Merostenus (Merostenus) micropterus Gibson, 2017, n. sp.
Creators: name: Gibson, Gary A. P.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Eupelmidae
Merostenus
Merostenus micropterus

description: M. (Merostenus) micropterus n. sp.
Figs 83–89
Type material. Holotype ♀ (MRAC). [Democratic Republic of the Congo] “I.R.S.A.C. [Institut pour la Recherche Scientifique en Afrique Centrale] - MUS. CONGO | Kivu: Terr. Kabare, | contref. S. E. Kahuzl, | 2080–2200m. VIII-51 | N. Leleup / HOLOTYPE ♀ | M. (Merostenus) | micropterus | Gibson”. Card-mounted by right side; entire except one front leg missing, one front leg detached beyond coxa and glued to card under mesosoma, one middle leg including coxa missing, one middle leg including coxa detached from body and glued separately to card, and left fore wing beyond humeral plate missing; uncontorted.
Etymology. A combination of micros (small) and pteron (wing), in reference to very short fore wings of females of this species.
Description. FEMALE (habitus: Figs 84, 85). Length = 2.9 mm. Head (Fig. 83) yellowish-orange; 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; frontovertex smooth and shiny from dorsal limit of scrobal depression to about midway between posterior ocelli and occiput, but vertex posteriorly, scrobal depression, and parascrobal region between torulus and lower inner orbit meshlike coriaceous reticulate, and lower face more finely meshlike coriaceous to smooth and shiny along malar sulcus; setose with dark setae above and below scrobal depression, with setae on frons sparse, separated by distance greater than anterior ocellar diameter; scrobal depression Πshaped, shallow with lateral margin directed dorsally from lateral margin of torulus toward inner orbit near midheight so as to differentiate triangular lower parascrobal region between torulus and lower inner orbit, and broadly concave dorsal margin indistinct except for sculptural difference but separated from anterior ocellus by distance equal to about POL; ratio of OOL: POL: LOL: MPOD = 1.0: 1.9: 1.3: 1.0. Antenna (Figs 83, 85) with scape yellowish and fl1 and fl2 brownish-yellow under most angles of light, but pedicel and fl3–clava darker brown; scape slender, about 5.3× 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(10), 10(8), 19(9), 19(10), 18(13), 15(14), 15(15), 14(16), 15(17), 44(20)]. Labiomaxillary complex and mandibles same color as head.
Mesosoma (Figs 84, 85) yellowish-orange to brown, with scutellum and particularly acropleuron darkest brown except pronotal collar dark posterolaterally anterior to spiracle. Pronotum (Fig. 86) completely sclerotized; collar finely meshlike coriaceous with scattered dark setae. Mesoscutum (Fig. 86) smooth and shiny; with anterior margin abruptly reflexed as strongly transverse band between posterior margin of pronotum and lateral lobes, the lateral lobes carinately margined dorsolongitudinally but lowly convex relative to comparatively broad and shallowly concave median region; with 2 setae on inclined inner surface of lateral lobe laterally within about posterior half and two-thirds, respectively (setae absent but setal pores evident) and with 4 setae on outer surface within anterior half (Fig. 86: arrows), the anterior-most seta very short. Scutellar-axillar complex (Fig. 87) with scutellum elongate-oval and uniformly convex, quite highly convex above plane of and only slightly longer than but conspicuously larger than axillae, with frenum meshlike coriaceous and bare, and anterior to frenum coriaceous to coriaceous-imbricate with dark setae laterally; axillae elongate-slender, more finely sculptured than scutellum but with two parallel carinae dorsolongitudinally between anterior margin and base of scutellum, with dark setae on outer surface, and anterior to scutellum separated by deep, longer than wide depression. Fore wing (Fig. 87) extending flat over mesosoma to level about equal with middle of propodeum; disc only about 2.4× as long as greatest width, slightly brownish, smooth, and bare except for marginal fringe of 3 setae apically and 1 seta slightly beyond middle of broad submarginal vein that differentiates bare costal cell extending most of disc length, but membrane angulate apically beyond vein. Mesopleurosternum with mesopectus meshlike reticulate anterior to acropleural sulcus below prepectus and more finely coriaceous posteroventrally, and with long white setae posteroventrally and in line along acropleural sulcus anteriorly; acropleuron (Fig. 88) broadly curved posteriorly to level of anterior margin of mesocoxa, meshlike coriaceous to coriaceous-imbricate anteriorly but mostly smooth and shiny. Metanotum (Fig. 87) with dorsellum vertically raised over apex of scutellum, shiny with only obscure longitudinal carinae. Metapleuron (Fig. 88) entirely setose with long, comparatively dense white setae; anterior margin at about midheight curved slightly over posterodorsal margin of acropleuron as slender, bare flange, 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. Remaining legs (Fig. 85) similar in color as mesosoma, though somewhat more yellowish, particularly compared to acropleuron; mesotibial pegs not visible; metacoxa with two separate bands of white setae, one ventrolaterally and one dorsolongitudinally. Propodeum (Fig. 87) long, medial length almost 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 delimiting slightly concave median plical region from slightly higher lateral callar regions, the paramedial ridge reflexed slightly toward median anteriorly; plical region with entire, somewhat sinuous 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 with longitudinal carina midway between lateral margin of spiracle and lateral margin of callus differentiating slender, setose region with long white setae in line lateral to spiracle and with more numerous setae posteriorly in region between metapleuron and propodeal foramen.
Metasoma with petiole transverse-quadrangular (Fig. 87). Gaster (Figs 84, 85) more or less uniformly meshlike coriaceous, but syntergum very finely so, and with sparse, inconspicuous dark setae dorsolaterally; syntergum in dorsal view (Fig. 84) with posterior margin transverse; supra-anal plate (Fig. 89) yellowish; ovipositor sheaths yellowish, projecting only slightly beyond syntergum.
MALE. Unknown.
Distribution. AFROTROPICAL: Democratic Republic of the Congo.
Hosts. Unknown.
Remarks. Putative relationships and differentiation of M. micropterus from M. reticulatus, M. speculum and M. distigma are discussed under the latter species. Females most closely resemble those of M. speculum because of a similarly colored and mostly smooth and shiny body, and the basal two flagellomeres under at least some angles of light being slightly lighter in color than the remainder of the flagellum. The most conspicuous difference between the two is that the fore wings extend to the base of the gaster in M. speculum (Fig. 119), but only to about mid-length of the propodeum in M. micropterus (Fig. 87). However, females also have a different scrobal depression structure, the scrobal depression in M. micropterus being quite shallow and high Π-like (Fig. 83) similar to M. reticulatus (Fig. 98), whereas in M. speculum it is distinctly concave and transversely Π-like (Fig. 115) similar to M. distigma (Fig. 31). Furthermore, the holotype of M. micropterus has two setae dorsally on the mesoscutum (Fig. 86: arrows) and only 1 submarginal seta visible on the single remaining fore wing, whereas the holotype of M. speculum has only one seta dorsally on the mesoscutum (Fig. 118: arrow) but five setae (four setae remaining plus one setal pore) visible in a line along the submarginal vein of the left fore wing. It remains to be proven with additional specimens whether these setal patterns are variable in either species.
description: Published as part of 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, pp. 1-65 in Zootaxa 4255 (1) on pages 40-41, DOI: 10.5281/zenodo.556479