Discochiton luzonicum (Cockerell) 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 : 35-37

Discochiton luzonicum (Cockerell) comb. n.

( Fig. 11 )

Paralecanium luzonicum Cockerell, 1914 , 333. Type data: PHILIPPINES: Los Baños, on Plectronia viridis Syntypes, female. Type depository: BMNH, London, England, U.K; and USNM, Washington, District of Columbia, U.S.A.

Podoparalecanium luzonicum ; Tao, Wong & Chang, 1983, 100. Change of combination.

Material examined. Syntype ff: PHILIPPINES: left label: Paralecanium / luzonicum / Ckll / Type / BM 1931, 203; right label: Paralecanium / luzonicum / Type Ckll / Los Baños, P.I. / (Baker) / on Alectronia viridis [see under Host-plants below] / B.M. 1931, 203 ( BMNH): 1/2adff (fp, labelled Luzon, Los Baños, on sleeve). Philippines: bottom label: Paralecanium / luzonicum / Ckll / on Tetrastigma sp. / Los Baños / Philippines / C.F. Baker ( BMNH): 1/3adff (f-g, but venter mostly somewhat damaged).

Other material. MALAYSIA, Sarawak, no other site data, on Piper sp. ( Piperaceae ), C.R. Wallace ~ 4391, ( BMNH, CIE 8392-18905): 1/1adf (g). Sarawak, as previous, on Piper nigrum, C.R. Wallace #2880 ( BMNH, CIE 8387-18905): 2/3adff (p, missing venters) + an unidentified species.

Note. The description is based on all five syntype specimens. No lectotype was designated because of the poor state of these specimens. Another syntype slide is present in USNM (not seen) but is also poor.

Slide-mounted adult female. Body oval, slightly more pointed anteriorly. Length 3.8–4.5 mm, width 3.1–3.7 mm.

Dorsum. Dermal ornamentation: derm membranous when young but becoming rather uniformly sclerotised medially and submedially on more mature specimens; on mature specimens, derm almost membranous marginally but with faint oval areolations extending into sclerotised areas of submargin, these rapidly becoming scarce more medially; narrow areolations with long axes parallel to margin not noted. A sparse polygonal pattern present, shown most obviously by distribution of dorsal setae and pores. Marginal radial lines indistinct, as follows (barely visible on immature specimens): 1 1–13 lines anteriorly between anterior stigmatic clefts, each side with 5 lines between clefts and 11 or 12 on abdomen; broader long rays from each stigmatic cleft present but each rather narrow; otherwise, derm without patternation. Abdominal clear areas numbering 4 (5 on one specimen) pairs, plus a further clear area just anterior to inner margin of each anterior stigmatic ray. Dorsal setae each more or less parallel-sided with a bluntly pointed apex but sometimes apex slightly clavate, each seta 7–9 µm long; most frequent along each marginal radial line but also extending well onto dorsum, not intermingling with dorsal pores; absent medially. Preopercular pores slightly oval, each with distinct micropores, present as follows: CA1–CA3 mostly each with 0 (rarely 1), CA4 with 28–34 pores. Other dorsal pores of two sizes: (i) larger pores, each situated in a less sclerotised area of derm 5–8 µm wide; present sparsely throughout submedial and medial areas, apparently part of a sparse polygonal pattern, and (ii) small simple pores represented by smaller clear spots in derm, each about 2 µm wide, tending to be more random than larger dorsal pores; other, possibly similar pores but less distinct, sparse close to margin, each about 1.5 µm wide. Anal plates each with a sharp angle on outer margin; each plate with 2–4 small pores medially and 3 or 4 small setae near apex; length of each plate 235–240 µm, width of both plates combined 145–155 µm. Anogenital fold with two pairs of small setae along anterior margin, each lateral margin with 1 seta anteriorly and another posteriorly. Anal ring with 3 pairs of setae, longest seta about 340 µm long.

Margin. Marginal ornamentation: short castellations, each with short radial lines or ridges. Marginal setae broadly fan-shaped; width of each fan 25–40 µm, length 28–40 µm; with about 108–130 setae anteriorly between anterior stigmatic clefts, each side with 43–56 between stigmatic clefts, and 82–123 along abdominal margin. Stigmatic clefts quite deep, each with a sclerotised inner margin and with 3 or 4 rather parallel-sided stigmatic spines; median spine longest, 35–55 µm long, each lateral spine 20–35 µm long. Eyespots each more or less circular; with socket about 28 µm at its widest, diameter of lens about 13 µm.

Venter. Membranous, apparently without marginal band. Multilocular disc-pores abundant around genital opening and on preceding two segments only, each side with 23–27 on segment VII, 19–22 on segment VI and 2–7 on segment V. Spiracular disc-pores present in a narrow band about 1 pore wide between margin and each spiracle, with 17–30 pores in each band; pores sparse medially in each posterior band. Ventral microducts very small, present in a group just posterior to mouthparts; otherwise not detected. Ventral setae: with 2 pairs of interantennal setae; a pair of long pregenital setae on abdominal segments VII, 2 or 3 pairs on VI and 1 pair on V; also with a group of long setae on either side of anal opening, each group with 1–5 setae, each seta about 65–75 µm long; submarginal setae few and minute; other setae very sparse. Antennae each with perhaps 6 segments but apical 3 segments fused on all available antennae; total length about 165 µm; apical seta short, about 25 µm long. Clypeolabral shield small, 100–105 µm long. Spiracles: width of each peritreme 40–42 µm. Legs reduced, with tibia and tarsus fused on most available legs; dimensions of hind leg segments (µm): coxa 100–105, trochanter + femur 160–165, tibia+ tarsus 185–190; claw about 13; tarsal digitules subequal in length to claw digitules, with capitate apices; claw digitules both broad; claw without a denticle. Setal distribution on hind leg: coxa 4; trochanter 1, quite long; femur 1; tibia 0 and tarsus with 3 or 4 setae.

Comments. Within Discochiton , only adult female D. luzonicum and D. trifasciatum have well-developed legs. They can be separated fairly easily as D. luzonicum has the preopercular pores restricted to CA4 whereas D. trifasciatum has them associated with CA2–CA4 or CA3 and CA4. In addition, D. luzonicum has hair-like setae on antennal segments IV and V whereas these are absent on D. trifasciatum .

Host-plants. Plectronia viridis (Oliniaceae) ; Tetrastigma sp. ( Vitaceae ) Piper nigra (Piperaceae) . However, note that Alectronia (as recorded on the BMNH slide), does not exist and the host name has clearly been misspelt. It is correctly labelled as Plectronia viridis on the USNM slide, which is listed in the International Plant Name Index (IPNI) but as an unresolved name. However, García Morales et al. (2016) have it as Alectronia [ Alectryon ] but IPNI indicates no species viridis in the genus Alectryon ). Also: Unconfirmed host record: Tetrastigma sp. ( Vitaceae ).

Figures

FIGURE 11. Discochiton luzonicum (Cockerell), adult female.