Contributions of antennal characters to phylogenetic analysis of Auchenorrhyncha

Scanning electron micrographs of antennal structure in Auchenorrhyncha show an amazing variety of synapomophic characters in Fulgoroidea and Cercopoidea, verifing the conclusions reached by H.J. Hansen in 1890: (1) that Fulgoroidea are radically different from Cicadomorpha; (2) that phylogeny is most easily and reliably demonstrated by characters unique to a taxon; and (3) that the stability of a classification depends upon analysis of variation and the degree of correlation among many synapomorphies. However, no matter how well studied, some paraphylies will be unavoidable. Phylogenetic analysis will be most reliable at the generic level, where extinction of relevant taxa is low, and both morphological and genetic evidence is in best accord because the probability of examining most of the taxa is greatest. Ordinal classification also must be stabilized by phylogenetic data, but evidence of lower phylogenetic levels is often incomplete due to lack of well-preserved fossils.