Zygon, Andrew Hamilton, K. G., 2014

Andrew Hamilton, K. G., 2014, The old-world Zygonini tr. nov. (Hemiptera, Cercopoidea, Clastopteridae), with new taxa from the related Machaerotinae, Zootaxa 3768 (4), pp. 437-459 : 450-451

Zygon gen. nov.

Type-species: Zygon desegregatum sp. nov., the only included species.

Etymology. zygon (n noun), Greek for “yoke”

Diagnosis. Head much narrower (0.70–0.65 ×) than pronotum, lateral margins of pronotum almost as long (0.8 ×) as interocular distance; antennal ledge small but prominent ( Fig. 1 C); antenna with arista arising near centre of postpedicel ( Fig. 27 C); postpedicel and base of arista as strongly imbricate as pedicel ( Fig. 27 D) almost concealing small, globular basiconic sensillum (b 1 in Fig. 38 ) flanked by an asymmetric pair of coeloconic sensilla (1 ventrally and 4 together in a dorsal pit, c1 and c 3 in Fig. 38 ) and a peglike coeloconic sensillum resembling a small basiconic sensillum (c1,c 3 in Fig. 27 D) beyond the coeloconic sensillum cluster; rostrum extending beyond hind trochanters; pronotum punctured, with obscure median ridge; scutellum sulcate. Tegmina densely punctate, opaque, veins strongly carinate throughout, forming 3 elongate anteapical cells, of which central one is more than half length of others and much longer than adjacent apical cell, basally closed by carinate vein ( Fig. 9 A). Hind wings each with 7 hooks on costal margin, 4 mounted on triangular process. Hind hind tibia short, broad, densely setose and with a single lateral spine located near midlength; tibial pectens broad, sometimes irregular, each with 11–12 spines, those of basitarsomere with 12–14 spines, of second tarsomere with 2–6 spines covered by long setae. Male anal tube with ringlike basal segment bearing a tiny pair of ventral lobes ( Fig. 9 C); paraprocts longer than 11th segment excluding epiproct; pygofer clearly divided into sclerous anterior two-thirds and membranous posterior one-third, with notch near dorsal margin; theca heavily sclerotized, stout, in lateral aspect abruptly angled at midlength, marginal serrations most clearly visible in lateral aspect, in posterior aspect ( Fig. 9 D) abruptly narrowed just before enlarged, cordate base, nearly parallel-margined above constriction almost to truncate tip. Ovipositor 2nd valvulae 1.8 mm long, crested on apical fifth, tip blunt ( Fig. 17A ).

Remarks. The small head contrasting with the wide, weakly bowed and elongate pronotum makes these insects appear to be wearing a yoke. The length of the apical cells differ considerably on the tegmina, but the middle one is always much shorter than its corresponding anteapical cell.

The highly imbricate arista arising in the centre of the postpedicel, and the two dissimilar forms of both basiconic and coeloconic sensilla are unique in Clastopteridae . These evidently are highly autapomorphic characters, perhaps representing a throw-back to the plesiomorphic condition of Cercopoidea, because the legs and genitalia show the close relationship between Zygon and Hemizygon .

Figures

FIGURES 1 – 4. New species of Zygonini, lateral aspect (A), dorsolateral aspect with pin erased (B), facial aspect (C) and hind legs (D). 1, Zygon desegregatum, male (A) and female (B) paratypes; 2, Pseudomachaerota cucullata, holotype; 3, Ambonga lanceolata, holotype; 4, Pseudoclastoptera irrubesco, holotype. Figs 1 and 3 A – B to same scale; Figs 2 and 4 A – B slightly larger; Figs C and D largest. Scale line: 1 mm.

FIGURES 18 – 32. Antennae of Clastopteridae: Clastopterinae (18 – 20) and Machaerotinae: Hindolini (21 – 23), Machaerotini (24 – 25) and Zygonini (26 – 32, boxed set). A, lateral aspect of head; B, detail of antennal and antenna ledge; C, tip of antenna, showing postpedicel; D, detail of postpedicel showing detail of pits, revealing 4 enclosed coeloconic sensilla in communal pits. 18, Clastoptera; 19, Sepullia; 20, Grellaphia; 21, Chaetophyes; 22, Hindola; 23, Allox; 24, Blastocaena; 25, Irridiculum; 26, Pseudomachaerota cucullata; 27, Zygon, with detail showing basiconic sensilla (b) and coeloconic sensilla (c) of various types (shown in greater detail in Fig. 38); 28, Ambonga lanceolata (Zygonini); 29, Ambonga apicenotata syntype with insert showing sensilla at base of arista; 30, Pseudoclastoptera irrubesco sp. nov., holotype; 31 – 32, Pseudoclastoptera invidia sp. nov., male holotype (32) and unassociated female (31).

FIGURES 33 – 39. Antennal sensilla of Cercopoidea compared to setal pit (33) left when seta is broken off: Epipygidae gen. nov. (34) and detail of pits (35), Cercopidae (36, detail of pits) and section through pit, showing moveable cup within pit (37), Zygon (Zygonini, 38) and Chaetophyes (Machaerotinae, 39) with details showing development of various forms of sensilla: a 1, plesiomorphic arista arising gradually from apex of postpedicel; a 2, apomorphic arista with excavated base; b 1, basiconic sensillum; b 2, globular sensillum; b 3, furcate sensillum; c 1, coeloconic sensillum in open cup; c 2, coeloconic sensillum in double cup; 3 c, multiple sensilla in deep cup.

FIGURES 5 – 9. Zygonini, dorsolateral aspect (A); male subgenital plates (B), ventral aspect; (C), genital capsule and theca (with style in 7 – 9), lateral aspect; (D), theca, caudal aspect; (E) habitus, dorsal aspect. 5, Pseudoclastoptera irrubesco (style as in Pseudomachaerota); 6, Pseudomachaerota olivacea, female holotype; 7, Pseudomachaerota cucullata; 8, Hemizygon saturnus; 9, Zygon desegregatum. Scale line for habitus drawings: 1 mm.

FIGURES 17 A – R. Ovipositor shapes in 17 genera and subgenera of Clastopteridae: Zygonini (A, G – J, Q), Machaerotinae (B – D, K, R) and Clastopterinae (E, F, L – Q). A, Zygon desegregatum, paratype; B, Irridiculum deformatum, holotype; C, Allox transfigurata, paratype; D, Taiorhina geisha Schumacher; E, Grellaphia costalis Schmidt; F, Beesoniella sylvestris Lallemand; G, Pseudomachaerota olivacea, holotype; H, Ambonga lanceolata; J, Hemizygon saturnus (as in Ambonga apicenotata); K. Machaeropsis dramatica; L, Tremapterus (Nyanja) bimaculata Synave, holotype; M, Tremapterus (Abbalomba) typica Distant; N, Tremapterus (Patriziana) janus Linnavuori; O, Tremapterus (s. s.) rufus (Thunberg); P, Sepullia fuscolimbata Lallemand; Q, Pseudoclastoptera irrubesco; R, Machaerota sp. Scale line: 1 mm.