Xenolecanium ryoichii Hodgson, 2022

Hodgson, Chris J., 2022, Three new species of the genus Xenolecanium Takahasi (Hemiptera: Coccomorpha: Coccidae), with an updated generic diagnosis and key to species, Zootaxa 5222 (5), pp. 457-466 : 458-459

Xenolecanium ryoichii Hodgson sp. nov.

Material examined. Three slides:

1. Holotype here designated: bottom label: Xenolecanium / eugeniae / Takahashi / 26.iv.1944 / Kuala / Lumpur / R. Takahashi (1 adf in good condition, NHM). Each slide has a small round Type label, plus another small label stating: Pres. by Comm. Inst. Ent. B.M. 1953-789. On the back are 2 further labels: left label clean, without writing; right label: Xenolecanium / ryoichii / Hodgson / holotype.

2 and 3. Paratypes here designated: top label: Eugenia / glandiflora (corrected to grandiflora); bottom label: Xenolecanium / eugeniae / Takahashi / 30.iv.1944 / Kuala / Lumpur / R. Takahashi (one slide with 11 adf + 2 x 2 nd /3 rd- instar f; in fairly good condition, but older specimens parasitized (NHM); one specimen almost completed moulting; other slide with 10 adf + 1 imm f + 2 x?2 nd instar males; adult females in fairly good condition, immature stages in poor condition, NHM). This slide has a small round Type label, plus another small label stating: Pres. by Comm. Inst. Ent. B.M. 1953-789. On the back of each slide are 2 further labels: left label clean, without writing, right label: Xenolecanium / ryoichii / Hodgson / paratypes.

Note: most of the specimens contain well-developed nymphs.

Adult female ( Fig. 1 ). Described mainly from holotype specimen but data also taken from several other paratype specimens.

Slide-mounted material. Body oval, 4.1–4.2 mm long, 3.3–3.4 mm wide. Stigmatic clefts obviously indented; anal cleft about 1/5–1/6th total body length, cleft probably fused.

Dorsum. Derm membranous when teneral, becoming more sclerotized with maturity; with a strongly sclerotized area around anterior margin of anal plates, with a few pores; and with strongly sclerotized inner margins to each stigmatic cleft. Derm with numerous round to oval sclerotized areas, each about 25–115 µm widest, with a central concave clear area 14–30 µm wide; these sclerotized areas smallest near margin and absent from a narrow band near margin and medially between anal plates and cribriform plate; inner concavity of each sclerotized area lacking pores but sometimes with a reticulate pattern. Dorsal setae short, setose, often bent, each 3–6 µm long, only slightly longer than width of setal socket, which stands proud of derm; abundant throughout, except sparse submedially where preopercular pores present. Preopercular pores each a strongly sclerotized closed pore, round to slightly oval, 5–6 μm wide, present in broad submedial bands extending anteriorly almost to a point dorsad to antennae; with at least 100 on each side. Three other types of dorsal pores present, each quite abundant and mostly absent from area covered by preopercular pores: (i) rather sclerotized round pores, each 3–4 μm wide; (ii) simple pores, each 2.0 µm wide, and (iii) microducts, each dark and 1.0 μm wide. In addition, an elongate-oval cribriform plate containing about 150 sclerotized pores present medially, more-or-less dorsad to mouthparts, each pore strongly sclerotized, closed, and about 6.0–12.0 μm wide. Dorsal tubular ducts, dorsal tubercles and pocket-like sclerotizations absent. Anal plates together pyriform, length 148–152 μm, combined width 160–177 μm long; each plate with anterior margin rather straight, broadest about 3/4ths along length, more-or-less pointed at posterior end; each plate with 4 short setae: 2 along inner margin, 1 on apex (each about 35 μm long) and 1 on posterior margin; no small pores apparent. Anogenital fold very unusual, with ventral margin displaced posteriorly to almost level with anal plate apex, with 2 pairs of setae on ‘anterior’ margin and none on each lateral margin. Anal ring rather small, probably with 4 pairs of setae. Eyespot not detected.

Margin strongly crenulated along entire length. Marginal setae appearing highly variable in shape but probably mostly blade-like, many strongly bent with frayed apices; each seta 32–50 μm long, with about 68–71 setae between anterior stigmatic clefts, 28–31 setae on each side between stigmatic areas, and 63–74 setae on each side of abdomen. Stigmatic clefts deep, narrow near margin but broadening inwardly, with a strongly sclerotized curved bar across inner margin with an extension on either side towards margin; clefts each with 3 spinose setae, generally of similar lengths, each seta 17–29 μm long, parallel sided with a very blunt apex.

Venter. Derm entirely membranous. Multilocular disc-pores absent. Spiracular disc-pores, each 3–4 μm wide, mainly with 5 loculi, present in broad bands in a stigmatic groove between margin and each spiracle, with about 30–37 pores in each anterior band and 30–58 in each posterior band, and with a few pores extending more medially over posterior spiracles. Ventral microducts minute, each perhaps 0.7 μm wide, present throughout. Ventral tubular ducts present in a narrow band of 5–9 on either side of posterior margin of vulva, each with an outer ductule about 16 μm long, but inner ductule absent or indistinct. Preantennal pores absent. Ventral setae frequent, submarginal setae shorter than those medially; with a pair of long prevulval setae, each about 100 μm long, present medially on segment VII only; each abdominal segment also with a line of shorter setae on each side, most abundant on segment VI; a single pair of inter-antennal setae present; other setae small and scattered, most abundant marginally and possibly absent medially on thorax; with a distinct group of 15+ setae more-or-less ventral to apex of each anal plate, each 16–20 μm long. Antennae very reduced, with segmentation indistinct, but perhaps with 5 ring-like segments; total length 48–60 μm. Clypeolabral shield 175–190 μm long, with 1 pair of setae. Spiracles well developed, width of peritremes: anterior 59–74 μm, posterior 62–75 μm. Legs very reduced, with segmentation very indistinct but probably 3 or 4 segmented; tarsal digitules similar, both probably setose; claw very reduced; claw digitules similar, each possibly with a small capitate apex.

Etymology. This species is named after first name of the collector, Ryoichi Takahashi.

Comments. Hodgson (1995) described the structure of the spiracles of X. eugeniae Takahashi , assuming that it was a good species. However, as Kondo et al. (2005) pointed out, this was a manuscript name and so the name X. eugeniae Takahashi is a nomen nudum.

Takahashi had originally collected two lots of material that he named X. eugeniae Takahashi , the above material (which he designated type) from Kuala Lumpur and the other from the Riau Islands, near Singapore. The latter material was studied by Kondo et al. (2005), who named it X. takahashii Kondo. It is here considered that the material from Kuala Lumpur, although close to X. takahashii , is not the same and so has been here named X. ryoichii Hodgson. Adult female Xenolecanium ryoichii spec. n. are very similar to those of X. takahashii , sharing with them: (i) blade-like marginal setae (although many on X. ryoichii are also fimbriate), and (ii) a crenulated margin. However, they differ in that X. ryoichii has two types of dorsal pore of which one is considered to represent preopercular pores, forming a more or less broad medio-lateral band from the anal plates to anterior to the mouthparts. These pores are considered to be absent on X. takahashii (Kondo, pers. com.).

Figures

FIGURE 1. Xenolecanium ryoichii Hodgson, sp. nov. Adult female.