Multivariate Analysis of Leg Morphology of Macrocyprididae

Abstract

The fifth, sixth, and seventh legs and furcae of cypridacean ostracods are widely supposed to have considerable taxonomic significance and are relatively easy to dissect and illustrate. Nevertheless, some of the characters used in the past to diagnose new taxa have turned out to be invariant and, hence, without taxonomic importance, while many others are strongly correlated with each other or directly dependent on general size and, thus, not independent in their taxonomic significance. R-mode cluster and principal components analyses can be used to evaluate the independence of characters, so that the most appropriate characters may be selected for taxonomic and evolutionary applications. To demonstrate this, 112 characters have been measured on these appendages and carapace for 71 species of Macrocyprididae, a relatively small and homogeneous family. The results show the potential of such methods for improving ostracod taxonomy. Q-mode cluster analysis of the same data provides evidence to test the generic classification of these species based on the carapace and subjective judgments. In general, the results confirm the prevailing opinion that the furcae and male fifth limbs offer more taxonomic information than the female fifth limb, sixth limb, and seventh limb. However, a few previously ignored characters may have taxonomic value, masked at present by possible non-linearity of their relationships.