Lachnodius parathrix Beardsley, Gullan & Hardy

Hardy, Nate B., Beardsley Jr, John W. & Gullan, Penny J., 2019, A revision of Lachnodius Maskell (Hemiptera, Coccomorpha, Eriococcidae), ZooKeys 818, pp. 43-88 : 43

Lachnodius parathrix Beardsley, Gullan & Hardy sp. n. Figs 2c, 11

Diagnosis.

Dorsum without sclerotic invaginations; marginal fringe of conical setae; some dorsal macrotubular ducts with seta touching rim; anal ring invaginated.

Description.

Adult female (n = 3). Body outline circular; length 1.60-2.70 mm (2.70 mm for holotype), greatest width 1.50-2.22 mm (2.08 mm for holotype). Eyes 25-40 μm wide. Antennae seven-segmented; length 405-700 μm; with six hair-like setae on segment I, six hair-like setae on segment II, 3-6 hair-like setae on segment III, four hair-like seta on segment IV, one fleshy seta on segment V, two hair-like setae + one fleshy seta on segment VI and six hair-like setae + three fleshy setae on segment V. Tentorial box with anterior extension of the dorsal arms, 150-210 μm long, 125-170 μm wide. Labium 90-110 μm long, 75-110 μm wide. Spiracles 88-110 μm long, 45-70 μm wide across atrium. Legs increasing in size caudad; fore legs: trochanter + femur 280-540 μm, tibia 210−420 µm, tarsus 120-170 μm; mid legs: trochanter + femur 290-560 μm, tibia 210-420 μm, tarsus 120-180 μm; hind legs: trochanter + femur 320-610 μm, tibia 245-470 µm, tarsus 125-180 μm; claw 30-45 μm; coxa with six setae, trochanter with 5-7 setae, femur with 10-16 setae, tibia with 18-26 setae, tarsus with 9-12 setae; tarsal digitules 50-70 μm long, claw digitules 30-50 μm long; translucent pores on all segments of hind leg (except coxae of one female), ca. 80 pores on dorsal surface and ca. 50 pores on ventral surface. Anal ring invaginated, cuticle surrounding ring sclerotic, 63-77 μm wide, with 12-16 setae; ring setae 35-90 μm long. Pair of elongate caudal setae absent.

Dorsum. Derm beset with sclerotic spicules (i.e., well-developed microtrichia). Sclerotic urns and varioles absent. Dorsal setae lanceolate, 3-5 μm long, sparsely scattered over dorsum. Macrotubular ducts 10-12 μm long, with rim of dermal orifice ca. 5 μm wide; many of larger ducts with one seta affixed to rim of dermal orifice. Microtubular ducts ca. 4 μm long, with rim of dermal orifice ca. 2 μm wide, scattered over dorsum. Dorsum delimited by fringe of 210-250 setae on each side of body; each seta with acute apex, length of setae 20-35 μm; marginal fringe interrupted between thorax and abdomen.

Venter. Ventral setae 10-35 μm long; elongate setae medial of each coxa (50-110 μm long), and in a transverse band posterior of frontal lobes (longest seta 105-135 μm long). Macrotubular ducts each 10-15 μm long, with rim of dermal orifice 3-4 μm wide, found along margin and in transverse band across each abdominal segment. Quinquelocular pores of two distinct size-classes: (i) larger pores 5-6 μm in diameter, found on posterior abdominal segments; and (ii) smaller pores ca. 3 μm in diameter, near spiracles and along margin.

Second-instar female (n = 1). Broadly oval, length 2.0 mm. Antennae 6-segmented, short (160-190 µm total length), tapering base to apex, apical segment longest. Legs short, broad, tibiae and tarsi fused, claws weakly developed. Anal ring ca. 40 µm wide, with 10 setae each ca. 25 µm maximum length; a pair of setae, 27-30 µm long, just anterior to anal ring. Dorsum with sparse, small, peg-like setae ca. 4-8 µm long; tubular ducts apparently absent. Marginal fringe with ca. 140 conical setae, each 35-45 µm long, on each side of body. Ventral setae very sparse, filiform, up to 15 µm long; tubular ducts absent; with a widely spaces series of quinquelocular pores, each 3-4 µm in diameter, just inside the marginal fringe and a very few on thorax between margin and spiracles.

Etymology.

The species name is based on the Greek words para, meaning near or beside, and thrix, meaning hair, referring to the close-set setae forming the marginal fringe. It is a noun in apposition.

Notes.

The description of the adult female is based on specimens from both Victoria and New South Wales because they agree in all diagnostic features. The adult female from near Narooma has longer antennae and leg segments and appears to have no translucent pores on the hind coxae, compared with the two Victoria females, but this variation may be due to differences in nutrition or developmental temperatures. Adult females of L. parathrix are most similar those of L. melliodorae and L. maculosus , but can be easily distinguished by lacking the peculiar dorsal urns and varioles present in those species. The two known host species of L. parathrix belong to Eucalyptus series Radiatae and are characterized by the juvenile leaves having numerous oil glands ( Brooker 2000).

Material examined.

Holotype: Victoria: adult female, on slide: ex open pit gall on young twig, Eucalyptus radiata , 15 miles [24 km] W of Drouin, Princess Highway, 23 Jan 1972, JWB (ANIC). Paratypes: Victoria: one adult female, same data as holotype (BPBM); one pre-adult female exuviae, same data as holotype except: 20 miles [32 km] W of Drouin, 30 Jan 1972 (BPBM). New South Wales: one adult female: ex pit on midrib of leaf, E. elata , ca. 8 km WNW of Narooma, Wagonga Scenic Drive, 36.20S, 150.05E, 31 Dec 2008, PJG (ANIC).