Acanthonavis deflexa, Dubey, 2022

Dubey, Anil Kumar, 2022, Description of Acanthonavis deflexa gen. et sp. nov. (Hemiptera: Aleyrodidae) from the Nicobar Island, India, and generic re-definition of Editaaleyrodes David, Zootaxa 5092 (2), pp. 209-220 : 210-216

Acanthonavis deflexa sp. nov.

( Figs 1–25 )

Puparium. In life, shiny white; with white wax on the dorsum and lateral margin; dorsum elevated above the lateral margin; submargin deflexed, folded under itself ( Fig. 6 ); elongate ( Figs 7 , 10, 11 ); dimorphic ( Figs 4, 5 ), female puparia larger than male; the former 1290–1300 microns long, 810–880 microns wide including the deflexed submargin; male 970–990 microns long, 550–590 microns wide; broadest at abdominal segment II–III, gradually narrowing towards ends, apical end depressed and posterior end opening as a comb. Found singly on underside of leaves; either attached to the midvein or side-veins or scattered in the middle ( Fig. 1 ); 20–30 puparia per leaf.

Margin. Crenulate, 11–13 crenulations in 0.1 mm for apparent margin (right side of Fig. 14 , submargin folded under the puparium) at merging of dorsal subdorsum-submargin, 15–17 crenulations in 0.1 mm for true margin (left side of Fig. 14 , submargin unfolded) located ventrally; true margin apparently hidden below deflexed submargin and appears as ventral fold. The merging of submargin and subdorsum (the ridge as shown in Fig. 6 , left part of the puparium only) is serving as the apparent margin when submargin is folded under the puparium (right side of puparium in Fig. 6 ). Thoracic tracheal pores not indicated at the margin. Caudal tracheal pore opening visible.

Dorsum. Prominently tuberculate. Dorsal disc demarcated from the submargin by a ridge ( Figs 6 , 10, 14 ), 960 microns long (cephalothorax 410 microns, abdomen 550 microns long), 440 microns wide. Dorsal disc merging with submargin bearing 16 pairs of long setae, including the caudal pair, eight pairs each on cephalothoracic and abdominal region, 90–125 microns long. Submargin 75–88 microns wide when mounted. The submargin folds ventrally from the ridge merging subdorsum and submargin ( Fig. 6 , submargin folded on the right side of the puparium), except for the caudal furrow area, and conceals the true margin, thus the subdorsal setae forming a row ( Fig. 12 ) appear to be marginal ( Fig. 10 ). The dorsal ridge is overlapping the true margin and the periphery of ventral fold, making the whole area appearing as a broad dorsal ridge/ventral demarcation ( Fig. 11 ) in slide mounts. Longitudinal and transverse moulting sutures reaching subdorsum. Intersegmental sutures not prominent; sutures and submedian depressions can be recognized by the arrangement of tubercles. Submedian pockets faint, on intersegmental sutures. Median length of cephalothorax and abdomen in female 475–480 microns and 720–760 microns long, respectively, and in male 415–425 microns and 525–560 microns long, respectively. Pro-mesothoracic suture obsolete. Mesometathoracic suture present. The median length of abdominal segments I–VIII in female A1: 63–73, A2: 65–68, A3: 83–85, A4: 85–88, A5: 83–88, A6: 83–85, A7: 50–65, A8: 50–51 microns; and in male A1: 50–58; A2: 45–55, A3: 45–60, A4: 55–60, A5: 52–58, A6: 55–60, A7: 27–35, A8: 40–42 microns. Abdominal segment VII shorter than VI and VIII. Thoracic tracheal furrows absent. Caudal tracheal furrow present. A zigzag row of simple pores present on submargin, similar pores scattered on dorsal disc, the distance between simple pores at least 50 microns. A pair of simple pores present between the first abdominal setae. The space between posterior end of vasiform orifice and puparial caudal margin 100–108 microns in female and 75–80 microns in male. Pockets discontinuous.

Vasiform orifice. Not elevated; subcordate; lateral margins surrounded by elevated cuticle continuous to caudal furrow; located anterior to caudal tracheal pore opening by 1.5 times its own length ( Fig. 8 ); posterior end narrow, notched, with a median projection forming bi-lobed structure ( Fig. 16 ); longer than wide; 70–73 microns long, 50–55 microns wide in female; 57–60 microns long, 50 microns wide in male; operculum subcircular, covering half the length of the orifice; wider than long; 32–43 microns long, 37–52 microns wide in female, 27–38 microns long, 32–35 microns wide in male. Lingula exposed, not reaching beyond posterior margin of vasiform orifice, 7–10 microns long.

Venter. Oblong ( Figs 9 , 17 ); 1110–1130 microns long, 550–560 microns wide in female, 900–910 microns long, 400–410 microns wide in male; submargin demarcated from subventral area by a single line fold with small constrictions at intervals ( Figs 18, 19 ). This demarcation is underlying subdorsal-submarginal ridge and confusing as subdorsal/submarginal furrow in slide mounted puparia. Submedian area with impressions of intersegmental sutures and pockets ( Fig. 20 ). A pair of ventral eighth abdominal setae present ( Fig. 21 ), 17–25 microns long, 35–38 microns apart in female, 27–30 microns apart in male. Antennae extending outside the prothoracic legs, including keel reaching little below the base of prothoracic legs ( Fig. 22 ), 42–55 microns long (including keel 5–10 microns). Legs not much curved. Microsetae in middle of metathoracic legs 8 microns long, pro-, and mesothoracic legs 5 microns long; rostral setae 2 microns long. Thoracic tracheal folds indicated on demarcated subdorsal area only, without stipples. Caudal tracheal fold not indicated, without stipples. Spiracles and adhesive sacs visible.

Chaetotaxy. Submargin with a row of 16 pairs of long setae, up to 125 microns long. Anterior marginal setae absent. Posterior marginal setae 68–78 microns long. Cephalic ( Fig. 13 ) and first abdominal setae ( Fig. 15 ) in female 60 microns and 65 microns long (in a single puparium 25 microns), respectively, and in male up to 95 microns long for both cephalic and first abdominal setae. Eighth abdominal setae located anterior to operculum, on cuticular ridge surrounding vasiform orifice laterally.

Third instar (n=6). Elongate ( Figs 3 , 25 ); white; flat; with white wax over dorsum; dimorphic, female 690–730 microns long, 340–370 micron wide, male 590–660 microns long, 210–290 micron wide. Dorsum tuberculate. Submargin not deflexed ventrally. Longitudinal moulting suture reaching submargin and transverse moulting suture reaching subdorsum, both faintly visible. Meso-metathoracic and abdominal segment sutures visible. Vasiform orifice subcordate, longer than wide, in female 50 microns long, 45–50 microns wide, in male 45–52 microns long, 37–42 microns wide; operculum sub-rectangular, covering half the length of orifice, wider than long, in female 30 long, 35–65 microns wide, in male 25–28 microns long, 30–33 microns wide. Lingula exposed, not reaching beyond posterior margin of vasiform orifice, 10 microns long. Submargin with 16 pairs of setae, three pairs on anterior and two pairs on posterior margins, 82–88 microns long, third anterior pair small, sometimes equal to anterior pairs, 11 pairs (5 cephalic, 6 abdominal), 18–20 microns long. Anterior marginal setae absent. Posterior marginal setae 50–53 microns long. Cephalic, first and eighth abdominal setae 50–88, 45–105 and 5–12 microns long, respectively. Ventral submargin faintly defined. A pair of ventral setae 12–17 microns long, 22–33 microns apart.

Second instar (n=2). White; oblong ( Figs 2 , 23 ), posterior end narrow; 195 microns long, 210 microns wide. Dorsum tuberculate. Longitudinal and transverse moulting sutures faint, but meso-metathoracic and abdominal segment sutures prominent. Vasiform orifice broadly triangular ( Fig. 24 ), 42 microns long, 37 microns wide; operculum 25 microns long, 30 microns wide. Caudal furrow 47 microns long. Posterior marginal, cephalic, first and eighth abdominal setae 32, 88, 90 and 3 microns long, respectively.

Egg. Oval ( Fig. 6 ), dull brown, transparent, attached to underside of leaves through a pedicle.

Host plant. An unidentified plant of family Meliaceae .

Distribution. India: Andaman and Nicobar Islands.

Holotype. India: Andaman and Nicobar Islands, Nicobar sands, Shompen hut, one puparium on one slide, female, on an unidentified plant of family Meliaceae , 13.xi.2018, 6º58′542′′ N, 93º51′544′′ E, A. K. Dubey ( Deposited in the National Zoological Collection , ZSI, Kolkata , India).

Paratypes. Twenty puparia (11 males, 9 females) on 12 slides (5 males, 1 female on slides 1-6; 2 females, 1 male on slide 7; 3 females, 2 males on slide 8; 1 male, 1 second instar on slide 9; 1 male, 5 ventral surfaces on slide 10; 2 females, 1 male, 2 ventral surfaces on slide 11; 1 female, 16 ventral surfaces on slide 12 (deposited in ZSI / ANRC Reg. No. T-13357)) , data same as of the holotype (one paratype slide will be deposited each in the National Forest Insect Collection, Forest Research Institute, Dehradun and the Natural History Museum, London, UK) .

Other specimens examined, not included in the type series. 81 incomplete puparia on 9 slides (20 ventral surfaces, 8 dorsal surfaces on slide 13; 20 ventral surfaces, 6 dorsal surfaces on slide 14; 6 ventral surfaces on slide 15; 8 ventral surfaces on slides 16; 4 ventral surfaces on slide 17; 8 ventral surfaces on slide 18; 1 dorsal disc on slide 19; 7 third instars (3 female, 4 male) on slide 20, 1 second instar on slide 21.

Etymology. The species name is based on the perfect participle of Latin verb ‘ deflecto ’, ‘ deflexa ’, meaning ‘bending downwards’ to indicate the ventrally folded submargin.

Remarks. Puparia of the new species have tuberculate dorsal surface, faint intersegmental sutures and depressions, location of vasiform orifice anterior to caudal pore opening by 1½ times of its own length and in lacking polygonal markings in the thoracic tracheal furrows. Cephalic and abdominal submedian depressions were not so clear on dorsal surface, but prominent on the ventral surface. The bases of pro-, and mesothoracic legs separated ( Fig. 18 ) by a distance of at least 75 microns, and space between simple pores was at least 50 microns (in E. indicus , 2–3 microns only, similarly pore/porette (geminus) distance was 10–13 microns). Removal of the dorsal disc of a puparium revealed that the dorsal setae were on the dorsal disc only ( Fig. 12 ).

In A. deflexa gen. and sp. nov., the separation of the dorsal disc from the submargin ( Figs 11, 12 ), the flattening of the submargin ( Fig. 14 ), and the separation of the ventral surface ( Fig. 17 ) proved to be the folding of the submargin, with the true margin and the demarcation of subventral area located ventrally. The true margin overlaps or borders the subventral fold demarcating the ventral submargin; the transverse moulting suture, in puparia with a deflexed submargin, seems to reach the lateral margin, but actually reaches the subdorsum/submargin. Further, examination of third and second instars confirmed that the subdorsal setae are much smaller than in the puparium and located on the submargin, except the two pairs located on the anterior and posterior margins in the third instar ( Fig. 25 ). The submargin is not differentiated from the dorsal disc, and not deflexed in these instars, but differentiated by a ridge and deflexed ventrally in the puparium. The population of puparia on the leaves was higher than that of the second and third instars, indicating that there is little overlapping of previous instars and the species may be completing only a few generations in a year. The population of male puparia was higher than the one of female puparia on leaves. It was also observed that the ventral surface mostly remains attached to the leaf surface whereas the dorsal surface is often lost; possibly the raised dorsal surface of empty puparia becomes more fragile and, thus easily detaches because of rain and wind. The separation between the ventral and the dorsal surfaces occurs along the true margin. Examination of immature stages showed that dimorphism was present in the third and fourth instars; the number of dorsal setae was constant (16 pairs) in both the third and fourth instars, however the submargin was not folded in the third instar.

Figures

FIGURE 1–6. Acanthonavis deflexa gen. and sp. nov., puparium and immatures, habitus on leaf: 1, occurrence on underside of a leaf; 2, second instar; 3, third instar; 4, dimorphic forms; 5, male puparium; 6, egg and female puparium, laterally raised submargin, ridge.

FIGURES 7–9. Acanthonavis deflexa gen. and sp. nov., holotype, female, line drawings: 7, dorsal surface; 8, vasiform orifice; 9, ventral surface.

FIGURES 10–16. Acanthonavis deflexa gen. and sp. nov., puparium: 10, holotype (HT), female; 11, deflexed submargin and ventral surface, paratype (PT); 12, dorsal disc, male (PT); 13, cephalic setae (HT); 14, submargin expanded (left) and folded (right) (PT); 15, first abdominal setae (HT); 16, vasiform orifice, caudal furrow (HT).

FIGURES 17–25. Acanthonavis deflexa gen. and sp. nov., puparium, paratypes (17–22), second instar (23–24) and third instar (25): 17, ventral surface; 18, legs; 19, subventral demarcation; 20, submedian pockets impressions; 21, ventral setae, spiracles, posterior end; 22, antenna, prothoracic leg; 23, habitus; 24, posterior end of second instar; 25, habitus, female.