Quadrastichus bardus, Prinsloo & Kelly, 2009

Prinsloo, Rd. L. & Kelly, Ne. A., 2009, The tetrastichine wasps (Hymenoptera: Chalcidoidea: Eulophidae) associated with galls on Erythrina species (Fabaceae) in South Africa, with the description of five new species, Zootaxa 2083 (1), pp. 27-45 : 36-38

Quadrastichus bardus sp. n.

Figs. 17–23 .

Female. Length: 0.8–1.3 mm. Colour: front aspect of head yellowish with sides, middle of face below toruli, and ocellar area, with variable dark suffusions; back of head black with dorsal margin broadly outlined in yellow, the ventral third or so white; antenna dominantly sordid white. Mesosoma uniformly black (blackishbrown in faded specimens), shiny, except acropleuron yellowish. Metasoma black save basal two and a half segments of gaster yellowish with a dark spot at each dorsolateral margin near base. Forewing disc entirely hyaline, venation pale brown. Legs white to yellowish except basal half or so of fore and hind coxae, and tarsal tips, dark.

Head, in frontal view ( Fig. 19 ) 1.1–1.3 X as wide as high, 1.6–1.7 X as wide as frontovertex at its narrowest; malar space 0.6–0.8 X as long as an eye, the sulcus distinctly curved, without a triangular fovea beneath the eye; POL 1.6 – 1.8 X OOL, 3.0–3.3 X OD; mandible bidentate with a truncation; head finely setose as in Fig. 19 , the eyes naked; lower margins of toruli about level with lower eye margins; clypeus bilobed.

Antenna ( Fig. 21 ) with scape 2.8–3.3 X as long as wide, a little shorter than the length of an eye, almost reaching vertex; pedicel 2.1–2.4 X as long as wide, 1.2–1.4 X as long as basal funicle segment; one transverse anellus; funicle three-segmented, segments subequal in size, each 2.0–2.4 X as long as wide; club about as long as distal two funicle segments combined; basal club segment 1.2–1.5 X as long as wide, a little broader than distal funicle segment; apical segment 1.3–1.4 X as long as wide; apical spine long, a little shorter than apical segment; sensilla sparse, flagellum rather sparsely setose, as in Fig. 21 .

Mesosoma ( Fig. 18 ) about 1.5 X as long as wide; mesoscutum in profile gently convex dorsally, in dorsal view gently rounded from side to side; mesoscutal midlobe a little wider than long, without or with slight traces of a median line, with 2–3 adnotaular setae at each side, in posterior half; mesoscutum with fine lineatereticulate sculpture; scutellum fairly strongly convex in profile, about 1.3 X as wide as long with distinct sublateral and submedian lines; sculpture much as in mesoscutum; scutellum with 2 pairs of setae, anterior pair level with the middle of scutellum; dorsellum convex, smooth, medially about as long as propodeum; propodeum with median carina and paraspiracular carinae absent; propodeum appearing a rather smooth with fine reticulate sculpture; spiracles less than their own diameter from anterior margin of propodeum; cali each with 2 setae. Middle leg with tibial spur slightly shorter than basitarsus.

Forewing ( Fig. 17 ) 2.4–2.6 X as long as wide; costal cell 17–20 X as long as broad, about equal in length to marginal vein, with a row of ventral setae; submarginal vein with 1 dorsal setae; marginal vein 3.3 – 4.0 X as long as stigmal, the postmarginal vein less than 0.25 X as long as stigmal; subcubital line of setae extending basally as far as basal vein, closing speculum posteriorly; longest marginal cilia about 1.1–1.5 X as long as longest setae on marginal vein.

Metasoma slightly longer than mesosoma in dried specimens, somewhat parallel-sided, tapering to an acute apex, approximately 1.5 X as long as broad; epipygium wider than long; hypopygium reaching to about half the length of gaster; ovipositor, as seen in cleared slide-mounted specimens ( Fig. 22 ), a little shorter than gaster, 1.2–1.4 X as long as middle tibia, 5.6–6.5 X as long as gonostyli, the latter short and broad, not protruding caudally, 1.5–1.9 X as long as middle tibial spur; 2 to 3 cercal setae.

Male. Length: 0.7–1.0 mm. Colour: distinctly bicolorous: head and antenna white, the triangle demarcated by the ocelli dusky; mesosoma blackish with sides of pronotum, mesoscutal side lobes, prepectus and acropleuron white in contrast; metasoma blackish save basal half of gaster white; wings hyaline; legs entirely white.

Differing structurally from the female mainly in the antenna ( Fig. 20 ): scape with a ventral plaque, placed in apical half and extending about halfway the length of scape, as in Fig. 20 ; one anellus present; funicle foursegmented, the basal segment quadrate to slightly wider than long, distinctly shorter than segments II–III which are subequal in size, each approximately twice as long as wide; flagellum sparsely setose, the setae on funicle segments long, slightly curved, not arranged in whorls; genitalia as in Fig. 23 .

Remarks. Quadrastichus bardus can be separated most readily from Q. ingens , Q. gallicola and Q. erythrinae in the female by: its colour, which is generally black, the basal half or so of gaster yellowish in contrast; long apical spine of the antennal club; 2–3 adnotaular setae at each side of mesoscutal midlobe; relatively short, tapering gaster with non protruding ovipositor. Quadrastichus bardus structurally closely resembles the undescribed Quadrastichus species from Tanzania, which has been reared from galls on E. abyssinica , although the two species are distinctly different in colour. Quadrastichus bardus fits the anysis - group of species as defined by Graham (1991).

Type material Examined. SOUTH AFRICA. Female holotype, 39 female, 14 male paratypes as follows: Gauteng Province: Pretoria, Rietondale experiment farm, 25°44’S 28°13’E, viii.2006, ex leafless twigs of Erythrina humeana (Female holotype, 10 females, 1 male; HYMC05730 ); same data except xi.2003, ex petioles and leaf veins (12 females; HYMC01918 ); Pretoria, Brummeria, Botanic Gardens, ii.2007, ex swollen petioles of Erythrina zeyheri (17 females, 13 males; HYMC05729 ). All specimens collected by S. Neser. 2 females, 2 males each: ANIC, BMNH, MNHN .

Non type material examined. SOUTH AFRICA. Gauteng Province: Pretoria, ii.1986, ex thickened leaf vein of Erythrina humeana (2 females, 2 males; HYMC 02271); same data except ii.1984 (2 females; HYMC 02278); same data except iii.1986, ex galls on E. humeana in laboratory originating from stock reared from E. zeyheri (14 females; HYMC 02273); KwaZulu-Natal Province: Midmar dam, nr. Howick, ii.1985, ex galls in petioles of E. humeana (2 females, 1 male; HYMC 02276). All specimens collected by S. Neser. TANZANIA: Kisase-Mwanza, 12.ii.2006, M. Ramadan, ex Erythrina af. abyssinica (2 females; in CIRAD)

Figures

FIGURES 17–23. Quadrastichus bardus sp. n.: 17, forewing, female; 18, mesosoma, female; 19, head, frontal view, female; 20, antenna, male; 21, antenna, female; 22, ovipositor and middle tibia, same scale, female; 23, male genitalia.