Nikkoaspis brevispina, Tian & Zheng & Xing, 2021

Tian, Feng, Zheng, Xinyi & Xing, Jichun, 2021, Description of a new species of the genus Nikkoaspis Kuwana, 1928 (Hemiptera Coccomorpha: Diaspididae) from China, Zootaxa 4949 (2), pp. 363-370 : 365-369

Nikkoaspis brevispina sp. n.

( Figs. 1–24 )

Material examined. Holotype: Adult ♀ ( GUGC), CHINA: Guizhou Prov., Jiangkou County, Fanjing Mountain , / 14 November 2020, / Feng Tian leg.

Paratypes: 9 ♀♀ ( GUGC), same data as holotype .

Description. Appearance in life. Adult female scale cover white, 2.3–2.5 mm long, about 2.0 mm wide, subtriangular, expanded towards posterior end; exuviae brown, situated at anterior end; margins of scale thin but dorsum thickened, with curved grooves. The ventral scale encloses the cephalothorax ( Figs 1, 3, 5 ). Exposed body of adult female yellow, narrowest anteriorly, gradually widening posteriorly before widening sharply at abdominal segment I; rear end rounded so that body is bottle-shaped ( Figs 6–8 ). Scale cover of immature male scale white, elongate, 1.5–1.7 mm long, about 0.4 mm wide, with parallel sides and 3 longitudinal ridges, median ridge most prominent. Exuviae pale yellow, situated at anterior end of scale ( Figs 2, 4 ).

Slide-mounted adult female (based on ten specimens): Body 1550–1580 (1563) µm long, 930–960 (938) µm wide, narrowest anteriorly, cephalothorax gradually broadening posteriorly before widening sharply at abdominal segment I; rear end rounded so that body is bottle-shaped.

Cephalothorax. Antennae separated by a space nearly as wide as mouthparts, each composed of a small tubercle and 2 long setae (a few specimens with antenna on one side with only 1 seta). Anterior spiracles each associated with 25–37 trilocular disc pores, in a cluster; posterior spiracles not associated with disc pores ( Figs. 9–11 ).

Pygidial margin. Lobes numbering 2 pairs; L 1 separated from each other by 7–10 µm and each lobe split into 3 or 4 lobules; L 2 each split into 5–8 (usually 6 or 7) lobules; all lobules similar in size, elongate, nearly as long as adjacent plates, occasionally with a dentate protuberance present at corner of apex, resembling a plate ( Fig. 23 ). Plates on abdominal margins dense, well developed, each slightly longer than a pygidial lobe, with base slightly constricted, middle thicker, and apex bifurcate. With 2 or 3 (usually 2) plates between L 1; 3–8 (usually 3 or 4) between L 1 and L 2 (on abd. VII); 11–18 (usually 12–14) on abd. VI; 12–19 (usually 15–17) on V; 12–20 (usually 14–16) on IV; 16–17 on III; plates becoming progressively shorter anteriorly until they obsolete on abd. II; plates absent from abd. I. With a small plate at each junction of the abdominal segments lateral to L 2, becoming gradually smaller anteriorly and finally obsolete ( Figs. 8, 13–19, 21–23 ). Gland spines very short, but ducts inside each gland spine obvious; with 0 or 2 gland spines between L 1; 0–3 between L 1 and L 2; 2–5 between abd. VII and VI; 2–6 (usually 3–4) between VI and V; 3–6 between V and IV; and 2–6 (usually 4 or 5) between IV and III. Where plates at the junction of the abdominal segments became short and finally obsolete, even very short gland spines are easier to see ( Figs 15–19 ).

Ducts and pores. Marginal macroducts slightly larger than dorsal ducts. Dorsal macroducts all about same size, numbering about 550–600 on each side of body, forming indistinct oblique or longitudinal rows or bands; on pygidium, macroducts densest near margins, becoming fewer towards midline. On each abdominal segment, the 2 lateral groups of ducts extend from each side and merge into one submedial group. Prepygidial abdominal segments with numerous dorsal macroducts between margin and submargin, also along posterior borders. Ventral ducts scattered, more numerous on abdomen than on cephalothorax ( Figs 7 , 8 and 20 ). Perivulvar pores forming 5 groups, with 18–20 in anteromedian group, 32–39 in each anterolateral group, and 38–45 in each posterolateral group. Anal opening situated slightly anterior to centre of pygidium ( Figs 20, 24 ).

Host plant. Bamboo ( Poaceae : Sinarundiaria spp.), at 1800 m altitude.

Habit. Females found at the base of the upper leaf surfaces along the midrib, separate from each other; immature males found on the middle of the lower leaf surfaces, also along the midrib, separate from each other. Heavily infested leaves were observed to wilt and develop black necrotic spots beneath the scale insects.

Remarks. Nikkoaspis brevispina sp. n. is distinguished from all other Nikkoaspis species by possessing numerous dorsal macroducts, very short gland spines, strongly segmented L 1 and L 2, and a large number of plates on the margins of the pygidium and between the pygidial lobes. The new species is similar to N. sikokiana Takagi, 1999 , in body shape but can be distinguished by the following characteristics (character states of N. sikokiana in brackets): (i) adult female with L 1 and L 2 split into lobules (L 1 and L 2 not split); (ii) gland spines shorter than plates (gland spines longer than plates); and (iii) about 70–90 plates and 550–600 dorsal macroducts on each side (about 40 plates and 250 dorsal macroducts on each side).

Etymology. The new species epithet is derived from the Latin word “ brevis ”, meaning short, and “ spina ’, meaning spine, referring to the short gland spines on pygidium.

Checklist. A checklist of Nikkoaspis species is provided in Table 1.

Figures

FIGURE 7. Nikkoaspis brevispina sp. n., slide-mounted adult female.

FIGURES 1–6. The habit of Nikkoaspis brevispina sp. n. 1–2. Female scale cover; 3–4. Male scale cover; 5–6. Exposed live adult female.

FIGURES 8–24. Nikkoaspis brevispina sp. n. 8. Slide-mounted adult female; 9. Antenna; 10. Anterior spiracle; 11. Posterior spiracle; 12. Margin of abdominal segment II; 13. Margin of abd. III; 14. Margin of abd. IV; 15–19. Gland spines; 15. Margin between abd. VII and VI; 16. Margin between abd. VI and V; 17. Margin between abd. V and IV; 18. Margin between abd. IV and III; 19. Margin between abd. III and II; 20. Pygidium (abd. V–VIII); 21. Margin of abd. V; 22. Margin of abd. VI; 23. L1 and L2; 24. Perivulvar pore.