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that between the “set 1” MC III and “set 1” MC V metacarpals of UM 87990 (1.27), than<br />

between the “set 2” MC III and the “set 1” MC V (1.47). The ratio between the two<br />

bones in N. intermedius USNM 442229 is slightly higher than that for P. tricuspidens<br />

(1.39). Secondly, the shape of the metacarpal heads differs between MC III’s of “set 1”<br />

and “set 2” (Table 4.10, Fig. 4.18). The heads are relatively shallower in the dorsoventral<br />

direction in the “set 1” morph. This is also a similarity to P. tricuspidens from Berru. If<br />

the attribution of the “set 1” MC III to P. cookei is accepted, then MC IV from set 1 must<br />

also belong due to the similar sizes and the good fit between the corresponding articular<br />

surfaces of the two bones. Likewise, a good fit between MC II, III, and IV of “set 2”<br />

suggest that they are all from the same animal, which was not P. cookei (Fig. 4.15). MC<br />

II of “set 1” can be attributed to P. cookei on the basis of its small size compared to MC<br />

II of “set 2”, and the shape of its head. Another point supporting the attribution of MC II,<br />

III, and V “set 1” metacarpals to P. cookei is the fact that they are more robust than the<br />

corresponding “set 2” metacarpals (see “SSV” of Table 4.10 – a larger value indicates a<br />

more gracile element). This greater robusticity of the “set 1” metacarpals makes them<br />

similar to those of P.tricuspidens and P. n. sp. from France. On the other hand the<br />

gracility of the “set 2” metacarpals III and V makes them similar to those of N.<br />

intermedius and N. gidleyi. However, this cannot be taken as evidence that the “set 2”<br />

metacarpals belonged to P. cookei, because MC I of N. intermedius is more gracile than<br />

MC I’s of P. cookei and P. n. sp. Therefore, it is expected that the lateral metacarpals of<br />

N. intermedius should also be more gracile than those of P. cookei, not equally gracile.<br />

Finally, comparing the surface areas of the distal carpal surfaces to those of the proximal<br />

articular surfaces of the metacarpals reveals that there is a much better correspondence<br />

316

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