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Endosymbioses are a major form of biological complexity affecting the ecological and evolutionary diversification of many eukaryotic groups. These associations are exemplified by nutritional symbioses of insects for which phylogenetic studies have demonstrated numerous cases of long-term codiversification between a bacterial and a host lineage. Some insects, including most leafhoppers (Insecta: Hemiptera: Cicadellidae), have more than one bacterial symbiont within specialized host cells, raising questions regarding the patterns of codiversification of these multiple partners and the evolutionary persistence of complex symbiotic systems. Previous studies reported the presence of two dominant symbiont types in a member of the leafhopper subfamily Cicadellinae (sharpshooters). In this study, 16S rRNA sequences were obtained and used to examine the occurrence and evolutionary relationships of the two dominant symbiont types across 29 leafhopper species. Candidatus Sulcia muelleri (Bacteroidetes) was detected in all leafhopper species examined, a finding that is consistent with a previous report of its ancient association with the Auchenorrhyncha (a grouping that includes leafhoppers, treehoppers, cicadas, planthoppers, and spittlebugs). Baumannia cicadellinicola (Proteobacteria), previously known from only five sharpshooter species, was found only in the sharpshooter tribes Cicadellini and Proconiini, as well as in the subfamily Phereurhininae. Mitochondrial and nuclear gene sequences were obtained and used to reconstruct host phylogenies. Analyses of host and symbiont data sets support a congruent evolutionary history between sharpshooters, Sulcia and Baumannia and thus provide the first strong evidence for long-term co-inheritance of multiple symbionts during the diversification of a eukaryotic host. Sulcia shows a fivefold lower rate of 16S rDNA sequence divergence than does Baumannia for the same host pairs. The term 'coprimary' symbiont is proposed for such cases.

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Summary A parsimony‐based phylogenetic analysis of eighty‐three morphological characters of adults and immatures of seventy representatives of the tribes and subfamilies of Membracidae and two outgroup taxa was conducted to evaluate the status and relationships of these taxa. Centrotinae apparently gave rise to Nessorhinini and Oxyrhachini (both formerly treated as subfamilies, now syn.n. and syn.reinst., respectively, of Centrotinae). In contrast to previous analyses, a clade comprising Nicomiinae, Centronodinae, Centrodontinae, and the unplaced genera Holdgatiella Evans, Euwalkeria Goding and Antillotolania Ramos was recovered, but relationships within this clade were not well resolved. Nodonica bispinigera, gen.n. and sp.n., is described and placed in Centrodontini based on its sister‐group relationship to a clade comprising previously described genera of this tribe. Membracinae and Heteronotinae were consistently monophyletic. Neither Darninae nor Smiliinae, as previously defined, was monophyletic on the maximally parsimonious cladograms, but constraining both as monophyletic groups required only one additional step. The monophyly of Stegaspidinae, including Deiroderes Ramos (unplaced in Membracidae), was supported on some but not all equally parsimonious cladograms. More detailed analyses of individual subfamilies, as well as morphological data on the undescribed immatures of several membracid tribes and genera, will be needed to elucidate relationships among tribes and genera. A key to the subfamilies and tribes is provided.

Deltocephalinae, a highly diverse and economically important subfamily of leafhoppers, contains over 6200 species and 36 tribes distributed worldwide in habitats ranging from xeric grasslands and shrublands to tropical rainforests. Recent morphological and molecular phylogenetic analyses of Cicadellidae and a morphology‐based analysis of Deltocephalinae and related subfamilies indicated that several previously recognized cicadellid subfamilies are closely related to or derived from within Deltocephalinae, but these analyses did not provide a comprehensive or well‐supported hypothesis of the phylogeny of Deltocephalinae s.l. due to either low taxon sampling or low branch support. Here, taxon sampling was increased to include members of most family‐group taxa of Deltocephalinae and molecular data (∼2800 bp 28S rDNA and ∼350 bp histone H3) were added to improve the phylogenetic estimate. Five putative outgroup taxa were included, and parsimony and Bayesian analyses of the combined molecular and morphological (119 characters) data and maximum likelihood analyses of the 28S data showed strong support for the monophyly of Deltocephalinae as defined here. Branches near the base of the tree and towards the tips were longer and better supported than many of the shorter internal branches. Similar to a previous morphological phylogenetic analysis of Deltocephalinae, all of the grass‐ and sedge‐specializing tribes were recovered in one common clade, with a few apparent reversals to nongrass feeding. Although support for this clade was low and requires further testing, the results suggest that grass/sedge specialization is a phylogenetically conservative trait within Deltocephalinae. The history of the classification of Deltocephalinae and related subfamilies is reviewed, and based on the results of the phylogenetic analyses presented here, a revised family‐group taxonomic classification is proposed. In addition to subfamilies that were recently included in Deltocephalinae, the following are considered junior synonyms of Deltocephalinae: Acostemminae syn.n., Arrugadinae syn.n., Drakensbergeninae syn.n., Mukariinae syn.n. and Stegelytrinae syn.n. The morphological characters supporting this interpretation of Deltocephalinae are provided and discussed, and a description of the subfamily is provided. A new tribe, Faltalini tribe n. (11 genera, 31 species) is described, and Magnentiini placement n. and Paraphrodini placement n. are transferred to Deltocephalinae from Nioniinae and Aphrodinae, respectively. New placements of genera include: Twiningia Ball and Eusama Oman (Athysanini: Platymetopiina), placement n.; Cerrillus Oman (Athysanini), placement n.; Scaphotettix Matsumura and Agrica Strand (Mukariini), placement n.; Loralia Evans and Phlogotettix Ribaut (Deltocephalinae, unplaced to tribe), placement n. The recognition of Scaphoideini Oman 1943 as a nomen nudum results in the following placements: Acunasus DeLong, Cantura Oman, Danbara Oman, Osbornellus Ball, Prescottia Ball, Scaphodhara Viraktamath & Mohan, Scaphoideus Uhl...

Abstract.  The phylogenetic analysis of ninety‐two adult morphological characters supports the treatment of Nirvaninae as a junior synonym of Evacanthinae and the redefinition of Evacanthinae to include the tribes Nirvanini, Balbillini, Evacanthini and Pagaroniini. The analysis indicates that Nirvaninae, as previously defined, is polyphyletic. A key to tribes and Neotropical genera is provided and diagnostic features for these taxa are reviewed. Jassoqualus Kramer, Neonirvana Oman, Synogonia Melichar (=Jassopronus Nielson & Godoy, syn.n.) and Tahura Melichar are retained within Nirvanini and two new Neotropical genera of this tribe are described and illustrated: Antillonirvana, gen.n., based on two new species from the Dominican Republic and one from Cuba; and Chibchanirvana, gen.n., based on two new species from Colombia. Pentoffia Kramer and Evanirvana Hill are treated as incertae sedis within Evacanthinae. Six new species of Pentoffia, a new species of Synogonia, a new species of Jassoqualus, two new species of Neonirvana and eleven new species of Tahura, all from South America, are also described and illustrated. The following taxa included previously in Nirvaninae are excluded from Evacanthinae, sensu lato: Tungurahuala Kramer to Cicadellinae; Columbonirvana Linnavuori to Typhlocybinae; Macroceratogoniini to Coelidiinae; Occinirvanini Evans to Deltocephalinae. Omaranus Distant, placed previously in Occinirvanini, is transferred to Doraturini (Deltocephalinae).

Single-strand conformation polymorphism (SSCP) analysis detects single point mutations in DNA molecules. We demonstrate that SSCP analysis of mitochondrial ribosomal DNA (rDNA) genes is a sensitive taxonomic tool because these genes often differ at numerous sites among closely related species. Using conserved primers, portions of the 12S or 16S rDNA genes were amplified using the polymerase chain reaction (PCR) in congeneric species of ticks, leafhoppers, mosquitoes, and closely related endoparasitic wasps. SSCP was performed and products were visualized with silver staining. Species-specific patterns were observed in all taxa. Intraspecific variation at the level of single nucleotide substitutions was detected. SSCP diagnostics are less expensive and time consuming to develop than PCR with species-specific primers, and, unlike PCR with arbitrary primers, there is minimal concern with DNA contamination from non-target organisms.

Homologies among traditional morphological characters in the Membracoidea (sensu futo ) are reassessed and the phylogenetic relationships among higher membracoid taxa are explored, incorporating new morphological evidence from nymphs and adults. Weighted and unweighted parsimony analyses of a matrix of sixty-three characters and thirty-nine OTUs representing the families Aetalionidae, Cicadellidae, Melizoderidae and Membracidae, and an outgroup (superfamily Cercopoidea) yielded various topologies that were largely congruent but presented alternative hypotheses of relationships among the Membracidae. These analyses indicate that the superfamily consists of the following clades: Cicadellidae + (Melizoderidae + (Aetalionidae + Membracidae)). The family Membracidae, traditionally characterized by the presence of a posterior pronotal process, apparently gave rise to Nicomia StZl and other genera that lack this process.