UC Riverside

This thesis comprises molecular phylogenetic and morphological studies focusing on the largest genus of litter bugs Schizoptera Fieber (Hemiptera: Dipsocoromorpha). Schizoptera, currently comprises 61 extant species in 4 subgenera. Specimens are abundant in New World bulk and residue samples. Schizoptera species showcase stunning morphologies including intricate, asymmetrical genitalia in males that have proven to provide excellent species diagnostic features in the past, and elytrous wings in females of some species. Three research topics are presented: 1) The molecular phylogeny of Schizoptera and related taxa, ancestral state reconstruction (asr) of elytrous wings in females of Schizopteridae, and asr of 11 morphological characters used to diagnose Schizoptera species. In this study, Schizoptera is shown to be polyphyletic, with two subgenera being recovered outside of the Schizoptera clade. Elytrous wings in females of Schizopteridae are shown to have evolved at least seven times, four times within Schizoptera, and reversed back to macropterous wings twice. ASR of 11 diagnostic characters is used to update generic and subgeneric diagnoses of Schizoptera and related taxa. 2) Taxonomic revision of Orthorhagus McAtee and Malloch. Previously a monotypic subgenus of Schizoptera, molecular and morphological evidence suggests that Orthorhagus is not part of Schizoptera. Unlike Schizoptera, Orthorhagus specimens are rare in samples, and the study is conducted with a total of nine specimens including the holotype. Orthorhagus is elevated to generic rank, and five new species from the Neotropics are described in this genus. 3) Taxonomic revision of the subgenus Schizoptera (Odontorhagus). The molecular phylogeny of Schizoptera shows that S. (Odontorhagus) is monophyletic, without Kophaegis, which was previously synonymized with this subgenus. Comprising 10 described species, six from Guatemala and Panama and four from Trinidad, this study results in the description of 20 new species from the Neotropics, increasing the species count in Schizoptera to 81. We predict that similar increases in species numbers are to be expected for the remaining subgenera of Schizoptera, making this genus and very diverse lineage of minute litter bugs.