Chidaea Emeljanov

Löcker, Birgit & Holzinger, Werner E., 2019, Revision of the Australian planthopper genus Chidaea Emeljanov with a redescription of Cixius sidnicus Stål, 1859 (Hemiptera: Auchenorrhyncha: Fulgoromorpha: Cixiidae), Zootaxa 4691 (5), pp. 401-443 : 404-405

Genus Chidaea Emeljanov

Chidaea Emeljanov, 2000: 13

Type species: Chidaea dayi Emeljanov, 2000 , by original designation and monotypy.

Description. Chidaea species are characterised by a mesonotum with three carinae; apex of hind tibia with 6 spines, the distal one largest, ScP+R fused distad of basal cell in fore wing ( Fig. 28H ); wings in resting position tectiform, but distal parts not touching each other. The most important diagnostic features of Chidaea are: Aedeagus with two movable spines at the distal end of the phallotheca, one on each side; phallotheca with a ventral ridge, at its base always with a rigid bifurcate projection pointing cephalad (‘bifurcate ventral process’) as in Figs 23 A–C; anal segment almost symmetrical in dorsal view; anal tube with a distinct ventral lobe at its end that in lateral view is usually narrow at the base and widening towards the apex ( Fig. 23E ); anal style about as long as remainder of 11 th segment(sometimes marginally shorter or longer). Apex of head with two straight or almost straight, transverse carinae (apical transverse carina and subapical carina). Frons without median ocellus, with one median carina, neither forked nor vanishing. Vertex (= coryphe sensu Emeljanov) at least about twice as wide as long, apical border more or less parallel to basal border, straight, slightly rounded or shallowly angulate. Pronotum narrow. Forewing without concavity at costal border; crossvein r-m 1 usually distad of fork MP1+2 and MP3+4; RA often forked apically. Females bearing a small or large wax plate at segment IX.

Differential Diagnosis: Chidaea is endemic to Australia and can be distinguished from all other genera of Australian Cixiidae by a combination of the following characters: Pronotum lacking ovoid inflated areas; apex of head with two transverse carinae (apical transverse carina and subapical carina); median carina of frons unforked; forewing with subcostal and radial vein (and for a very short section even medial vein) united near basal cell to form a distinct stem; second hind tarsomere with two platellae less than number of apical spines; frons without a median ocellus, postclypeus convex but not distinctly swollen and prominent; male anal tube with ventral lobe in lateral view narrow near base, widening towards apex.

Chidaea differs from the New Zealand species that were originally placed in Cixius , but have since been transferred to Cermada Emeljanov, 2000 in the shape of the vertex and features of the male genitalia: In Chidaea the vertex is very wide (about twice as wide as long or wider) whereas in Cermada the vertex is as wide as long or longer than wide. The aedeagus in Cermada lacks a bifurcate ventral process and doesn’t have the typical arrangement of 2 moveable spines.

According to Emeljanov (2000) Macrocixius Matsumura, 1914 , a genus occurring in the Oriental region, can be separated from Chidaea by the presence of a median ocellus (absent in Chidaea ).

Morphology. Body length: ♂ 3.9–6.9 mm; ♀ 4.7–9.6 mm.

Head: Vertex widest at base, and narrowest at subapical carina; lateral carinae moderately elevated; angle formed by caudal border of vertex broadly obtuse; apical and subapical carina slightly to moderately v- or u- shaped or almost straight; median carina covering parts of or the entire length of basal compartment of vertex, absent in apical compartment (apart from a rudimentary presence in some specimens of Ch. carinata and Ch. punctata ). In dorsal view head (including eyes) narrower than pronotum. Frons invisible in dorsal view. Maximum width of frons no more than 2x apical width, sometimes almost the same width. Median carina on frons complete, sometimes evanescent near frontoclypeal suture. Lateral carinae of frons foliaceous, moderately extending laterally, concealing base of antennae. Median ocellus absent. Postclypeus with well developed lateral carinae except for Ch. belairensis where it is weakly developed. Anteclypeus lacking lateral carinae apart from Ch. orangensis and Ch. algida which sometimes have evanescent lateral carinae. Apical and subapical rostrum segments more or less equal in length.

Thorax: Pronotum with median carina weakly developed (with the exception of Ch. carinata , Ch. punctata and Ch. kimbaensis with well developed median carina); pronotum shortest in middle; submedian carinae running parallel to eyes. Forewings moderately tectiform; surpassing tip of abdomen; widest at same level or distad of apex of clavus; concavity at costal border absent (apart from Ch. carinata and Ch. punctata ); veins except marginal ones granulate (with tubercles); tubercles on costal margin in single row; tubercles in pterostigma arranged in 1–2 rows; no tubercles in cells at apex of wing, only along veins; pterostigma subtriangular; basal cell subtransverse apically; ScP+R+M usually forming a minute or small common stem distad of basal cell (see Fig. 28H ); crossvein r-m 1 distad of fork MP1+2 and MP3+4 (basad only in a few specimens of Ch. dayi ); icu distinctly distad (rarely slightly distad) of apex of clavus; additional subapical cell C3a between branches of MP1 and MP2 present; CuA apically unforked (rarely bifid); nodus of y-vein more or less central within clavus (rarely slightly basad of centre of clavus); vein delimiting subapical cell C4 (m-cu 2) distinctly distad of vein delimiting C5 (icua); subapical cell C5 distinctly longer than C4. Hind leg: tibia with 0–7 minute to small lateral spines, with 6 (rarely 5 or 7) apical spines, grouped in two groups with a large (rarely small) gap in between; outermost spine of tibia largest, followed by 2 smaller spines with their tips well separated; the 3 innermost spines of tibia almost as long as outermost spine, with their tips in close proximity to each other; 1 st tarsomere with 8–14 (rarely 7) apical teeth and either without platellae or with 5–9 (rarely 4 or 10) platellae; 2 nd tarsomere with 9–13 (rarely 14–15) apical teeth and with platellae (two less than number of apical teeth).

Male genitalia: Phallotheca with a bifurcate ventral process ( Figs 23 A–C). Movable apical part (called endosoma or flagellum by authors) unarmed (but sometimes with a few more sclerotised sections that may appear to be spines at first glance). Anal segment almost symmetrical in dorsal view; ventral lobe of anal tube in lateral view narrow at base, widening towards the apex; anal style about as long as remainder of 11 th segment (length of 11 th segment about 5/6–7/6 of length of anal style).

Female genitalia: Ovipositor, wax plate and anal tube as in Fig. 1 : Ovipositor sabre-shaped (curved upwards), sometimes protruding further than anal tube. Segment IX bearing wax plate, ranging from large, circular shaped to small ovoid. Anal tube varying in length from slightly longer than wide (e.g. Ch. etelis ), about as long as wide (e.g. Ch. punctata ) to shorter than wide (e.g. Ch. orangensis and Ch. kimbaensis ). Anal style very short, about same length as 11 th segment or slightly shorter.

Distribution: Australia (all states and territories except for Northern Territory), see Fig. 31 .

Notes. Emeljanov (2007) refers to Chidaea as an Australian-New Zealand genus. This cannot be confirmed by the authors. The species number “3” for Chidaea given by Holzinger et al. (2002) was erroneous. Prior to this paper only one species of Chidaea has been described which is restricted to Australia.

Figures

FIGURE 1. Female genitalia: Chidaea pulyonna: A lateral, C caudoventral, E caudal; Chidaea armidalensis: B lateral, F caudal; Chidaea etelis: D caudoventral.

FIGURE 23. Chidaea dayi: A aedeagus left lateral; B aedeagus ventral; C aedeagus right lateral; D–E anal tube; F–G genital styles.

FIGURE 28. Chidaea pulyonna: A aedeagus left lateral; B aedeagus ventral; C aedeagus right lateral; D–E anal tube; F–G genital styles; H fore wing: abbreviations of longitudinal veins (black capital letters), crossveins (in italics), cell names (red letters) and other characters see chapter “Materials & Methods”.

FIGURE 31. Known distribution of Chidaea species.