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Boyer diss 2009 1046..

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Nannodectes and other plesiadapids, these were not quantified here and are not strongly<br />

suggestive of suspensory postures anyhow. In fact, some of the humeral morphology that<br />

was quantified shows all plesiadapids to be similar in morphology of the distal humerus.<br />

A smaller amount of lateral torsion in the humeral shaft of small-bodied plesiadapids as<br />

compared to large-bodied ones is the opposite from what is predicted for a suspensory<br />

habit in large plesiadapids: suspensory primates and xenarthrans are characterized by<br />

medial torsion, if any. On the other hand, the intermediate phalanges of P. cookei are<br />

distinctly different from those of P. tricuspidens and Nannodectes in ways that could<br />

suggest a suspensory habit. These intermediate phalanx features of P. cookei are also<br />

found in Cynocephalus, bats, and sloths (<strong>Boyer</strong> and Bloch, 2008). However, Daubentonia<br />

also exhibits intermediate phalanges with extraordinarily mediolaterally narrow proximal<br />

ends, like P.cookei and suspensory taxa (<strong>Boyer</strong> and Bloch, 2008). Although the Aye aye<br />

is adept in quadrumanus suspensory locomotion (pers. observ.), it is not a “suspensory<br />

animal” in the manner of a sloth or dermopteran. Finally, the claws of P. cookei, while<br />

being slightly narrower than those of smaller-bodied plesiadapids and being more hooklike<br />

in having a longer shaft, are overall very similar to the claws of other plesiadapids.<br />

The features that do differentiate the claws of P. cookei from those of smaller<br />

plesiadapids could easily be related to allometric trends in phalanges with the “same”<br />

functional capacity, although this remains to be demonstrated.<br />

Postcranial proportions<br />

The position of plesiadapids and other plesiadapiforms in the principal<br />

coordinates plots based on body segment length data is consistent with the suggestion<br />

385

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