Dear Adeline Yong Right now you are essentially plotting size (of the claw) against size (of the crab). What you are interested in is shape against size. I am not sure what program you are using now, but I would suggest MorphoJ, as it is quite user friendly. You should do a multivariate regression of the Procrustes coordinates onto size.You could then play around with different size measures. (ln) centroid size of the object of interest is commonly used for these types of analyses, but you could also try doing it with carapace size and see if you get different results. I hope that helps.
Best wishes, Anneke van Heteren -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org To unsubscribe from this group and stop receiving emails from it, send an email to morphmet+unsubscr...@morphometrics.org.