Discochiton mancum (Green) Chris J. Hodgson & Douglas J. Williams, 2018

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 : 40-42

Discochiton mancum (Green) comb. n.

( Fig. 13 )

Lecanium mancum Green, 1922, 1023 . Type data: SRI LANKA: Namunakuli Hill, Badulla, on Calophyllum walkeri. Syntypes, female. Type depository: BMNH, London, England, U.K.

Paralecanium mancum ; Green, 1937, 305. Change of combination.

Material examined. Lectotype f and paralectotype ff (here designated): SRI LANKA (as Ceylon): top label: Type in red on small round label; bottom label: Lecanium / mancum / (Type) Green / from Calophyllum / walkeri / Namunakuli [probably Namunukula], Ceylon / Feb. 1910 (BMNH): 1/8adff (f: 2 young, 6 more mature; many missing venters; lectotype top-most specimen under type label; envelope states E.E. Green coll.).

Note. The description is based mainly on those specimens with venters.

Unmounted material. “Adult female flat, deltoid, with rounded angles, usually asymmetrical, always narrower in front. Colour dark castaneous with a narrow hyaline border and with hyaline canals extending inwards from each stigmatic cleft. Dorsum with a more or less well defined, thin, colourless, polygonal, waxy plates.” “Length 4 to 4.5 mm. Breadth across abdomen 2.75 to 3 mm.” ( Green, 1922, p. 1023).

Slide-mounted adult female. Body broadest posteriorly, slightly more pointed anteriorly; most specimens showing some asymmetry. Length 3.0– 4.5 mm, width 2.0– 2.75 mm.

Dorsum. Derm of younger adults membranous; that of more mature specimens rather uniformly sclerotised, with numerous minute clear spots; without any sign of a more sclerotised polygonal pattern; also with a broad submarginal band of large rather oval areolations, largest 20–25 µm widest, becoming smaller and obscure medially and marginally; areolations also forming a border on either side of anal plates; elongate areolations with their long axes parallel to margin absent. Stigmatic rays present; marginal radial lines obscure but positions indicated by distribution of pores and setae, with probably 13 lines anteriorly between anterior stigmatic clefts, each side with 5 lines between clefts and 13 on abdomen. Clear areas numbering 5 pairs on abdomen but thoracic clear areas absent. Dorsal setae large, rather parallel-sided and mostly straight with a slightly capitate apex, each 20–28 µm long, rather sparse on some specimens but abundant on others, present throughout apart from medially, where absent; usually each socket associated with a dorsal pore or an unsclerotised area of derm. Preopercular pores, each 2.0–3.5 µm wide, few, present as follows: CA1 with 2–10; CA2 with 1–8; CA3 with 4–9 and CA4 with 2–8 (i.e. about equally frequent associated with all clear areas). Other dorsal pores as follows: (i) pores, each 3–4 µm wide, present sparsely in a vaguely polygonal pattern throughout, including medially; some perhaps associated with a dorsal seta, and (ii) minute simple pores each appearing as a small clear spot about 1.5 µm wide, very sparse throughout, probably mainly in a polygonal pattern. Anal plates together slightly longer than wide, each plate with probably 4 short setae near apex (1 on outer margin, an apical seta plus 2 on inner margin, of which 1 situated near middle of each inner margin); with 0 or 1 minute pore medially; length 22 0–230 µm, combined width 190–200 µm. Anogenital fold with 3 pairs of small setae on each corner of anterior margin, each lateral margin with 1 pair anteriorly and another posteriorly.

Margin. Marginal ornamentation present as groups of very short radial lines, with usually 3 groups between 2 marginal setae. Marginal setae each fan-shaped and somewhat oval, most with rather straight lateral margins; width of each fan 30–38 µm, length 18–28 µm; with 91–106 setae anteriorly between anterior stigmatic clefts, each side with 39 or 40 between stigmatic clefts, and 79–96 along abdominal margin. Stigmatic clefts quite deep, each with a sclerotised inner margin and 3 elongate, rather narrow stigmatic spines, longest extending outwards almost to level with margin; median spine usually shortest or subequal in length to lateral spines; length of median spines each 40– 75 (mostly less than 45) µm, each lateral spine 50–90 (mainly less than 65) µm long. Eyespots: each with socket 70 µm wide and diameter of lens 25–30 µm.

Venter. All specimens with a pale marginal border 35–50 µm wide. Multilocular disc-pores in groups on either side of genital opening and on preceding two segments only, each side with 12–18 on segment VII, 17–25 on segment VI and 7 or 8 on segment V. Spiracular disc-pores present in a narrow band between margin and each spiracle; rather variable in frequency, perhaps 8–21 in each band, posterior band often with a gap medially. Ventral microducts most obvious near mouthparts. Ventral setae: 1 or 2 interantennal setae present; longest setae in abdominal segment VII, each 50–75 µm long; setae in segments VI and V shorter; long setae absent from elsewhere, including laterad of anterior end of anal cleft. Antennae each 3-segmented (with segments III–VI fused); total length 160–200 µm; most setose setae on long apical segment absent; apical setae short, each about 16–20 µm long. Clypeolabral shield about 120 µm long. Spiracles of moderate size, width of each peritreme 33–40 µm. Legs entirely absent.

Comments. Discochiton mancum belongs to the group of Discochiton species that have preopercular pores associated with all four clear areas. It differs from others in this group in having the following combination of characters: (i) only 3 stigmatic spines in each stigmatic cleft; (ii) usually fewer than 12 preopercular pores associated with each clear area; (iii) rather long stigmatic spines, with median spine frequently shortest and (iv) dorsal setae rather long, each 20+ µm long, with a blunt apex.

Host-plants. Calophyllum walkeri ( Clusiaceae ).

Figures

FIGURE 13. Discochiton mancum (Green), adult female.