Ripersiella malschae (Williams)

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 : 39-40

Ripersiella malschae (Williams)

( Fig. 12 )

Rhizoecus malschae Williams, 2004b: 779 .

Ripersiella malschae (Williams) : Kozár & Konczné Benedicty, 2007: 495.

Material examined. Paratype: Sabah, Kinabalu National Park, Poring Hot Springs , 700m, with (the ant) Pseudolasius sp. , 28.vii.1998, A. Malsch ( BMNH): 1/1 ad ♂ (good) .

Mounted material: apterous; very small, total body length about 600 µm, greatest width 250 µm; antennae 6 segmented, short, much less than half total body length; flagellar segments square to oblong, third segment unusually long; antennae with only hair-like (hs); fleshy setae (fs) apparently absent or undifferentiated throughout body; hs on body mostly rather short, about 7–8 µm long, present in dense, mainly segmental, bands over dorsum; loculate pores (lp) each about 6–7 µm wide with 3–5 loculi (mainly 4), present intersegmentally on dorsum and perhaps venter; simple pores absent. Without either ocelli or simple eyes; tarsi (ta) 1 segmented; trochanter with 2 pairs of campaniform pores.

Head: small, greatest width about 93 µm. Unsclerotised; with an area of dense hs dorsal head setae (dhs) on dorsum and a similar smaller area between antennae on venter (vmcrs); loculate pores (lp) and simple pores absent. Simple eyes and ocelli both absent. Ocular sclerite (ocs) not apparently differentiated. Ventrally without any sign of a ventral midcranial ridge (vmcr) or lateral arms of midcranial ridge (lmcr). Preocular ridge (procr) absent.

Antennae: 6 segmented; length about 150 µm long (ratio of total body length to antennal length 1:0.25). Scape (scp): 30 µm long, 26 µm wide, with 4 hs. Pedicel (pdc): length 15 µm, width 19 µm; with 4 hs + a small campaniform pore. Segments III–VI all about 18–22 µm wide and parallel-sided, with narrow intersegmental membranes; lengths of segments (µm): III 43, IV 15, V 15, and VI 42; fs absent; hs short on scape, becoming longer towards apex; approximate number of hs per segment: III 15; IV 7; V 7 + 1 antennal bristle (ab) and VI 15 + 3 ab.

Thorax. Each segment with a dense covering of short setae, each about 8 µm long. Loculate pores few, all apparently intersegmental. Venter with a very few, slightly longer setae medially. Loculate pores few, most abundant near spiracles and along margin of prothorax. Mesothoracic furca clear. Pleural ridges well developed. Spiracles: width of peritremes 22–25 µm.

Wings and hamulohalteres (h) absent.

Legs: metathoracic legs longest. Coxae (cx): I 60; II 66; III 70 µm long; coxa III with about 8 hs. Trochanter (tr) + femur (fm): I 108; II 116; III 133 µm long; trochanter III with about 4 hs; each trochanter with 2 roundly oval sensoria in a line parallel to trochanterofemur articulation, but without strong Y-shaped sclerotised ridges; long trochanter seta not differentiated but seta in this position 7–8 µm long; femur III with about 20 hs. Tibia (ti): I 66; II 70; III 83 µm long; tibia III each with about 28 setae, mainly hs, becoming spur-like ventrally towards distal end; all tibiae with 3 apical spurs (tibs); length of longest 17 µm. Tarsi (ta) 1 segmented; length (µm): I 36; II 36; III 38 µm long (ratio of length of tibia III to length of tarsus III 1:0.46); tarsus III with 5 setae, all spur-like ventrally, with more proximal ventral spur about 18 µm long; tarsal digitules (tdgt) setose, much shorter than length of claw. Claws (c) long and narrow, without a denticle; length: III 27 µm; claw digitules (cdt) extremely short, perhaps 1 µm long.

Abdomen: segments I–VIII: tergites (at) and sternites (as) unsclerotised. Loculate pores (lp) absent dorsally but with 1 lp on each side of each segment on venter + a group laterally on each side of segment II. Dorsal setae (ads) short (7–8 µm long), present in dense bands across all segments, including segment VIII; ventral setae (avs) of similar length; with a total of about 8–10 avs in a line across each segment; pleural setae not differentiated from other setae. Each caudal extension on segment VIII (ce VIII) barely differentiated, without long pleural setae; tergite VIII with a pair of ads medially and a pair of lp laterally on each side; sternite without setae or pores.

Genital segment: penial sheath (ps) extending some way anteriorly under segments VIII with rounded posterior margin. Length of ps about 182 µm, width 66 µm at widest point; with a finger-like dorsal ridge, about 27 µm wide, pointing posteriorly; ridge with a large anus, about 25 µm wide, near anterior end; also with about 25 setae between anus and apex of ps; ventrally, ps with a broad slit-like opening ventrally, with about 3 pairs of setae near anterior end and 3 more pairs posteriorly; aedeagus (aed) quite short and strongly curved, perhaps 75 µm long, apex not bifid; anteriorly, aed fuses with a short sclerotised basal rod (bra). Apex of ps slightly upturned, with a series of fine concentric ridges; presence of sensilla (psp) on apex unknown.

Comment. Along with those of Ripersiella sp. A , and Ri. kondonis , the adult male of Ri. malschae differs significantly from other apterous rhizoecine males seen during this study. In particular, they differ in having: (i) no eyes; (ii) only a single tarsal segment; (iii) trochanter with only 2 pairs of campaniform pores and (iv) no Y-shaped sclerotisation on the trochanter. In addition, Ri. malschae has: (i) abundant short dorsal setae in dense bands across each segment; (ii) loculate pores that appear to be intersegmentally arranged, at least on dorsum; (iii) antennae with an unusually long segment III, and (iv) penial sheath relatively large, with many setae on dorsal ridge. Many of the features found on Ri. kondonis , Ri. malschae and Ripersiella sp. A are extremely similar to those on Pseudorhizoecus proximus , described above. It seems likely that these four species are closely related. This is discussed below.

Figures

FIGURE 12. Ripersiella malschae (Williams). Adult male. Where A = hair-like seta; C = loculate pores; H = side view of apex of penial sheath;l K = distal end of posterior leg, and M = side view of aedeagus + basal rod. For other labels, see under Materials and methods: conventions.