Platylecanium asymmetricum Morrison, 1921

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 : 155-159

publication ID

https://doi.org/10.11646/zootaxa.5646.2.1

publication LSID

lsid:zoobank.org:pub:83F03AF1-85CF-4347-A0B4-1A0438108391

persistent identifier

https://treatment.plazi.org/id/03F287E1-AF14-FFA1-4AE4-8F685A367A7B

treatment provided by

Plazi

scientific name

Platylecanium asymmetricum Morrison
status

 

Platylecanium asymmetricum Morrison View in CoL

Platylecanium asymmetricum Morrison, 1921: 667 View in CoL .

Platylecanium assymmetricum Morrison, 1921 View in CoL ; Takahashi 1950: 57. Misspelling of species epithet.

Platylecanium cocotis Laing, 1925: 59 View in CoL , syn. nov.

Material examined

Specimens previously identified as Platylecanium asymmetricum :

Type material: SINGAPORE: left label: Platylecanium / asymmetricum / n. sp. / paratypes / on Pinanga / Government Hill / Singapore / (C.F. Baker #8942) / J.H. Birkhill / Aug. 1917 (2/5 adff: 1/2 adf in fair to good condition, but both with some damage to venter: 1/3 adf, each missing most of venter and damaged) ( USNM) . As previous (1/2 sets of anal plates) ( USNM) . As previous (1/5 first-instar nymphs and 1 second-instar nymph, poor.) ( USNM) . SINGAPORE: left label: Platylecanium / asymmetricum / paratype Morr. / Malaya, (Singapore) / ex coll . U.S. Bur. Ent. / det. H. Morrison / EEG, 16/34. No. 11 ( NHML) (1/2 adf, in fair to good condition but specimen nearest label lacking much of venter. Both specimens clearly asymmetrical) ( NHML) . MALAYSIA: bottom label: Platylecanium / asymmetricum / (Paratype) Morr. / Malaya, (Singapore) ex coll . U.S. Bur. Ent., /det. H. Morrison / EEG, q6/34. No. 11 (1/2 adf, both narrow, both with a symmetrical dorsum but one with an asymmetrical venter; both missing most of venter) ( NHML) .

Non-type material: SOUTH PACIFIC: left label: Platylecanium sp. / On Dendrobium sp. / So. Pacific at San. Fran. / Parsons coll. / Aug. 28, 1944 / San. Fran., 18746. Right label: Platylecanium / asymmetricum / Morrison / det. C.J. Hodgson (1/1 adf, very good, unsclerotised; both dorsum and venter symmetrical) ( USNM).

SOLOMON ISLANDS: left label: Solomon Islands / Guadacanal, Tenaru / on Ficus glandulifera / leaf, 21.ii.1984 / M. Bigger / No. 00160 / CIE A 15889; right label: Platylecanium / asymmetricum / Morrison / Coccus / acutissimus / (Green) (1/2 adff, one of each species, both good) ( NHML).

Specimens previously identified as Platylecanium cocotis :

Type material: VANUATU: left label: NEW HEBRIDES [now VANUATU] / Efate. 1923 / on Coconut / H.W. Simmons / I.B.E. 966; right label: COCCIDAE / Platylecanium / cocotis sp. n. / Paralectotype / F. Laing det (oval in shape, symmetrical, in good condition) ( NHML).

Other material: VANUATU: left label: Platylecanium / cocotis / Laing / BM 1990-194 ; a gold vertical label on right side: Entomology Div., DSIR, NZ ; right label: Vanuatu / Malekula [misspelling of Malakula] / Unmet / 23 Nov. 1983 / P.A. Maddison [458] / on leaflets of Cocos / nucifera / #84–040a / Entomology Division D.S.I. R. NZ. (oval, symmetrical, in good condition) ( NHML) .

SOLOMON ISLANDS: left label: Platylecanium / cocotis / Laing / asymmetricum M.; right label: Solomon Is. / Reef Island / TTT 1984 / ex Areca leaf / No. 00414 / CIEA 15912; (1/2 adff, both narrow, with a symmetrical dorsum and one with an asymmetrical venter; in fair-good condition) ( NHML).

Note: data for specimens previously identified as P. cocotis are given in brackets.

Unmounted material. Platylecanium asymmetricum was described as follows: “elongate, narrowed at each end, flat, dark reddish brown, sometimes almost blackish in the dried specimens, with more-or-less black mottling, probably due to the drying of the internal organs; eye spots pale, surrounded by a blackish area; all specimens prominently asymmetrical ….” ( Morrison 1921). Platylecanium cocotis was originally described as: “dark reddish brown, flat, longish oval, slightly narrower in front than behind, length about one-half greater than breadth, a median longitudinal ridge of white, brittle secretion (which may cover the whole dorsum) present” ( Laing 1925).

Slide-mounted adult female ( Figs 1 View FIGURE 1 & 2 View FIGURE 2 ). Body of most specimens previously identified as P. asymmetricum elongate and strongly asymmetric on venter but dorsum often symmetrical; sometimes somewhat pointed anteriorly and posteriorly; anal cleft about 1/7 th of body length. Body of specimens previously identified as P. cocotis broadly oval and symmetrical. Length 2.9‒4.9 (2.93) mm, width 1.4‒1.9 (1.9) mm.

Dorsum. Derm fairly uniformly sclerotised but palest near margin and in centre of each reticulation plate; with two complete paler marginal bands of areolations, those in more marginal band small, those more submarginally larger and denser; most of derm variously sclerotised on older specimens but pattern of reticulations often symmetric even on otherwise asymmetric specimens. Reticulation plates mainly in 3 longitudinal bands on each side, with a narrow additional band running from anal plates to anterior margin; reticulation points reasonably distinct, 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 when visible). With a distinct unsclerotised ray extending radially inwards from each stigmatic cleft, length depending on degree of asymmetry, each 105‒275 μm long. Dorsal setae each 6‒10 (8‒10) μm long (much shorter than marginal setae), setose, mostly distinctly curved, each set in socket about 4 μm wide (wider than that of a marginal seta), more medial setae frequently raised on a distinct fleshy base, with seta located on apex; most abundant towards margin but present throughout in most reticulation lines. Clear areas present as in diagnosis, each surrounded by a group of preopercular pores very similar in size to dorsal microducts (and difficult to distinguish from them) but possibly with a more distinct border (also possibly convex), approximately distributed as follows: (anteriormost) CA 1, 0‒2? (2‒4); CA 2, 0‒7 (6‒15); CA 3, 3‒10 (8‒14); CA 4, 5‒10 (11‒15); each preopercular pore about 3 μm wide. Dorsal microducts represented by small non-sclerotised areas in derm, forming (along with dorsal setae) a distinct reticulate pattern; each microduct 1‒2 μm wide. Anal plates each 180‒ 197 (189‒197) μm long, combined width 139‒168 (160‒172) μm; together almost quadrate, each with anterior margin slightly shorter than posterior margin, and with a rather elongated pointed apex; each plate with 4 setae, 5‒7 μm long, present as in diagnosis; also with 2 or 3 small pores medially; underside of each plate apparently thickened with a secondary posterior apex on inner margin, and with a deep indentation about half-way up each inner margin (arrowed in Figs). Anogenital fold with 2 pairs of short fine setae on anterior margin, 1 pair of fine setae in middle of each lateral margin (often very difficult to see) and 1 seta at posterior end of apodeme, plus an extra seta situated more medially nearer indentation on inner margin of each plate (arrowed in Figs); all anogenital fold setae short, each about 5‒7 μm long. Eyespots more-or-less round, located away from margin on dorsum; maximum width of each about 25‒27 μm.

Margin. Margin distinctly crenulated. Marginal setae all rather short, each about 13‒22 (16‒20) μm long (much longer than dorsal setae), and finely setose, with 1‒3 (rarely 4) roughly associated with each marginal reticulation point; with 31‒39 (33‒37) setae anteriorly between anterior stigmatic clefts, 7‒11 (11‒17) on each side between stigmatic clefts, and 16‒22 (27‒30) along each abdominal margin. Stigmatic clefts quite deep, each with outer margins almost touching; inner part of cleft quite broad, with margin strongly sclerotised, and with 3 (rarely 4) stigmatic spines; spines subequal in length or median spine longest; length of median spine 25‒50 (41‒54) μm, each lateral spine 25‒38 (28‒54) μm long; each cleft with 0‒2 marginal setae along each outer margin. Anal cleft with margins touching.

Venter. Multilocular disc-pores each 8‒9 μm wide with mainly 10 loculi, frequent on either side of genital opening and on preceding segment only; number of pores on each side of segment: VII 10‒17 (10‒16) and VI 14‒23 (16‒25). Spiracular disc-pores, each about 3 μm wide with mainly 5 loculi, present in a narrow band between each spiracle and margin; number of pores on each side dependant on asymmetry–asymmetric specimens with as few as 5 on narrow side and up to 25 on broad side (symmetrical specimens, i.e., P. cocotis , with 26‒32 in each anterior band and 28‒38 in each posterior band). Ventral microducts minute, distribution unclear. Ventral setae: interantennal setae absent; longer setae on abdominal segments VII each 56‒66 (61‒66) μm long, those on segment VI, 18‒ 24 (23) μm long; setae sparse across other abdominal segments, otherwise very scarce. Antennae very reduced, with segmentation obscure, with basal scape narrow, other segments fused; P. asymmetricum with a strong seta on scape, each 11‒17 μm long (absent) and with 4 or 5 fleshy setae on apex; total antennal length 42‒53 (41‒56) μm. Clypeolabral shield 117‒126 (122‒126) μm long. Spiracles small, width of each peritreme 35‒63 (26‒43) μm. Legs minute or probably sometimes absent; when present, more-or-less reduced to a claw; digitules not visible.

Comments. The unique structure of the anal plates, i.e., with the deep cleft on the inner margin of the underside of each plate, and the presence of the “extra” small seta away from each lateral anal cleft margin (both arrowed in Figs 1 View FIGURE 1 & 2 View FIGURE 2 ), is taxonomically significant and is typical of material previously identified as P. asymmetricum and P. cocotis . As can be seen from the above description, these two species are otherwise remarkably similar. Indeed, the only constant morphological difference found between the two sets of slides was that a strong seta was present on the scape of all specimens of P. asymmetricum whereas not even setal sockets could be detected in this position on specimens of P. cocotis . This small difference is not considered sufficient here to separate the two species, so here P. cocotis is sunk as a junior synonym of P. asymmetricum Morrison , syn. nov. It is perhaps worth pointing out that they also have the same main host plant family, Arecaceae .

Platylecanium asymmetricum can be diagnosed by the following combination of character-states: (i) anal plates only slightly longer than their combined width; (ii) each anal plate with a deep cleft on underside of inner margin; (iii) body margin crenulated; (iv) marginal setae significantly longer than dorsal setae; (v) preopercular pores difficult to separate from dorsal simple pores; (vi) preopercular pores relatively few, generally absent from around anterior clear areas; (vii) each stigmatic cleft with 3 long, narrow stigmatic spines; (viii) multilocular disc-pores restricted to abdominal segments VII and VI; (ix) legs each very reduced, mainly to a claw, without digitules, and (x) antennae very reduced, consisting of a basal scape and a further section consisting of remaining segments.

Platylecanium asymmetricum is closest to P. mesuae and P. sarawakense in having (i) a crenulate margin; (ii) very reduced antennae; and (iii) multilocular disc-pores with mainly 10 loculi, but recognizable immediately by the unique structure of the anal plates.

Distribution and host plants. Platylecanium asymmetricum has now recorded from Singapore, Malaysia, some Pacific Islands ( Vanuatu, Solomon Is), Indonesia and Papua New Guinea ( García Morales et al. 2016). Most host records are from Arecaceae but there are also records from Lauraceae and Zingiberaceae ( García Morales et al. 2016) .

USNM

Smithsonian Institution, National Museum of Natural History

NHML

Natural History Museum, Tripoli

DSIR

Department of Scientific and Industrial Research

R

Departamento de Geologia, Universidad de Chile

CA

Chicago Academy of Sciences

VI

Mykotektet, National Veterinary Institute

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hemiptera

Family

Coccidae

Genus

Platylecanium

Loc

Platylecanium asymmetricum Morrison

Hodgson, Chris 2025
2025
Loc

Platylecanium assymmetricum

Takahashi, R. 1950: 57
1950
Loc

Platylecanium cocotis

Laing, F. 1925: 59
1925
Loc

Platylecanium asymmetricum

Morrison, H. 1921: 667
1921
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