Aprostocetus nitens, 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 : 41-43

Aprostocetus nitens sp. n.

Figs. 31–37 .

Female. Length: 1.1–1.7 mm. Colour: head and body black, shiny with a distinct dark metallic green tinge, the base of gaster broadly suffused with yellow; antenna mostly yellowish, or with flagellum a little darker in some specimens; legs yellowish save hind coxa largely black with a metallic tinge, the middle and hind coxae slightly darkened in some specimens; tarsal tips dark; wings hyaline, venation pale brown.

Head ( Fig. 35 ) in frontal view 1.2–1.3 X as wide as high, about 1.7 X as wide as frontovertex at its narrowest; malar space 0.5–0.6 X as long as an eye, the sulcus almost straight, without a triangular fovea beneath the eye; POL 1.6–1.9 X OOL, more than 4 X OD; mandible with two teeth and a truncation; head rather densely setose as in Fig. 35 , eyes naked; lower margin of the toruli a little above lower eye margins; clypeus distinctly bilobed.

Antenna ( Fig 32 ) somewhat variable: scape approximately 3 X as long as wide, about 0.7 X the length of an eye, not reaching vertex; pedicel 1.8–2.5 X as long as wide, subequal in length to basal funicle segment; antenna with four strongly transverse anelli, the middle two distinctly shorter than the remaining two, which are about equal in size; funicle three-segmented, either with basal two segments about equal in length, each 2.0–2.6 X as long as wide and segment III a little shorter, or segment II intermediate in length between segments I and III; club as long as the distal two to two and a half funicle segments combined, 2.7–3.3 X as long as wide; basal club segment as long as wide to distinctly longer than wide, wider than apical funicle segment; apical club segment as wide as long to wider than long; apical spine distinctly shorter than length of apical club segment; sensilla sparse, the flagellum rather sparsely setose, as in Fig. 32 .

Mesosoma ( Fig. 34 ) about 1.3 X as long as broad; mesoscutum in profile slightly convex dorsally, in dorsal view gently rounded from side to side; mesoscutal midlobe about 1.2 X as wide as long with a distinct median line, with 2–3 strongly developed adnotaular setae at each side; mesoscutum with clearly discernible lineate-reticulate sculpture; scutellum strongly convex, 1.1–1.3 X wider than long with distinct submedian and sublateral lines; sculpture much as in mesoscutum; scutellum with 2 pairs of setae, anterior pair placed slightly behind mid-length of scutellum; dorsellum a narrow band, hardly convex, smooth, medially much longer than propodeum; propodeum medially very short, barely visible in some specimens, without a median and paraspiracular carinae, mostly smooth with fine, poorly defined sculptural cells; spiracles less than their own diameter from anterior propodeal margin; cali each with 3 – 4 setae. Middle leg with tibal spur slightly shorter than basitarsus.

Forewing ( Fig. 31 ) 2.2–2.5 X as long as wide; costal cell 14–18 X as long as broad, about 0.75 X as long as marginal vein, with a short row of 3–4 ventral setae at distal end; submarginal vein with 2 dorsal setae; marginal vein 4.3–5.3 X as long as stigmal; postmarginal vein very short, 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 varying from 0.5 X to almost as long as longest setae on marginal vein.

Metasoma with gaster (including protruding gonostyli) long, slender, about 3.5 X as long as wide, 2.5 X as long as mesosoma, tapering strongly to an acute apex; epipygium conical, at least about 1.3 X as long as wide; hypopygium extending about half way length of gaster; ovipositor, as seen in cleared slide mounted specimens ( Fig. 36 ), longer than gaster, 2.2–2.9 X as long as middle tibia, 2.9–3.5 X as long as gonostyli, the later very long, slender, protruding prominently caudally, more than 5 X as long as middle tibial spur.

Male. Length: 0.8–1.1 mm. Colour: head and body black, shiny with a dark metallic green tinge as in female, the basal third or so of gaster white in contrast; antenna whitish or with flagellum a little darker in some specimens; plaque shiny brown in contrast, visible as a distinct dark subapical patch on ventral margin of scape; legs entirely white save dark tarsal tips; wings entirely hyaline.

Differing structurally from female mainly in antenna ( Fig. 33 ): scape 3.0–3.4 X as long as wide with a short, strongly raised subapical plaque on ventral margin as in Fig. 33 ; two transverse anelli; funicle with four subequal funicle segments, each 1.4–1.7 X as long as wide; flagellar setae fairly sparse, gently curved; Genitalia as in Fig. 37 .

Remarks. Some of the specimens from Tanzania that are listed below differ from the majority of the study material by the base of the gaster which is not palely marked and by the legs which are, besides the coxae, not entirely yellow but with the femora distinctly infuscated to a varying degree. In addition, a few Tanzanian specimens have a single dorsal seta on the submarginal vein, instead of the normal two. Since these differences were found among specimens of the same series they are attributed to intraspecific variation.

Aprostocetus nitens is readily separated from A. tritus , A. exertus and the known undescribed Erythrina gall-associated Aprostocetus species by the following combination of characters: body with a metallic green tinge and prominently protruding ovipositor (but not unusually long and tail-like as in A. exertus ); strongly developed row of 2–3 adnotaular setae; 2 (rarely 1) dorsal setae on the submarginal vein; male antenna with 2 anelli, scape with a short, strongly raised plaque. Although Kostjukov (2004) restored the generic status of Ootetrastichus Perkins we here follow Graham (1987), La Salle (1994) and many other subsequent authors in treating this taxon as a subgenus of Aprostocetus . In so doing the subgeneric placement of A. nitens remains uncertain since it has several character states that have been attributed to either Ootetrastichus or Aprostocetus , as defined by Graham (1987) and La Salle (1994).

Type material examined. Female holotype, 39 female, 26 male paratypes as follows: SOUTH AFRICA. Limpopo Province: Blouberg NW of Polokwane, 23°04’S 28°59’E, v.2006, ex leaf galls on Erythrina lysistemon (Female holotype, 1 female; HYMC03797 ) ; Gauteng Province: Pretoria, Rietondale experiment farm, 25°43’S 28°14’E, ii.2006, ex leaf galls on E. lysistemon (14 females, 14 males; HYMC05082 ); Pretoria, Botanical Gardens, 25°44’S 28°16’S, ii.2006, ex leaf and vein galls on E. acanthocarpa (8 females, 7 males; HYMC03798 ) ; Mpumalanga Province: Pongola , 27°23’S 30°38’E, v.1996, from Erythrina sp. (3 females, 5 males; HYMC02269 ) ; Western Cape province: Stellenbosch , vii.1980, ex leaf galls on E. lysistemon (13 females; HYMC02281 ). All series collected by S. Neser. 2 female, 2 male paratypes each: BMNH, ANIC, MNHN .

Non type material examined. SOUTH AFRICA: Gauteng Province: Pretoria, Rietondale experiment farm, 25°43’S 28°14’E, xi. 2004, ex leaf galls on E. lysistemon (14 females, 3 males; HYMC03774 ) ; same data except ii.2006 (3 females, 6 males; HYMC03790 ) ; Pretoria, Rietondale experiment farm, ii.1997, in inflorescens of E. humeana (1 female, 1 male; HYMC02275 ) ; Pretoria , iii.1986, ex leaf galls on E. lysistemon (3 females, 2 males; HYMC02284 ) ; same data except iii.1990 (2 females, 1 male; HYMC02279 ) ; Pretoria , ii.1986, ex leaf veins of E. zeyheri (1 male; HYMC02272 ) ; Western Cape Province: Stellenbosch , xii.1975, ex leaf galls on E.? caffra (1 female; HYMC03780 ) ; all series collected by S. Neser; KwaZulu-Natal Province: Durban , i.2006, M. Ramadan, ex leaf galls on E. lysistemon (8 females) . TANZANIA. Morogoro region, ii.2007, ex galls on Erythrina abyssinica from the following villages: Bwawani and Gweta (28 females) ; Arusha region, Masai camp village, ii. 2007 ex galls on E. abyssinica (8 females) ; Mwanza region, Emeleia village , ii.2007, ex leaf galls on E. variegata var.? indica (15 females) ; Iringa, i.2006, ex leaf galls on E. latissima (2 females); all series collected by M. Ramadan; in ANIC .

Figures

FIGURES 31–38. Aprostocetus spp.: 31–37, A. nitens sp. n.: 31, forewing, female; 32, antenna, female; 33, antenna, male; 34, mesosoma, female; 35, head, frontal view, female; 36, ovipositor and middle tibia, same scale, female; 37, male genitalia. 38, A. exertus La Salle, female, lateral view.