Athysanella (Amphipyga) Osborn

Zahniser, James N. & Hicks, Andrew, 2007, Three new species of Icaia Linnavuori (Hemiptera: Cicadellidae: Deltocephalinae) from Peru and distinction of the genus from Athysanella Baker, Zootaxa 1390, pp. 27-39 : 32

Athysanella (Amphipyga) Osborn

rubicunda Ball & Beamer placement reinstated from A. (Diphipyga) triodana Ball & Beamer placement reinstated from A. (Diphipyga)

Parsimony analysis of the characters in Table 1 yielded 21 most parsimonious (MP) trees, and the strict consensus tree ( Fig. 46 ) generally reflects the observations outlined above. Athysanella and Icaia were each recovered as monophyletic groups. Characters that supported the monophyly of Athysanella are the wide basal separation of the anterior arms of the connective (Figs. 38,39)— a character that was difficult to score for A. (Diphipyga) mexicana and I. straminea , and the presence of an apodeme above the aedeagus, although this character is not consistent in either genus. This phylogeny suggests that A. (Diphipyga) s. s. is basal with respect to the rest of Athysanella , apparently in agreement with our observations of the similarity in the male genitalia of A. (Diphipyga) s. s. and Icaia . A. (Diphipyga) s.s. was never resolved as a monophyletic group. The only character supporting the monophyly of Icaia is the presence of a pair of apical or subapical processes of the aedeagus— a character that is not universally shared among species of Icaia , but appears in 6 or 7 of the 9 described species. This character does not occur in Athysanella and rarely occurs in other genera of Chiasmini (one exception is Aconura Lethierry ). Icaia spp. lack the wide separation of the anterior arms of the connective which supported monophyly of Athysanella (including Diphipyga) and lack the characters defining the Athysanella clade A. Also, preliminary molecular data (Zahniser and Dietrich, unpublished) suggest that each genus is monophyletic. Thus, retention of Icaia as a genus separate from Athysanella is justified at this time. We did not identify any unambiguous characters that define Athysanella (including Diphipyga) or that would unite Icaia and Athysanella as a monophyletic group distinguishable from other chiasmine genera. Further collecting and morphological characterization of more species of Icaia will undoubtedly help to clarify the relationship between these genera and other Old World chiasmine genera.

The apparent lack of unique and shared characters in Icaia and overlap in character states with some species of Athysanella makes placing newly discovered species into Icaia somewhat difficult, but a combination of some external characters cited by Linnavuori (1973), especially of the head and face, and characters of the male genitalia identified here should separate Icaia spp. from most Athysanella . Placement of the new species described here in Icaia is based on the absence of characters defining other chiasmine genera, their similarity to other Icaia species externally, the short and falcate style apophysis, the mostly membranous segment X, and their South American distribution.

Figures

FIGURE 46. The strict consensus of 21 most parsimonious trees. Clade labeled “ A ” is referred to in the text. Numbers below branches indicate Bremer support values / bootstrap values over 50 %.