James N. Zahniser
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All interactive keys were created with the software package 3I by Dmitri Dmitriev.
Taxonomic Names: All valid genus and species names of Deltocephalinae (~6700 valid species names) are up to date and are listed hierarchically. Synonyms, homonyms, and misspellings are also listed. If you should discover any discrepancies or have questions regarding the names, please contact me, and I will correct the database or may be able to provide more taxonomic information regarding your question. I thank Stu McKamey for generously providing preliminary lists of names and Dmitri Dmitriev for general assistance and for entering the misspellings into the database. Also, if you have any information you would like to contribute to the key and website (e.g. images), please contact me!
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This key recognizes a recent broader interpretation of the subfamily (Deltocephalinae sensu lato) that includes several tribes which were previously considered by Oman et al. (1990) to be separate subfamilies (Zahniser & Dietrich, 2010; 2013; Dietrich and Raktiov, 2002; Dietrich and Dmitriev, 2003). Phylogenetic analyses of Deltocephalinae and related groups based on morphological (Dietrich, 1999; Zahniser & Dietrich, 2008) and combined morphological and molecular data (Zahniser & Dietrich, 2010; 2013) showed that Deltocephalinae as defined by Oman et al (1990) is polyphyletic and that these other "delt-like" subfamilies have their closest relatives in Deltocephalinae. These phylogenetic studies have helped to define the subfamily and to suggest some relationships between tribes and genera, but much work is still needed to gain a more complete understanding of the relationships among the Deltocephalinae.
The largest and most poorly defined tribe of Deltocephalinae, Athysanini, may be difficult to separate from some other tribes in the key because it is so large, encompasses so much morphological diversity, and is not defined by any unique characters.
Athysanini is the largest tribe of Deltocephalinae (~250 genera, ~2200 spp.) and has long been a "dumping ground" in which taxonomists have placed genera which retain the plesiomorphic or most common conditions of some characters and lack the distinctive characters that define other tribes. Thus, this tribe contains a mix of some related and some unrelated genera, and is itself not defined by any universally shared characters. Recent phylogenetic analyses of Deltocephalinae confirm that the tribe is highly polyphyletic. Part of the difficulty in understanding this group results from the apparent lack of known morphological characters that are able to define related groups of genera. This situtation may stem from several causes: 1) the world fauna has not been comprehensively reviewed or compared; 2) high degrees of character evolution and homoplasy have blurred historical signal of phylogenetic relationships among these and other leafhoppers; 3) deltocephaline leafhoppers historically underwent a period rapid radiation which did not permit morphological or molecular characters to stabilize. It is likely that all of these explanations played some role in the currently unclear taxonomy and evolution of this group. In order to more fully understand the diversity and evolution of these leafhoppers, we are undertaking a comparative study of the genera of Athysanini.
This project is funded by a grant from the National Science Foundation's Revisionary Syntheses in Systematics program. Our project, "Reclassification of the leafhopper subfamily Deltocephalinae (Hemiptera: Cicadellidae) with emphasis on the polyphyletic tribe Athysanini (DEB 0841612)" has the following goals: 1) examine the type species and when possible other representatives of all genera of Athysanini and unplaced genera of Deltocephalinae, score morphological characters to be used in an online interactive key to the world genera, and provide high quality images for a generic level revision of the tribe; 2) identify morphological characters that are able to diagnose generic groups, and potetnially recognize such groups in a revised classification; 3) review the tribes of Deltocephalinae, clarifying their current circumscriptions and defining characters and updating an existing online key to deltocephaline tribes; and 4) conduct a phylogenetic analysis of genera of Athysanini using the morphological data gathered.