Platylecanium watsoniae 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 : 194-196

Platylecanium watsoniae Hodgson , sp. nov.

Material examined

PHILIPPINES: Holotype: 1 slide with 1 adult female: left label: Platylecanium / watsoniae / Hodgson / holotype ♀ / J. Dooley coll.; right label: Orchid / Philippines / 09/13/[19]79 / COI LI SW/ PM / CF009442 / Euparol (1/1 adf, fairly good) ( USNM).

Unmounted material. Unknown.

Slide-mounted adult female ( Fig. 18 ). Body oval and symmetrical, length 3.8 mm, width 2.3 mm; anal cleft about 1/7 th of body length.

Dorsum. Derm lightly sclerotised throughout, with little sign of heavier sclerotisation apart from a little around each eyespot and heavy sclerotisation in each stigmatic cleft. With a complete broad submarginal band of areolations, each areolation quite large and roundish. Reticulation plates probably in 4 longitudinal bands on each side but reticulation lines indistinct; marginal reticulation points reasonably clear, with 13 on head between anterior stigmatic clefts and, on each side, 4 between stigmatic clefts and 12 or 13 on abdomen (latter including line close to anal cleft, often difficult to distinguish). Unsclerotised ray arising from each stigmatic cleft distinct, extending medially to dorsad to each spiracle or even a little further medially. Dorsal setae each 8‒9 μm long (shorter than a marginal seta), robustly setose, mostly distinctly curved; socket about 5 μm wide (larger than that of a marginal seta), with only a few setae raised on a distinct fleshy base; restricted to within reticulation lines and setae most abundant nearer margin, becoming distinctly scarce medially. Clear areas as in diagnosis, but with 5 pairs on abdomen and an extra pair medially at inner end of each anterior unsclerotised ray; clear areas CA 2- CA 4 each surrounded by a group of preopercular pores, each 2.5‒3.5 μm wide with a granulate surface and a distinct border; distributed as follows: (anteriormost) CA 1, 0; CA 2, 4; CA 3, 7 or 8; CA 4, 12 or 13, and CA 5, 0. Dorsal microducts minute, each about 1 μm wide, located in an unsclerotised area of derm within reticulation lines. Anal plates together longer than broad, 150‒153 μm long, combined width about 118 μm; each plate with anterior margin clearly shorter than posterior margin, with a rather pointed apex and with 4 setae near apex, each 5‒8 μm long, distributed as in diagnosis; one plate with a small pore medially; posterior margin slightly wavy and sclerotised; inner margin with a broad area of thickening on underside of each plate. Anogenital fold with 2 pairs of short fine setae on anterior margin, 2 pairs of fine setae in middle of each lateral margin and 1 short seta at posterior end of each apodeme, all setae only indicated by basal sockets. Apodemes simple, not fused anteriorly. Eyespots each more-or-less round, located on dorsum away from margin; maximum width of each lens about 30 μm.

Margin. Margin distinctly crenulated. Marginal setae longer than dorsal setae, setose but perhaps with a blunt apex, 12‒14 μm long, with basal socket distinctly smaller than that of a dorsal seta; with mainly 2 (occasionally only 1) setae approximately associated with each marginal reticulation point, with 32 setae between anterior stigmatic clefts and, on each side, 11 or 12 between stigmatic clefts, 25‒28 on abdomen, plus 0‒3 on outer margins of each cleft. Stigmatic clefts quite deep, each with outer margins nearly touching; inner part of cleft quite broad with margin strongly sclerotised; with 3 or 4 stigmatic spines, median spine longest, each 43‒50 μm long, not extending out to margin, lateral spines each 28‒33 µm long. Anal cleft with margins touching.

Venter. Multilocular disc-pores each 5‒7 μm wide, mostly with 10 loculi, frequent on either side of genital opening and on preceding segment only; with, on each side of segment, 1 ‒19 on VII and 22‒24 on VI. Spiracular disc-pores, each about 3.0 μm wide with 5 or 6 loculi, present in a narrow band between each spiracle and margin; with 18‒21 in each band. Ventral microducts minute, each about 1 µm wide, possibly sparsely distributed throughout. Ventral setae: inter-antennal setae probably absent; preanal setae on abdominal segments VII rather robust, each about 30‒43 μm long; those on segment VI missing; setae sparse elsewhere but smaller submedially that medially. Antennae very reduced, with a suggestion of a scape, otherwise segmentation obscure; setae restricted to apical half; total antennal length about 40 μm. Clypeolabral shield about 120 μm long. Spiracles small, width of each peritreme 26‒30 μm. Legs minute, each more-or-less reduced to a claw, only visible on one side on some segments; claws each 7‒10 μm long; digitules not visible.

Comments. Although there is only one specimen of this species, P. watsoniae sp. nov. is distinctive, and is characterised by the following character-states: (i) margin crenulated; (ii) dorsal setae shorter than marginal setae but with broader basal sockets; (iii) preopercular pores associated with clear areas CA2-CA4 only; (iv) preopercular pores easily distinguishable from other dorsal pores; (v) with 5 pairs of clear areas on abdomen; (vi) with an additional clear area at inner end of anterior unsclerotised ray; (vii) anal plates longer than broad; (viii) anal plates without a deep cleft underneath each inner margin; (ix) each inner margin of anal plates with a broad area of thickening; (xii) antennae very short, and (x) legs, when visible, reduced to just claws without digitules.

Platylecanium watsoniae is somewhat similar to P. sarawakense , described above, in having the inner margin of each anal plate with a broad area of thickening on underside of each plate and anal plates that are longer than their combined widths and each plate with a rather pointed apex, but P. watsoniae differs in having: (i) 5 pairs of clear areas dorsally on the abdomen, plus an additional clear area at inner end of anterior unsclerotised ray, and (ii) much smaller anal plates, each 150‒153 μm long and about 118 μm combined width (compared with 176‒244 μm long and 134‒164 μm combined width on P. sarawakense ). In addition, these two species have been recorded from very different hosts: P. watsoniae on Orchidaceae and P. sarawakense on Piperaceae .

The presence of the additional clear area near the inner end of each unsclerotised ray in P. watsoniae is unique within Platylecanium but is also found in several species of Discochiton and Paralecanium .

Two other Platylecanium species are known only from intercepted specimens on Orchidaceae , namely P. vanda and P. coelogyne , both described as new above. Platylecanium watsoniae differs significantly from P. vanda in having: (i) a crenulated margin; (ii) only 3 stigmatic spines in each stigmatic cleft, and (iii) in having many marginal setae (more than 45 on each side); in contrast, P. vanda has an uncrenulated margin, up to 7 stigmatic spines in each cleft and very few marginal setae (about 10 per side). Platylecanium watsoniae differs from P. coelogyne in having a crenulated margin and very reduced antennae (whereas P. coelogyne has an uncrenulated margin and the antennae are well developed). Platylecanium watsoniae is currently only known from this single specimen, intercepted at San Francisco on Orchidaceae from the Philippines.

Name derivation. The species is named after Dr Gillian W. Watson, current scale insect subject editor for Zootaxa , who has contributed greatly to our understanding of this group.

Figures

FIGURE 18. Platylecanium watsoniae Hodgson, sp. nov., adult female.