Ctenochiton eucalypti 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 : 233-235

Ctenochiton eucalypti Maskell ( Fig. 91 )

Ctenochiton eucalypti Maskell 1895 , 52. Type data: Australia, New South Wales, Maitland and Newcastle, on Eucalyptus siderophloia . Syntypes, female. Type depositories: NZAC, USNM.

Material studied: Australia, New South Wales, Wyong, on large leaved ironback eucalyptus, 10.viii.1916, McPhearson (Forester) ( ASCU, #710): 2/3ad ♂♂ (good-poor). Also: Australia, Ctenochiton eucalyti , no other data, ( ASCU): 1/1adm (poor; mounted from dried material by CJH).

Described from all specimens, where possible.

Mounted material. Of moderate size; antennae each about 3/4 total body length; head with two pairs of particularly large simple eyes; head and rest of body with almost no setae, all hair-like (hs); fleshy setae (fs) on appendages usually easy to separate from hs; procoxae each with two stout bristles; trochanterofemur articulation clear. Abdominal caudal extensions on VIII rounded; glandular pouches present but glandular pouch setae rather short. Total body length 1.6–1.93 mm, width across triangular plates 425–450 μm. Wings subequal to total body length and about half as wide as long.

Head. Roughly diamond-shaped; length 300–350 μm; width across genae 290–320 μm. Setae almost absent. Median crest (mc) well developed, with narrow reticulate striations; postoccipital ridge (por) absent; with 1 pair of hs dorsal head setae (dhs). Mid-cranial ridge (mcr) absent dorsally; ventrally, mid-cranial ridge (vmcr) narrow but welldefined, extending posteriorly as far as ocular sclerite (ocs); with a lightly striated margin. Preocular ridge (procr) quite long dorsally; ventrally extending anterior to ventral simple eyes. Genae (g) large and membranous, without genal setae (gs) but with many large polygonal reticulations without inner microridges. Eyes (se): two pairs of particularly large, round, simple eyes, dorsal larger than ventral: dorsal simple eye each 90–105 μm wide, ventral simple eye 75–85 μm wide. Ocelli (o) each oval in shape, about 35 μm long. Ocular sclerite (ocs) heavily polygonally reticulated, each reticulation without inner microridges. Postocular ridge (pocr) extending medially almost to median crest. Dorsal ocular setae (docs): 1 pair. Ventral head setae (vhs) absent. Tentorial bridge (tb) well developed. Cranial apophysis (ca) possibly bi- or trifid.

Antennae: 10 segmented and filiform. Scape (scp): 50–55 μm long, 48–53 μm wide, with 3 hs. Pedicel (ped): 58–65 μm long, 50–55 μm wide, apparently without transverse reticulations; with 7 or 8 fleshy setae (fs) + 3–7 hs (mainly on ventral surface); campaniform pore (camp) present. Segments IV–X each 23–30 μm wide; length of fs 28–40 μm (longest towards apex): lengths (μm): III 65–87; IV 145–165; V 170–175; VI 190–200; VII 190–195; VIII 136; IX 115; X 140; approximate number of fs per segment: III 11–13 fs; IV–X each with 20–30; segments VIII & IX each with 1 antennal bristle (ab); X also with 3 long ab, small ab not differentiated from fs, plus 3 capitate setae (caps).

Thorax. Prothorax: pronotal ridge (prnr) well developed, fused medially, where it sometimes broadens and even divides; pronotal sclerite (prn) narrow or absent; with 1 pair of lateral pronotal setae (prns). Post-tergites (pt) faint; without post-tergital setae (pts). Medial pronotal (mpns) and other dorsal (dpms) and pleural setae (dpl 1 s) absent. Proepisternum + cervical sclerite (pepcv) well developed. Sternum (stn 1) with a strong transverse ridge; median ridge absent; sternite membranous without dermal ridges; prosternal (stn 1 s), anteprosternal (astn 1 s) and antemesospiracular setae (asp 2 s) absent.

Mesothorax: probably strongly convex in life; prescutum (prsc) wider than long, 135–165 μm long, 220–265 μm wide; sclerotised, with obscure nodulations; prescutal setae (prscs) absent; prescutal ridge (pscr) and prescutal suture (pscs) well developed. Scutum (sct): median membranous area probably 45–80 μm long, 215–240 μm wide, with strong lateral ridges, without scutal setae (scts); lateral margins of membranous area sclerotised; scutum without polygonal nodulations laterad to scutellum. Scutellum (scl) 80–100 μm long, 245–270 μm wide; with a moderately large foramen; scutellar setae (scls) absent. Mesepisternum (eps2) not nodulated. Postalare (pa) with a few reticulations at anterior end; without postalare setae (pas). Basisternum (stn 2) large, 200–225 μm long, 340–365 μm wide; median ridge (mdr) well developed and complete; bounded anteriorly by strong marginal ridges (mr) and posteriorly by strong precoxal ridges (pcr 3); without basisternal setae (stn 2 s); lateropleurite (lpl) with a strong extension from marginal ridge; furca (f) well developed and extending anteriorly to a point anterior to where marginal ridge and precoxal ridges meet laterally. Subepisternal ridge (ser) well developed. Mesothoracic spiracle (sp 2): width of peritreme 28–36 μm; postmesospiracular setae (pm 2 s) absent. Mesopostnotum (pm 2) normally developed. Tegula (teg) with 4 or 5 hs tegular setae (tegs).

Metathorax: metapostnotum (pn 3) small or absent; metatergal setae (mts) absent. Dorsospiracular setae (dss) absent. Dorsal and ventral parts of metapleural ridge (plr 3) well developed; metepisternum (stn 3) unsclerotised, without postmetaspiracular setae (psp 3 s); metepimeron (epm 3) short, without setae. Metathoracic spiracle (sp 3): width of peritreme about 33 μm. Antemetaspiracular setae (asp 3 s) absent. Metasternum (stn 3) membranous and not reticulated. Anterior metasternal (amss) and posterior metasternal setae (pmss) absent.

Wings: hyaline; of moderate length and width, about 1.9 mm long, 1.03 mm wide (ratio of length to width 1:0.54). Alar lobe (al) present. Alar setae (als) and sensoria (sens) absent. Hamulohalteres (h) each 120–125 μm long, 30 μm wide; each with one hamulus, length 65–70 μm.

Legs: prothoracic legs perhaps marginally longest; all segments with many setae, mainly fs. Coxae (cx): length (μm): I 115–145, II 125–145, III 140–150; each procoxa with 2 stout coxal bristles, each 50–75 μm long; meso- and metacoxae each with a long coxal seta 65–70 μm long; metacoxa with 20–34 fs + 5 or 6 hs. Trochanterofemur (tr+f) with distinct segmentation; length (μm): I 365–380; II 315–345, III 315–335; each trochanter with 2 pairs of small campaniform sensilla; ‘long’ trochanteral seta short, 80–85 μm long; metatrochanter with 7–15 fs + 3–5 hs; each femur with many fs + fewer hs. Tibia (tib) long: length (μm) I 445–475; II 420–430; III 400–425; metatibia with many fs + a few hs, latter becoming spur-like distally on ventral margin; apical spur (tibs) long and strong, each 45–50 μm long. Tarsi (tar): lengths (μm): I 175–185; II 185–195; III 175–195; metatarsi with many fs + a few hs; tarsal campaniform pore (tac) absent; distal tarsal spur (tars) about 33–37 μm long; tarsal digitules (tdt) shorter than claw. Claws (c) short, each 26–30 μm long, subequal to or longer than width of tarsi, with perhaps a hint of a denticle; claw digitules (cdg) both with small capitate apices and longer than claw.

Abdomen. Segments I–VIII: tergites (at) represented by distinctly polygonally reticulated sclerites on segments II–VII; sclerotised sternites (as) only apparent on segments VII and VIII, but that on VIII more distinct. Caudal extensions (ce) of segment VII absent; those on segment VIII rounded, with 3 or 4 shortish hs pleural setae. Dorsal abdominal setae (ads) few, with a total of 2 on each of segments II–VII; segment VIII generally with 2 rather long hs ante-anal setae, each about 60 μm long. Pleural setae (plrs) all hs; dorsal pleural setae: I–V each with 0; VI & VII each with 2; ventral pleural setae (on each side): I–IV each with 0; V–VII each with 2. Ventral abdominal setae (avs) all hs: II & III each with 0; IV & V each with 1; VI & VII each with 4 or 5. Glandular pouches (gp) deep, each divided into an inner and an outer section; glandular pouch setae (gls) proportionately rather short, each 115–140 μm.

Genital segments. Segment IX and style (st) fused. Penial sheath typical of male Coccidae : fairly long, gradually narrowing to a blunt apex; length 310–350 μm, about 1/5th total body length (ratio of total body length to penial sheath length 1:0.19); width at base 100–125 μm; with strongly sclerotised margins. Basal rod (bra) short, 28–35 μm long, anterior end 20–40 μm from basal membranous area. Aedeagus (aed) 185–210 μm long, gradually narrowing and then broadening near apex. Apex of penial sheath with a cluster of small sensillae (sens) and with about 10–15 unusually long (though still small!) setae along each margin, each about 20 μm long.

Comment. The male of Ctenochiton eucalypti somewhat resembles that of Akermes scrobiculatus (here included in the Myzolecaniinae) but differs particularly in having very large protruding simple eyes and in possessing glandular pouches.

The Australian Coccidae are currently being revised (Gullan & Hodgson, in prep.). From this study of the adult females, it is clear that C. eucalypti belongs to the family Paralecaniini but it is not congeneric with the type species, Ctenochiton viridis Maskell, 1897 . Nor is it congeneric with C. serratus , the adult male of which is described below.

Figures

FIGURE 91. Ctenochiton eucalypti Maskell. Macropterous male. (Coccidae). Where R=dermal reticulations on ocular sclerite.