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 using data sets composed of nucleotide sequences of 18S rDNAs (genes encoding 18S rRNAs) support a monophyletic Fulgoromorpha. All analyses depict Tettigometridae as a relatively derived lineage in a monophyletic relationship with Tropiduchidae. Unscored and unweighted data sets position the tettigometrid + tropiduchid clade as sister to Flatidae. The tettigometrid + tropiduchid clade is supported by four synapomorphic sites, two deletions and two transversions. Constraining tettigometrids 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 phylogenetic information in regions containing deletions also supports a non-basal tettigometrid + tropiduchid clade. However, this method results in three equally most parsimonious trees and a sister relationship of the tettigometrid + tropiduchid clade to Flatidae becomes ambiguous. The molecular-based results showing a derived Tettigometridae agree with previous morphological interpretations of Bourgoin. The current biogeographical distribution of tettigometrids and morphological features supporting the 18S rDNA-based phylogeny are discussed.