Merostenus (Merostenus) speculum, Gibson, Gary A. P., 2017

Gibson, Gary A. P., 2017, Synonymy of Reikosiella Yoshimoto under Merostenus Walker (Hymenoptera: Chalcidoidea: Eupelmidae), with a checklist of world species and a revision of those species with brachypterous females, Zootaxa 4255 (1), pp. 1-65 : 49-52

M. (Merostenus) speculum n. sp.

Figs 115–123

Type material. Holotype ♀ (NMK). “ BURUNDI, Kibira | National Park | 2177m, 2.93315°S, | 29.50583°E / Malaise trap, edge of | mixed forest/bamboo, | near meadow, 15–29 | JAN 2010, R. Copeland / HOLOTYPE ♀ | M. ( Merostenus ) | speculum | Gibson ”. Point-mounted by right acropleuron; entire except left fore wing with leading margin missing beyond submarginal vein ( Fig. 119 ) and body variably extensively covered with droplets of oily substance (e.g. Figs 115, 118 ); mesonotum not arched but pronotum pulled posteriorly over anterior margin of mesopectus such that prepectus rotated ventrally and mesoscutum anteriorly curved down to partly conceal pronotum ( Fig. 118 ).

Etymology. The Latin word speculum (mirror), in reference to the generally smooth and shiny body of females, one of the differentiating features for this species.

Description. FEMALE (habitus: Figs 116, 117 ). Length about 2.7 mm. Head ( Fig. 115 ) orangish; in frontal view subquadrate, about 1.2× as wide as high, and in lateral view lenticular, about 1.6× as high as long with anterior surface uniformly curved; smooth and shiny between scrobal depression and posterior ocelli and within concave part of scrobal depression above interantennal prominence, but vertex and lower face finely meshlike coriaceous, and upper face more coarsely reticulate-rugulose sculpture in transverse band along upper inclined part of scrobal depression and parascrobal region to inner orbit; entirely setose with dark setae except for bare scrobal depression, with setae on frons mostly separated by distance equal to or greater than anterior ocellar diameter; scrobal depression quite deep and transversely Π-shaped above interantennal prominence with lateral margin outcurved from torulus but not extending to inner orbit so distinct parascrobal region differentiated, and broadly arched dorsal margin widely separated from anterior margin and with small depression on either side of midline ( Fig. 119 ); ratio of OOL: POL: LOL: MPOD = 1.1: 2.3: 1.7: 1.0. Antenna ( Figs 115–117 ) with scape yellowish and fl1 and fl2 brownish-yellow under most angles of light, but pedicel and fl3–clava darker brown; scape slender, about 5.6× apical width, and slightly curved; flagellum clavate with fl1 longer than wide and at least fl2–fl5 obviously longer than wide, but fl6–fl8 shorter, slightly longer to slightly shorter than wide [length(width) of pedicel and flagellomeres = 20 (9), 11(7), 23(8), 18(10), 15(11), 15(13), 14(14), 15(15), 38(16) (clava collapsed)]. Labiomaxillary complex and mandibles same color as head.

Mesosoma ( Figs 116, 117 ) similarly orangish to yellowish-orange as head, except pronotal collar dark posterolaterally anterior to spiracle. Pronotum completely sclerotized ( Fig. 118 ); collar finely meshlike coriaceous with scattered dark setae. Mesoscutum ( Fig. 118 ) smooth and shiny; structure anteriorly concealed between pronotum and down-curved part of mesoscutum, but anterior margin likely narrowly reflexed; lateral lobes lowly convex relative to broad, shallowly concave median region, but completely carinate dorsolongitudinally; with single seta dorsolaterally on inclined surface of lateral lobe near mid-length ( Fig. 118 : arrows) and with 4 setae on outer surface of lateral lobe, one near mid-length and 3 more anteriorly (on anteriorly curved part of mesoscutum, not visible in Fig. 118 ). Scutellar-axillar complex ( Fig. 119 ) with scutellum elongate-oval and uniformly convex, quite highly convex above and only slightly longer than but conspicuously larger than axillae, and finely meshlike coriaceous with dark setae laterally anterior to frenum; axillae elongate-slender, similarly sculptured as scutellum but with dorsolongitudinal carina between anterior margin and base of scutellum, with line of dark setae on outer surface, and anterior to scutellum separated by deep, longer than wide depression. Fore wing ( Fig. 119 ) extending flat over mesosoma to base of gaster; disc elongate-slender, about 4× as long as greatest width, slightly brownish, smooth and mostly bare, but with about 3(?) marginal setae apically, and with line of 5 setae along broader, more strongly melanized submarginal vein extending about two-thirds length of disc differentiating bare costal cell, and with 1 seta on venation subapically (presumptive marginal vein) not extending to apically angulate margin. Mesopleurosternum with mesopectus meshlike reticulate anterior to acropleural sulcus below prepectus and more finely coriaceous posteroventrally, with long white setae posteroventrally and narrowly along acropleural sulcus anteriorly; acropleuron ( Fig. 120 ) broadly curved posteriorly to level of anterior margin of mesocoxa, meshlike coriaceous near anterior margin but mostly smooth and shiny (attachment of acropleural muscle fibers visible beneath cuticle). Metanotum ( Fig. 119 ) with dorsellum vertically raised over apex of scutellum, shiny and without longitudinal carinae. Metapleuron ( Fig. 120 ) entirely setose with long, comparatively dense white setae; anterior margin over about middle one-third reflexed as slender, bare flange abutting posterodorsal margin of acropleuron, with anteroventral margin angled posteroventrally over posterodorsal angle of mesocoxa, and ventral margin only slightly reflexed and not distinctly differentiating ventral region between acropleuron and metacoxa. Legs ( Fig. 117 ) same color as mesosoma; mesotibia with row of 6 apical pegs ( Fig. 123 ); metacoxa with two separate bands of white setae, one ventrolaterally and one dorsolongitudinally. Propodeum ( Fig. 119 ) long, medial length about 0.75× distance between transscutal articulation and posterior margin of dorsellum; posterior margin shallowly, broadly incurved, and anterior margin shallowly incurved medially behind dorsellum; with paramedial longitudinal ridges comparatively narrowly separated from median carina delimiting slightly concave median plical region from slightly higher lateral callar regions, the paramedial ridge reflexed slightly toward median anteriorly; plical region with complete median carina, otherwise very finely coriaceous to alutaceous; callus similarly sculptured as plical region, with spiracle separated from lateral margin by distance similar to own diameter, but basally with longitudinal carina between spiracle and lateral margin, the carina lateral to spiracle with line of long white setae but with more numerous setae in posteriorly widened band to posterior margin.

Metasoma with petiole transverse, smooth and shiny ( Fig. 119 ). Gaster ( Figs 117, 121 ) yellowish-orange dorsobasally, but darker brown beyond; shiny and mostly smooth though apical two tergites very finely meshlike coriaceous, and with sparse, inconspicuous dark setae dorsolaterally; syntergum in dorsal view ( Fig. 122 ) with posterior margin transverse; supra-anal plate yellowish; ovipositor sheaths yellowish, projecting only slightly beyond syntergum.

MALE. Unknown.

Distribution. AFROTROPICAL: Burundi.

Hosts. Unknown.

Remarks. Putative relationships and differentiation of females of M. speculum from those of M. micropterus , M. reticulatus and M. distigma are discussed under the latter species. Females most closely resemble those of M. micropterus in most features, as discussed under the latter species, but have small paramedial depressions at the dorsal limit of the scrobal depression similar to M. distigma .

Figures

FIGURES 115 – 123. M. (Merostenus) speculum n. sp., holotype ♀: 115, head, frontal; 116, dorsal habitus; 117, lateral habitus; 118, pronotum and mesoscutum, dorsolateral [arrows point to setae]; 119, scutellar-axillar complex to propodeum plus wings; 120; mesosoma, lateral; 121, gaster, dorsal; 122, gastral apex, dorsal; 123, apex of mesotibia and tarsus. [spp = supra-anal plate]