Dear GM community, I'd like to get some opinions on methods for comparing ontogenetic trajectories of extant taxa within a phylogenetic framework. I've read several papers and spoken to colleagues about this and there appears to be no satisfactory conclusion. It seems that one can either describe trajectories as vectors (usually based on PC axes) and compare angles between them against a phylogeny using ancestral state reconstruction/PIC, or use the Procrustes data themselves, divided into age bins, to reconstruct ancestral morphologies of juveniles and adults, use those to build an ancestral ontogeny, and then compare that to the tip taxa. Both of these methods seem unsatisfactory to me, in that they rely on observed data to reconstruct ancestral states, which by definition will not fall outside of the current range. I know ASR is implicit and necessary in most phylogenetic tests, but I wonder if there is another way, or at least a complementary way to e.g., test for heterochronic shifts in ontogenetic allometry.
Thanks for any thoughts on this, and I realize it may be a difficult subject. References to any papers with relevant methods would also be appreciated! Christy School of BioSciences University of Melbourne Parkville VIC 3010, Australia Email: chips...@unimelb.edu.au Museum Victoria GPO Box 666 Melbourne VIC 3001, Australia Ph: +61 (0)3 8341 7423 Email: chips...@museum.vic.gov.au -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- You received this message because you are subscribed to the Google Groups "MORPHMET" group. To unsubscribe from this group and stop receiving emails from it, send an email to morphmet+unsubscr...@morphometrics.org.
