Discochiton javanicum (Green)

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 : 33-35

Discochiton javanicum (Green) comb. and stat. n.

( Fig. 10 )

Lecanium expansum javanicum Green, 1904a , 205. Type data: INDONESIA, Java, on Anomianthus heterocarpus . Syntypes, female. Type depository: BMNH, London, U.K.

Paralecanium expansum javanicum ; Sanders, 1906, 9. Change of combination.

Material examined. Lectotype f (here designated): INDONESIA, Java: top label: Lectotype adf; bottom label: Lecanium / expansum Green / var. javanicum / from Anomianthus / heterocarpus / Buitengorg [probably a misspelling of Buitenzorg] / Java / coll. Zimmermann No. 64 (BMNH): 1/1adf (g; young and unsclerotised). Java: top labels: round label with TYPE in red, and narrow label: paralectotype; bottom label: Lecanium / expansum Green / var. javanicum / from / Anomianthus / heterocarpus / Buitengorg / Java / coll. Zimmermann No. 64 (BMNH): 1/1adf (f, more sclerotised than lectotype). Java: top label: paralectotype; bottom label: Lecanium / expansum Green / var. javanicum / from Anomianthus / heterocarpus / Buitengorg / Java / coll. Zimmermann No. 64 (BMNH): 1/1adf (p, missing venter).

Other material. INDONESIA, Java, Buitenzorg, on Lepidadenia (Litsea) wightiana , no date, A. Zimmermann # 95 ( BMNH): 3/3adff (mainly g-fg).

Note. The description is based mainly on the lectotype specimen but with some data from other type specimens.

Unmounted material. “Differs from type [ P. expansum ] in having a minute but regular reticulation.” (Green, 1904, p. 205).

Slide-mounted adult female. Body broadly oval. Length 6.0–7.0 mm, width 5.0–6.0 mm.

Dorsum. Dermal ornamentation: most mature specimen with derm only slightly sclerotised near margin and medially, but with slightly heavier sclerotisation submarginally and submedially; most of dorsum covered in a polygonal pattern of cell-like areas, with darker lines between cells but these absent from around some pores; areolations present submarginally, rather obscure but those nearest margin narrow, with long axes parallel to margin and those situated slightly more medially, more circular. Marginal radial lines absent but indicated by setae and pore distribution; stigmatic rays present, that for each anterior cleft longest. Dorsal setae and dorsal pores together forming 12 or 13 radial lines around head, each side with 5 between stigmatic clefts and 12 lines along abdominal margin. With 4 pairs of abdominal clear areas and another in prothorax at median end of anterior stigmatic ray. Dorsal setae finely spinose, each with either a sharp apex or a long fine point, 14–17 µm long; many situated in a less sclerotised area of derm. Each abdominal clear area with a group of 14–23 convex preopercular pores, each pore 6–7 µm wide. Dorsal pores (probably simple pores) each in an area of sclerotised derm and appearing more or less as a clear spot when dorsum sclerotised; also with a few simple pores just dorsad to margin. Anal plates rather small and together longer than wide, with anterior margins shorter than posterior margins; each plate with 3 or 4 minute setae near posterior apex, plus 1 or 2 small pores medially; length of plates 260–285 µm, together 220–240 µm wide. Anogenital fold with 4 or 5 minute setae at each corner of anterior margin and 2 setae on each lateral margin. Anal ring with 6 setae, longest seta about 250 µm long.

Margin. Marginal ornamentation present in the form of shallow corrugations, each with short radial lines or ridges. Marginal setae broadly fan-shaped, each about 38–45 µm wide, 35–40 µm long; with about 130–170 setae anteriorly on head between anterior stigmatic clefts; each side with 45–75 between stigmatic clefts and about 160 on abdomen. Stigmatic clefts quite deep, each with a narrow entrance, a sclerotised inner margin and 3 short, stout, sharply-pointed stigmatic spines, spines either subequal in length or middle spine slightly longer, laterals each 25– 35, median 33–45 µm long. Eyespots: each socket about 150–160 µm wide, diameter of each lens 40–45 µm.

Venter. Derm membranous; presence of ventral marginal band uncertain. Multilocular disc-pores abundant around genital opening and on preceding two segments only, each side with 7 or 8 on segment VII, 24–26 on segment VI and 16 or 17 on segment V. Spiracular disc-pores present in complete broad bands about 4 or 5 pores wide between margin and each spiracle, with 45–65 pores in each anterior band and 65–80 in each posterior band. Ventral microducts minute, present in a dense group just posterior to and on either side of labium; also present elsewhere but sparse. Ventral setae: with possibly only 1 pair of interantennal setae; with pairs of pregenital setae on segments VII–V (that on VII about 90 µm long); smaller setae sparse; submarginal setae minute and few, with only 1 on each side between stigmatic clefts. Antennae reduced, with only slight signs of segmentation between segments IV–VI; total length 110–145 µm. Clypeolabral shield 145 µm long. Spiracles: width of each peritreme 70–85 µm. Leg stubs present on young specimen but these not visible on older specimens due to sclerotisation.

Comments. Whilst the adult female of D. javanicum is superficially similar to D. expansum , it differs in a number of significant characteristics (character states for D. expansum in brackets): (i) the stigmatic spines are short, stout and sharply pointed (much longer and narrower, more or less parallel-sided and often slightly swollen apically); (ii) the dorsal setae are sharply pointed (parallel-sided with a blunt apex); (iii) preopercular pores about equally frequent around all four abdominal clear areas (generally only present in posterior 2 clear areas), and (v) spiracular disc-pores in complete, broad bands, generally with more than 50 in each band and with each band about 4 or more pores wide (generally less than 40 in a band, each band more or less one pore wide and posterior band incomplete). These differences are clearly enough to raise this subspecies to a full species, D. javanicum (Green) stat. n.

Host-plants. Anomianthus heterocarpus (Annonaceae) ; Lepidadenia (Litsea) wightiana (Lauraceae) .

Figures

FIGURE 10. Discochiton javanicum (Green), adult female.