Paralecanium planum (Green)

Chris J. Hodgson & Douglas J. Williams, 2018, Revision of the soft scale genus Paralecanium (Hemiptera: Coccomorpha: Coccidae) with the introduction of three new genera and twenty new species, Zootaxa 4443 (1), pp. 1-162 : 134-136

Paralecanium planum (Green)

( Fig. 56 )

Lecanium planum Green, 1896 , 9. Type data: SRI LANKA: Pundaluoya, on undetermined tree. Syntypes, female. Type depository: BMNH, London , U.K.

Lecanium planum ; Cockerell & Parrott, 1899, 228.

Paralecanium planum ; Fernald, 1903, 200. Change of combination.

Material examined. Lectotype f (here designated): SRI LANKA (as Ceylon): top label: CO-TYPE in black on an oval label + Lectotype in red on a narrow label; bottom label: Lecanium / planum / Green / from Nothopegia / colebrookiana / Pundaluoya / Ceylon ( BMNH): 1 slide with 1 young adf (f, but rather poorly cleared) lectotype (clearly marked), plus 1 immature (probably second/third-instar f; envelope indicates E.E.G. as collector). Top label: CO-TYPE in black on an oval label; bottom label: Lecanium / planum / Green / from / Nothopegia colebrookiana / Pundaluoya / Ceylon ( BMNH): 2/8adff (f-fg, almost all well sclerotised and about half missing venters). Top label: TYPE in red on a round label; bottom label: Lecanium / planum / Green / from Nothopegia / colebrookiana / Pundaluoya / Ceylon ( BMNH): 1/3adff (fg, mature f, two with venters).

Other material. SINGAPORE, on Fagraea sp., no date, C.F. Baker #9313 ( BMNH): 1/7adff (fg, identified as P.? maritimum Green ).

Note. The description is based mainly on the Lectotype but some details were taken from the rest of the type series.

Unmounted material. ‘Bright castaneous to dark chocolate brown. Flat, broad. Subtriangular; pointed in front.’ ‘On upper surface of leaves of unidentified tree.’ ( Green 1896, p. 9)

Slide-mounted adult female. Body of all specimens distinctly asymmetrical but otherwise rounded at both ends, broadest across abdomen. Length 2.1–2.6 mm, width 1.7–2.3 mm.

Dorsum. Derm of younger adults fairly uniformly coloured but older specimens with darker areas of sclerotisation forming a pattern medially, with a medial dark longitudinal line and about 7 radial lines emanating from it, 3 or 4 on abdomen, perhaps 3 on thorax and with those on head less clear. Areolations abundant submarginally, either elongate and each about 30–35 µm long, becoming oval, smaller and more obscure medially, where each about 10–15 µm wide, or darker and rounder submarginally, again fading medially; most of derm covered in minute pale spots. Marginal radial lines not visible on young specimens and obscure on older specimens, with perhaps 9 lines between anterior stigmatic clefts; lines from each cleft obscure or absent; each side with 3 lines between clefts and 11 on abdomen. Abdominal clear areas occasionally obscurely present but mainly not detected. Dorsal setae rather short, each 5 µm with a non-flagellate apex; sometimes curved, occasionally present in submargin; absent medially. Large dorsal pores possibly absent or represented by small pores, each about 2–3 µm wide and appearing within a clear spot in sclerotised derm, present in a sparse polygonal pattern but perhaps absent medially; abundance rather variable, perhaps as many as 60 per side on some specimens but other specimens with far fewer; smaller dorsal pores not visible. Anal plates together obviously longer than combined width; each plate with a rounded outer angle, 1 or 2 small pores medially and 2 or 3 small setae near outer margin on apex; length of plates 140–150 µm, combined width 95–108 µm (ratio of length to width 1:0.7). Anogenital fold with 1 small seta on each end of anterior margin, each lateral margin with 1 seta anteriorly and perhaps up to 3 other small setae (very hard to detect).

Margin. Marginal ornamentation present as quite strongly sclerotised small triangles, each with a long “stalk”, each stalk sometimes as deep as marginal setal sockets; with usually 7 or 8 between each pair of marginal setae. Marginal setae almost round and fan-like; width of each fan 25–28 µm, length 25–28 µm; with 72–88 setae anteriorly between anterior stigmatic clefts, each side with 23–33 between clefts, and 70–85 along abdominal margin. Stigmatic clefts quite deep, each with a sclerotised inner margin and 3 stigmatic spines, each spine rather parallel sided; median spine longest, each 30–35 µm long, each lateral spine 15–24 µm long. Eyespots each oval; width of socket 50–55 µm, diameter of lens 16–17 µm.

Venter. Membranous, with a narrow darker marginal band about 45–60 µm wide. Multilocular disc-pores in groups on either side of genital opening and on preceding segment only, each side with 7–10 on abdominal segment VII and 14–17 on segment VI. Spiracular disc-pores present in a narrow band between margin and each spiracle, with 12 or 13 in each band on short side and 15 or 16 on each longer side. Ventral setae: with 2 pairs of interantennal setae; long pairs of setae on abdominal segments VII–IV; other setae sparse, perhaps most frequent near margin in each radial line. Ventral microducts not detected but almost certainly present. Antennae well developed, each with 6 segments; total length 240–250 µm; each apical seta about 16 µm long. Clypeolabral shield about 105 µm long. Spiracles small, width of each peritreme 21–27 µm. Legs well developed, apparently with trochanter + femur and tibia + tarsus fused or with only indistinct segmentation; dimensions of hind leg (µm): coxa 76–78, trochanter + femur 120–124, tibia + tarsus 127–133; claw 8. Tarsal digitules slightly longer than claw digitules, with capitate apices; claw digitules both broad; claw without a denticle; setal distribution: coxa 6; trochanter 1, moderately long; femur 1 or 2; tibia 2 and tarsus 3.

Comments. Adult female P. planum are extremely similar to those of P. maritimum , differing most obviously in the form of the marginal ornamentation, that on P. planum consisting of 6–8 strong radial sclerotisations between each pair of marginal setae, whilst those on P. maritimum are narrower and fewer, with only 2–4 between each pair of marginal setae. The species also differ in the presence of large dorsal pores, with those on P. maritimum being 4– 7 µm wide whereas they are either absent or extremely small on P. planum , each 2–3 µm wide. Paralecanium machili is also very similar to P. planum but lacks the strong marginal ornamentation, having (at most) shallow sclerotised areas along margin.

Host-plants. Nothopegia colebrookiana (Anacardiaceae) ; Fagraea sp. ( Loganiaceae ). Unconfirmed host record: Nothopegia monadelpha (Anacardiaceae) .

Figures

FIGURE 56. Paralecanium planum (Green), adult female.