I am doing a morphometric study about a shark, but I've got difficulties with the interpretation of the results. I've digitalized 75 specimens and marked 19 landmarks. I don't know whether is better to see the visuallization plot of the partial or of the relative warps for the interpretation of the results.
I've obtained 16 partial warps and 34 relative warps(RW). The 3 first RW explain only the 57% of the total change, and the 90% is explained by the 12 first RW. Moreover I think that RW 1 and 3 represent a bending due to the fact that a slender, long fish is difficult to position completely straight. I don't know if it is possible to eliminate this "artificial change" from the analysis in order to quantify only the real change. (In fact, I'm not sure if it is reasonable to study shape in slender fish from their digital images or if it would be better to use the traditional morphometrics and make the measures from each specimen) The main objective of my study is to evaluate the ontogenetic change and the change between sexes (if it exists). In my preliminary results I've treated all the specimens as a whole, not making groups by size or sex. It would be better to do so? I've read one paper in which partial warp scores and uniform were regressed on size to test the hypothesis of ontogenetic allometry, but I don't understand why size must be used for testing it. I think that the partial warp scores are the weight matrix, though I'm not sure. In case I was right, I should enter the weight matrix into the option data of the tpsRegr program and the centroid size as an independent variable, or it has no sense ? Any advice or comment to the extense number of questions and doubts will be welcome. Thanks in advance for all your help. Javier Mariana (mail: [EMAIL PROTECTED]) Barcelona (Spain) == Replies will be sent to list. For more information see http://life.bio.sunysb.edu/morph/morphmet.html.
