Geelus driehoekdraad Stiller 2020, sp.n.
Creators: name: Stiller, Michael
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Cicadellidae
Geelus
Geelus driehoekdraad

description: Geelus driehoekdraad sp.n.   
(Figs 13 A–L)  
 Diagnosis. Aedeagal shaft elongate, tubular, with apex to subapex with acute, triangular, lateral tooth-like flange. Pygofer lobe short, triangular, apex medially with process orientation mediad. Subgenital plate elongate, with uniseriate macrosetae along most of lateral margin. Female sternite 7 with V-shaped notch flanked by rounded lateral margins.   
 Etymology. Afrikaans nouns in apposition, drie, three, hoek, corner, angle, and draad, wire, for the delicate triangular process at the apex of the aedeagal shaft. Gender masculine.   
 Male. Measurements. n=31. Length from apex of crown to apex of tegmina 5.23–5.49 mm. Crown median length 0.35–0.39 mm. Crown length next to eye 0.32–0.35 mm. Pronotum length 0.53–0.56 mm. Head width across eyes 1.46–1.52 mm. Pronotum width 1.36–1.41 mm. Ocellus diameter 41.0–54.8 μm; interocular distance 74.7– 94.2 µm. Apical angle of crown 127.7°±2.6°.   
 Pygofer lobe. Process orientation medial, rarely ventral, apices overlap; process denticulation, 2–4 teeth (Fig. 13G); process origin apical; process curvature sublinear; anterior apodeme short, dorsal. Apex of pygofer lobe extended beyond apex of subgenital plate (Fig. 13F).   
 Anal tube. Conical (Fig. 13J), incised about half way into pygofer.   
 Subgenital plate. Number of macrosetae 6–10; medioposterior angle variable, right-angle or acute; length: width 1.5–1.8; position of macrosetae across three quarters distally on subgenital plate (Fig. 13H).   
 Valve. Shape obtuse triangular (Fig. 13H).   
 Style. Apophysis with subapical tooth absent; apical tooth ventral; apophysis width about two thirds of width across preapical lobe; ratio of length to width of apophysis 5.5–6.9 (Fig. 13E).   
 Connective. Stem length relative to arm length one fifth length of arms; stem width relative to width across arms half as wide as greatest width across arms (Fig. 13I).   
 Aedeagus. Shaft thin, tubular; apex to subapex of shaft triangular laterally; denticulation of shaft basally, edentate; curvature of shaft, straight; dorsal apodeme, in lateral view, elongate, curvate, base right angled; preatrium reduced (Figs 13 A–D).   
 Female. Measurements. n=24. Length from apex of crown to apex of tegmina 5.74–5.99 mm. Crown median length 0.37–0.41 mm. Crown length next to eye 0.34–0.38 mm. Pronotum length 0.58–0.61 mm. Head width across eyes 1.61–1.66 mm. Pronotum width 1.50–1.56 mm. Ocellus diameter 47.9–61.7 μm; interocular distance 81.7–94.4 µm. Apical angle of crown 129.2°±2.2°.   
 Sternite 7. Shape of posterior margin deep V-shaped notch, lateral margin broadly rounded (Fig. 13K).   
 Valvifer 1. Symmetrical (Fig. 13L) or ventral margin produced narrowly, asymmetrical.   
 Material examined. Holotype male. South Africa, Western Cape Province, CCDL26919, Wiedouw Farm base of Gifberg Pass, -31.7334, 18.7666, 3–10.x.2002, M. Stiller, sweeping, low growing vegetation (grass and forbs) in area where bush was cleared/burned (SANC). Paratypes. 34♂, 23♀, 23 nymphs. Western Cape Province, records below all this locality: Wiedouw Farm base of Gifberg Pass, -31.7334, 18.7666, 3–10.x.2002, M. Stiller, sweeping. 1♂, CDL26922, Wiborgia mucronata, Fabaceae; 5♂, 1♀, CCDL 26921, indeterminable plant near Phylica; 3♂, 5 nymphs, CCDL 26920, two unidentified plants; 24♂, 21♀, 18 nymphs, ibid. holotype; 1♂, 1♀, CCDL 18847, Aristida zeyheri subsp. mucropus Poaceae and mainly Aristida vestita, Poaceae (BMNH, INHS, SANC).   
 Remarks. Geelus driehoekdraad and G. dundraad have overlapping distributions at Wiedouw, with the former only known from this locality, albeit from a long series of specimens. Fourteen dissected males had the elongate style apophysis, elongate subgenital plate (length: width 1.5–1.8), triangular apex of the aedeagal shaft and medially curved pygofer process. The style apophysis in G. dundraad is always shorter (length: width, 1.1–1.3), with three variants, but not resembling that of the former. The apex of the shaft of G. dundraad is immaculate, and in G. driehoekdraad it is laterally triangular. The pygofer process in G. dundraad is curved mediodorsally or dorsally. None of the many examined specimens (n=45) of G. dundraad showed signs of damage to the apex, nor of the 14 dissected males of G. driehoekdraad. Females of these two species from Wiedouw cannot be distinguished readily, with the small differences in shape of the valvifer 1 not considered reliable. Females of G. driehoekdraad are slightly larger, with length from apex of crown to apex of tegmina 5.74–5.99 mm and head width 1.61–1.66 mm, with similar dimensions of other parts. Females of G. dundraad are 3.72–4.11 mm and 1.48–1.58 mm respectively. In males of G. driehoekdraad only length from apex of crown to apex of tegmina (5.23–5.49 mm) supersedes that of G. dundraad (3.47–3.97 mm).
description: Published as part of Stiller, Michael, 2020, A new leafhopper genus Geelus and 12 new species (Hemiptera, Cicadellidae Deltocephalinae) from Southern Africa, pp. 301-344 in Zootaxa 4786 (3) on pages 326-328, DOI: 10.11646/zootaxa.4786.3.1, http://zenodo.org/record/3876635