Aka White

Löcker, Birgit, 2015, Revision of the Australian species of Aka White, 1879 (Fulgoromorpha: Cixiidae) with the description of a new genus, Zootaxa 3956 (2), pp. 199-223 : 200-205

Genus Aka White

Aka White, 1879: 216

Type species: Cixius finitimus Walker, 1858 , by original designation.

Diagnosis. The three genera Aka , Chathamaka and Yanganaka gen. nov. share a very small to almost inconspicuous pterostigma, a forked frontal carina and a curved apical and subapical carina of the vertex connected by two ridges. Aka can be distinguished from Chathamaka and Yanganaka by the shape of the lateral carinae of the pronotum. In Aka these carinae are s-shaped. The first bend of the “s” is rounded but with its sides forming a rectangular angle, therefore not following the contour of the eye. The second bend forms an obtuse angle (arched) and gently turns towards the mesonotum ( Figs 2–5 B,D, 6B). In Chathamaka the first bend is more evenly rounded, following the contour of the eye. Then the carina turns abruptly (angularly) towards the mesonotum ( Fig. 1 ). In Yanganaka the lateral carinae are c-shaped, with their lateral parts (ends) directed towards the head ( Fig. 6 D).

Compared to other Australian Cixiidae , the intercubitus (icu) in Aka is very long, almost appearing to be a second or third branch of CuA2. Emeljanov (2002) reported a similar elongated icu, directed obliquely longitudinally, from the tribes Brixidiini and Bennini and the subfamily Borystheninae.

The following combination of characters uniquely identifies Aka within other Australian Cixiidae : frons with forked median carina; vertex in midline about as long as pronotum.

Morphology. Body length: ♂ 3.8–5.6 mm; ♀ 5.1–5.7 mm.

Head: Vertex 0.8–1.1 x as long as pronotum (1.4–1.5 x longer than pronotum in the 2 specimens of New Zealand species measured); with lateral carinae concave, vertex widest at base, narrowest between subapical and apical carina; lateral carinae slightly elevated; angle formed by caudal border of vertex broadly obtuse; subapical carina M-shaped, connected to apical carina by two short ridges. Frons with forked median carina. Lateral carinae of frons in facial view convex, rectilinear apically or slightly sinuate. Frontoclypeal suture slightly semicircular, bent upwards, median part not reaching lower margin of antennal scape. Postclypeus with well developed median and lateral carinae. Anteclypeus lacking lateral carinae. Rostrum in Australian species very long (situation in New Zealand species of Aka unclear, but may be shorter), surpassing hind coxa by far and extending into femur, subapical segment reaching hind trochanter. Head including eyes much narrower than pronotum.

Thorax: Pronotum with median carina well developed; lateral carinae s-shaped, lateral parts directed towards mesonotum (sometimes median and lateral parts of carinae evanescent), lateral carinae not following contour of eyes; angle of hind margin of pronotum widely obtuse. Mesonotum 1.6–3.1 x longer than pronotum (3.2–4.5 x in the two specimens of New Zealand species measured); with moderately or well developed median carina, fading before it reaches hind margin of mesonotum; lateral carinae well developed, reaching hind margin; with or without sublateral carinae, which do not reach hind margin. Forewing short, curved to fit body (with the exception of A. issidopsis ); surpassing tip of abdomen; concavity at costal border poorly developed or absent; pterostigma very small and indistinct (slightly larger in A. kuraka ), triangular; forewing widest anterior to apex of clavus; icu elongated; y-vein with A1 to a varying degree higher elevated than PCu. Hind leg: tibia with 1–4 very small to large lateral spines, with 6 apical spines, grouped in two groups with or without a small gap in between, outermost spine largest, innermost and 3rd innermost spine almost as long as outermost spine; 1st tarsomere with 5–7 apical teeth and no platellae; 2nd tarsomere with 5–8 apical teeth and no platellae but with 1–5 fine setae.

Female genitalia: Ovipositor, wax plate and anal tube as in Fig. 7 A–C: Ovipositor sabre-shaped (curved upwards), extending well beyond abdomen, sometimes protruding forewings. Wax plate oval shaped (widest from left to right). Anal tube varying in length (very short to medium length), in ventral view either trapezoid (widening towards apex) or rectangular. Anal style very long (about as long or longer than dorsal length of anal tube).

Distribution. Australia, New Zealand.

Remarks. On the tibia of one specimen of A. dobsonensis 5 apical spines were observed. The other leg showed the usual configuration of 6 spines. As all other specimens of Aka have 6 apical spines this appears to be an aberration.

Figures

FIGURE 1. Chathamaka andrei Larivière, 1999: head and thorax.

FIGURE 2. Aka balma: A habitus; B, C head. Aka dobsonensis: D, E head; F habitus. Scale bar 1 mm.

FIGURE 3. Aka gwana: A habitus; B, C head. Aka hardyi: D, E head; F, G habitus. Scale bar 1 mm.

FIGURE 4. Aka issidopsis: A habitus; B, C head. Aka kuraka: D, E head; F, G habitus. Scale bar 1 mm.

FIGURE 5. Aka pirri: A habitus; B, C head. Aka sorellensis: D, E head; F habitus. Scale bar 1 mm.

FIGURE 6. Aka tasmani (specimen from Thumbs Parallel Gully): A habitus; B, C head. Yanganaka ariecornia: D, E head; F habitus. Scale bar 1 mm.

FIGURE 7. Female genitalia: A Aka gwana ventral view; B, C Aka kuraka: (B) caudal view, (C) right lateral view.