Discochiton milleri Takahashi

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 : 48-50

Discochiton milleri Takahashi comb. n.

( Fig. 16 )

Paralecanium milleri Takahashi, 1939 , 114. Type data: MALAYSIA: Kuala Lumpur, on Annona muricata . Syntypes, female. Type depository: BMNH, London, England, U.K.

Paralecanium milleti ; Tang, 1991, 131. Misspelling of species epithet.

Material examined. MALAYSIA, Sepang, on Annona muricata , 22.ix.1927, G.H. Corbett ( BMNH): 3/9adff (f-g; derm not sclerotised) . BRUNEI, Kilansas Agr. Sta., on Elaeis guineensis, Dec. 1973 , no coll. ( BMNH): 1/2adff (fg, derm not sclerotised).

Other material. BRUNEI, Kilansas Agr. Sta., on Cocos nucifera , - vi. 1973, No coll. #584 ( BMNH): 2/4adff (fg).

INDONESIA, Java, no other site details, on coconut, - iii.1939, no coll. #731 ( BMNH): 1/11adff (p) – originally identified as P.?cocophylae).

MALAYSIA, Kuala Lumpur, on palm, 3.x.1943, R. Takahashi (BMNH): 1/15adff (fg). Kuala Lumpur, on Ficus religiosa , 2.i.1943, R. Takahashi (BMNH): 2/36adff (g-f). Kuala Lumpur, no host, 5.iii.1944, R. Takahashi (BMNH): 2/20adff (f). Kuala Lumpur, on mango ( Mangifera indica ), 1.i.1943, R. Takahashi (BMNH): 1/1adf (f). Malaysia, no other site data, on Cinnamomum zeylanicum , 22.iv.1932, Ent. Div. #8505 (BMNH): 4/19adff (f-g). Sepang, C. nucifera , 19.vii.1928, G.H. Corbett (BMNH): 3/13adff (fg) + 2 second/third-instar female (fg). Selangor, Banting, C. nucifera , 25.vi.1951, H.T. Pagden #07446 (BMNH): 4/10adff (f-g). Selangor, Stombak, on mango, 19.iv.1946, R. Takahashi (BMNH): 1/4adff (p). Sepang, on Elaeis guineensis , 22.v.1934, G.H. Corbett #9559 (BMNH): 5/13adff (fg-p; previously identified as P. vacuum ). Sarawak, Kuala Baram, on unknown host, 11.vii.1978, V.F. Eastop (BMNH; CIE A10642): 2/3adff (g; + 1adf of unknown sp.).

VIETNAM, on Arecu catechu [= Areca catechu ], 24.vi.1998, A. Berlowitz (USNM, SF 029423): 3/3adff (f-g).

Note. Type specimens were not seen. For the description, details were taken from all of the specimens listed under “Material examined”.

Slide-mounted adult female. Body oval, broadest posteriorly. Length 2.6–3.0 mm, width 2.2–2.3 mm.

Dorsum. Derm barely sclerotised but central area becoming slightly more sclerotised on older specimens; specimens from Brunei with a narrow darker border and faint oval areolations submarginally. Marginal radial lines obscure, indicated by distribution of setae and pores, as follows: with 10–12 lines on head, each side with 5 between stigmatic clefts and 12 on abdomen; with distinct stigmatic rays extending medially from each stigmatic cleft. Dorsum with 4 pairs of abdominal clear areas. Dorsal setae usually setose, often curved with a sharp point, each about 8 µm long in a broad setal socket about 5 µm wide, most frequent in a submarginal band (mainly in radial membranous lines) and submedially, but present throughout in a sparse polygonal pattern. Preopercular pores, each 3–4 µm wide and with distinct micropores, present more or less in 3 groups, with pores more dispersed than on other species and groups often appearing to fuse; frequency as follows: CA4 with 9–24 pores; CA3 with 11–20 and CA2 with 7–11; no group found associated with anteriormost clear areas (CA1). Larger dorsal pores absent. Simple pores, each about 2 µm wide, situated in a clear, unstained area of derm, sparsely present throughout in a more-or-less a polygonal pattern; also present sparsely along margin. Anal plates together quadrate, each with a sharp outer angle, and with anterior margin subequal to or slightly shorter than posterior margin; setal distribution on each plate rather variable, mostly with 4 setae—1 or 2 medially and 1 or 2 near apex; small pores possibly absent; length of each plate 124–135 µm, combined width about 115 µm. Anogenital fold with 3 pairs of small setae along anterior margin, each lateral margin with 1 pair anteriorly and another posteriorly.

Margin. Marginal ornamentation: shallow castellations, each with short lines or ridges. Marginal setae strongly oval and fan-like; width of each fan 28–35 µm, length 14–18 µm; with 60–68 setae anteriorly between anterior stigmatic clefts, and each side with 25–31 between stigmatic clefts, and 50–66 along abdominal margin. Stigmatic clefts quite deep, each with a sclerotised inner margin and 3 (or more rarely 4) parallel-sided, blunt stigmatic spines; median spines subequal to or longer than lateral spines; length of median spines each 33–35 µm; lateral spines each 25–33 µm long. Eyespots: width of each socket about 40 µm, diameter of lens uncertain.

Venter. Derm with only faint signs of a border about 80 µm wide. Multilocular disc-pores present in groups around genital opening and in preceding two segments, each side with 11–14 by anal opening in segment VII, 8–15 on segment VI and 3–6 on segment V. Spiracular disc-pores present in narrow bands of 13–23 between margin and each spiracle; posterior band without an obvious gap in middle. Ventral microducts very small, present throughout but most abundant posterior to labium. Ventral setae: with 2 pairs of interantennal setae; a pair of long setae in abdominal segment VII, each about 50 µm long, and with sparse bands of shorter setae across other abdominal segments; some specimens with a line of setae on either side of anterior end of anal cleft, each seta up to about 18 µm long; submarginal setae frequent but very short. Antennae very much reduced, many with a basal scape and 1 further elongate segment but other specimens with faint indications of some segmentation, giving a 4-segmented antenna; total length 65–90 µm; apical segment with 5 fleshy setae near apex, plus 2 more setose setae and 2 stiff setae; length of apical seta about 12 µm. Clypeolabral shield 105–115 µm long. Spiracles small, width of each peritreme 35–40 µm. Legs absent.

Comments. The adult females of D. milleri are fairly easily recognised by the following combination of character-states: (i) the rather dispersed distribution of the preopercular pores, associated with only 3 pairs of clear areas, (ii) lack of large dorsal pores, (iii) dorsal setae setose, many of which are curved, (iv) the absence of legs, (v) very short antennae and (vi) a more or less unsclerotised dorsum.

Although García Morales et al. (2016) state that the type specimens are deposited in the BMNH collection, no slides with type data were found there. Ben-Dov (1993) indicated that these specimens were originally deposited in the Selengor Museum, Kuala Lumpur, Malaysia. However, all scale insect slides in that collection were transferred to the BMNH in 1955 (see Williams, 2017). The whereabouts of the type slides of D. milleri is therefore uncertain.

Host-plants. Mangifera indica (Anacardiaceae) ; Annona muricata (Annonaceae) ; Elaeis guineensis , Areca catechu , Cocos nucifera (Arecaceae) ; Cinnamomum zeylanicum (Lauraceae) ; Ficus religiosa (Moraceae) .

Figures

FIGURE 16. Discochiton milleri (Takahashi), adult female.