Reclassification of the leafhopper subfamily Deltocephalinae with emphasis on the polyphyletic tribe Athysanini

NSF Systematic Biology Program DEB 0841612

James Zahnsier and C. H. Dietrich

Based on numbers of described species (5,987), Deltocephalinae is the largest subfamily of leafhoppers (Hemiptera: Cicadellidae). Ecological and evolutionary studies of this ubiquitous, ecologically and economically important group are hindered by the lack of identification keys and a stable, phylogenetically based classification. Recent analyses indicate that, while Deltocephalinae (sensu lato, including some taxa recently treated as separate subfamilies) is monophyletic, its largest tribe, Athysanini (277 genera and 1965 species), is polyphyletic. Athysanini has long been a dumping ground for genera lacking the synapomorphies used to characterize other deltocephaline tribes. Morphology- and DNA-sequence-based phylogenies have revealed previously unrecognized deltocephaline clades and new morphological features useful for diagnosing tribes; these provide the basis for a revised tribal classification. However, because current datasets comprise only ~12% of known genera of Athysanini, the correct tribal placements of the remaining athysanine genera need to be determined through morphological study and more detailed phylogenetic analysis. The large size of the group necessitates the use of efficient electronic tools to synthesize morphological and nomenclatural information, and facilitate the creation of user-friendly identification tools.

The goals of the proposed project are to: 1) expand and re-analyze an existing morphological dataset to include ca. 310 genera representing all previously recognized tribes of Deltocephalinae; 2) assign previously described genera to tribes, with particular emphasis on determining the correct placements of the 277 genera currently included in the polyphyletic tribe Athysanini; 3) update an existing database and online interactive key to tribes and genera; 4) publish a revised, phylogenetically-based higher classification, including descriptions, lists of included genera, and images for all tribes and subtribes, and a key to tribes and subtribes. Morphological, nomenclatural, distributional, and bibliographic data for Deltocephalinae will be synthesized using 3I (Internet-accessible Interactive Identification), software developed in the PIs’ lab comprising a specimen-level database and ASP-driven web interfaces that facilitate production of Internet-accessible interactive keys and virtual monographs. Recent applications of 3I in the PIs’ lab include species-level revisions of two large (>500 spp.) cicadellid groups and a key to deltocephaline tribes. Phylogenetic analysis of morphological data will be used to inform decisions on the tribal placements of genera. Results will be made available via the Internet and through print publication.

More information on Deltocephalinae and interactive keys are available here.