Discochiton browni 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 : 18-20

Discochiton browni Hodgson spec. n.

( Fig. 3 )

Material examined. Holotype adult female: SOLOMON ISLANDS: left label: SOLOMON IS. / Guadalcanal, Kukum / on coconut / E.S. Brown / 9.vii.56 5453 / CIE 4211/14908; right label: Paralecanium / nr. expansum / quadratum / Green [all crossed out] / D.J. Williams; middle label: Discochiton browni / Hodgson / Holotype (BMNH): 1/1 young adf (g). Paratype ff: Solomon Islands: left label: Solomon Is / Kukum / on coconut / coll. E.S. Brown / 4619 14.ii.56 / CIE 3900/14669; right label: Paralecanium / nr. expansum / quadratum / Green [all crossed out] / D.J. Williams; middle label: Discochiton browni / Hodgson / Paratype f (BMNH): 1/1adf (missing venter). Paratype ff: Solomon Islands: left label: Solomon Is / Guadalcanal / on coconut / coll. E.S. Brown / 532(c) vii.54 / CIE 3176/13920; right label: Paralecanium / nr. expansum / quadratum / Green [all crossed out] / D.J. Williams; middle label: Discochiton browni / Hodgson / Paratype ff (BMNH): 6/8adff (mainly g, but some with no venter). Also: left label: Solomon Is. / Guadalcanal / Mt. Austin / on coconut / xii.1983 No. 10 / R. Macfarlane / no. T.169 / CIEA16935; right label: Paralecanium [crossed out] / Discochiton / browni / Hodgson / paratype f (BMNH): 1/1adf (fg). Also: left label: Solomon Is. / Lunga / on coconut coll. E.S. Brown / 8.vii.1956 #5474 / CIE4374/14963; right label: Paralecanium [crossed out]/ nr. expansum [crossed out]/ quadratum [crossed out] / Green [crossed out] / paratype f; middle narrow label: Discochiton / browni / Hodgson (BMNH): 1/1adf (dorsum and venter separate). Also: left label: Solomon Is. / Tenaru / on coconut / E.S. Brown / #3849 24.x.1955 / CIE3591/14493; right label: Paralecanium [crossed out]/ nr. expansum [crossed out]/ quadratum Green [crossed out] / paratype f; middle narrow label: Discochiton / browni / Hodgson (BMNH): 1/1adf (f).

Other material. SOLOMON ISLANDS, Guadalcanal, on Ficus sp., -. viii.1954, E.S. Brown #735 ( BMNH): 1/1adf (p, missing venter) . Guadalcanal, on sour-sop, 1.vii.1956, E.S. Brown #5434 ( BMNH): 1/1adf (g). Kukum, on coconut, 14.ii.1956, E.S. Brown #4619 ( BMNH): 1/1adf (p). Russell Is., Pepesala, on coconut, 6.ix.1955, E.S. Brown #3717 ( BMNH): 2/2adff (fg). Russell Is., on orchid, 19.ix.1934, R.A. Lever #1942 ( BMNH): 6/8adff (mainly p). Vella, Lavella, on Cocos sp., 31.v.1934, H.T. Pagden #1714 ( BMNH): 2/2adff (p). Rua Vatu, on coconut, 10.xi.1955, E.S. Brown #4088 ( BMNH): 4/4adff (p, no venter).

Note. The following description is based on the type series.

Slide-mounted material adult female. Body oval, broadest across abdomen. Length 4.0– 7.5 mm, width 3.0– 5.5 mm.

Dorsum. Derm rather uniformly sclerotised but, on older well-stained specimens, with stronger sclerotisation medially and a pale, less sclerotised marginal area about 150 µm wide; submarginally with round to oval areolations in radial bands, these forming patterns more medially; derm with abundant minute pale spots; derm around anal plates often less sclerotised. Stigmatic rays present. Marginal radial lines obscure, indicated by lines of pores and setae, with 13 on head between anterior stigmatic clefts; each side with 5 between stigmatic clefts and 13 on abdomen. With mostly 4 pairs of abdominal clear areas plus another at inner end of anterior stigmatic ray. Dorsal setae each finely spinose to setose with a pointed apex, about 10 µm long with a strongly sclerotised basal socket; present throughout, including medially; many setae each situated on end of a long fleshy tube, each tube 5– 8 µm wide and up to 33 µm long, shortest near margin; tubes absent from some setae nearest margin (setae actually missing from many fleshy tubes—see Morphology of Paralecanium -group above); frequent in a polygonal pattern. Preopercular pores present, each pore strongly convex and about 3 µm wide, present as follows: CA1 with 6–15, CA2 with 7–16, CA3 with 14–19 and CA4 with 10–24 pores. Other dorsal pores of two types present: (i) larger pores, each small and about 4.5 µm wide, present in a sparse polygonal pattern throughout; also (ii) smaller pores, each in a unsclerotised spot about 1.5 µm wide, perhaps more randomly distributed. Anal plates rather small

and elongate, together narrowly quadrate, with anterior margins slightly shorter than posterior margins and some specimens with a faint polygonal pattern on dorsal surface; each plate with 2 or 3 minute setae near posterior apex, plus 0 or 1 small pores medially; length of plates 2 50–285 µm, combined width 185–235 µm. Anogenital fold with 4–6 minute setae at each corner of anterior margin, each lateral margin with 1 at anterior end and another posteriorly.

Margin. Margin slightly wavy, with short, shallow radial lines or ridges. Marginal setae broadly fan-shaped, clearly wider than long; width of each fan about 40–50 µm, length about 20 µm; with about 130–145 setae anteriorly on head between anterior stigmatic clefts, each side with 40–55 between stigmatic clefts and 88–135 on abdomen. Stigmatic clefts quite deep, with a narrow entrance, each with a deep, sclerotised inner margin, each margin with a saw-like edge and surface of sclerotised inner margin covered with sclerotised nodules (could be spiracular disc-pores); each cleft with 3 stigmatic spines, each parallel-sided with a blunt apex and subequal in length, 25–36 µm long. Eyespots each in a clear socket about 160 µm wide; diameter of each lens about 30 µm.

Venter. Derm membranous, with a narrow, poorly sclerotised marginal band about 50 µm wide. Multilocular disc-pores frequent on either side of genital opening and on preceding segment only, each side with 31–54 on abdominal segment VII and 30–50 on segment VI. Spiracular disc-pores in a broad band 4+ pores wide between margin and each spiracle, with 28–52+ pores in each anterior band and 25–60 in each posterior band, latter always without pores in middle part of band. Ventral microducts minute, present in a rather dense group just posterior to and on either side of labium, sparse elsewhere. Ventral setae: with 1–3 pairs of setae between antennae; with pairs of long pregenital setae on segments VII–V (those on VII each 66–85 µm long); with a group of 3–9 setae laterad to anterior end of anal cleft; small setae frequent medially just anterior to vulva in abdominal segment VII, otherwise very sparse; and submarginal setae sparse and extremely short. Antennae reduced, each with 3–5 segments (divisions between many segments obscure or absent); total length 153–185 µm; hair-like setae absent from fused apical segments. Clypeolabral shield 130–145 µm long. Spiracles: width of each peritreme 48–60 µm. Legs reduced to very small stubs.

Comments. Discochiton browni spec. n. differs from all other known Discochiton species in that the adult females have the following, so far unique, combination of characters: (i) each stigmatic cleft with a sclerotised, saw-like margin and basal sclerotisation with numerous nodule-like structures, (ii) spiracular disc-pores in broad bands 4+ pores wide, (iii) multilocular disc-pores only present on abdominal segments VII and VI (usually VII–V), (iv) dorsal setae each finely spinose or setose, (v) leg stubs present, and (vi) preopercular pores associated with all abdominal clear areas. Judging from the number of times this species has been collected in the Solomon Islands, it appears to be widespread and quite common. Discochiton browni is currently restricted to the Solomon Islands.

Host-plants. Cocos nucifera (Arecaceae) ; Ficus sp. ( Moraceae ); Annona squamosa (Annonaceae) ; Orchidaceae .

Name derivation. This species is named in honour of E.S. Brown, who collected most of the specimens. E.S. Brown was the British Colonial Entomologist who belonged to a team going wherever there was an outbreak of any insect causing concern. He was an avid collector and always collected scale insects on any trip. He died quite young, of cancer.

Figures

FIGURE 3. Discochiton browni Hodgson, spec. n., adult female. Where ar = areolations; ca = clear area; g = gap without spiracular disc-pores; ls = leg stub; mb = ventral marginal band; mo = marginal ornamentation; mrl = marginal radial line; mt = membranous dermal tube with dorsal seta on apex; pp = preopercular pore; sr = stigmatic ray, and v, vi and vii = abdominal segmentation on venter.