Phylogenetic relationships and revised classification of the true bug infraorder Dipsocoromorpha (Insecta: Hemiptera: Heteroptera)

Currently comprising only about 430 species, Dipsocoromorpha or minute litter bugs are one of the small infraorders of Heteroptera. They are classified into five morphologically distinct families--Ceratocombidae, Dipsocoridae, Hypsipterygidae, Schizopteridae and Stemmocryptidae--but relationships among and within these families are poorly understood owing to the lack of phylogenetic studies. A phylogenetic hypothesis based on combined molecular and morphological data is important to both evaluate and revise the higher-level classification and to explore the evolutionary history of morphological features including elytriform (or beetle-like) forewings, that seem to have evolved multiple times in this group, jumping devices, and the highly modified and diverse male genitalia. We here use a dataset combining Sanger-derived (~4500 bp; 108 taxa) and Illumina-generated (~7500 bp; 24 taxa) sequence data with a morphological matrix (159 characters) and taxon sampling that comprises all currently recognized family-, subfamily- and tribal-level taxa and comprehensive genus-level sampling to investigate phylogenetic relationships within litter bugs. Our results support the monophyly of Dipsocoromorpha, Schizopteridae and Dipsocoridae, whereas Ceratocombidae and the schizopterine subfamily "Ogeriinae" are polyphyletic and paraphyletic, respectively. A new classification is proposed that recognizes six families, including Trichotonannidae, stat.n., and two subfamilies each within the two larger families Ceratocombidae and Schizopteridae. Ancestral state reconstructions outline the complex evolutionary history of many morphological characters, including 15 independent origins of elytriform forewings, and at least five shifts in the degree of genitalic asymmetry.

Synopsis of Schizopteridae (Hemiptera, Heteroptera, Dipsocoromorpha) from the United States, with description of seven new species from the US and Mexico

Because species diversity of the small true bug family Schizopteridae is greatest in tropical and subtropical areas, it is not surprising that only four species have been described from the United States. As part of a larger project on the taxonomy and phylogenetics of Schizopteridae, 178 specimens from the United States were examined. This material contained representatives of the previously described species Glyptocombussaltator Heidemann, 1906, Corixideamajor McAtee & Malloch, 1925, Nannocorisarenarius Blatchley, 1926, and Schizopterabispina McAtee & Malloch, 1925, but also six undescribed species. These new taxa are described as Glyptocombushalbertaesp. n., Glyptocombussuterisp. n., Nannocorisanophorussp. n., Nannocorisbrevipilussp. n., Schizoptera (Cantharocoris) rileyisp. n., and Schizoptera (Schizoptera) henryisp. n. Habitus images and genitalic illustrations of the previously described and the new species are provided as well as a map showing distribution ranges of these species in the United States and Mexico. To provide a comprehensive treatment of the small genus Glyptocombus Heidemann, 1906, Glyptocombusmexicanussp. n. is also described that, to our knowledge, occurs only in Mexico, and the female of one additional undescribed Glyptocombus species is documented from Mexico.