury1900, bookcollectionbiodiv, booksubjectnaturalhistory
