Discochiton diplodiscus Hodgson

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 : 26-28

Discochiton diplodiscus Hodgson spec. n.

( Fig. 7 )

Material examined. Holotype f and paratype ff: PHILIPPINES: left label: Paralecanium / expansum / Green / on Diplodiscus paniculatus / Pueta Laguna, P.I. / R.C. M c Gregor / Mar. 30. 1917; left label: Discochiton / diplodisus / Hodgson / Holotype & / Paratype ff. (USNM): 1/5adff (g-p, several specimens cut into bits and misshapen; holotype f bottom left, arrowed).

Note. The description was made from all 5 specimens.

Slide-mounted adult female. Body almost round. Length about 3.4 mm, width 3.2 mm.

Dorsum. Derm rather uniformly sclerotised apart from an area of slightly heavier sclerotisation medially, with about 7 pairs of transverse darker arms, mainly over abdomen; with a fairly broad band of elongate areolations close to margin, long axis of each areolation parallel with margin; inner submargin with oval areolations, these fewer submedially and medially; rest of derm with a polygonal pattern of cell-like areas and with abundant minute pale spots. Marginal radial lines obscure, indicated by distribution of pores and setae, with 13 on head between anterior stigmatic clefts, each side with 5 between stigmatic clefts and 13 on abdomen; stigmatic rays present. With 4 pairs of abdominal clear areas and another at apices of anterior stigmatic rays. Dorsal setae each spinose, with parallel sides and often a slightly capitate apex, 6–7 µm long, frequent in a sparse polygonal pattern; dorsal seta frequency rather variable but setae absent medially; submarginal and submedial setae each in a membranous area of derm about 8 µm wide. Preopercular pores present, each pore 2–3 µm wide: CA1 with 4–9, CA2 with 9–19, CA3 with 19–25 and CA4 with 30–42 pores. Other dorsal pores of two sizes: larger pores each about 2.5 µm wide, with a sclerotised border; and a smaller simple pore with a narrow border; few, probably present throughout. Anal plates together narrowly quadrate, with anterior margin clearly shorter than posterior margin, and surface of each plate rather crumpled near apex; each plate with 4 minute setae near posterior apex, plus a small pore medially; length of plates 180–190 µm, combined width 175–180 µm. Anogenital fold with 3–5 minute setae at each corner of anterior margin, each lateral margin with 1 seta anteriorly and another posteriorly.

Margin. Marginal ornamentation formed of short sclerotised blocks or corrugations, each with a group of short radial lines, with mostly 3 or 4 corrugations between each pair of setae. Marginal setae broadly fan-shaped, mostly about as wide as long; width of each fan about 33–36 µm, length 30–35 µm; with about 99–105 setae anteriorly on head between anterior stigmatic clefts; each side with 38–54 between stigmatic clefts and 7 4–99 on abdomen. Stigmatic clefts deep, each with a narrow opening, a sclerotised and corrugated outer margin and a quite broad, strongly sclerotised inner margin, with 3 (occasionally 4) elongate, parallel-sided, blunt stigmatic spines; length of median spines each 43–45 µm, laterals each 20–38 µm long. Eyespots, each with socket 60 µm across at most; diameter of lens 28–30 µm.

Venter. Derm membranous apart from a marginal band about 80 µm wide. Multilocular disc-pores frequent on either side of genital opening and on preceding two segments only, each side with 16–19 on abdominal segment VII, 26–30 on segment VI and 17–20 of segment V. Spiracular disc-pores in a narrow band mostly 1 pore wide between margin and each spiracle, with 11–23 pores in each anterior band and 10–14 in each posterior band; each posterior band without pores in middle. Ventral microducts minute, very sparse throughout. Ventral setae: with 2 pairs of interantennal setae; pairs of pregenital setae on segments VII–V (that on VII about 60 µm long); small setae very sparse, and submarginal setae sparse and extremely short; also with a group of 4–7 longer setae, each about 16–35 µm long, on either side of anterior end of anal cleft. Antennae reduced, each with 3 or 4 segments (segmental divisions between segments IV–VI obscure or absent); total length 120–145 µm; setal distribution normal apart from absence of setose setae from segments IV and V. Clypeolabral shield 100–110 µm long. Spiracles: width of each peritreme 40–48 µm. Legs entirely absent.

Comments. Adult female D. diplodiscus spec. n. differ from other Discochiton species with preopercular pores associated with all 4 clear areas in having the following combination of characters: (i) each stigmatic cleft quite deep and narrow, with sclerotised margins along almost the entire length; (ii) almost round marginal setae, (iii) stigmatic spines long and narrow, (iv) dorsal setae short (less than 10 µm long), (v) apex of each anal plate rather blunt, with dorsal surface near apex corrugated, and (vi) spiracular disc-pore bands broad. Adult female D. cocophyllae also have the margins of each anal plate corrugated; but the apex of each plate is pointed, the marginal setae are mostly distinctly oval, and pregenital setae are lacking.

Host-plant. Diplodiscus paniculatus ( Tiliaceae ).

Name derivation. This species is named after the genus of host-plant (Diplodiscus) on which it was collected. It is a noun in apposition.

Figures

FIGURE 7. Discochiton diplodiscus Hodgson, spec. n., adult female.