Cortona

Duan, Yani, Dietrich, Christopher H. & Zhang, Yalin, 2017, Revision of the South American grassland leafhopper genus Cortona Oman (Hemiptera: Cicadellidae: Deltocephalinae: Deltocephalini) with description of four new species from Argentina, Zootaxa 4242 (2), pp. 359-371 : 360-361

Cortona Oman

Cortona Oman, 1938: 390 . Type species: Cortona minuta Oman, 1938 .

Coloration and morphology. Overall coloration pale yellowish to orange, with darker markings, if present, restricted to legs and sternites, variable intraspecifically. Face mostly pale brown to orange with paired white arcs corresponding to muscle scars of frontoclypeus. Forewing hyaline. Mesosternum pale brown to orange. Legs and abdomen mostly pale, with or without small, symmetrically arranged dark maculae.

Head much wider than pronotum, crown flat, distance between eyes slightly narrower than eye width, anterior margin distinctly angulate in dorsal view, rounded to face, glabrous medially, finely granulose laterally; ocellus small, separated from eye by approximately one ocellar diameter on anterior margin. Face relatively flat, shagreen, width greater across eyes than length; frontoclypeus relatively narrow; clypeal suture usually well-developed, slightly arcuate; eye emarginate adjacent to antenna; antenna longer than width of head; gena obtusely emarginate below eye; lorum semicircular, narrower than anteclypeus, well separated from lateral and ventral margins of face; anteclypeus flat, slightly to moderately tapered from base to apex, apex truncate and even with lower margin of gena.

Pronotum with fine transverse striations, lateral margin very short, eye nearly touching forewing base. Forewing of male macropterous, with two anteapical cells, vein R usually with 3 branches (second branch sometimes missing), crossvein r-m1 long and oblique, m-cu2 absent (inner anteapical cell open), second apical cell narrower than first and third, clavus with crossvein connecting 1A with claval suture; appendix well-developed but narrow. Hind wing of male well-developed with venation complete. Forewing of female rarely as in male, usually brachypterous with apex obliquely truncate and not extended beyond posterior margin of abdominal segment IV, venation well delimited and as in male except apical cells extremely short and other cells also relatively short. Hind wing of female rarely as in male, usually vestigial. Front femur row AV with 5 setae moderately large and widely spaced in basal half, intercalary row with 7–8 fine setae; tibia with dorsal macrosetal formula 1+4. Middle femur relatively wide compared to front femur, with 7 stout AV setae in basal half and AV1 present. Hind femur macrosetal formula 2+2+1; tibia with ca. 15, 10, and 12 macrosetae in rows PD, AD, and AV, respectively, PD macrosetae alternating short and long, AD with short setae between macrosetae; tarsomere I with two rows of plantar setae, pecten with 3 platellae, medial and lateral setae of pecten tapered and slightly longer than platellae; tarsomere II with 2 platellae and 2 tapered flanking setae of same length.

Male genitalia. Pygofer weakly sclerotized dorsally, incised dorsally to or beyond midlength, without appendages, apex of lobe rounded, with numerous macrosetae in distal half. Segment X short and unsclerotized dorsally. Valve subtriangular with posterior margin sharply angulate. Subgenital plates articulated to valve, lateral margin concave, with uniseriate macrosetae arising laterally, apex acute, with several long, fine setae. Style with articulating arm short to long; preapical lobe distinct; apophysis fingerlike. Connective arms close to each other, stem long, fused to aedeagus. Aedeagus with shaft tubular or depressed, sinuate or curved dorsad in lateral view, with pair of appendages arising at or beyond midlength and extended distally (vestigial in C. concordica ), gonopore preapical on ventral surface.

Female abdomen. Tergite VIII with grouped macrosetae near lateral margin. Pygofer with numerous macrosetae laterally near base forming continuous band with larger group of macrosetae in distal half. Sternite VIII membranous or very weakly sclerotized, concealed by sternite VII in repose. Sternite VII truncate with median lobe arising preapically, overlapping posterior margin, varying in shape interspecifically. First valvula evenly tapered from near base to acuminate apex, dorsal sculpturing imbricate, extended to dorsal margin, ventral sculpturing reticulate. Second valvula very slightly broadened distad of dorsal cleft, then tapered to acuminate apex, dorsal margin irregularly serrate in distal half with teeth small and somewhat widely spaced.

Distribution. Argentina.

Remarks. Linnavuori (1959), Knight and Webb (1993), and Zahniser and Dietrich (2013) placed the genus Cortona in Macrostelini based on the forewing having only two anteapical cells, however, Oman et al. (1990) listed it under Deltocephalini . We place this genus in Deltocephalini based on characteristics of the male genitalia, particularly the linear connective fused to the aedeagus. In Linnavuori's (1959) key to genera, most species here included in Cortona key out to couplet 9 (aedeagus with long appendages). However, Cortona may be easily separated from genera that key to the same couplet in Linnavuori (1959), as well as other South American Deltocephalini , by the presence of only two anteapical cells in the forewing, the absence of a claw-like pygofer appendage (present in Tumupasa ), and absence of a distinct socle (present in Loreta (Bahitella) and Haldorus ). Overall, Cortona may be separated from other Deltocephalini by the following combination of characteristics: head much wider than pronotum; forewing with two anteapical cells; males macropterous and females usually brachypterous.

Cortona was previously known solely from the male holotype of the type species collected in 1931 from Loreto , Misiones Province, northern Argentina . Recent samples collected in Argentina, mostly by vacuum sampling in native grasslands, yielded additional specimens of the type species including the first females, as well as specimens of four new species, all represented by both males and females. In contrast to the males, which have fully developed wings, all but one of the female specimens studied are brachypterous (see remarks under individual species below). Brachypterous females of Cortona resemble those of Lonatura , a North American genus of Deltocephalini in which both males and females are usually brachypterous, but may be distinguished by the larger eyes, shorter lateral pronotal margin, and the presence of macrosetae on the tergum of the pregenital abdominal segment.