Species clustering
A PCA of harmonic coefficients was carried out in order to visualise
intra- and interspecific shape variation and generate PC scores to be
used in species clustering (Figure 4). The PCA appears to show a higher
degree of intraspecific than interspecific differences in both segments.
Furthermore, there was marked overlap between species in both segments,
this was particular marked in the femur where species within the same
family often overlapped. In both segments, PC1 appears to correlate to
pedipalp elongation, where PC2 seems to be related to the relative
position of the longest spines and the length of those spines in the
tibia and femur. PC1 accounted for just over half of observed variation
in both segments (femur = 56%, tibia = 59.2%) and mainly separated
Phrynichidae species (D.diadema , D.medius andPh.exophamus ) from other species. PC2 contributed roughly 15% of
variation in both the femur and tibia. PC’s 1 through 10 accounted for
just over 95% of total observed variation in both segments, thus
PC1-PC10 were carried forward into the species clustering analysis.