Micronecta virgata Hale, 1922

Tinerella, Paul P., 2008, Taxonomic revision and systematics of New Guinea and Oceania pygmy water boatmen (Hemiptera: Heteroptera: Corixoidea: Micronectidae), Zootaxa 1797 (1), pp. 1-66 : 53-59

Micronecta virgata Hale, 1922

( Figs. 16k–l , 32–35 )

Micronecta virgata Hale, 1922: 327 .

Micronecta virgata: Lundblad, 1933: 76 . [list]

Micronecta virgata: Wróblewski, 1962b: 320 . [redescription]

Micronecta virgata: Chen, 1965: 164 . [faunistics]

Micronecta virgata: Wróblewski, 1970: 691 . [additional description]

Micronecta virgata: Cassis and Gross, 1995: 69 . [catalog]

Micronecta virgata: Nieser and Chen 1999: 82 . [additional diagnosis]

Micronecta virgata: Andersen and Weir, 2004: 250 , 335. [key; list]

Micronecta virgata: Tinerella and Polhemus, 2005 : [key; faunistics]

Micronecta virgata: Chen et al., 2005: 420 . [list]

Micronecta virgata: Tinerella, 2006a: 700 . [phylogeny discussion]

Diagnosis: Readily distinguished by the interocular space greater than width of eye, hemelytral patterning ( Figs. 16k–l , 32c ) and size. Similar in general habitus to M. carbonaria ; however, the species is distinguished by the four distinct longitudinal hemelytral stripes and by the combination of characters given below.

Size: ( Table 12). Macropterous form: 2.89–3.50. The given metrics expand the previously recorded size for the species. Brachypterous form unknown.

L= length, LP= length of pronotum, W= body width, WH= width of head, S= synthlipsis, WE= width of eye, WP= width of pronotum, L:W= ratio body length to width, S:E= ratio of synthlipsis to eye width, OcI= ocular index.

Derivation of specific epithet: From the Latin virgata , meaning striped, probably referring to the black striped hemelytra of this species.

Notes on type material: Type series deposited in SAMA. Holotype ( Figs. 32a–c ): SAMA I.15190, ♂, “Townsville, G. F. Hill, N. Q.”; mounted on point card. Label bearing “ TYPE ” as well as handwritten label bearing: “ Micronecta virgata Hale , Queensland ”; “ TYPE ” handwritten in red on right side of label. “I.15190” handwritten at top right corner of label. Paratypes: (1♂, 1♀), SAMA. (♂): mounted on point card; “ Cairns Dist., A. M. Lea ”. Pin with pink “Co-Type” label. Large handwritten label printed “ paratype ” at right edge. Handwritten: “ Micronecta virgata Hale ”. (♀): mounted on point card; printed: “ Cairns Dist. , A. M. Lea ”. Pin with pink “Co-Type” label. Determination label bearing: Micronecta virgata Hale , det. L. C. Chen , 1962.

Description: Based on macropterous form. Measurements. Length: male 2.94–3.36; female 2.89–3.50; Width: male 1.51–1.61; female 1.66–1.75; Width of head: male 1.15–1.27; female 1.19–1.33; Synthlipsis: male 0.49–0.57; female 0.55–0.65; Width of eye: male 0.29–0.38; female 0.29–0.39; Width of pronotum: male 1.08–1.22; female 1.14–1.27; Length of pronotum: male 0.36–0.40; female 0.36–0.40.

Color. Ground color brown to reddish brown ( Figs. 16k–l ). Head same color, eyes grayish-brown. Vertex and frons pale brown, clypeus darker brown, appearing mottled. Labium darker brown. Genal area lighter brown, same general color as head. Antennae pale. Pronotum dark brown, margins lighter, faint, narrowed pale band along apical margin. Scutellum pruinose mediolaterally. Clavus with basal pale diagonal area, apical portion same general ground color as corium and membrane. Corium with four darker contiguous longitudinal bands present, though sometimes faint. Pre-nodal embolar area entirely pruinose. Post-nodal embolar area very short, pruinose. Left membrane hyaline in both sexes, paler laterally, with inner portion embrowned, medioapical portion with narrowed darkened band present. Right membrane coriaceous, brown. Venter light brown, natatorial setae darker brown.

Structural characteristics. Ratio of body length/width: males 1.96; females 1.91. Head slightly wider than pronotum, interocular space greater than width of eye, synthlipsis 1.7 times as wide as posterior width of eye. Ocular index: males 1.56; females 1.74. General facies of head (vertex, frons, and labium) proportionate. Antennae densely pilose, segments one and two very short, segment three longer, club-shaped. Pronotum robust, convexly rounded and short, nearly four and one-half times as wide as long (W/L: males 1.59/0.37; females 1.70/0.38). Prothoracic lobe broad, anterior margin quadrate, posterior margin broadly rounded ( Fig. 33a ). Hemelytra with short, transverse microsculpturing. Short setae distributed mainly over corium, setation of clavus restricted to apical portions. Pre-nodal embolar area well developed, nodal furrow and post-nodal embolar area like that of M. carbonaria Horváth. Metathoracic wings well developed, reaching apices of hemelytra. Lateral spines and setae on abdominal segments IV–VIII: IV: one stout, short spine, one long, thin; V: two short stout spines, one long, stout spine, one long, thin spine; VI: two short, stout spines, one long, stout spine; VII: two short, stout spines, one long, stout spine; VIII: four stout, short spines, three thin, long spines. Metaxyphus of both sexes short, triangular, acutely pointed ( Fig. 33b ).

Male foreleg ( Fig. 33c ): femur with two short, stout spines on basal third near ventral surface, a cluster of four to six stout spines basally, and two spines, one stout long spine and one shorter, thin spine, medially on dorsal surface. Tibia with one large lateroventral spine on anterior portion and one large spine dorsoapically.

Pala with four to five larger setae dorsally, palmar area with nine setae in dorsal row and 13–15 in ventral row. Ventral row setae more pronounced than dorsal row. Apex of pala with single thickened claw-like seta. Palar claw ( Fig. 33d ) tapered sharply proximad, widening with upper surface broadly rounded, lower margin nearly straight. Female foreleg with same general setal arrangement as male. Mesotarsal claws long, nearly 3/4 the length of mesotarsus.

Lateral lobes of abdominal tergum IV short, rounded, left lobe with 13 setae evenly spaced along margin and right row with 16 long setae along margin. Prestrigilar flap of abdominal tergum V short and wide, with margins rounded ( Fig. 33e ). Strigil very long, rectangular in outline, width variable but never wider than long. Median lobe of abdominal sternum VII ( Fig. 34a ) short, length nearly equal to width, apex acutely pointed, setal lengths variable and confined to extreme basal portion. Free lobe of abdominal tergite VIII ( Fig. 34b ) broad, with well produced rounded inner angle. Setae restricted to upper inner angle and apex, numbering 11 to 16. Pars stridens processus cleaner ridges of abdominal segment VIII appearing as a fine-ridged mat, with upper narrow series and broad lower widened series. Left paramere ( Figs. 34c–f ) markedly shorter than right, shaft equally broad along length, with sharp, recurved distal hook. Base short, broadly rounded. Right paramere ( Figs. 34c–g ) with long medially constricted shaft, apex broad and sharply pointed. Base of right paramere broad ( Fig. 34h ) with 28–36 plectral ribs spanning width. Aedeagus as in Figures 34c–f .

Distribution and habitat: ( Fig. 35 ). A widespread species, known from Sulawesi, Timor, Australia, New Guinea, and the Solomon Islands ( Tinerella and Polhemus 2005). Most specimens examined in this work were taken at lights. Specimens from the Solomon Islands were taken from permanent, stagnant ponds in rangelands (D. A. Polhemus, personal communication).

Discussion: Micronecta virgata is clearly allied to M. carbonaria and other species of the annae species group. The species is widespread through New Guinea. Within Australia, the species is very abundant in Northern Territory southwestward through Western Australia.

As with most widespread species, variation among the species occurs throughout its geographical range. Nieser and Chen (1999) highlighted differences seen in specimens, from Wróblewski’s redescriptions (1962b, 1970) with Sulawesi specimens, suggesting clinal variation.

Specimens Examined: INDONESIA: Irian Jaya Prov. [= Papua Prov.]: Nabire, S. Geelvink Bay , 10–40

m. 7-X-1962. Light Trap, jungle. H. Hotman. (1♂). [ BPBM]; PAPUA NEW GUINEA: New Britain: Keravat , 135m. (20–25) - XI-1959. MV Light Trap. T. C. Maa. (1♀) . [ BPBM]; NE: Wau Morobe District, 1150 m . 17-IX-1962. J. Sedlacek. (1♂). [ BPBM]; SE: Western Distr., Oriomo River , 3 m. 1-VIII-1964. Light Trap. H. Clissold. (1♂, 2♀♀). [ BPBM]; same data : 4-VIII-1964. Light Trap. H. Clissold. (1♂, 1♀). [ BPBM]; SE: Ruka , 9 m. 12-VIII-1964. Light Trap. H. Clissold. (2♂♂, 2♀♀). [ BPBM]; SE: Western Distr., Oriomo River , 3 m. 16-VIII-1964. Light Trap. H. Clissold. (1♀). [ BPBM]; SE: Mamai Pltn. , E of Port Glasgow, 150 m. 6-III- 1965. Light Trap. R Straatman. (1♂) . [ BPBM]; SOLOMON ISLANDS: Guadalcanal: Kukum . 13-I-1955. E. S. Brown. (1♂, 2♀♀). [ BMNH]; Guadalcanal: 9.6 km SE Honiara, Lunga River (Bridge) . 4-VI-1960. C. W. O’Brien. (2♂♂, 1♀). [ BPBM]; same data : 5-VI-1960. C. W. O’Brien. (4♂♂, 6♀♀). [ BPBM]; Guadalcanal: Kukum . 29-V-1963. P. Greenslade. (2♀♀). [BMNH]; Malau Lalo: 26-IV-1955. E. S. Brown. (1♀). [ BMNH]; Russell Island : Ufa . 4-IX-1955. E. S. Brown. (8♂♂, 12♀♀). [BMNH]; San Cristobal: Ugi. 28-IV-1955. E. S. Brown. (2♂♂, 1♀). [BMNH].

Figures

FIGURE 16. Dorsal habitus of Micronecta species. a–b. M. ludibunda Breddin, male and female. c–d. Micronecta jenniferae Tinerella, male and female. e–f. M. quadristrigata Breddin, male and female. g–h. M. queenslandica Chen, male and female. i–j. M. carbonaria Horvath, male and female. k–l. M. virgata Hale, male and female. Scale bars = 0.5 mm.

FIGURE 32. Micronecta virgata Hale, holotype and dorsal habitus. a–b. Locality and type labels. c. Holotype male, dorsal habitus.

FIGURE 33. Micronecta virgata Hale. a. Prothoracic lobe, female. b. Metaxyphus. c. Left male foreleg, posterior aspect. d. Left male pala (tarsus), anterior aspect, palar claw folded in. e. Prestrigilar flap of abdominal segment V. Scale bars = 0.1 mm.

FIGURE 34. Micronecta virgata Hale, male abdominal terminalia. a. Sternal process of abdominal segment VII. b. Free lobe of abdominal tergite VIII. c. Left paramere, lateral aspect, right paramere, dorsolateral aspect. d. Left paramere, dorsolateral aspect. e. Left paramere, dorsolateral aspect (cf Figs. c, d, f; base). f. Left paramere, lateroventral aspect, right paramere dorsolateral aspect. g. Right paramere, tip. h. Pars stridens processus, base of right paramere.

FIGURE 35. New Guinea distribution of Micronecta virgata Hale.