Ripersiella hibisci (Kawai & Takagi)

Hodgson, Chris, 2012, Comparison of the morphology of the adult males of the rhizoecine, phenacoccine and pseudococcine mealybugs (Hemiptera: Sternorrhyncha: Coccoidea), with the recognition of the family Rhizoecidae Williams 3291, Zootaxa 3291 (1), pp. 1-79 : 34-37

Ripersiella hibisci (Kawai & Takagi)

( Fig. 10 )

Rhizoecus hibisci Kawai & Takagi, 1971: 181 .

Material examined. Holland, Wageningen , bred out in laboratory, 10.ii.2001, M. Jansen ( BMNH): 8/16ad ♂♂, mostly rather distorted and many without wings; data taken from several specimens but most measurement restricted to 2 or 3 specimens. Original collection details: imported into Netherlands at De Kwake (No. PD 20011249), leg. P. Dijkema / P.D. Aalsmeer, 9.xi.2000, ex Serissa [penjing?] ( Rubiaceae ), China .

Mounted material: macropterous, wings about 1.15 total body length and about 0.38 as wide as long. Very small, total body length about 720–750 µm; antennae a little more than half total body length, most segments barrel-shaped, with short and long fine hair-like setae (hs) and fleshy setae (fs), latter easily separable; body with few setae, all hs and robust; loculate pores (lp) each large, with 5–9 loculi, each pore 8–10 µm wide. Legs well developed, with 2 tarsal segments. Penial sheath (ps) constricted about half way along length.

Head: approximately triangular; dorsally apparently extending further posteriorly (100–105 µm) than ventrally (70–75 µm); greatest width about 100 µm. Dorsal epicranium lightly sclerotised throughout; with (on each side) about 7 robust hs dorsal head setae (dhs) distributed along full length of head; loculate pores absent. Ventral epicranium also lightly sclerotised; without a ventral midcranial ridge (vmcr) but with small but distinct lateral arms (lmcr) between scapes; with 4 or 5 ventral midcranial ridge setae (vmcrs) on each side between scapes, each 28–35 µm long; no other setae present on head ventrally. With 2 or 3 hs genal setae (gs) on each side just posterior to each dorsal eye, each 21–24 µm long. Simple eyes (se) round, subequal in size, each 23–27 µm wide. Ocular sclerite (ocs) not differentiated from rest of head but lightly sclerotised. Preocular ridge (procr) restricted dorsally to a small sclerotisation laterad to each scape; ventrally, procr possibly represented by narrow ridges which meet medially.

Antennae: 10-segmented; 390–400 µm long (ratio of total body length to antennal length 1:0.54). Scape (scp) slightly elongate; each 35–40 µm long, 27–30 µm wide, with 3–5 hs. Pedicel (pdc) each 43–50 µm long, 28–30 µm wide; with 6–11 fs, 6–10 hs + a campaniform pore. Segments III–X all rather barrel-shaped, with narrow intersegmental membranes; lengths of segments (µm): III: 35–37; IV: 30–34; V: 32–35; VI: 38–40; VII: 39–44; VIII: 42 and IX: 40–44; fs each about 20–30 µm long; approximate number of setae per segment: III–IX: 4–6 fs + 6–9 hs (of which 3–5 are long and flagellate (length 40–55 µm); segments VIII & IX with 1 antennal bristle (ab). Segment X not constricted apically: length 53–55 µm; with 8 fs, 3 large bristles on apical third + 2 sensilla basiconica (sb); also with 4 long flagellate setae which are probably capitate setae (caps) without capitate ends (probably also true for longest setae on segments III–IX).

Thorax. Prothorax: distinctly swollen laterally (mounted material with prothorax broader than most of mesothorax), and unusually long; propleural setae (pl 1 s) probably represented by 2 or 3 robust hs + 1 or 2 lp on each side; median pronotal setae (mpns): 1 or 2 hs + 1 lp on each side; post-tergites (pt) absent but with 1 hs post-tergital seta (pts) in this position. With 2 hs antemesospiracular setae (am 2 s) but no lp. Sternum (stn 1) unsclerotised apart from a thin, short transverse ridge; median ridge absent; with 1 hs prosternal seta (stn 1 s) + 1 lp on each side. Anteprosternal setae absent but with 0 or 1 lp in this position.

Mesothorax: prescutum (prsc) oval to rather rectangular, 38–45 µm long, 68–72 µm wide; with 2 pairs of hs prescutal setae (prscs). Scutum (sct): distance from prescutum to scutellum (scl) 50–57 µm; scutal setae (scts): 4 hs on each side laterally; with a distinct sclerotised apodeme on anterior margin near prealare (pra); prealar ridge (prar) quite well developed, triangular plate (tp) present. Scutellum (scl) 66–70 µm wide, 28–33 µm long; with a distinct scutellar ridge (sclr) but no foramen; with 2 pairs of scutellar setae (scls). Basisternum (stn 2) 115–125 µm wide, about 73–80 µm long; bounded anteriorly by a narrow marginal ridge (mr) and posteriorly by fairly strong precoxal ridges (pcr 2); with perhaps 3 or 4 pairs of hs basisternal setae (stn 2 s); lateropleurite (lpl) moderately broad, possibly showing some reticulation, and with a strong extension from marginal ridge along anterior margin; furca (f) well developed, narrow-waisted, arms very divergent and extending about 1/2 way to marginal ridge anteriorly. Mesothoracic spiracle (sp 2): width of peritreme 11–15 µm, without associated loculate pores. Postmesospiracular setae (pm 2 s): 2–4 hs + 1 lp on each side posterior to each spiracle. Tegula (teg) large, with 2 hs tegular setae (tegs).

Metathorax: with 1 pair of robust hs metatergal setae (mts); dorsospiracular setae (dss): 3 or 4 robust hs on each side; metapostnotal sclerite (pn 3) lightly sclerotised. Metepisternum (eps 3) without postmetaspiracular setae (eps 3 s). Metepimeron (epm 3) sclerotised, but without setae. Antemetaspiracular setae (am 3 s) absent. Metathoracic spiracle (sp 3): width of peritreme 14–16 µm, without associated loculate pores. Metasternum (stn 3) lightly sclerotised, with a 1 pair of hs anterior metasternal setae (amss) and 2 pairs of posterior metasternal setae (pmss) + 1 pair of lp.

Wings: hyaline, each 830–840 µm long, 310–320 µm wide (ratio of length to width 1:0.38; ratio of total body length to wing length 1:1.13); each wing with 2 hs alar setae (als) + 3 circular sensoria (sens) just distal to where medial vein branches from radial vein.

Legs: metathoracic legs longest. Coxae (cx): I: 58–65; II: 58–65; III: 60–69 µm long; with about 9 or 10 hs on coxa III; long setae on each coxa not differentiated, but seta in this position about 13–17 µm long. Trochanter (tr) + femur (fm): I: 120–133; II: 120–133; III: 135–153 µm long; trochanter III with 4 or 5 hs; each trochanter with 3 roundly oval sensoria arranged in a triangle medially and with strong Y-shaped sclerotised ridges; long trochanter seta undifferentiated but seta in this position 23–27 µm long; femur III with 8–10 hs. Tibia (ti): I: 66–85 (102); II: 90–104; III: 124–140 µm; tibia III with a total of about 13 or 14 setae, mainly hs, becoming spur-like distally; all tibia with 2 apical spurs (tibs); length of longest 25–30 µm. Tarsi (ta) 2 segmented, ta 1 very short and ring-like; length of both segments combined: I: 60–67; II: 60–67; III: 70–75 µm long (ratio of length of tibia III to length of tarsus III 1:0.54); tarsus III with 13–16 setae, mainly spur-like; tarsal spurs not differentiated; tarsal digitules (tdgt) long, setose and without capitate apices, originating rather a long way from claw. Claws (c) very long and thin, without a denticle; length: III: 30–35 µm; claw digitules (cdt) robust, finely pointed, each 23–25 µm long.

Abdomen: segments I–VII: tergites (at) perhaps lightly sclerotised; sternites (as) more obviously sclerotised. Caudal extension (ce) of segment VII small but distinct. Loculate pores (lp) present dorsally in lines across all abdominal segments, with 2–4 on each side; dorsal setae (ads) also in lines of 3 or 4 robust hs on each side with lp. Pleural setae: dorsopleural setae (dps) and lp probably included in total numbers of dorsal setae above; ventropleural setae (vps): IV–VII: 1 hs on each side. Ventral abdominal setae (avs) (totals): II: 2; III–VI: 5 or 6 hs; VII 2. Segment VIII: tergite (at) membranous, with 1 pair of hs dorsal abdominal setae (ads) medially + 1 or 2 lp; sternite (as) with a narrow sclerotisation along anterior margin of penial sheath; sternite without setae or pores; caudal extension (ce) small but distinct, with 1 hs ventral pleural seta on each side and 3 longish setae (length 35–50 µm) in position of glandular pouches (gp).

Genital segment: penial sheath (ps) rather large and bulbous; length 121–130 µm, 85–95 µm wide at widest point. Bulbous part mainly lightly sclerotised, but open ventrally; posteriorly narrows rapidly and then drawn out into a narrow, pointed extension, about 35 µm long. Dorsally with a quite wide anus (a) (width 16–20 µm) and with 4 longish setae, each 25–40 µm long. Ventrally, with a median slit-like opening through which aedeagus emerges; borders of slit lightly sclerotised, with 1 or 2 longish setae near posterior margin, each about 35–40 µm long. Aedeagus (aed) about 70 µm long, with parallel margins when viewed dorsally and apex sharply pointed, with apex emerging under pointed extension of penial sheath, but anteriorly bending ventrally and fusing with a short sclerotised basal rod (bra). Also with two sharp, blade-like structures laterad to where aedeagus emerges from penial sheath, each heavily sclerotised but with unknown homology. Apex of penial sheath apparently without small sensilla (psp).

Comment. The males of Ri. hibisci and Rh. falcifer were the only fully macropterous species seen during this study. For differences, see under Rh. falcifer above. Ripersiella sp. B , described below, is rather similar to Ri. hibisci but is apterous. For comments, see under Ripersiella sp. B . below.

Figures

FIGURE 10. Ripersiella hibisci (Kawai & Takagi). Adult male. Where C = loculate pore; F = alar sensoria; H = Xth antennal segment; J = dorsal view of posterior end of abdomen; K = distal end of posterior leg; L = ventral view of posterior end of abdomen, and N = side view of posterior end of abdomen. For other labels, see under Materials and methods: conventions.