MARINE AREA RELATIONSHIPS FROM 20 SPONGE PHYLOGENIES - A COMPARISON OF METHODS AND CODING STRATEGIES

Published phylogenies of 20 marine sponge groups are used to build gen eral area cladograms of marine areas of endemism under three different methods for which algorithms adapted for personal computers are avail able, viz. COMPONENT, BPA and TAS, and two different coding strategies , Assumption 0 (AO) and ''no assumption'' (NA). The latter is a recent ly proposed procedure for handling the distributions of widespread tax a by treating these as separate areas of endemism, rather than as suit es of smaller constituent areas. The 20 phylogenies contained large nu mbers of problem data which prevented an exhaustive search for all pos sible equally ''best'' general area cladograms. The Nelson consensus t rees and their equivalents in parsimony analysis for all six attempts (viz. three different methodologies under two different coding strateg ies) were compared using their fit with the 20 sponge phylogenies as a measure of quality. Fit was determined using the number of ''cospecia tions'' between a general area cladogram and a taxon area cladogram co mputed with TreeMap 1.0. No single method or coding strategy yielded a clearly better fit, each cladogram fitting variously better or worse with various phylogenies. In general, fit with NA coding was higher th an with AO coding, but random tree tests failed to generate statistica lly significant support for the conclusion that NA coding improves fit . Assuming that available sponge phylogenies are representative of mar ine benthic groups, software and hardware limitations are serious obst acles to a successful development of marine general area cladograms un der any method or coding strategy. (C) 1997 The Willi Hennig Society.