If adaptive radiation has influenced size evolution in mammals, the effect is not apparent in the distributions of size disparity. Without outliers, positive skew, or bimodality, there are no criteria for identifying exceptional clades. The magnitudes of disparity found in lemuriforms and platyrrhines can be interpreted as consistent with adaptive radiation, but size disparity does not provide decisive support for recognizing them as such.
Jeremiah E. Scott (Wed,) studied this question.