Platylecanium dendrobii 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 : 167-169

Platylecanium dendrobii Hodgson , sp. nov.

Material examined

SINGAPORE: 1 slide with 1 specimen: left label: Platylecanium / On Dendrobium leaf / India at Seattle / I.W. Berryhill Coll. / June 2 1939 / Seattle 7975. Right label: Platylecanium / dendrobii / Hodgson / holotype ♀ (1/1 adf, fairly good) ( USNM).

Unmounted material. Unknown.

Slide-mounted adult female ( Fig. 6 ). Body elongate and fairly narrow, symmetrical and somewhat pointed at each end, length 3.95 mm, width 0.94 mm; anal cleft about 1/7 th of body length.

Dorsum. Derm quite uniformly sclerotised but palest near margin; areolations somewhat obscure but largest and most abundant near margin and smaller and more indistinct medially. Number of bands of reticulation plates not clear, but with probably 13 marginal reticulation points on head between anterior stigmatic clefts and, on each side, 4 between stigmatic clefts and 12/13 on abdomen (latter including line close to anal cleft, when visible). With distinct unsclerotised ray extending radially from each stigmatic cleft, each ray 430‒500 μm long. Dorsal setae stoutly setose with a non-flagellate apex, mostly slightly curved, 7‒9 μm long (only slightly shorter than a marginal seta), set in a socket about 3 μm wide (only slightly wider than those of marginal setae); more medial setae frequently raised on a distinct fleshy base, with seta on apex; setae most abundant towards margin, becoming very sparse medially. Clear areas present as in diagnosis, each surrounded by a group of preopercular pores, each pore about 3 μm wide, clearly larger and more distinct than dorsal simple pores, each with a distinct border (also possibly convex); preopercular pores distributed as follows: (anteriormost) CA 1, 0; CA 2, 1‒3; CA 3, 5‒6; CA 4, 6. Dorsal pores, probably microducts, represented by small non-sclerotised spots in derm, each pore 1‒2 μm wide, forming (along with dorsal setae) a distinct reticulate pattern.Anal plates about 240 μm long, combined width about 145 μm, together less than 2 times longer than broad, each plate with anterior margin clearly shorter than posterior margin, and with a rather elongated pointed apex; each plate with 4 setae 6‒8 μm long, present as in diagnosis; underside of each plate simple, without thickening or indentations in inner margin. Anogenital fold with 2 pairs of short fine setae on anterior margin and 2 pairs of fine setae on each lateral margin, each seta about 5 μm long, plus 1 larger seta about 7 μm long at posterior end of apodeme. Eyespots each more-or-less round, located on dorsum away from margin; width of each lens about 35 μm.

Margin. Margin not crenulated. Marginal setae all short, each about 8‒10 μm long (only slightly longer than a dorsal seta), and finely setose, with 1 (rarely 2) approximately associated with each marginal reticulation point; with 23 setae anteriorly between anterior stigmatic clefts, and, on each side, 6‒10 between stigmatic clefts, and 17‒22 along abdominal margin. Stigmatic clefts quite deep, each cleft with outer margins almost touching; inner part of cleft quite broad with innermost margin strongly sclerotised; with 3 (one with 4) stigmatic spines, median spine longest, extending out as far as margin; length of median spine 75‒78 μm, each lateral spine 35‒52 μm long; clefts without marginal setae along each outer margin, although these present at entrance. Anal cleft with margins touching.

Venter. Multilocular disc-pores each 6‒8 μm wide, mainly with 10 loculi, frequent on either side of genital opening and on preceding segment only; number on each side of segment: VII, 12‒14 and VI, 18. Spiracular disc-pores, each about 3 μm wide with mainly 5 loculi, present in a narrow band between margin and each spiracle; with 21‒22 in each anterior band and 22‒24 in each posterior band. Ventral microducts minute; distribution unclear. Ventral setae: interantennal setae not detected; longer setae present on abdominal segments VII and VI but only represented by basal sockets; setae otherwise very scarce. Antennae very reduced, segmentation obscure, basically with a narrow scape and with other segments fused; scape without setae but apex apparently with 5 fleshy setae and no setose setae; total antennal length 33‒35 μm. Clypeolabral shield about 118 μm long. Spiracles small, width of each peritreme 35‒40 μm. Legs not detected, perhaps absent.

Comments. Platylecanium dendrobii sp. nov. can be diagnosed by the following combination of character-states: (i) body elongate and symmetrical in shape; (ii) anal plates clearly longer than their combined width; (iii) each anal plate with anterior margin clearly shorter than posterior margin and with a pointed apex; (iv) body margin not crenulated; (v) marginal setae only slightly longer than dorsal setae; (vi) preopercular pores clearly larger than other dorsal pores; (viii) preopercular pores relatively few, and absent from around anteriormost clear area; (ix) each stigmatic cleft with 3 long, narrow stigmatic spines, median spine extending out to margin; (x) multilocular disc-pores restricted to abdominal segments VII and VI; (xi) legs possibly absent, and (xii) antennae very reduced.

In having: (i) an elongate body more than twice as long as broad; (ii) a non-crenulated margin; (iii) much reduced antennae, and (iv) anal plates clearly longer than their combined widths, P. dendrobii is close P. elongatum and P. cyperi . Based on Takahashi’s description, P. dendrobii differs from P. elongatum in having a very long median stigmatic spine, extending out as far as margin (median stigmatic spine on P. elongatum subequal to or shorter than other stigmatic spines), and in possessing dorsal areolations (apparently absent on P. elongatum ). Platylecanium dendrobii differs from P. cyperi in having (i) a body with somewhat pointed ends (evenly rounded in P. cyperi ), (ii) long median stigmatic spines reaching to margin (not reaching margin in P. cyperi ), and (iii) in having normally only 1 marginal seta associated with each marginal reticulation point ( P. cyperi usually has 2‒4 setae associated with each reticulation point). The new species is currently known only off a species of Dendrobium ( Orchidaceae ), intercepted at Seattle in US but originating from India.

Name derivation. The species is named after the orchid host-plant genus, Dendrobium Sw. , on which it was found.

Figures

FIGURE 6. Platylecanium dendrobii Hodgson, sp. nov., adult female.