Platylecanium vanda Hodgson, 2025

Hodgson, Chris, 2025, Revision of the soft scale genus Platylecanium (Hemiptera: Coccomorpha: Coccidae), with descriptions of eight new species, Zootaxa 5646 (2), pp. 151-198 : 188-194

Platylecanium vanda Hodgson , sp. nov.

Material examined

Type material: THAILAND: left label: Platylecanium / on Vanda coerulea / Bangkok, Siam at S.F. / Various colrs / Apr. 19, 1948 / San Francisco 24962; right label: Platylecanium / vanda / Hodgson / holotype / paratype ad ♀♀ (3 young adf, plus 2 x second-instar ♀ nymphs: holotype: right-hand specimen, marked with a black line, furthest from label; other specimens here designated paratypes, good) ( USNM) . Other paratypes: THAILAND: left label: Platylecanium / on Vanda coerulea / Siam at D.C. / Lumsden & Adamas coll. / Jan. 20, 1939 / EQ# 65825; right label: Platylecanium / vanda / Hodgson / paratype ♀♀ (1/3 specimens: 1 immature adf + 2 x second-instar ♀ nymphs: good) ( USNM) . Also THAILAND: left label: Platylecanium / sp. / on Vanda coerulea / Bangkok, Siam at S.F. / Aug. 27, 1948 / San Fransico 25262; right label: Platylecanium / vanda / Hodgson / paratype ♀♀ (1/5 adff - 1 immature and 4 mature adf, good) ( USNM) .

Other, non-type, material: THAILAND, on Orchidaceae leaf, 11.viii.1975, JFK 1A20371, W. Adams (1/1 mature adf, fair) ( USNM). THAILAND, on leaf of Ascocentrum sp. ( Orchidaceae ), 16.viii.1979, Miami 21476, E.B. Lee (1/3 adf, good) ( USNM). THAILAND, on Vanda sp. ( Orchidaceae ), 17 Mar. 1954, B.P. Stewart, Miami 3042 (1/1 adf, 2 x second-instar males and 1 x second-instar ♀ nymphs; good) ( USNM). THAILAND ( Siam), at D.C., on Vanda coerulea leaf, 31 Mar. 1939, H.L. Sanford, Coll. # 63648 (1/3 adf, fair) ( USNM). INDIA, ex Vanda sp. leaf, 12.1.1971, B. R. Dozier, Miami # 2506 (1/1 adf + 2 x second-instar female nymphs, good) ( USNM).

Note: all of the above material was intercepted on entry into the U.S.A. The description is taken mainly from the type series.

Unmounted material. Unrecorded but some mounted specimens with remains of a thin waxy, glassy test.

Slide-mounted adult female ( Fig. 15 ). Body oval and symmetrical, quite broad and rounded at both ends, length 2.0‒ 4.3 mm, width 1.5‒3.3 mm; anal cleft about 1/7 th of body length.

Dorsum. Derm unsclerotised when young, becoming fairly uniformly sclerotised at maturity but generally palest near margin and most heavily sclerotised medially; a band of areolations present submarginally but often indistinct; with slightly denser derm associated with anal plates, around each clear area and around each eyespot; derm showing no specific variations in sclerotisation in relation to reticulation plates; each stigmatic cleft with a strongly sclerotised inner margin. Layout of reticulation plates rather vague but probably with 4 longitudinal bands on each side. Marginal reticulation points: with 13 between anterior stigmatic cleft and, on each side, 4 between stigmatic clefts and 13 on abdomen (including that along each anal cleft margin). Unsclerotised ray arising from each stigmatic cleft distinct on mature specimen; length of each ray: 500‒750 μm. Dorsal setae robust, each 8‒12 μm long, with a wide basal socket 5‒6 μm wide (socket clearly larger than that of a marginal seta), mostly distinctly curved with a blunt apex; on mature specimens, setae only occasionally slightly raised on a distinct fleshy base, with seta located on apex; setae common in reticulation lines but scarcer medially. Clear areas present as in diagnosis, each surrounded by a group of preopercular pores, each mostly 4.5‒5.0 μm wide (distinctly larger than a dorsal microducts) but a few as large as 8.0 μm wide; each pore with a distinct border and a few dark spots medially; distributed as follows: (anteriormost) CA1, 2‒15; CA2, 7‒16; CA3, 9‒16; CA4, 7‒16. Dorsal microducts each represented on mature specimens by a clear area in derm, each 2‒3 μm wide, possibly with a short inner ductule; present in a distinct reticulate pattern along with dorsal setae. Anal plates each 176‒210 μm long and 130‒168 μm wide, clearly longer than broad, with a pointed apex; each plate with 4 setae, distributed as in diagnosis; underside of each plate with a distinctly wrinkled posterior margin, and some thickening along inner margin but with no cleft underneath about half-way along inner margin. Anogenital fold with 2 pairs of short fine setae on anterior margin, 2 or 3 pairs of fine setae along each lateral margin plus a seta at posterior end of each apodeme, 8‒16 μm long. Anal ring with 6 setae, located at end of an anal tube about same length as anal plates; length of anal ring setae each up to 270 μm. Eyespots oval, located on dorsum away from margin, almost dorsad to scape; width of each lens about 17 μm in a socket 20‒40 x 17‒40 μm wide.

Margin. Margin not crenulated. Marginal setae all short, each about 14‒17 μm long (subequal to or slightly longer than a dorsal seta), seta perhaps slightly narrower than dorsal setae but also with a blunt (or slightly capitate) apex; basal-socket also slightly smaller than that of a dorsal seta, with 0 or 1 approximately associated with each marginal reticulation point, each side with a total of about 10‒15 setae (not including those in each cleft). Stigmatic clefts quite deep, with outer margins of cleft almost touching; inner part of cleft widening and becoming quite broad, with inner margin strongly sclerotised; each cleft with 4‒7 long, narrow, blunt stigmatic spines, each 16‒75 μm long, shortest spines located laterally when 7 spines present; cleft margins each usually with 1‒3 marginal setae. Anal cleft with margins touching along entire length.

Venter. Multilocular disc-pores mostly with 10 loculi, present in segments VII and VI only, with 10‒17 on each side of VII and 15‒21 on each side of VI. Spiracular disc-pores, each rather small, mostly with 5 loculi, present in a narrow band mainly 1 pore wide between each spiracle and margin, with 18‒29 disc-pores in each band. Ventral microducts minute; distribution uncertain. Ventral setae: a pair of short setae present between antennae; a pair of long setae, each about 85 μm long, present on abdominal segment VII, plus some quite long setae across all abdominal segments, more anterior and lateral setae becoming shorter; submarginal setae very short, each about 4‒5 μm long. Antennae reduced, usually with a narrow scape and all other segments fused with occasional signs of pseudo-articulations; setae only visible on apical segment; total antennal length 68‒86 μm. Clypeolabral shield about 112 μm long. Spiracles small, width of each peritreme 28‒42 μm. Legs absent (but see Comments below second-instar female below).

Comments. Platylecanium vanda sp. nov. can be recognised by the following combination of character-states: (i) broadly oval shape; (ii) anal plates longer than wide, with posterior margin longer than anterior margin and with a rather pointed apex; (iii) underside of each anal plate showing nothing distinctive; (iv) margin not crenulated; (v) dorsal setae with a blunt apex and a large basal socket; (vi) marginal setae slightly longer than dorsal setae but with a narrower basal socket, each seta with a blunt apex; (vii) marginal setae very few, with only 0 or 1 associated with each marginal reticulation point and with only about 10‒15 per side; (viii) preopercular pores easily separable from dorsal simple pores; (ix) each stigmatic cleft with 4‒7 long, narrow stigmatic spines; (x) multilocular disc-pores restricted to abdominal segments VII and VI; (xi) legs normally absent, and (xii) antennae with a short scape, other segments fused.

Platylecanium vanda is morphologically very similar to P. nepalense but is much smaller when mature and occurs on different hosts. For a comparison, see under P. nepalense above

All of this material was intercepted on entry into the U.S.A., mainly on leaves of the orchid Vanda coerulea Griff. Ex Lindl. Platylecanium vanda , sp. nov. appears to be restricted to Orchidaceae and so far is known only from Thailand and India.

Second-instar female

Described from all available specimens.

Unmounted material. Unrecorded.

Slide-mounted specimens ( Fig. 16 ). Body roundly oval, length 1.50‒1.65 mm, greatest width 1.05‒1.23 mm.

Dorsum. Derm membranous apart from small areas of heavy sclerotisation on inner margin of each stigmatic cleft. Reticulation lines, reticulation plates and membranous rays either absent or not visible. Dorsal setae absent. Clear areas, dorsal pores and microducts not visible. Dorsal tubular ducts absent. Anal plates each 116‒125 μm long, combined width 88‒98 μm; together almost quadrate, but each plate with anterior margin slightly shorter than posterior margin; posterior margin generally with a distinct nick about half way along; each plate with 4 setae distributed as in diagnosis; without small pores; underside of each plate mildly thickened underneath along inner margin and with a strongly sclerotised posterior margin. Anogenital fold with 1 pair of short fine setae on anterior margin, 1 on each lateral margin and 1 seta at posterior end of each apodeme. Eyespots approximately round, located on dorsum away from margin; maximum width of each eye about 20 μm.

Margin. Margin not crenulated. Marginal setae all short, each mostly about 8‒10 μm long but with 1 or 2 on outer margins of each spiracular cleft up to 16 μm long; finely setose, mostly slightly bent, possibly set slightly onto dorsum, with (not counting those on cleft margin) 6 on margin between anterior spiracular clefts and, on each side, 1 between spiracular clefts and 6 on abdomen. Stigmatic clefts quite deep, each with outer margins of cleft almost touching; inner part of cleft quite broad but short, with inner margin strongly sclerotised, each cleft containing 3‒6 stigmatic spines (usually 4 or 5); spines each 15‒38 μm long, none extending laterally as far as margin.

Venter. Multilocular disc-pores absent. Spiracular disc-pores, each about 2 μm wide, mostly with 5 loculi, present in a narrow band between margin and each spiracle; with 6‒15 in each band, usually with slightly more in anterior band than in posterior band. Ventral microducts minute, present at least near spiracular disc-pore bands. Ventral setae very scarce and short, each perhaps 2 μm long; submarginal setae set close to margin; interantennal setae absent; long setae in abdominal segment VII each about 40 μm long. Antennae very reduced, segmentation obscure but with pseudo-articulations suggesting 6 segments, with 4 or 5 fleshy setae and 3 or 4 setose setae present only on apical 3 segments; total antennal length 55‒63 μm (but occasionally only 35 μm, or up to 68 μm long). Clypeolabral shield 120‒132 μm long. Spiracles small, width of each peritreme 20‒25 μm. Legs entirely absent.

Comments. For differences from the second-instar male, see under that stage below.

The complete absence of legs on most second-instar female nymphs clearly indicates that the adult females of P. vanda are normally legless. However, one of the three specimens on Ascocentrum species has quite distinct legs on all three thoracic segments, although each leg is much reduced, as follows: on prothorax: slightly swollen, 45‒50 μm long, with a minute claw, one with a tarsal digitule; on mesothorax: not as swollen, 50‒52 μm long with a claw and 1 or 2 tarsal digitules, and on metathorax: 68‒75 μm long, rather swollen, with both a minute claw and 0 or 1 digitule. These leg stubs are very different from those of the second-instar male, described below, which are not swollen.

Second-instar male

Unmounted material. Unrecorded.

Slide-mounted specimens ( Fig. 17 ); described from both available specimens. Body roundly oval, length 1.5‒1.9 mm, greatest width 0.9‒1.0 mm, significantly smaller than second-instar female nymphs.

Dorsum. Derm membranous apart from small areas of heavy sclerotisation on the inner margin of each stigmatic cleft. Reticulation lines, reticulation plates and membranous rays either absent or not visible. Dorsal setae absent. Clear areas, dorsal pores and microducts not visible. Dorsal tubular ducts present, of 2 sizes: (i) long ducts, with outer ductule about 28‒35 μm long and inner ductule equally broad and about the same length with a glandular end; present in a sparse submarginal line, with about 12 between anterior stigmatic clefts and, on each side, 5 between stigmatic clefts and 6 on abdomen, each submarginal line terminating about 2/3rds down abdominal margin; and (ii) smaller, narrower ducts, with outer ductule about 15‒18 μm long and with a short inner ductule without a glandular end, present in a submedial line on each side from anterior margin to anal plates, each line with about 15‒18 ducts; also similar ducts in radial lines extending medially from near each spiracular cleft to the submedial line, with 1‒3 in each line. Anal plates each 85‒88 μm long, combined width 66‒73 μm; together almost quadrate, but with anterior margin slightly shorter than posterior margin; each plate with 4 setae distributed as in diagnosis; without small pores; underside of each plate mildly thickened underneath along inner margin and with a strongly sclerotised posterior margin. Setae along margins of anogenital fold not visible, but a setal socket present at end of each apodeme. Eyespots each approximately round, located on dorsum away from margin; maximum width of each about 20 μm.

Margin. Margin not crenulated. Marginal setae all short, each about 8‒10 μm long but with 1 or 2 on outer margins of each cleft up to 14 μm long; finely setose, mostly slightly bent, possibly set slightly onto dorsum; with (not counting those on cleft margin) 6 on margin between anterior stigmatic clefts and, on each side, 1 between stigmatic clefts and 6 or 7 on abdomen. Stigmatic clefts quite deep, with outer margins of cleft almost touching; inner part of cleft quite broad but short, with inner margin strongly sclerotised, each with 3 stigmatic spines; length of lateral spines 20‒33 μm long, medial spines usually obviously shorter, each 18‒26 μm long; lateral spines often extending out to margin.

Venter. Multilocular disc-pores absent. Spiracular disc-pores, each about 2 μm wide, mostly with 5 loculi, present in a narrow band between each spiracle and margin; with 10‒17 in each band, usually with slightly more in anterior band than in posterior band. Ventral microducts present but distribution uncertain. Ventral tubular ducts absent. Ventral setae very scarce and short, perhaps 2 μm long; submarginal setae set very close to margin; both specimens with a long seta near antenna, each about 13 μm long; long setae in abdominal segment VII each about 35‒41 μm long. Antennae reduced, segmentation obscure but with pseudo-articulations suggesting 6 or 7 segments; with 2 setae on scape, 2 setae on pedicel and 2 setae on segment III, plus 4 or 5 fleshy setae and 3 or 4 setose setae on apical 3 segments (not all setae present on all antennae); total antennal length 60‒63 μm. Clypeolabral shield about 110 μm long. Spiracles small, width of each peritreme 17‒20 μm. Legs reduced to short triangular structures, each with base 28‒30 μm wide and length/height 20‒25 μm, each with pseudo-articulations suggesting fusion of about 4 basal ‘segments’, many with small setae; each leg with 2 tarsal digitules each about 7‒8 μm long, a minute claw on apex and 2 claw digitules (sometimes hard to see), each about 3‒4 μm long.

Comments. Second-instar male nymphs of P. vanda differ from the second-instar females in being much smaller, and in having (character-state in second-instar female in brackets): (i) only 3 stigmatic spines in each cleft (usually 4 or 5); (iii) two types of tubular ducts on the dorsum (absent), and (iv) in possessing legs (absent). In addition, the second-instar male appears to have 7-segmented antennae whereas the second-instar female appears to have only 6-segmented antennae, although the segmentation on both is rather obscure.

Miller & Williams (1997) described the suture configuration on the tests of a range of second-instar male tests of many Coccidae . The sutures on the tests of second-instar male nymphal Coccidae have the same layout as the distribution of the dorsal tubular ducts on the dorsum of the second-instar nymphs. The only male test in Miller & Williams that has the same distribution of dorsal tubular ducts as found on P. vanda was that of P. asymmetricum !

Name derivation. The species epithet, vanda , is a noun in apposition; it is named after the orchid host plant genus, Vanda Jones ex R. Br.

Figures

FIGURE 15. Platylecanium vanda Hodgson, sp. nov., adult female.

FIGURE 16. Platylecanium vanda Hodgson, sp. nov., second-instar female.

FIGURE 17. Platylecanium vanda Hodgson, sp. nov., second-instar male.