Ripersiella sp. B

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 : 46-49

Ripersiella sp. B

( Fig. 15 )

Material examined. Ethiopia, 3.xii.1980, host unknown, Demeter ( PPIHH): 1/ 1♂, poor condition, body twisted, much of it sideways on and head crumpled .

Note: although this specimen was poor, several significant or unique characteristics were clearly visible and it was considered worthwhile to describe and illustrate this male.

Mounted material: apterous; very small, total body length about 490 µm, greatest width about 185 µm; antennae 10 segmented, moderately long, slightly longer than half body length; most flagellar segments almost binodal and slightly longer than wide, more apical 7 segments with short, stout fleshy setae (fs); hair-like setae (hs) on antennae rather variable in length; body with rather few setae, all hs, variable in length but longer on dorsum (about 15–20 µm) than on venter (8–10 µm); loculate pores (lp) infrequent, each about 8 µm wide with 4 or 5 loculi, distribution uncertain but perhaps mainly near margins; simple pores absent. With 1 pair of simple eyes but no ocelli. Tarsi (ta) two segmented; trochanter (tr) with 3 pairs of campaniform pores; penial sheath (ps) narrowing abruptly to a narrow process with a triangular apex; also ps with a pair of short processes extending posteriorly, each with 2 small points.

Head: dorsum badly distorted and few characters detectable with certainty. Epicranium apparently unsclerotised; with at least 7 pairs of hs dorsal head setae (dhs) + perhaps 1 loculate pore (lp) on each side posteriorly; simple pores absent. Simple eyes: only 2 detected, considered to be only 1 pair; ocelli both absent. Ocular sclerite not apparently differentiated. Ventral epicranium also apparently unsclerotised, without any sign of ventral midcranial ridge or lateral arms of midcranial ridge; with perhaps 2 pairs of ventral midcranial ridge setae (vmcrs). Preocular ridge possibly not detected.

Antennae: 10 segmented; length about 270 µm (ratio of total body length to antennal length 1:0.55). Scape (scp): 35 µm long, 35 µm wide, with 3 hs. Pedicel (pdc): 41–43 µm long, 28–30 µm wide; with 6–8 hs + a small campaniform pore. Segments III–VII all about 21–24 µm wide; each almost binodal; longer wider than wide, with narrow intersegmental membranes; lengths of segments (µm) III 39–42; IV–VI 30–38, VII 39–40; VIII 43–45; IX 46–48; X 68; hs each 16–27 µm long, mainly in whorls; approximate number of setae per segment: III 7 hs, IV–VI 7 hs +2 fs; VII 9 hs + 2–7 fs; VIII & IX 8 or 9 hs, 4–8 fs, + 1 antennal bristle (ab) on IX; X a few hs, many fs + 3 ab.

Thorax. Membranous, without any sclerites. Structure very unclear possibly each segment with a pair of loculate pores dorsally near margin. Dorsal setae apparently few. Ventrally with 1 lp just posterior to each procoxa, and laterad to each spiracle. Spiracular peritremes each 10–12 µm wide.

Wings and hamulohalteres (h) absent.

Legs: metathoracic legs longest. Coxae (cx): I 75; II 71; III 71 µm long; coxa III with about 6 hs. Trochanter (tr) + femur (fm): I 158; II 141; III 155 µm long; trochanter III with about 5 hs; each trochanter probably with 3 roundly oval sensoria in a triangle; Y-shaped sclerotised ridges present associated with trochanterofemur articulation; long trochanter seta not differentiated; femur III with about 8 hs. Tibia (ti): I 139; II 139; III 168 µm long; tibia III each with about 18 setae, all tibiae with 2 apical spurs (tibs); length of III 16 µm. Tarsi (ta) 2 segmented; length of both segments: I 75; II 75; III 85 µm (ratio of length of tibia III to length of tarsus III 1:0.5); tarsus III with 12 setae, most distal ventral seta not significantly spur-like; tarsal digitules (tdgt) setose, none detected but basal sockets present. Claws (c) long and narrow, without a denticle; length: III 25–27 µm; claw digitules (cdt): only basal sockets detected.

Abdomen: segments I–VIII: tergites (at), sternites (as) and pleural areas apparently unsclerotised. Loculate pores (lp): single pores perhaps only present near margins on segments II, IV, VI and possibly VIII. Setae on I– VII: dorsal setae (ads) each 15–20 µm long, present in a single line of perhaps 7 across each segment, ventral setae (avs) more setose and shorter than ads (each 8–10 µm long), with maybe 1 or 2 avs across each segment; division into dorsal (dps) and ventral pleural setae (vps) not clear, but probably with 2 longer dps and 1 shorter avs. Caudal extensions (ce) unclear; segment VIII with 3 much longer and more robust setae, each about 60 µm long along margin; tergite VIII perhaps with 2 large hs ads medially; sternite without setae or pores?

Genital segment: penial sheath (ps) extending slightly anteriorly into segment VIII along ventral margin; ps with a dorsal, finger-like ridge which narrows posteriorly to a point; apex of ps with a small triangular structure; length from anterior dorsal margin to apex 96 µm, ventrally 118 µm; width 86 µm at widest point; finger-like dorsal ridge about 40 µm wide; narrow apical extension 20 µm; triangular tip 7 µm wide and long. Posterior margin of broad part of ps with a pair of short extensions, each with a pair of pointed structures each 3–4 µm long, which look as though they might articulate with the base part. Anus not definitely detected, perhaps 10 µm wide. Dorsal ridge with 2 longish setae on each side, each about 25 µm long. Ventrally, penial sheath with a broad slit-like opening through which aedeagus (aed) emerges; borders of opening not apparently sclerotised, each border with possibly 2 short setae, each about 3–7 µm long. Aedeagus (aed) perhaps 70 µm long, 5 µm wide, apex not bifid; anteriorly, aedeagus bends and fuses with a short sclerotised basal rod (bra). A few sensilla (psp) on triangular apex to ps.

Comment. The adult male of Ripersiella species B is unique in having: (i) the two short extensions each with a pair of pointed structures posteriorly on the penial sheath, the homologies of which are unknown; and (ii) a short triangular apex to the penial sheath. Ri. hibisci has some ridges or bumps along the posterior margin of the penial sheath in about the same position, but can hardly be said to be similar! However, Ri. hibisci , although macropterous, does resemble Ripersiella sp. B in having: (i) 10-segmented antennae; (ii) antennal segments of a rather similar shape; (iii) fleshy setae on most antennal segments; (iv) 3 campaniform pores on each side of each trochanter; (v) penial sheath of basically similar shape (broad, narrowing abruptly to a narrow apex); (vi) legs with many setae, and (vii) 2-segmented tarsi. Ripersiella sp. B differs most obviously in being apterous whereas Ri. hibisci is macropterous.

Ripersiella sp. B also resembles the adult male of Ri. cryphia in having only a single pair of simple eyes.

Figures

FIGURE 15. Ripersiella sp. B. Adult male. Where A = hair-like seta; B = fleshy seta; C = loculate pores; L = ventral view of penial sheath, and K = distal end of posterior leg. For other labels, see under Materials and methods: conventions.