Discolopeus diacaenus Stiller 2019, sp.n.
Creators: name: Stiller, Michael
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Cicadellidae
Discolopeus
Discolopeus diacaenus

description: Discolopeus diacaenus sp.n.
Figs 1 a–n, 5a–l, 6g, 6h, 18a, 18b.
Diagnosis. Crown elongate. Subgenital plate scalpiform; ratio of length to width 1.67–2.08. Aedeagal shaft with paired apical or medial teeth; shaft straight, tubular; apex membranous, base sclerotized; dorsal apodeme in dorsal view C-shaped; aedeagal process thin, gracile, elongate, base free. Style apophysis digitate, short. Connective with transverse bar straight, arms short. Pygofer lobe with narrow digitate ventral process.
Etymology. The name of the species is made up with two nouns in apposition, from the Greek, di (two) and akaina, (tooth), referring to the two, paired teeth on the shaft.
Male, female and nymph. Color. Generally ochraceous to stramineous. The long series of specimens from Biesiesfontein with three forms, specimens from other localities as in the latter two points.
1. Rarely pale yellow, with small paired spots on crown (Fig. 5a), specimens not teneral, all collected at same time, treated similarly.
2. Ochraceous to stramineous with few, small light to dark brown markings on crown or without markings on disc, pronotum and tegmina (Figs 5b, 5c, 6g).
3. Ochraceous with distinct dark brown markings on crown and light to dark brown circular spot on disc (Figs 5 d–f, 6h).
Nymphs examined were all of similar size. Nymphs from Biesiesfontein with variable colour forms: Light brown or dark brown longitudinal marking, narrowed in thorax, wide across abdomen, longitudinal line sometimes narrow, rarely yellow and without marking. Nymphs from Wiedouw similar to nymphs from Biesiesfontein. Large and small nymphs from Rondekop with narrow, light brown median longitudinal line.
Male. Measurements. Overall length 3.18–3.56 mm; crown length 0.44–0.52 mm; crown length next to eye 0.38–0.43 mm; pronotum length 0.35–0.39 mm; head width 1.04–1.12mm; pronotum width 0.95–1.05 mm; ocellus diameter 25.2–30.8 µm; interocellar distance 31.7–44.7 µm.
Male. Genitalia. Tergite X ventrally with anterior membranous concavity (Fig. 1b). Genital capsule elongate, anteriorly with apodeme (Figs 1a, 1b). Pygofer lobe narrowly rounded elongate process; group of up to 15 macrosetae dorsomedially; medial surface with numerous short stout setae (Fig. 1b). Subgenital plate apex narrowly rounded; medial margin straight, subparallel, lateral margin curvate (Fig. 1c); numerous macrosetae in distal half, marginally and submarginally. Ratio of subgenital plate length medially/greatest width = 1.67–2.08 (n=31). Style dorsally with right angled preapical lobe, apophysis digitate (Figs 1l, 1m)). Aedeagal shaft straight, tubular, with dorsomedial or dorsoapical paired tooth (Figs 1 d–g), apex of shaft desclerotized; dorsal apodeme inverted C-shaped with wide, compressed arms anteriorly; aedeagus, style and paraphysis, laterally as in Fig. 1h; serrate apex of paraphysis as in Fig. 1i. Connective in posterior view as in Fig. 1j, dorsally in Fig. 1k. Abdominal apodeme as in Figs 2a, 2b.
Female. Measurements. Overall length 3.56–3.93 mm; crown length 0.49–0.55 mm; crown length next to eye 0.41–0.45 mm; pronotum length 0.39–0.43 mm; head width 1.1 2– 1.19 mm; pronotum width 1.05–1.13 mm; ocellus diameter 25.9–30.1 µm; interocellar distance 38.3–48.2 µm.
Female. Genitalia. Sternite VII posterior margin with wide, shallow V-shaped or uniformly concave notch (Figs 1n, 2 c–f), width of notch about as wide as sternite at distal margin. Sternite VII of Rondekop specimen with narrower, V-shaped notch (Fig. 2f). Valvifer 1 about as long as wide, posterior margin uniformly rounded (similar to that of D. lissus in Figs 3k, 3m), bases attached to each other membranously.
Material examined. Holotype male. Northern Cape Province. CCDL18463, Biesiesfontein farm south Springbok, -29.75, 17.9333, 2002/09/29, M. Stiller, sweeping Galenia africana Aizoaceae. Paratypes. 102♂, 86♀, 79 nymphs. Northern Cape Province. CCDL26027, Calvinia Augustfontein, -31.6166, 19.35, 1947/09/15, museum expedition; 1♀, CCDL26025, Bitterfontein, -31.05, 18.2667, 1976/11/28, J.G. Theron, sweeping; 13♂, 8♀, CCDL26026, Calvinia, -31.4666, 19.7833, 1978/02/02, J.G. Theron, sweeping Galenia africana (Aizoaceae, not repeated below); 10♂, 2♀, CCDL26028, Garies, -30.5633, 17.98976, 1983/01/20, J.G. Theron, sweeping; 2♂, 3♀, CCDL18455, Loeriesfontein 20km South, -31.1167, 19.2667, 2002/07/10, M. Stiller, sweeping Galenia africana; 3♂, 2♀, CCDL18456, Loeriesfontein 20km south, -31.1167, 19.2667, 2002/07/10, M. Stiller, sweeping Galenia fruticosa var fruticosa; 17♂, 13♀, 29 nymphs, Ibid. holotype; 1♂, CCDL18464, Biesiesfontein farm south Springbok, -29.75, 17.9333, 2002/09/29, M. Stiller, sweeping Berkheya canescens Asteraceae; 1♀, CCDL18465, Biesiesfontein farm south Springbok, -29.75, 17.9333, 2002/09/29, M. Stiller, sweeping Zygophyllum morgsana Zygophyllaceae; 1♂, 1♀, CCDL18466, Biesiesfontein farm south Springbok, -29.75, 17.9333, 2002/09/29, M. Stiller, sweeping Pteronia divaricata Asteraceae; 1♀, CCDL18467, Bitterfontein 5km N, -30.9833, 18.25, 2002/ 10/03, M. Stiller, sweeping Galenia africana; 1♂, 1♀, CCDL18457, Nieuwoudtville 20km N, -31.2333, 19.2, 2002/10/07, M. Stiller, sweeping Galenia africana; 4♂, 16♀, 12 nymphs, CCDL18462, Doring River waterfall N Nieuwoudtville, -31.3167, 19.1167, 2002/10/07, M. Stiller, sweeping Galenia africana. Western Cape Province. 1♂, 5♀, CCDL26233, De Doorns, -33.4667, 19.7167, 1971/05/02, M.W. Strydom; 3♂, 4♀, CCDL26035, Nuwerus, -31.1483, 18.35479, 1971/10/11, J.G. Theron, sweeping; 3♂, CCDL26036, Robertson near Langvlei, -33.7605, 19.7419, 1973/03/31, J.G. Theron, sweeping; 1♀, CCDL26037, Witkranspoort, Prince Albert, -33.25, 22.25, 1973/04/07, J.G. Theron, sweeping; 1♂, 1♀, CCDL26254, Vanrhynsdorp, -31.6, 18.7333, 1976/09/ 15, J.G. Theron, sweeping; 4♂, CCDL26033, Clanwilliam Dam, -30.2167, 18.9, 1976/12/26, J.G. Theron, sweeping Galenia africana; 5♂, 1♀, CCDL26024, Calitzdorp, -33.533, 21.6833, 1977/04/02, J.G. Theron, sweeping Galenia africana; 1♂, CCDL26030, Klawer, -31.7741, 18.6245, 1978/01/30, J.G. Theron, sweeping; 2♂, 3♀, CCDL18468, Vanrhynsdorp, -31.6, 18.7333, 1978/01/31, J.G. Theron, sweeping Galenia africana; 1♀, CCDL26034, Clanwilliam, -32.1667, 18.8833, 1979/08/10, J.G. Theron, sweeping; 1♂, 1♀, CCDL26039, Piketberg Piekenierskloof, -32.6333, 18.9166, 1983/09/02, J.G. Theron, sweeping; 1♀, CCDL07919, Klaarstroom, -33.3167, 22.55, 1990/02/10, V.M. Uys, sweeping; 2♂, 6♀, 2 nymphs, CCDL18458, Wiedouw farm base of Gifberg Pass, -31.7334, 18.76661, 2002/10/03, M. Stiller, sweeping Lebeckia multiflora Fabaceae; 7♂, 6♀, 8 nymphs, CCDL18460, Wiedouw farm base of Gifberg Pass, -31.7334, 18.76661, 2002/10/03, M. Stiller, sweeping Galenia africana; 1♀, CCDL18461, Wiedouw farm base of Gifberg Pass, -31.7334, 18.76661, 2002/10/03, M. Stiller, sweeping Zygophyllum morgsana Zygophyllaceae; 1♂, 1♀, CCDL18459, Wiedouw farm base of Gifberg Pass, -31.7334, 18.76661, 2002/10/03, M. Stiller, sweeping Gorteria personata Asteraceae; 1♂, CCDL18793, Leipzig farm east Worcester, -33.65, 19.6333, 2004/12/12, M. Stiller, sweeping Galenia sp.; 2♂, 1♀, CCDL26232, Oudtshoorn 5km south, -33.64904, 22.22212, 2015/05/05, M. Stiller, DVac Pteronia sp. Asteraceae; 11♂, 2♀, 28 nymphs, CCDL26231, Rondekop farm, -33.45157, 23.17649, 2015/05/06, M. Stiller, DVac Galenia sp.
Remarks. This is a variable species with distinct markings on the crown or sometimes without markings, or rarely yellow. Genitalia are also variable, with two states recognized by the position of the teeth on the aedeagal shaft. Specimens with subapical teeth were from Biesiesfontein, Bitterfontein, Calitzdorp, Calvinia, Clanwilliam, Doring River, Garies, Klawer, Loeriesfontein, Nuwerus, Piketberg and Wiedouw. Apical teeth were found in specimens from Augustfontein, Calvinia, De Doorns, Leeukopsand, Rondekop and Vanrhynsdorp. Despite the clear distinction in the position of the paired spines on the aedeagal shaft, no other differences were observed to support the splitting of this group into two species. The pygofer lobe of one dissected specimen from Rondekop was triangular, whereas all other four dissected specimens displayed the digitate lobe.
Three species were collected at Biesiesfontein, namely D. diacaenus, D. colopeus and D. arctus. The former two are smaller than D. arctus, with an elongate crown, whereas D. arctus has a short crown and colour pattern as in Figs 8a, 8b. The most common associated or feeding plant has a similar, but wider distribution (Fig. 18a) to the potential natural distribution of D. diacaenus (Fig. 18b). Records of plants on which this species was collected indicate the widest range of potential host plants of any species of the genus, but the species probably is most closely associated with the distribution of Galenia africana. The four records above with males females and nymphs from Biesiesfontein, Wiedouw, Doring River and Rondekop support this observation. This plant has been well examined for its toxicity (see references above), medicinal value, ecology (Ripley et al. 2013) and environmental concerns (Saayman et al. 2017, Simons & Allsopp 2007), where grazing animals could possibly have promoted its spread, and even mentioned twice in Burchell (1822). Possibly the tendency of this plant to grow in overgrazed areas has also enabled D. diacaenus to expand it range. A similar well-established example is the guild of leafhoppers associated with renosterbos, Dicerothamnus rhinocerotis as described by Theron (1984a, b).
description: Published as part of Stiller, Michael, 2019, A new leafhopper genus Discolopeus and nine new species (Hemiptera, Cicadellidae, Deltocephalinae) associated with shrubs, trees and poisonous plants in South Africa, pp. 201-244 in Zootaxa 4559 (2) on pages 207-210, DOI: 10.11646/zootaxa.4559.2.1, http://zenodo.org/record/2626811