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Boyer diss 2009 1046..

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Ectocuneiform<br />

Description.—A left ectocuneiform is preserved (Figs. 4.36B, 4.37). No other<br />

plesiadapids have an ectocuneiform preserved; thus it cannot be confirmed with<br />

comparative information that this bone is correctly identified as belonging to P. cookei.<br />

However, it seems to fit with the cuboid, which clearly belongs to P. cookei based on<br />

comparative information (see above). Furthermore, it is quite similar to the<br />

ectocuneiform of another plesiadapiform, Ignacius clarkforkensis (<strong>Boyer</strong> and Bloch,<br />

2008). Thus, it is tentatively attributed to P. cookei.<br />

It is square in lateral or medial view and mediolaterally narrow (2.9 mm)<br />

compared to its dorsoplantar (4.8 mm) and proximodistal (4.7 mm) dimensions. It is<br />

dorsoventrally wedged, with it dorsal surface mediolateraly wider than its ventral surface.<br />

Its proximal surface is concave and slopes medially relative to its proximodistal axis,<br />

while its distal surface is slightly concave and faces directly distal. The proximal surface<br />

is notched on its medial side, while the distal surface has a shallow notch on its lateral<br />

side. The dorsal surface is smooth and non-articular. The plantar surface is notched for<br />

the continued course of the peroneus longus tendon. The dorsolateral corner of the<br />

proximal end has a proximolaterally facing surface that would have contacted the distal<br />

tip of the anterodistomedially-facing surface of the medial side of the cuboid. The<br />

plantoproximal corner of the lateral side has a tiny facet that would have contacted a<br />

corresponding facet on the cuboid (Fig. 4.37). Distal to these two points for the cuboid is<br />

a concave articular area that seems to fit the distal region of the medial articular surface<br />

of the cuboid. However, in order to approximate these facets, the distal metatarsal<br />

surface of the ectocuneiform must be inset proximally to the metatarsal facet of the<br />

351

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