. Bulletin. Natural history; Natuurlijke historie. 5 cm ent. sup ent sup^ Fig. 18. Left humerus of Corosaurus alcovensis, based primarily upon UW 5485 and YPM 41033. A, proximal aspect, anterior to top; B, anterior aspect, proximal end up; C, extensor aspect; D, flexor aspect; E, posterior aspect; F, distal aspect, anterior to bottom, ect = ectepicondylar notch; ent = entepicondylar foramen; sup = supinator process; sup r = supinator ridge. Humerus. The humerus is strongly curved caudad and is generally similar to those of other nonplesiosaurian nothosauriforms (Fig. 18). The shaft is relative
. Bulletin. Natural history; Natuurlijke historie. 5 cm ent. sup ent sup^ Fig. 18. Left humerus of Corosaurus alcovensis, based primarily upon UW 5485 and YPM 41033. A, proximal aspect, anterior to top; B, anterior aspect, proximal end up; C, extensor aspect; D, flexor aspect; E, posterior aspect; F, distal aspect, anterior to bottom, ect = ectepicondylar notch; ent = entepicondylar foramen; sup = supinator process; sup r = supinator ridge. Humerus. The humerus is strongly curved caudad and is generally similar to those of other nonplesiosaurian nothosauriforms (Fig. 18). The shaft is relatively short and stout. The proximal head of the humerus is expanded dorsoventrally and is somewhat rectangular in cross section; the distal end is lateromedially expanded w^ith an ovate cross section. Both ends of the bone are unfinished, being originally capped by cartilage. There is a prominent ectepicondylar notch for the passage of the radial nerve and blood vessels and a large entepicondylar foramen allowing supply of the flexor surface of the antebrachium. Just distal to the foramen, the entepicondylar corner of the humerus bears a small process which enlarged the surface area available for the origins of the flexor musculature. There is no demarcation between the ulnar and radial facets. A small, though distinct, supinator process for the origin of the M. supinator longus is situated immediately proximal to the ectepicondylar groove. A sharp, sinuous supinator ridge runs along the anterior edge of the shaft from this process to the anteroventral corner of the proximal articular head. There is essentially no deltopectoral crest, merely a sharp anteroventral edge to the proximal part of the shaft for apparent insertion of the M. pectoralis. A roughened convexity on the dorsoproximal end of the bone probably served as the attachment site for the M. deltoideus. The dorsal surface. Please note that these images are extracted from scanned page images that may have been digitally
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Keywords: ., bookcentury1900, bookcollectionbiodiv, booksubjectnaturalhistory
