Osbornellus Ball 1932

Domínguez, Edwin & Godoy, Carolina, 2010, Taxonomic review of the genus Osbornellus Ball (Hemiptera: Cicadellidae) in Central America 2702, Zootaxa 2702, pp. 1-106 : 9-12

Genus Osbornellus Ball 1932

Type species. Scaphoideus auronitens Provancher, 1889:276 .

Diagnosis. In external morphology this genus is close to Scaphoideus , but the latter has the costal area of the forewing with more reflexed veinlets near the external subapical cell and the male lacks filamentous plates ( Oman 1949, Linnavuori 1959).

Male 3.5–7.0 mm. General color brownish-yellow, usually with dark brown markings. Head about as wide as pronotum or slightly narrower. Antennae long. Face elongate, bluntly triangular. Clypeus elongate, widened apically; genae broad, lateral margins slightly sinuate, lorum large, almost reaching lateral margins of genae. Anterior margin of vertex roundly angulate in dorsal view; ocelli large and close to eyes. Anterior wing long and slender, appendix distinct; pale yellowish, transparent, with spot, two closed anteapical cells, outer anteapical cell parallel to costa, slightly reflexed veinlet from each end to costa ( Fig. 64a, b, c).

Pygofer projected posteriorly, with numerous macrosetae, expanded on dorsal side beyond base, apical portion narrowed and usually tapered ( Fig. 2a, b, c). Male plate with apical portion elongated into filamentous, often plumose, ventral processes. Style with basal part wide and apical part slender; angle between the parts obtuse; apex truncate, with spine in dorsal view, preapical lobule with fine setae. Connective Y-shaped. Aedeagus bilaterally symmetrical in ventral view; slender at base, with short; dorsal projection near base; main shaft usually long, slender, curved dorsad; bearing pair ventral processes (rarely absent). Female sternite VII at least twice as long as preceding sternite, usually produced medially.

Discussion. All species in the genus share certain characters, such as the two closed anteapical cells, outer anteapical cell parallel to costa in anterior wing, and male plate with apical portion elongated into filaments. These characters might be synapomorphies supporting the monophyly of the genus, but a more extensive study is required to confirm this. Linnavuori (1959) divided the genus in three subgenera: Osbornellus, Sorbonellus and Nereius . The first has an apical gonopore, the second a subapical gonopore, and Nereius has a claw-like stylus and the outer subapical cell in the forewing very small. We found it convenient to use the four species groups recognized by Martinson (1977), based on the marks or bands of color on the head ( Figs. 1a– d).

1. O. auronitens group: Margin of vertex with narrow lines; upper dark line not interrupted in middle; with area behind marginal lines long and narrrow, not appearing triangular, reaching ocelli which are bordered with black; pale band along posterior margin of vertex, ends not extended into red band, usually with no brown markings along anterior edge ( Fig. 1a). Pronotum orange-yellow, anterior margin lighter, with bright orange spot in middle. Scutellum the same color with large, darker spots in basal angle, white spots at tip of basal angle and halfway along lateral margins. Anterior wing transparent yellowish, apices marked with dark brown; outer anteapical cell generally shorter than usual. Pygofer of male longer than broad, projected posteriorly, rounded at apex ( Fig. 2a). Plate broad at base, long medial portion and apex narrow, generally long.

2. O. rarus group: Dorsum of head with mark on posterior half of vertex formed by broad, pale yellow band, generally bordered with brown along coronal suture; it may or may not extend to the ocelli; anteriorly with small pale spots at apex of vertex and with pale curved dashes to each side along margin and a more or less triangular spot behind; with semitriangular or semiquadrate black spot behind each ocellus, with pale spot on internal margin ( Fig. 1b). Anterior wing transparent, largely whitish, often heavily marked, several cells with elongate brown spots, usually with brown spots along costa and commissural line. Pygofer of male longer than wide, margin broad and projected dorsally, or slightly concave or lobulate, sometimes projected and rounded posteriorly ( Fig. 2b, 2c). Triangular plates with wide base, wide middle portion, and narrow to very narrow apex, in general not very long; fold in lateral margin plumose; sometimes with wide base, short, rounded, with few short setae.

3. O. maesi group: Apex of vertex with transverse brown line, which is curved, and extends up to margins of eyes and reaches anterior part of ocelli; with wide, transverse, white band extending below ocelli. Middle part with broad, transverse, shiny yellow band, surrounded posteriorly by short, narrow, brown line. Posteriorly very broad, pale shiny yellow or orange band extends to eyes, across to coronal suture ( Fig. 1c). Pygofer of male longer than wide, apex attenuated and projected dorsally ( Fig. 2a). Plates with broad long base; middle portion and apex broad, plumose and rounded.

4. O. affinis group: Vertex pale to dark brown with small, light colored spots posteriorly and on both sides of coronal suture ( Fig. 1d). Pronotum pale yellow to brown, with faint band or with irregular light and dark bands along anterior margin. Scutellum light yellow. Wing with brown spots at apices of claval suture and claval veins, rarely also at ends of costal veinlets. Anterior wing pale yellow, with brown spots at apex of claval suture; claval veins, costal veinlets, and some cross-veins brown; usually with middle pair of brown spots along comissural line larger and darker than rest. Pygofer of male longer than wide, apex rounded and projected posteriorly ( Fig. 2a). Plates long and plumose, with base wide and short; middle and apical portion very narrow, tapered at apex.