Opisthoscelis tuberculata Hardy & Gullan

Hardy, Nate B. & Gullan, Penny J., 2010, Australian gall-inducing scale insects on Eucalyptus: revision of Opisthoscelis Schrader (Coccoidea, Eriococcidae) and descriptions of a new genus and nine new species, ZooKeys 58, pp. 1-74 : 15-17

Opisthoscelis tuberculata Hardy & Gullan sp. n. Figs 1k9

Leaf pit

(Fig. 1k). Female. On leaf. Pit-shaped gall, opening round to oblong, 2.0-3.0 mm wide, surrounded by raised lip, ca 0.2 mm high, apparently on adaxial leaf surface; gall hemispherical on side of leaf opposite opening, 1.0-1.5 mm high.

Male. Not known.

Adult female

(Fig. 9) (n = 4). Body broadly oval in outline, length 2.0-4.0 mm, greatest width 1.4-3.2, venter larger than dorsum. Eyes each 40-50 um wide, slightly ventral of line of marginal setal fringe. Antennae 7-segmented, moderately long (0.72-1.10 mm) and slender; with segment III longest (180-290 µm) and segment VII shortest (70-95 µm); segment I with 3 hair-like setae; II with 7-11 hair-like setae; III with 8-12 hair-like setae; IV 5-7 hair-like setae; V with 4-6 hair-like setae + 1 fleshy seta; VI with 3 or 4 hair-like setae + 1 fleshy seta; VII with ca 6 hair-like setae + 3 fleshy setae. Frontal lobes difficult to discern, each perhaps 200-280 µm long, 110-120 µm wide. Tentorial box 125-200 mm long; labium 100-150 mm long, 120-140 mm wide, 2-segmented with basal segment indicated by presence of setae; pump chamber 20-27 µm long, 17-20 µm wide. Spiracles 90-140 mm long, 55-95 mm wide across atrium. All legs well developed, hind legs larger than fore or mid legs: fore leg with coxa 240-400 µm long, trochanter + femur 370-550 µm long, tibia 280-440 µm long, tarsus 110-160 µm long; mid leg with coxa 270-450 µm long, trochanter + femur 380-580 µm long, tibia 280-460 µm long, tarsus 110-150 µm long; hind leg with coxa 320-520 µm long, trochanter + femur 400-620 µm long, tibia straight, 310-500 µm long, tarsus 120-180 µm long; each leg with claw 35-45 µm long; small translucent pores scattered on both surfaces of all hind-leg segments, densest on tibia; femur-tibia articulation functional; tarsal and claw digitules distinctly expanded at apices. Anal opening 53-75 µm wide, on ventral body surface, surrounded by sclerotic anal ring 68-100 µm wide bearing 12-14 setae, each 150-175 µm long with setal base surrounded by 4-10 minute pores.

Dorsum. Delineated by unbroken fringe of moderately dense setae, with approximately 140-170 moderately slender bluntly rounded or minutely capitate setae per side, setae each about 80-165 µm long on abdomen, somewhat shorter anteriorly, 65-100 µm long. Derm membranous. Dorsal body setae sparsely scattered, short (ca 7-15 µm long) and stout, with acute apex. Macrotubular ducts of one kind and size: short, ca 4-7 µm long, with a rim 3-4 µm wide; sparsely scattered singly or in pairs on central part of dorsum, but aggregated into distinct groups on peripheral areas, aggregations increasing in size toward margin, outer ones mostly containing about 10-25 ducts, maximum 30; duct aggregations borne on small, roughly oval to circular, sclerotised tubercles (cribriform plates). Microtubular ducts absent. Quinquelocular pores absent.

Venter. Oral lobes membranous. Ventral body setae sparse, mostly 50-100 µm long, up to 150 µm long on head behind frontal lobes, shorter (20-50 µm long) in lateral pore band. Macrotubular ducts slender, inner portion dilated, 15-17 µm long, 2.0-2.5 µm wide, with poorly sclerotised rim 2.5-3.5 µm in diameter; ducts distributed in a moderately dense peripheral band, ducts distributed evenly across abdominal segments III–VI, but apparently absent on segments immediately in front of and behind vulva where disc pores are most numerous. Quinquelocular pores 5 µm in diameter, mostly confined to abdominal segments V–VIII anterior to anal ring, but a few (12-20) associated with each spiracle.

Material examined.

Holotype of Opisthoscelis tuberculata (here designated): AUSTRALIA: New South Wales: 1 adult female (4.0 mm long, 3.2 mm wide):ex open top pit gall in leaf midrib, Eucalyptus sp., Penrith, 24 Nov., 1899, WWF No. 304 (ASCU).

Paratypes: AUSTRALIA: Victoria: 3 adult females (1 slide), 6 first-instar nymphs (including NH205), 7 embryos, 1 leaf with vacated pit galls: insects from under bark of Eucalyptus sp. (perhaps Eucalyptus microcarpa ), ca 10 km NNW of Benalla, Midland Highway, near turnoff to Hwy C371 to Tocumwal, -36.47°; 145.94°, 29 Dec., 2008, PJG, NH205 (ANIC).

Comments.

Adult females of Opisthoscelis tuberculata are closely related to Opisthoscelis thurgoona with which they share well-developed fore, mid and hind legs, 7 distinct antennal segments, a ventral anal opening, with a sclerotic anal ring bearing numerous setae, each of which is surrounded at the base by a number of minute pores. These features of the adult females of Opisthoscelis tuberculata and Opisthoscelis thurgoona are shared with species of Lachnodius . One morphological clue of the closer relationship between Opisthoscelis tuberculata and Opisthoscelis thurgoona and the other Opisthoscelis species (recovered by analysis of DNA sequence data (NBH, unpublished data)) is the presence of macrotubular duct clusters on the dorsum (possibly homologous to the cribriform plates found in Opisthoscelis subrotunda and Opisthoscelis beardsleyi ). However, as in Lachnodius , Opisthoscelis tuberculata has 5 fleshy setae on each antenna (4 on Opisthoscelis thurgoona ).

The adult female of Opisthoscelis tuberculata can be distinguished readily from that of Opisthoscelis thurgoona as follows (features of Opisthoscelis thurgoona in parentheses): (1) 5 fleshy setae on each antenna (4 on each); (2) dorsal ducts in clusters of up to 30 ducts (2-8 ducts per cluster); and (3) the adult female sits in an open-top leaf pit (in an enclosed leaf gall in Opisthoscelis thurgoona ).

The holotype of Opisthoscelis tuberculata is from the collection of W.W. Froggatt and the female was removed from an open pit gall in a leaf midrib and slide-mounted by J.W. Beardsley. Froggatt’s first accession notebook ( Gullan 1984b) records collection #304 as " Dactylopius eucalypti .? Penrith (no.2) (Berlese 234). small ascelis like gall". The reference to Berlese may refer to Professor Antonio Berlese (dal Laboratorio di entomologia agraria, Portici, Italy), because two nearby entries in the notebook say "Sent to Berlese" and give different numbers. The 3 adult females from Victoria were collected dead (post-oviposition), in association with their salmon-pink eggs, under loose bark just above the ground on the main trunk of a stunted tree (about 1.5 m high) growing in the middle of a picnic area car park. Several leaves on the tree had vacated pit galls (Fig. 1k), which are presumed to have been the feeding sites of the females prior to their movement to the bark for oviposition. The live eggs were maintained in a small plastic container and started eclosing on 1 Jan., 2009; DNA was extracted from the first-instar nymphs by NBH.

There is only minor variation between the adult female holotype from New South Wales and the three paratype females from Victoria; in particular, there are fewer clusters of macrotubular ducts on the dorsal submargin of the Victorian collection.Etymology

The species name is a manuscript name of the late J. W. Beardsley who was describing the species as part of a revision of Lachnodius . We assume that his name refers to the sclerotised dorsal duct clusters.