Akermes pinguis (Maskell)

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 : 227-230

Akermes pinguis (Maskell) ( Fig. 89 )

Lecanium pingue Maskell 1895, 58 . Type data: Australia, New South Wales, Bankstown near Sydney, on Dillwynia juniperina . Syntypes, female and first instar, Type depositories: NZAC, USNM.

Lecanium scrobiculatum pingue ( Maskell 1893) ; Maskell 1896, 392. Change in status

Akermes pinguis ( Maskell 1893) ; Cockerell 1902c, 453.

Material examined: Australia: labelled Lecanium scrobiculatum: Maskell coll. No. 263 ( USNM): 2/2ad ♂♂ but this probably part of type series of A. pinguis .

Mounted material. Of moderate size, probably with rather short antennae although all broken; head with two pairs simple eyes; head and rest of body with very few setae, all hair-like (hs); fleshy setae (fs) on appendages usually easy to separate from hs; procoxae each with two stout bristles; trochanterofemur segmentation poorly demarcated. Abdomen with caudal extensions on segment VIII only, each with a dorsal, lightly sclerotised, protuberance (cicatrix); glandular pouches absent. Total body length about 1.55 mm, width across triangular plates (tp) about 350 μm. Wings slightly shorter than total body length and width about half length.

Head. Roughly diamond-shaped; length about 230 μm; width across genae about 240–270 μm (but head very flattened). Setae extremely few. Median crest (mc) well developed, with vaguely reticulate striations; postoccipital ridge (por) absent; with a total of 2 pairs of hs dorsal head setae (dhs). Mid-cranial ridge either absent dorsally or represented by a very short ridge just dorsad to lateral arms of mid-cranial ridge; ventrally, mid-cranial ridge (vmcr) narrow but well-defined, extending posteriorly as far as ocular sclerite; without a reticulated margin; ventral midcranial ridge setae (vmcrs) absent. Preocular ridge (procr) long dorsally; ventrally extending medially and fusing with posterior end of ventral mid-cranial ridge. Genae (g) large and membranous, without genal setae (gs) and without polygonal reticulations but with a few striations. Eyes: two pairs of round simple eyes, 1 pair dorsally (dse) and 1 pair ventrally (vse), each subequal in size, 40–44 μm wide. Ocelli distinct, each about 15 μm wide. Ocular sclerite (ocs) sclerotised and heavily polygonally reticulated, each reticulation without inner microridges. Postocular ridge (pocr) extending medially almost to median crest. Dorsal ocular setae absent although a small hs seta present between postocular ridge (pocr) and median crest (mc). Ventral head setae absent. Tentorial bridge (tb) well developed. Cranial apophysis (ca) possibly absent.

Antennae: all broken; segments VII–X missing. Scape (scp): 40–42 μm long, 55–60 μm wide, with only 2? hs. Pedicel (pdc): 45–47 μm long, 60–64 μm wide, not reticulated at distal end, with 3 or 4 hs, mainly on ventral surface; campaniform pore present. Segments III–VI each 25–35 μm wide; length of fs 20–22 μm: lengths (μm): III 62–66; IV 110–125; V 105–109; VI 115–125; approximate number of setae per segment: III 11 or 12 fs + 0 hs; IV 21–25 fs + 0 hs; V 23–25 fs + 0 hs; VI about 25.

Thorax. Prothorax: pronotal ridge (prnr) well developed, apparently fused medially; pronotal sclerite (prn) narrow or absent; without lateral pronotal setae. Post-tergite (pt) considered to be present; without post-tergital setae. Median pronotal and other dorsal and pleural setae absent. Proepisternum + cervical sclerite (pepcv) well developed. Sternum (stn 1) with strong transverse ridges; median ridge absent; sternite with shallow transverse ridges; prosternal setae (stn 1 s), anteprosternal setae (astn 1 s) and antemesospiracular setae (asp 2 s) absent.

Mesothorax: probably convex in life; prescutum (prsc) slightly wider than long, 180–190 μm long, 130–140 μm wide; sclerotised, with obscure nodulations; prescutal setae (prscs) absent; prescutal ridge (pscr) and prescutal suture (pscs) well developed. Scutum (sct): median membranous area (sma) probably about 50–75 μm long, 225– 250 μm wide with 0 or 1 pairs of hs; lateral margins of membranous area bounded by sclerotised ridges; scutum without polygonal nodulations laterad to scutellum. Scutellum (scl) 76–80 μm long, 205–220 μm wide; with a mod- erately large foramen; scutellar setae absent. Mesepisternum (eps 2) not nodulated. Postalare (pa) striated at anterior end; without postalare setae. Basisternum (stn 2) large, 190–205 μm long, 245–270 μm wide; median ridge (mdr) present but not complete; bounded anteriorly by strong marginal ridges (mr) and posteriorly by strong precoxal ridges (pcr 2); without basisternal setae (stn 2 s); lateropleurite (lpl) without an extension from marginal ridge; furca (f) well developed and extending anteriorly to about level with point where marginal ridge and precoxal ridges meet laterally. Subepisternal ridge (ser) well developed. Mesothoracic spiracle (sp 2): width of peritreme 40–44 μm; post- mesospiracular setae absent. Antemetaspiracular setae absent. Mesopostnotum (pn 2) normally developed. Tegula (teg) without tegular setae (tegs).

Metathorax: metapostnotum (pn 3) apparently absent; metatergal setae: 1 pair hs. Dorsospiracular setae absent. Dorsal and ventral part of metapleural ridge (plr 3) well developed; metepisternum (eps 3) lightly sclerotised, but without postmetaspiracular setae (pms); metepimeron (epm 3) short, without setae. Metathoracic spiracle (sp 3): width of peritreme 40 μm. Metasternum (stn 3) membranous and not reticulated. Anterior metasternal (amss) and posterior metasternal setae (pmss) absent.

Wings: hyaline; of moderate length and width, about 1.28 mm long, 615 μm wide (ratio of length to width 1:0.5). Alar setae (als) and sensoria (sens) absent. Hamulohalteres about 125 μm long, 33 μm wide; usually each with one hamulus (one with 2); length of each about 58 μm.

Legs: metathoracic legs marginally longest; all segments with few setae, mainly fs. Coxae (cx): length (μm): I 115–118, II 120–125, III 120–125; each procoxa with 2 stout coxal bristles (cb), each 35–65 μm long; meso- and metacoxae each with long coxal setae about 65–70 μm long; metacoxa with about 12 fs + 6 hs. Trochanter (tr) + femur (fm) with fairly distinct diagonal segmentation; length (μm): I 260–265; II 235–240, III 250–255; each tro- chanter (tr) with a line of small campaniform sensilla; long trochanter seta short, about 60 μm long; metatrochanter with 5 fs + 2 hs; each femur about 13 fs + 7 hs. Tibia (ti) long: lengths (μm) I 295–300; II 330–335; III 340–345; metatibia with about 55–60 fs + 11 hs, latter becoming spur-like distally on ventral margin; apical spurs (tibs) variable, those on protarsi weak or absent, those on metatarsi strong, each about 28–30 long. Tarsi (ta): lengths (μm) I 135–140; II & III 130–135; metatarsi with about 14 fs + 4 hs; tarsal campaniform pore absent; distal tarsal spurs (tars) only slightly differentiated, each about 30 μm long; tarsal digitules (tdt) subequal in length to claw. Claws (c) short, each about 27 μm long, subequal in length to width of tarsi, without a denticle (cd); claw digitules (cdt) both with small capitate apices and slightly longer than claw.

Abdomen. Segments I–VIII: tergites (at) represented by light sclerotisations on segments IV–VIII; sternites (as) present as a light sclerotisation on all segments, but that on VIII more distinct. Caudal extension on segment VII absent; that on segment VIII (ce VIII) rounded, each with a dorsal, lightly sclerotised protuberance (cicatrix?); each with 4 or 5 small pleural hs. Dorsal abdominal setae (ads) very few, with 0 or 1 hs on each side; without ante-anal setae (aas) on VIII. Pleural setae all hs; dorsal pleural setae (dpls) (on each side): I–VI each with 0; V & VI each with 1; VII perhaps 3; ventral pleural setae (vpls): I–III each with 0; IV & V each with 1; VI & VII each with 2 or 3. Ventral abdominal setae all hs, with none on II, III–VII each with 1 or 2, VIII with 0. Glandular pouches (gp) absent.

Genital segments. Segment IX and style intimately fused. Penial sheath (ps) typical of male Coccidae , gradually narrowing to a blunt apex; about 1/5th total body length (ratio of total body length to penial sheath length 1:0.2); length 300–330 μm; width at base about 95 μm; with strongly sclerotised margins. Basal rod (bra) very short, 35–45 μm long, anteriorly not nearly reaching basal membranous area (bma). Aedeagus (aed) quite long, 160–165 μm long, gradually narrowing towards apex, latter distant from apex of style. Apex of style with a cluster of small sensillae (gtp) and with about 14 minute setae (gts) along each margin.

Comment. The adult males of Akermes scrobiculatus and A. pingue are very similar, only differing in a few small particulars, the significance of which is uncertain due to the few specimens studied. However, the study of the adult females shows that these two species are distinct (Gullan & Hodgson, in prep). Neither A. scrobiculatus nor A. pinguis are congeneric with Akermes bruneri Cockerell but are considered to belong to the Myzolecaniinae as currently understood.

Based on the morphology of adult females and first-instar nymphs, Kondo and Williams (2002) have suggested that the Myzolecaniinae is composed of several unrelated lineages, an hypothesis also supported by a Bayesian phylogenetic analysis of the family Coccidae using DNA sequences based on 18S, 28S and partial CO1 data (T. Kondo & L.G. Cook, unpublished data, in Kondo 2013). Males of several Toumeyella Cockerell spp., Mesolecanium nigrofasciatum (Pergande) , Neolecanium cornuparvum (Thro) , and Pseudophilippia quaintancii Cockerell , species currently included in the Myzolecaniinae, have been described in detail by Miller and Williams (1995). However, it is not certain whether these really represent this family whose type species is Myzolecanium kibarae Beccari from Papua New Guinea, the males of which are unknown.

Figures

FIGURE 89. Akermes pinguis (Maskell). Macropterous male.(Coccidae).Where K=procoxa showing coxal bristles and R=dermal reticulations on ocular sclerite.