Palaealeurodicus borneensis, Martin, 2008

Martin, Jon H., 2008, A revision of Aleurodicus Douglas (Sternorrhyncha, Aleyrodidae), with two new genera proposed for palaeotropical natives and an identification guide to world genera of Aleurodicinae, Zootaxa 1835 (1), pp. 1-100 : 47-49

Palaealeurodicus borneensis sp. nov.

(Figs 79, 83–89, 136, 137)

PUPARIUM. Habitus. Immature stages feeding on leaf petioles and under leaf midribs. Maturing puparia (with developing adults inside) become tall, with sides obscured (probably protected) by waxy pallisade (Figs 136, 137). Dorsum with glassy wax carapace (Fig. 136) that readily detaches from dried puparia and can be slide-mounted directly into balsam. Adjacent to puparia, on leaf surface, can be seen fine pieces of wax filament, but the mature specimens of the type sample have no sign of filaments emerging from compound pores: it is likely that the earlier (feeding) puparial stage would have these filaments visible, emerging from the compound pores. Species strongly size-dimorphic, with male puparia much smaller than those of females. Margin. Outline 1.15–1.21 mm long, 0.60–0.67 mm wide (female, n=14), 0.83–0.90 mm long, 0.45–0.48 mm wide (male, n=14, Fig. 83), generally widest at abdominal segment III/IV. Marginal teeth very well-developed, rather rounded-castellate when in perfect lateral view, 3.5–4 per 0.1 mm on lateral parts of thorax and abdomen in female, 4.5–5 per 0.1 mm in male. Dorsum. Cuticle brown, slightly mottled, and rather roughened by granular markings and corrugations, especially submarginally. Outer submargin with wavy folding that gives illusion of margin having double row of teeth (Fig. 83). Longitudinal moulting suture reaching puparial margin; transverse moulting sutures extending over half-way towards margin, often indicated almost to margin. Abdomen with most segmental divisions well marked into submargin but with segments I and II only apparent submedially and separated by a short fold only; segment II/III boundary marked by a “W”-shaped fold, and remaining segmentation similarly indicated, with segment VII not reduced in length medially. Meso-/metatho- racic boundary marked by transverse fold but other cephalothoracic segmentation only subtly indicated. A pair of cephalic markings, anteromesal to compound pores, visible in some specimens (Fig. 83), possibly vestigial “eyespots”. Vasiform orifice rounded-cordate; operculum transverse-ovoid, surface marked similarly to lingula, its posterior margin very slightly convex and with pair of fine setae visible only sometimes; lingula head tongue-shaped, slightly darker than rest of puparium, densely covered by fine dark blunt spinules, bearing the normal 4 stout setae and with half its length extending beyond vasiform orifice. Chaetotaxy. A pair of posterior marginal setae present, long and fine, up to 75µ in female puparia, a little shorter in males. Dorsum entirely without setae except for 2 outer submarginal pairs, close to posterior end of puparium, similar to posterior marginal pair (Fig. 83). Pores. Cephalic pair and 5 abdominal pairs of compound pores, all similar to each other in size and form, up to 40µ in outer diameter (female) or 30µ (male), abdominal pairs situated on segments IV–VIII. Axial processes of large compound pores long and sword-like, each with more than half its length extending beyond pore mouth, longest pair (almost always on abdominal segment VIII) 0.13– 0.155 mm in females or 0.09– 0.115 mm in males. No simple pores discernible on the dorsum. Venter. Ventral abdominal setae long and fine, underlying vasiform orifice, often longer than dorsal and posterior marginal setae. Legs with two segments faintly indicated, almost straight-sided, smooth, apically rounded and without apical claws (Fig. 86). Antennae very short, similar to legs but pointed apically and with no segmentation (Fig. 86). Tracheal folds absent. 4 pairs of spiracles readily visible.

THIRD-INSTAR NYMPH (Fig. 84). Same brownish pigmentation as puparium. Ovoid, 0.5–0.64 mm long (n=8). Margin smooth to slightly irregular. Chaetotaxy as in puparium. 2 pairs of compound pores situated on thorax, similar to those in puparia. 2 pairs of cicatrices present (scars of compound pores in secondinstar nymph), one pair cephalically and the other pair to either side of lingula. Ventral abdominal setal pair and spiracles readily discernible; legs not evident at all, but antennae visible as tiny triangular points on two specimens.

SECOND-INSTAR NYMPH. Brown-pigmented, ovoid, 0.40 X 0.21 mm (n=1). Margin smooth. Chaetotaxy as in puparium. 2 pairs of compound pores present, 16µ in diameter, one pair cephalically, the other pair on either side of vasiform orifice. Cicatrices absent. Vasiform orifice trapezoidal, operculum transversely elliptical, lingula with 4 hairs discernible. Abdominal segmentation well marked medially. Ventral characters mostly obscured by fungal mycelium but ventral abdominal setal pair present.

FIRST-INSTAR NYMPH. Cuticle slightly pigmented, outline ovoid, 0.28 X 0.17 mm (n=1). Margin smooth. Chaetotaxy: single pairs of anterior and posterior marginal setae present; with a submarginal row of setae, 18 on one side and 17 on the other; with an apparent pair of setal bases some distance anterior to vasiform orifice; ventral abdominal setal pair discernible. Compound pores and cicatrices absent. Vasiform orifice triangular, operculum trapezoidal and occupying over half of vasiform orifice, detail of lingula not readily discernible. Much of ventral surface apparently lost, with no indication of antennae or legs.

ADULTS. Wings evenly dusky brownish, entire surface punctuated by minute black dots, venation as shown (Figs 87, 88); forewing (female, n=2) 1.80-1.85 mm long, 0.91-0.95 mm wide, R 1 / R s branch in about basal one-third of wing; hind wing 1.47 mm long, 0.70 mm wide (n=1). Abdominal wax plates numbering 4 pairs in males, but 5 pairs in females, posteriormost 2 pairs apparently on same segment (Fig. 85); dorsal posteriormost pair of female wax plates subcircular and punctuated by faintly-marked polygonal reticulations (Fig. 85, expanded detail), other wax plates with more typical finely sculptured surfaces visible with X400 magnification. Female antennae 7-segmented, densely spinulose, with sparse setae, apical segment rather swollen and with two large hemi-annular sensoria (Fig. 89). Head with 2 discreet groups of ommatidia on each side (Fig. 79), effectively with 4 compound eyes, with a distinct ocellus contiguous with each dorsal compound eye, and a spinulose swelling between each dorsal and ventral compound eye (Fig. 79). Tarsi with 2 claws, the paronychium apparently spatulate with a few short spines. Apical rostral segment about 0.2 mm long.

MATERIAL EXAMINED. Holotype puparium (male), East Malaysia , SARAWAK, Gunung Mulu massif, Melinau Gorge, on unidentified broadleaf tree, 11.iii.1989 (J.H.Martin #5451) ( BMNH) . Paratypes: 28 puparia (male), 46 puparia (female), 8 third-instar nymphs, 1 second-instar nymph, 1 first-instar nymph, 9 adult females, 2 adult males, same data as holotype ( BMNH, USNM) ; duplicate dry puparial material on leaves, same data ( BMNH) .

ETYMOLOGY. The specific epithet reflects the known domicile of this species, the island of Borneo.

COMMENTS. P. borneensis is unusual in having been discovered with the colony feeding on woody twigs of its tree host. The individual puparia had their dorsal surfaces significantly raised from the venters, the sides being covered (probably supported) by waxy secretions (Fig. 136, 137). Third-instar nymphs are somewhat different from those of other Palaealeurodicus species , in the extreme degree of reduction in legs and antennae, the legs not being discernible and the antennae reduced to mere triangular points – these characters have not been illustrated because there is little to see! Adult females of P. borneensis are highly unusual in having five pairs of abdominal wax plates (Fig. 85).