Euthoracaphis oligostricha, Chen, Jing, Fang, Yan & Qiao, Gexia, 2009

Chen, Jing, Fang, Yan & Qiao, Gexia, 2009, Euthoracaphis Takahashi (Hemiptera: Aphididae: Hormaphidinae), a generic account, description of a new species from China, and a key to species, Zootaxa 2284, pp. 30-40 : 33-39

Euthoracaphis oligostricha sp. nov.

( Figs. 16–34 )

Etymology. The new species is named for the dorsum of the prosoma that lacks fine setae, only with thick and long setae; dorsal setae fewer. The name is composed of “ oligos ” (Greek = few or little) and “ tricha ” (Greek = setae).

Diagnosis. The new species is closely related to E. heterotricha , but differs from the latter as follows: dorsum of prosoma with only 12 pairs of long thick submarginal setae and 4 pairs of long thick spinal setae, without short and fine setae ( Fig. 16 ) (in heterotricha : dorsum of prosoma with long and short fine setae mixed with long thick setae ( Fig. 1 )); suture on anterior prosoma indistinct and discontinuous ( Fig. 26 ) (in heterotricha : distinct and continuous ( Fig. 13 )); abdominal tergite VIII with 2 setae (in heterotricha : 4 setae).

Description. Apterous viviparous females: Body oval, flat, thickened, and strongly sclerotized ( Figs. 16 , 23 ). General measurements see Table 1.

Mounted specimens: Body dark brown; antennae, legs, cauda, anal plate and genital plate light brown. Prosoma consisting of fused head, thorax and abdominal segment I, abdominal segments II–VII fused, abdominal segment VIII free. Dorsum of prosoma divided by sutures into four areas, a semicircle anterior, a median inverse trapezoidal and two lateral areas ( Fig. 16 , 23 ).

viviparous females, in mm).

Parts Apterous vivipara (n=11)

Mean Range Standard Deviation

Length (mm) Body length 1.231 1.113–1.349 0.065 Body width 1.040 0.877–1.202 0.095 Whole Antennae 0.140 0.120–0.159 0.012 URS 0.060 0.054–0.066 0.005 Cauda 0.026 0.017–0.034 0.006 Each lobe of AP 0.033 0.025–0.040 0.005 Ant. III WD 0.020 0.017–0.022 0.001 Cephalic setae 0.120 0.098–0.142 0.014 Setae on Tergite VIII 0.133 0.104–0.161 0.024

No. of setae on PT 2–4

Tergite VIII 2

URS 4

Cauda 10

Each lobe of AP 5–6

Anterior margin of GP 3

Posterior margin of GP 25–26

Ratio (times) Whole Antennae / Body 0.12 0.09–0.13 0.01 URS / BW URS 1.33 1.16–1.59 0.14 Cauda / BW Cauda 0.56 0.41–0.64 0.08 Each lobe of AP / BW each lobe of AP 0.66 0.49–0.80 0.09 Cephalic setae / Ant. IIIWD 6.18 5.00–7.25 0.89 Setae on Tergite VIII / Ant. IIIWD 6.74 5.20–9.47 1.73

Remarks: Ant. III WD, the widest diameter of antennal segment III; AP, anal plate; BW, basal width; GP, genital plate; PT, processus terminalis; URS, ultimate rostral segment.

Dorsum of prosoma with scattered irregular pustules. Muskelplatten distinct, forming radial pattern with dorsal pustules ( Fig. 24 ). Abdominal tergites II–VII wrinkled. Cauda ( Figs. 20 , 28 ), anal plate ( Figs. 21 , 29 ) and genital plate ( Figs. 22 , 30 ) with spinulose sculpture. Body with numerous long fine marginal setae ( Fig. 25 ). Dorsum of prosoma with 12 pairs of long thick submarginal setae, posterior margin of head dorsum with 2 pairs, pronotum with 2 pairs, mesonotum with 3 pairs, metanotum with 3 pairs, abdominal tergite I with 2 pairs ( Fig. 16 ). Pro-, meso-, meta-notum and abdominal tergite I each with 1 pair of long thick spinal setae; abdominal tergites II–VII each with 1 pair of long thick submarginal setae, tergite VII with 1 pair of long thick spinal setae; tergite VIII with 2 dorsal setae ( Fig. 16 ). Length of cephalic setae 0.098–0.142 mm, length of dorsal setae on abdominal tergite VIII 0.104–0.161 mm, 5.00–7.25 times and 5.20–9.47 times as long as widest diameter of antennal segment III, respectively. Front slightly protuberant ( Figs. 16 , 23 ). Eyes 3-faceted ( Fig. 16 ). Antennae ( Figs. 17 , 27 ) very short, indistinctly 3-segmented, 0.120–0.159 mm long, 0.09–0.13 times as long as body; apex of segment III with 2–4 setae. Primary rhinaria small, round, protuberant, placed wide apart at the apex of terminal segment. Rostrum short and thick, ultimate rostral segment wedge-shaped, 0.054–0.066 mm long, 1.16–1.59 times as long as its basal width, with 2 pairs of primary setae and without secondary setae ( Fig. 18 ). Legs short, trochanter and femur fused. Siphunculi pore-like, on abdominal tergite VI ( Fig. 19 ). Cauda constricted at base and distinctly knobbed, 0.017–0.034 mm long, 0.41–0.64 times as long as its basal width, with 10 setae ( Figs. 20 , 28 ). Anal plate bilobed, each lobe 0.025–0.040 mm long, 0.49–0.80 times as long as basal width, with 5 or 6 setae ( Figs. 21 , 29 ). Genital plate broad round, with 3 anterior setae and 25 or 26 setae along the posterior margin ( Figs. 22 , 30 ).

First instar nymphs: Body elongate oval, 0.571–0.650 mm long, 0.296–0.355 mm wide ( Fig. 31 ).

Mounted specimens: Body light brown. Body segments normal, not fused. Dorsum smooth. Cauda and anal plate with spinulose sculpture. Dorsum of prosoma with 9 pairs of long thick submarginal setae, posterior margin of head dorsum with 2 pairs, pronotum with 2 pairs, mesonotum with 2 pairs, metanotum with 2 pairs, abdominal tergite I with 1 pair. Pro-, meso-, meta-notum and abdominal tergite I each with 1 pair of long thick spinal setae; abdominal tergites II–VII each with 1 pair of long thick submarginal setae, tergite VII with 1 pair of long thick spinal setae; tergite VIII with 2 dorsal setae. Eyes 3-faceted. Antennae long, distinctly 4- segmented, segments III and IV with reticulations; 0.225–0.247 mm long, 0.35–0.42 times as long as body; apex of segment IV with 2–4 setae. Primary rhinaria small and round. Rostrum short and thick, ultimate rostral segment wedge-shaped. Legs long, trochanter and femur fused; first tarsal chaetotaxy: 2, 2, 2. Siphunculi small, pore-like, on abdominal tergite VI. Cauda rounded at apex, not well developed, with 2 setae. Anal plate bilobed, not well developed, each lobe with 2 setae.

Second instar nymphs: Body elongate oval, 0.699–0.778 mm long, 0.335–0.355 mm wide ( Fig. 32 ).

Mounted specimens: As in first instar nymphs, but: Antennae 0.243 mm long, 0.31–0.35 times as long as body; apex of segment IV with 3 or 4 setae. First tarsal chaetotaxy: 3, 2, 2. Cauda with 2 or 4 setae.

Third instar apteroid nymphs: Body oval, flat, 0.719–0.818 mm long, 0.414–0.581 mm wide ( Fig. 33 ).

Mounted specimens: Body pale in color; head, antennae, ultimate rostral segment, legs, cauda and anal plate light brown. Abdominal segments atrophied, lightly fused. Dorsum smooth, with distinct seta-bearing sclerites. Cauda and anal plate with spinulose sculptures. Dorsal setal pattern same as adult. Eyes 3-faceted. Antennae a little short, distinctly 3-segmented, 0.174–0.191 mm long, 0.22–0.25 times as long as body; apex of segment III with 3 or 4 setae. Primary rhinaria small, round, protuberant, placed wide apart at the apex of terminal segment. Rostrum short and thick, ultimate rostral segment wedge-shaped. Legs long, trochanter and femur fused; first tarsal chaetotaxy: 3, 3, 2. Siphunculi pore-like, on abdominal tergite VI. Cauda rounded at apex, not well developed, with 6 or 8 setae. Anal plate bilobed, not well developed, each lobe with 4 setae.

Fourth instar apteroid nymphs: Body oval, flat, 0.906–0.995 mm long, 0.601–0.690 mm wide ( Fig. 34 ).

Mounted specimens: As in third instar apteroid nymphs, but: head, thorax and abdominal segment I fused; abdominal segments II–VII fused incompletely; abdominal segment VIII not free, still connected to abdominal segment VII. Antennae 0.189–0.223 mm long, 0.19–0.25 times as long as body; apex of segment III with 2 or 3 setae. Cauda with 6 setae.

Specimens examined. Holotype: apterous viviparous female, CHINA: Yunnan (Kunming City), Jan. 2007, No. Y 8799-1-1-2, on Machilus yunnanensis , coll. C. Q. Lin ( ZMCAS). Paratypes: 5 apterous viviparous females, 2 second instar nymphs and 1 fourth instar apteroid nymph with the same collection data as holotype; 16 apterous viviparous females, CHINA: Yunnan (Kunming City), Jan. 2007, No. Y 8798, on Machilus yunnanensis , coll. C. Q. Lin ( ZMCAS); 17 apterous viviparous females, 17 first instar nymphs, 5 second instar nymphs, 14 third instar apteroid nymphs and 3 fourth instar apteroid nymphs, CHINA: Yunnan (Kunming City, Alt. 1900m), 18 Oct. 2003, No. 15299, on Machilus yunnanensis , coll. G. X. Qiao and S. S. Ren ( ZMCAS).

Host plant. Machilus yunnanensis .

Biology. This species infests the undersurface of leaves and shoot tips and is covered with much white waxy secretion.

Figures

FIGURES 16 – 22. Euthoracaphis oligostricha sp. nov. Apterous viviparous female: 16. dorsal view of body, with pustules in left, chaetotaxy in right, 17. antennal segments I – III, 18. ultimate rostral segment, 19. siphunculus, 20. cauda, 21. anal plate, 22. genital plate. Scale bars = 0.1 mm.

FIGURES 23 – 30. Euthoracaphis oligostricha sp. nov. Apterous viviparous female: 23. dorsal view of body, 24. pustules on dorsum, 25. long fine marginal setae, 26. indisitinct and discontinuous sutures on anterior prosoma, 27. antennal segments I – III, 28. cauda, 29. anal plate, 30. genital plate. Scale bars = 0.1 mm.

FIGURES 31 – 34. Euthoracaphis oligostricha sp. nov. First instar nymph: 31. dorsal view of body. Second instar nymph: 32. dorsal view of body. Third instar apteroid nymph: 33. dorsal view of body. Fourth instar apteroid nymph: 34. dorsal view of body. Scale bars = 0.1 mm.

FIGURES 1 – 11. Euthoracaphis heterotricha. Apterous viviparous female: 1. dorsal view of body, with pustules in left, chaetotaxy in right, 2. antennal segments I – III, 3. cauda, 4. anal plate. Alate viviparous female: 5. dorsal view of head, 6. antennal segments I – V, 7. ultimate rostral segment, 8. siphunculus, 9. cauda, 10. anal plate, 11. genital plate. Scale bars = 0.1 mm.

FIGURES 12 – 15. Euthoracaphis heterotricha. Apterous viviparous female: 12. dorsal view of body, 13. distinct and continuous suture on anterior prosoma, 14. long thick spinal prosomal setae (indicated by black arrow, thick and with distinct and well developed seta-bearing tubercle) and fine prosomal setae (indicated by red arrow, fine and with indistinct seta-bearing tubercle). Alate viviparous female: 15. dorsal view of body. Scale bars = 0.1 mm.