MOLECULAR PHYLOGENY OF FULGOROMORPHA (INSECTA, HEMIPTERA, ARCHAEORRHYNCHA) - THE ENIGMATIC TETTIGOMETRIDAE - EVOLUTIONARY AFFILIATIONS AND HISTORICAL BIOGEOGRAPHY

Previous morphologically based studies by several taxonomists disagree on whether the Tettigometridae represent a sister group to all other fulgoromorphans or whether they are a relatively derived family within the Fulgoromorpha. In this study, several parsimony-based analyses us ing data sets composed of nucleotide sequences of 18S rDNAs (genes enc oding 18S rRNAs) support a monophyletic Fulgoromorpha. All analyses de pict Tettigometridae as a relatively derived lineage in a monophyletic relationship with Tropiduchidae. Unscored and unweighted data sets po sition the tettigometrid + tropiduchid clade as sister to Flatidae. Th e tettigometrid + tropiduchid clade is supported by four synapomorphic sites, two deletions and two transversions. Constraining tettigometri ds to a basal fulgoromorphan lineage significantly reduces parsimony, with several hundreds to thousand of trees being more parsimonious. An analysis employing the Barriel method for scoring potential phylogene tic information in regions containing deletions also supports a non-ba sal tettigometrid + tropiduchid clade. However, this method results in three equally most parsimonious trees and a sister relationship of th e tettigometrid + tropiduchid clade to Flatidae becomes ambiguous. The molecular-based results showing a derived Tettigometridae agree with previous morphological interpretations of Bourgoin. The current biogeo graphical distribution of tettigometrids and morphological features su pporting the 18S rDNA-based phylogeny are discussed. (C) 1997 The Will i Hennig Society.