Acanthococcus adenostomae (Ehrhorn)

Hodgson, Chris, 2020, A review of neococcid scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) based on the morphology of the adult males, Zootaxa 4765 (1), pp. 1-264 : 44-46

Acanthococcus adenostomae (Ehrhorn) ( Fig. 15 )

Eriococcus adenostomae Ehrhorn 1898, 244 . Type data: USA, California, Santa Clara Co., near Mountain View, on Adenostoma fasciculatum , date unknown, E.M. Ehrhorn. Lectotype, female, by subsequent designation ( Miller & Miller 1992, 7 –9). Type depository: USNM.

Acanthococcus adenostomae (Ehrhorn) ; Miller & Miller 1992, 7 –9. Change of combination.

Material examined. USA, California, Stanislaus Co., Del Puerto Cyn., on Adenostoma sp. ( Rosaceae ), 19.iii.1982, R.J. Gill ( USNM): 2/4ad ♂ (g).

Mounted material: small, total body length 1.15–1.45 mm; antennae quite long, about 2/3rds total body length, most segments with capitate setae plus short fleshy setae (fs); body with few setae, all hs; fleshy setae (fs) apparently absent; length of fs on antennae half to one-third width of antennal segments; fs on legs very short and stubby. Wings about equal to total body length and about a third as wide as long.

Head: approximately triangular, broadest posteriorly; length 185–210 μm, width across genae 220–235 μm. Median crest (mc) not demarcated and not reticulated but with a very long dorsal mid-cranial ridge (dmcr), extending to postoccipital ridge posteriorly; postoccipital ridge (por) distinct, with lateral arms extending both anteriorly and posteriorly; with (on each side) 4–7 hs dorsal head setae (dhs) plus 2 or 3 pores (+ a very short fs or convex pore on each side). Ventral mid-cranial ridge (vmcr) short and narrow, extending from lateral arms (lmcr) posteriorly to occipital sclerite; without any reticulation laterally. Genae (g) not reticulated; each side with 1–3 hs genal setae (gs) just laterad to postoccipital ridge. Eyes: with two pairs of round simple eyes, each subequal in size, 20–25 μm wide; dorsal eyes (dse) placed rather laterally, slightly posterior to ventral simple eyes (vse). Ocelli (o) large, situated laterally, each 8–15 μm wide, just touching postocular ridge. Ocular sclerite (ocs) partially sclerotised, particularly around and between simple eyes; lightly reticulated around each simple eye. Preocular ridge (procr) possibly extending medially to anterior to each ventral simple eye ventrally; dorsally possibly absent. Postocular ridge (pocr) strongly developed. Interocular ridge absent. Dorsal ocular setae absent. Ventral head setae (vhs): with 4 or 5 on each side just anterior to each ventral simple eye and with a pair of ventral mid-cranial (vmcrs) hs anteriorly. Preoral ridge (pror) poorly developed. Cranial apophysis (ca) short, 13–18 μm long, 25–30 μm wide, with a trifid apex.

Antennae: 10-segmented and filiform; 850–925 μm long (ratio of total body length to antennal length 1:0.68). Scape (scp) 48–60 μm long, 55–67 μm wide, with 5 hs. Pedicel (pdc) arising anteriorly from scape: length 70–80 μm, width 45–52 μm; with a few faint concentric ridges, mainly on distal half; with 8–14 hs + 10–16 fs; no cam- paniform pore detected. Segments III–X 24–42 μm wide; each fs fairly short and stout, 13–25 μm long; lengths of segments (μm): III 153–166; IV 110–145; V 100–118; VI 95–100; VII 75–93; VIII 60–84; IX 50–58 and X 48–68; approximate number of setae per segment: III 26–29 fs + 13–15 hs; IV 17–22 fs + 2 hs; V 23–30 fs, 0–3 hs + 4 or 5 capitate setae (caps); VI 18–27 fs, 1 or 2 hs + 3–5 caps; VII 15 or 16 fs, 0 or 1 hs + 3–5 caps; VIII 13 or 14 fs, 0 or 1 hs, 5 caps + 1 bristle; IX 10 or 11 fs, 1 hs, 4 caps + 1 bristle, and segment X with 4 or 5 fs, 2 or 3 hs (1 on apex), 3 large + 2 smaller bristles (one apical) on apical third + 4 or 5 caps; sensilla basiconica (sb) not detected; apex bluntly pointed.

Thorax. Prothorax: pronotal ridge (prnr) well-developed and probably fused dorsally; extending ventrally and nearly touching proepisternum + cervical sclerite (pepcv); pronotal sclerite (prn) absent or represented by a small triangular area dorsolaterally; without lateral pronotal setae (lpns). Medial pronotal setae absent; post-tergite possibly present, small, without post-tergital and antemesospiracular dorsal setae or pores. Sternum (stn 1) lightly sclerotised, without a median ridge but transverse ridge fairly well developed; without prosternal setae or pores. Anteprosternal setae absent.

Mesothorax: prescutum (prsc) oval, 70–85 μm long, 145–160 μm wide; sclerotised but not reticulated, with 1 pair hs prescutal setae (prscs); prescutal ridge (pscr) well developed anteriorly but quickly narrowing; prescutal suture (pscs) narrow. Scutum (sct): median area with 2 oval unsclerotised areas, each 35–45 μm long, 43–47 μm wide; distance of prescutum from scutellum 40–60 μm; scutal setae (scts): 2 hs on each side; margins laterad to prescutum sclerotised and reticulated. Prealare ridge (prar) and triangular plate (tp) well developed. Scutellum (scl) 140–167 μm wide, 70–80 μm long; with a distinct scutellar ridge (sclr) and a large foramen; scutellar setae (scls): 1 or 2 hs on each side + an occasional minute pore; postnotal wing process (pnp) broad and extending postero-laterally. Basisternum (stn 2) 215–240 μm wide, 125–150 μm long; without a median ridge; bounded anteriorly by a strong marginal ridge (mr) and precoxal ridge (pcr 2); without basisternal setae; lateropleurite (lpl) broad, with a distinct extension from marginal ridge along anterior and lateral margins; furca (f) well developed, narrow-waisted, arms very divergent and extending about half-way to marginal ridge anteriorly. Mesopostnotum (pn 2) well developed; postnotal apophysis (pna) well developed. Area bounded anteriorly by scutellum and laterally and posteriorly by mesopostnotum not sclerotised but sometimes with some striations. Mesepisternum (eps 2) not reticulated; subepisternal ridge (ser) long and well developed. Postalare (pa) without postalare setae. Mesothoracic spiracle (sp 2): width of peritreme 20–22 μm; without associated loculate pores. Postmesospiracular setae absent. Tegula (teg) present, with 2–5 hs tegular setae (tegs).

Metathorax: with 1 or 2 hs metatergal setae (mts) medially. Dorsospiracular setae: a group of 0–3 laterally on each side. Metapostnotal sclerite (pn 3) distinct. Dorsal part of metapleural ridge (plr 3) present, but without a suspensorial sclerite (ss). Posterior part of metapleural ridge well developed; episternum (eps 3) not sclerotised and without postmetaspiracular setae; precoxal ridge (pcr 3) lightly sclerotised, extending medially 80–100 μm; metasternal apophysis (sta) not detected. Metepimeron (epm 3) sclerotised, but without setae. Antemetaspiracular setae absent. Metathoracic spiracle (sp 3): width of peritreme 21–28 μm; without loculate pores. Metasternum (stn 3) membranous, with 2 hs anterior metasternal setae (amss) and 2–4 hs posterior metasternal setae (pmss).

Wings: hyaline, 1250–1300 μm long, 450–500 μm wide (ratio of length to width 1:0.37; ratio of total body length to wing length 1:0.98); alar lobe (al) well developed; each wing with 1–3 hs alar setae (als) but no circular sensoria. Hamulohalteres (h) 102–110 μm long, 25–33 μm wide, each with a single hooked hamulus, 62–80 μm long.

Legs: subequal in length. Fleshy setae (fs) present on all or most segments, each very short and fat. Coxae (cx): I 80–110; II 100–120; II: 95–110 μm long; setae of coxa III: 0–2 fs + 10–13 hs; long setae on each coxa not differ- entiated. Trochanter (tr) + femur (fm): I 195–235; II 150–230; III 200–230 μm long; trochanter III with 0 fs + 5–7 hs; each trochanter with 3 semi-circular sensoria on each side arranged in a triangle medially; long trochanter seta 40–45 μm; femur III with 6–8 fs + 18–24 hs. Tibia (ti): I 250–275; II 240–260; III 270–280 μm; tibia III with 19–20 fs + 39–44 hs, a few becoming spur-like on distal third of leg; with 2 apical spurs (tibs) on all legs; length of longest 18–25 μm. Tarsi (ta) two segmented, proximal segment narrow and ringlike, length of both segments combined: I 75–90; II 78–90; III 90 μm long (ratio of length of tibia III to length of tarsus III 1:0.32); tarsus III with 1–3 fs + 19–25 other setae, mainly spur-like; tarsal spurs undifferentiated; tarsal campaniform pore present; tarsal digitules (tdt) subequal to length of claw. Claws (c) subequal to or slightly longer than width of tarsus; length III: 25–30 μm; with a small denticle; claw digitules (cdt) with minute capitate apices and slightly longer than claw.

Abdomen: segments I–VII: tergites and sternites lightly sclerotised, tergum (at) and sternum (as) otherwise unsclerotised and without obvious oval membranous areas in inter-segmental membranes. Caudal extension (ce) on segment VII absent. Without loculate pores. Dorsal setae (ads): segments I–VII each with 2–8 hs. Pleural setae: dorsopleural setae (dps) on each side: I–IV 2 hs; V & VI 3 hs; VII 2 hs; ventropleural setae (vps) on each side: I–VII 1 hs. Ventral setae (avs): II 2 hs; III–VII each with 4–6 hs.

Segment VIII: tergite (at) sclerotised in a transverse band; sternite (as) more heavily sclerotised, with a pair of small lateral, longitudinal sclerotisations; with 2 hs ante-anal setae; sternite with 1 or 2 hs ventral abdominal setae (avs) on each side; caudal extension (ce) rounded, each with 4 or 5 hs pleural setae. Glandular pouches (gp) present, moderately deep, each with loculate pores spreading out of glandular pouch; each glandular pouch with 2 setae (gls) often of different lengths and both capitate, length 95–120 μm.

Genital segments: penial sheath (ps) divided into two sections: a broad segment IX and a short, triangular style (st); ventrally with a broad, possibly unsclerotised, area around and anterior to basal rod; segment IX with 2 or 3 long setae dorsally, 2 long setae ventrally and 2 or 3 long setae (each 21–45 μm long) laterally, more or less around membranous area; style without setae. Length of penial sheath (from anterior border to apex: 132 μm, width across base 95–100 μm); style 55–67 μm long. Basal rod (bra) short, 13–17 μm. Aedeagus parallel-sided at base, gradually narrowing towards apex, but not reaching apex of penial sheath, 64–73 μm long.

Comment. This is a typical male acanthococcid except that there is a pair of small membranous areas medially on the scutum. The very short fleshy setae on the legs also appear to be unusual.

Figures

FIGURE 15. Acanthococcus adenostomae (Ehrhorn). Macropterous male. (Eriococcidae, Acanthococcid group). Where A=cranial apophysis, D=fleshy setae and X=pores on head.