FIGURE 1. Mounted skeleton of AMNH 5338, Corythosaurus casuarius, in left lateral view. Note that in the right forelimb the radius is mounted in articulation with the laterial condyle of the humerus without distally crossing over the ulna, and that the palm faces sub-medially. Abbreviations: r, radius; u, ulna.

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FIGURE 2. Forelimbs of hadrosaurid skeletons mounted with caudally-facing palms; black arrow indicates medial condyle of humerus, and white arrow indicates lateral condyle of humerus. 2.1. AMNH 5886, Edmontosaurus annectens, anterior view. 2.2. Cast of Edmontosaurus sp. at North American Museum of Ancient Life (Lehi, Utah), anterolateral view. 2.3. AMNH 5730, Edmontosaurus annectens, right lateral view. Note that palms face caudally in 2.1 and 2.2 due to mounting the radius in articulation with the medial condyle of the humerus, and that palms face caudally in 2.3 due to unnatural crossing of the distal end of the radius medially over that of the ulna.

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FIGURE 3. Manually rearticulated forearm bones of hadrosaurid specimens, with red arrows indicating concave surfaces on ulna that hold radius in place and thereby prevent active pronation. 3.1. CMN FV 2289 (Edmontosaurus regalis), proximal view. 3.2. CMN FV 2289, distal view 3.3. AMNH 5357 (Hypacrosaurus altispinus), proximal view. 3.4. AMNH 5357, distal view. 3.5. AMNH 5357, oblique distal view. 3.6. CMN FV 2289, lateral view, with distal end moved out of place to show concave surface on ulna. 3.7. AMNH 5357, lateral view. 3.8. AMNH 5357, medial view. Abbreviations: r, radius; u, ulna.

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FIGURE 4. AMNH 5030, mummified Edmontosaurus annectens, showing articulations between forelimb bones; black arrow indicates medial condyle of humerus, and white arrow indicates lateral condyle of humerus. 4.1. Anterior end of specimen in dorsal view. 4.2. Anterior end of specimen in right ventral view. 4.3. Right hand in dorsal view. 4.4. Left forearm and hand in oblique (part palmar, part pollucal) view. 4.5. Right forearm in palmar view. 4.6. Right hand in palmar view. Abbreviations: c, coracoid; h, humerus; m, mandible; r, radius; sc, scapula; sk, skull; st, sternal plates; u, ulna. Roman numerals indicate metacarpals, and Arabic numerals indicate phalanges of the digit indicated by each numeral (e.g., all phalanges of digit II are indicated by "2").

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FIGURE 5. CMN FV 8399, articulated skeleton of Edmontosaurus regalis, showing articulations between forelimb bones. 5.1. Anterior end of skeleton in lateral view. 5.2. Right hand (left side of 5.2) in palmar view and left hand (right side of 5.2) in palmolateral view. 5.3. Articulations between bones of left elbow. 5.4. Articulations between bones of the right forearm (left side of 5.4) and of the left forearm (right side of 5.4). Abbreviations as in Figure 4.

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FIGURE 6. Overlay of several manus-pes pairs in hadrosaur trackways, after Lockley and Wright (2001). 6.1. Tracks from the Gething Formation (Lower Cretaceous, Canada). 6.2. Tracks from the Saint Mary River Formation (Upper Cretaceous, Canada).

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FIGURE 7. Articulated left hand of CMN FV 8703 (Lambeosaurus sp.), showing that the palmar surface (outlined with broken yellow line) of digit II faces digit III.

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