SCAPULAR SHAPE AND PRIMATE CLASSIFICATION

Certain quantitative features of the primato scapula bear no obvious mechanical relevance to such functions of the bone as are known to be significant in the employment of the forelimb during progression. Statistically these “residual” features are but weakly correlated with those of established locomotor significance and do not show a correspondingly regular pattern of contrast between Primates in different locomotor categories. These features would, therefore, appear not to be adapted to locomotor function. Consequently, unless they have other functional significance or are linked genetically with other adaptive characters, their parallel variation may indicate genetic relationship. Thus, residual metrical features of this type may be of significance in primate classification. This is in contrast to features of proved locomotor significance whose concurrent appearance in several groups probably represents the result of parallel selection acting in unrelated species. Eight such features examined in thirty genera (covoring most of the primate order) differentiate significantly between genera within subfamilies and somewhat fewer features differentiate between the components of progressively higher taxonomic groups. But the degree of overlap between genera is such as to minimize the value of individual dimensions in classifying an unknown specimen. It would, however, seem likely that the combination of these dimensions by multivariate techniques might effect a more efficient separation of forms within the primate order.