ON PHYLOGENETIC-RELATIONSHIPS WITHIN DENDROTRITON (AMPHIBIA, CAUDATA,PLETHODONTIDAE) - IS THERE SUFFICIENT EVIDENCE

Previous phylogenetic analyses of the relationships among five Central American salamanders of the genus Dendrotriton are reviewed. The avai lable data was reanalysed using parsimony under a variety of analytica l treatments. The results are highly sensitive to (1) the coding metho d used to convert quantitative characters into discrete character stat es; (2) different scalings (weighting) of multistate characters; and ( 3) the omission or inclusion of potentially problematic characters. Ex plorations of length differences between most parsimonious trees and s elected less parsimonious alternatives reveal that under each treatmen t, most parsimonious trees are only marginally more parsimonious than alternatives and that Bremer support for the clades occurring in MPTs is always low. Tree length distributions are not highly left-skewed as would be expected of phylogenetically informative data. These analyse s suggest that there is little phylogenetic signal in the available da ta and that these data provide little basis for well supported phyloge netic inferences. Both parsimony and compatibility-based randomization tests confirm this interpretation. The null hypotheses that the data are not significantly different from phylogenetically uninformative ra ndomly permuted data cannot be rejected for any of the analytical trea tments. Given failure to reject the null hypothesis, phylogenetic hypo theses for Dendrotriton based on the available data are uncompelling. Additional data are needed. Results of the randomization tests are con sistent with the view that there has been extensive homoplasy in bolit oglossine salamanders.