Boyer diss 2009 1046..

value for P. tricuspidens. In summary, it seems likely that P. tricuspidens (like P. cookei,
P. insignis, and Nannodectes) will be revealed to have phalangeal indices of around 130-
140 when more confidently identified digit rays are available. This is less than that of
most arboreal euprimates, but much higher than that of many terrestrial mammals (Kirk
et al., 2008). If, on the other hand, it turns out that P. tricuspidens truly does have such
short fingers, then this information appears to contradict much other information from the
skeleton suggesting arboreal habits (Youlatos and Godinot, 2004). It should, however, be
noted that it would be consistent with the absolutely thicker and proportionally shorter
limbs of P. tricuspidens as compared to those of P. cookei and extant arboreal mammals
(Runestad and Ruff, 1995).
Body mass estimates
Differences in results of the two sets of postcranial regressions used to generate
body mass estimates are interesting because they suggest that P. cookei has exceptionally
relatively long limbs among mammals (based on the Gingerich [1990] equations), but
relatively short limbs compared with extant primates (based on the unpublished extant
primate sample). The absolute body mass estimates generated by both sets of postcranial
regressions are of some interest because they sample the skeleton so broadly and show
such congruence that they may actually be fairly accurate. That is, P. cookei probably
weighed somewhere between 1-3 kg, but not as much as the 5 kg suggested by a
regression from Silcox et al. (in press) based on skull length of extant primates.
Proportional differences in body mass between P. cookei and other plesiadapids
as suggested by the postcranium are much smaller than estimates of proportional
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