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Boyer diss 2009 1046..

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DISCUSSION AND CONCLUSIONS<br />

Morphology of P. cookei<br />

The skeleton of P. cookei UM 87990 is significant in that it provides a more<br />

complete view of several regions of the anatomy than previously available for any<br />

plesiadapid. Bones preserved in UM 87990 that were previously unknown for any<br />

species of Plesiadapis include the pollical metacarpal, scaphoid, lunate, pisiform,<br />

trapezoid, trapezium, ectocuneiform, hallucal metatarsal and much of the vertebral<br />

column. Bones previously only known from fragmentary elements for Plesiadapis<br />

include the innominate and tibia. The new morphology has allowed some significant<br />

progress in understanding the articular relationships of wrist bones, metacarpals, and<br />

metatarsals. It must be acknowledged, however, that due to problems with associations<br />

and the persistent lack of an actual complete wrist of a single individual there is still a<br />

large amount of uncertainty regarding the reconstructions of the wrist and hand presented<br />

in the descriptions.<br />

Phylogenetic significance.—Several new observations with possible phylogenetic<br />

significance came to light. These will be discussed in detail with regard to specific<br />

character matrices in Chapter 5.<br />

A reconstruction of the wrist showing that the lunate intervened between the<br />

scaphoid and triquetrum refutes the reconstruction by Beard (1989, 1993a) who<br />

suggested that the scaphoid and triquetrum articulated with one another. However,<br />

Stafford and Thorington (1998) have already showed that, if plesiadapiforms were in fact<br />

characterized by the configuration proposed by Beard (1989, 1993a), this would be an<br />

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