Vilargus Theron 1975: 198

Stiller, M., 2010, Revision of Vilargus Theron (Hemiptera: Cicadellidae: Deltocephalinae) from South Africa, Zootaxa 2674 (1), pp. 1-25 : 2-4

publication ID	https://doi.org/ 10.11646/zootaxa.2468.1.1
persistent identifier	https://treatment.plazi.org/id/D11C8787-7D43-FFDC-FF11-6933FEF4FEEC
treatment provided by	Felipe
scientific name	Vilargus Theron 1975: 198
status

Treatment

Vilargus Theron 1975: 198 View in CoL .

Type species: Deltocephalus pumilicans Naudé, 1926: 49 ; by original designation.

Type locality. Viljoen’s Pass [ South Africa, Western Cape Province, Viljoen’s Pass north of Grabouw, c. 34°04ʹS 19°04ʹE] GoogleMaps .

Diagnosis. 2.0– 3.2 mm in length. Ochraceous. Alary polymorphic, macropters rare. Aedeagus modified, usually with basal, lateral or ventral appendage of variable length, arising from preatrium, or shaft; or rarely absent, with shaft apex expanded asymmetrically; gonopore apical or subapical; aedeagus usually articulated with connective. Plate variable, usually short and rounded or truncate, sometimes acutely triangular, or with narrow, truncate or rounded posterior process. Sternite 7 of female with various configurations: posterior medial, wide, shallow notch (four species); notch narrow (one species); raised notch flanked by rounded lobes (one species); short, blunt medial ligula (one species).

Male and female. Dimensions. Head 1.0–1.1 times wider than pronotum. Vertex 1.3–1.6 times longer medially than length next to eyes; anteriorly rounded to face; discal region smooth, fontal region and face granular. Clypeus with horizontal arcs; clypellus narrowing distally. Gena below lorum about as wide as ocellocular distance. Ocellus separated from eye by distance 1.1–1.6 times the diameter of ocellus. Lateral margins of pronotum very short, non-carinate. Brachypterous forms common (occasionally up to four abdominal segments visible, commonly pygofer and tergite 8 visible, tergite 7 partially visible (e.g. Figs 2, 5 View FIGURES 1–6 , 9 View FIGURES 7–14 , 18 View FIGURES 15–21 )), macropters and submacropters rare, more common in females (tegmina and hind wing as long as or extending beyond apex of abdomen (e.g. Figs 20, 21 View FIGURES 15–21 , 33 View FIGURES 28–34 )). Tegmina in brachypter without appendix or reduced, four reduced apical cells, 3 closed anteapical cells, veins wide, often pigmented, basal costal and opaque Tegmina in macropter with narrow appendix, apical cells elongate, 3 closed anteapical cells, veins narrow, pigmentation indistinct, cells sometimes with fuscous markings, otherwise translucent. Hind wing of brachypter reduced, 0.3–0.5 times as long as length of forewing. Hind wing of macropter normal, four anteapical cells, R 2+3, median, cubitus 1 and 2, postcubitus, vanal 1 and 2 and jugal lobe. Spinulation of protibia 1+4. Profemur setal row AV short, setae relatively thick, intercalary row up to about three times longer than AV, AV 1 slightly longer and thicker than intercalary setae; AM 1 close to and slightly longer and sometimes darker than AV 1. Mesotibial setal formula 4+4. Metafemoral setal formula 2+2+1, apical pair slightly shorter than subapical setae, medial pair of different length and thickness, distal seta longer than other setae.

Male. Genitalia. Aedeagus variable, usually with basal (e.g. Figs 44 View FIGURES 43–51 , 69 View FIGURES 68–85 ), lateral (e.g. Figs 53 View FIGURES 52–59 , 93 View FIGURES 92–103 , 104 View FIGURES 104–115 ) or ventral appendage ( Figs 36 View FIGURES 35–42 , 87 View FIGURES 86–91 ), appendage of variable length, arising from atrium, preatrium; or rarely shaft without appendage, then shaft with apex modified asymmetrically ( Figs 60, 61 View FIGURES 60–67 ); gonopore apical or subapical; preatrium articulated with connective.

Connective linear, stem and arms of similar length, sometimes arms asymmetrical, with one arm more curved, the other arm more straight (e.g. Figs 45 View FIGURES 43–51 , 54 View FIGURES 52–59 , 70 View FIGURES 68–85 , 94 View FIGURES 92–103 , 106 View FIGURES 104–115 ); articulating with aedeagus.

Style with conspicuous preapical angle; dorsal apophysis about half as wide as width across preapical angle, apex truncated or acute, directed lateroposteriad, of variable position relative to plate, with ventral teeth; distal and basal parts of similar length; anterior medial lobe right-angled (e.g. Figs 46 View FIGURES 43–51 , 71 View FIGURES 68–85 , 89 View FIGURES 86–91 ) or acutely angled to base (e.g. Figs 38 View FIGURES 35–42 , 55 View FIGURES 52–59 , 63 View FIGURES 60–67 , 107 View FIGURES 104–115 ); anterior lateral lobe directed anteriad, weakly sclerotized.

Plate of variable shape, usually broadly triangular with rounded posterior margin ( Figs 39 View FIGURES 35–42 , 47 View FIGURES 43–51 , 72, 73 View FIGURES 68–85 ), sometimes acutely triangular with acute posterior margin ( Fig. 99 View FIGURES 92–103 ); or posterior margin with narrow truncate or rounded posterior process ( Figs 56 View FIGURES 52–59 , 64 View FIGURES 60–67 ) or with posterior margin broadly truncate ( Fig. 90 View FIGURES 86–91 , 108 View FIGURES 104–115 ); uniseriate macrosetae along lateral margin.

Valve large, wide, apex triangular, base somewhat rectangular.

Pygofer setose; posterodorsal angle usually lobate (reduced as in Fig. 49 View FIGURES 43–51 ); base of pygofer lobe less than half as wide as width of pygofer, near dorsal margin of pygofer, apex acute ( Figs 66 View FIGURES 60–67 , 74 View FIGURES 68–85 , 91 View FIGURES 86–91 , 110 View FIGURES 104–115 ) or blunt ( Figs 41 View FIGURES 35–42 , 58 View FIGURES 52–59 , 101, 102 View FIGURES 92–103 ); posteromedial margins curved medially, sometimes with sclerotized ridge ( Figs 39 View FIGURES 35–42 , 58 View FIGURES 52–59 ). Pygofer, dorsally, with anal tube shallowly incised; tergite 10 weakly sclerotized, about as long as tergite 11; articulating dorsally with internal sclerotized ridge; ventrally articulating with dorsal apodeme of aedeagus (e.g. Figs 40, 41 View FIGURES 35–42 , 48, 49 View FIGURES 43–51 , 100, 101 View FIGURES 92–103 ).

Female. Genitalia. Sternite 7 variable, usually with rounded notch, of variable depth and width.

a. Notch shallow, rounded, variable depth, width; e.g. Vilargus dentulicans sp. n. ( Fig. 59 View FIGURES 52–59 ), V. lobulicans sp.

n. ( Fig. 67 View FIGURES 60–67 ), V. pumilicans sp. n. ( Figs 77–79 View FIGURES 68–85 ) and V. trunculicans sp. n. ( Figs 111–115 View FIGURES 104–115 ). b. Notch parallel-sided, narrow; e.g. Vilargus bicornicans sp. n. ( Fig. 42 View FIGURES 35–42 ). c. Posterior margin with narrow, rectangular ligula; e.g. Vilargus triquetricans sp. n. ( Fig. 103 View FIGURES 92–103 ). d. Margin variable, generally with shallow notch flanked by variably narrow, long lobes; e.g. Vilargus budenticans sp. n. ( Figs 50, 51 View FIGURES 43–51 ).

Valvula 3: 2–4 macrosetae, usually more distal, up to 14–24 µm long, about 1.0 µm wide at base, smaller setae, up to 9–13 µm in length, usually more proximal; number of larger setae variable between left and right valvula.

Valvula 2: Variable serration, as follows: V. triquetricans teeth uniformly rounded, rounded trough; V. dentulicans and V. bicornicans apical teeth very small, distal teeth contiguous; V. lobulicans and V. budenticans teeth broadly rounded, narrow trough, posterior margin of tooth with small teeth, anterior margin smooth; V. trunculicans shallow, small teeth.

Valvula 1: Lanceolate, with dorsal microsculpture reticulate ( Vilargus pumilicans , V. lobulicans , V. trunculicans ) or imbricate ( V. dentulicans , V. bicornicans ).

Valvifers: First and second valvifer shape and sensory setae, similar in all species.

Relationships. Vilargus closely resembles Pravistylus in colour, shape and wing length. However, the configuration of the male genitalia differs considerably between these two genera. In Pravistylus the aedeagus usually has a symmetrical shaft, that is generally C-shaped in lateral view, without basal, lateral or ventral process or without the preatrium or rarely with the atrium produced into a spine-like process. The plate in Pravistylus is more elaborate, being produced at the apex, notched or sinuous. In contrast the aedeagus of Vilargus bears a basal, lateral or ventral process on the atrium, preatrium or base of the aedeagal shaft. The plate in Vilargus is usually less modified, and is short and rounded or truncate, with two exceptions that resemble that of Pravistylus . The style of Vilargus generally has the basal part differing from that of Pravistylus . In Vilargus the anterior medial lobe is usually short and angled acutely to the distal part of the style, or sometimes it is right angled to the distal part. The anterior lateral lobe is usually well developed. In Pravistylus the style usually has the anterior medial lobe elongate, variably angled, and the anterior lateral lobe reduced.

The females of Vilargus and Pravistylus are more difficult to distinguish. The shape of the posterior margin of the sternite 7 in Vilargus is usually notched or sometimes ligulate. In Pravistylus the sternite 7 is usually ligulate and rarely notched. In these exceptions species recognition is facilitated by associated male genitalia.