Merostenus (Merostenus) reticulatus 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 reticulatus

description: M. (Merostenus) reticulatus n. sp.
Figs 98–114
Type material. Holotype ♀ (NMK). “ KENYA, Coast Prov. | Taita Hills, Vuria | Forest, 3.41428°S, | 38.29178°E, 2162m / Malaise trap, just | inside indigenous | forest, 13–27 MAY | 2012, R. Copeland / HOLOTYPE ♀ | M. (Merostenus) | reticulatus | Gibson ”. Point-mounted by meso- and metacoxae and base of gaster; entire; uncontorted.
Allotype ♂. Same data as holotype (NMK).
Etymology. The Latin word reticulatus (netlike), in reference to the generally reticulate body sculpture of females.
Description. FEMALE (habitus: Figs 99, 101). Length = 3.6 mm. Head (Fig. 98) orangish-brown or frontovertex somewhat darker brown depending on angle of light; in frontal view subquadrate, about 1.1× as wide as high, and in lateral view lenticular, about 1.8× as high as long with anterior surface slightly, uniformly curved; face mostly meshlike reticulate, but more punctate-reticulate within scrobal depression and lower parascrobal region above toruli transversely reticulate-strigose in part; entirely setose except for bare scrobal depression, with conspicuous dark setae on frons separated by distance less than anterior ocellar diameter; scrobal depression shallow, comparatively obscurely differentiated, but Π-shaped above interantennal prominence, about as high as wide and extending at most half distance to anterior ocellus; ratio of OOL: POL: LOL: MPOD = 1.2: 2.8: 1.5: 1.0. Antenna (Fig. 101) dark except scape orangish-yellow; scape slender, about 6.2× greatest width, and slightly curved; flagellum clavate with fl1 slightly 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 = 21(10), 11(10), 26(10), 25(12), 24(14): 20(16), 16(17), 15(18), 42(21)]. Labiomaxillary complex and mandibles same color as head.
Mesosoma (Figs 99, 101) orangish to orangish-brown except pronotal collar dark posterolaterally anterior to spiracle. Pronotum completely sclerotized, though collar posteriorly with short mediolongitudinal sulcus (Fig. 100: arrow); collar coriaceous-alutaceous dorsally to slightly imbricate posterolaterally and with dark setae obviously longer than distance between setae. Mesoscutum (Fig. 100) with distinct, somewhat roughened, coriaceousreticulate sculpture; with anterior margin only slightly reflexed behind pronotum and with comparatively lowly convex lateral lobes relative to broad and shallowly concave median region, the lateral lobes dorsolongitudinally carinate only within posterior half; dorsally with comparatively long and similarly dense dark setae as pronotum and with line of similar setae along outer inclined surface of lateral lobe. Scutellar-axillar complex (Fig. 103) 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 more coarsely meshlike reticulate to reticulate-imbricate with conspicuous dark setae laterally; axillae elongate-slender, more finely sculptured than scutellum but with two short carinae dorsomedially adjacent to scutellum, with dark setae on outer surface, and anterior to base of scutellum separated by deep, slightly longer than wide depression. Fore wing (Fig. 103) extending flat over mesosoma to base of gaster; disc elongate-slender, almost 5× greatest width, about basal three-quarters brown but hyaline apically and slightly, transversely wrinkled basally, but bare except for line of setae along broader, more distinctly melanized submarginal vein that differentiates bare costal cell extending about two-thirds length of disc, and with 2 or 3 setae apically on less distinct, narrower vein (presumptive marginal vein) extending to apex of leading margin of wing apex, with membrane angulate apically beyond venation. Mesopleurosternum with mesopectus meshlike reticulate anterior to acropleural sulcus below prepectus and more finely coriaceous posteroventrally, with long white setae posteroventrally and linearly along acropleural sulcus anteriorly; acropleuron (Fig. 102) broadly curved posteriorly to level of anterior margin of mesocoxa, meshlike coriaceous-imbricate anteriorly, longitudinally striate medially, and meshlike coriaceousreticulate posteriorly, the posterior meshlike sculpture only slightly raised in part. Metanotum (Fig. 103) with dorsellum vertically raised over apex of scutellum, with anteriorly diverging longitudinal carinae. Metapleuron (Fig. 102) setose with long, comparatively dense white setae; anterior margin linearly bare, straight and abutting posterodorsal margin of acropleuron along about dorsal two-thirds, 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 (Figs 99, 101) same color as mesosoma; mesotibia (right) with row of 5 apical pegs (Fig. 99: insert); metacoxa with two separate bands of white setae, one ventrolaterally and one dorsolongitudinally. Propodeum (Fig. 103) long, medial length almost two-thirds 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 at about level of lateral margin of dorsellum 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 finely but distinctly coriaceous-reticulate; callus mostly concealed by wings but apparently similarly sculptured as plical region and with spiracle separated from lateral margin by distance greater than own width, with posteriorly widened band of long white setae along lateral margin.
Metasoma with petiole transverse, smooth and shiny. Gaster (Figs 101, 104) with Gt1 orangish, bare, shiny and smooth dorsobasally but very finely meshlike coriaceous to more longitudinally sculptured apically; Gt2 similar in color to Gt1 but hyaline so dark color of Gt3 shows through and appearing more distinctly coriaceous-reticulate than Gt1 (possibly because sculpture of Gt3 shows through), with transverse line of setae basally; Gt3–Gt6 dark with metallic bluish luster under most angles of light, distinctly meshlike reticulate and with similar setae as for Gt2; syntergum similar in color to preceding tergites but meshlike coriaceous, with posterior margin in dorsal view slightly outcurved; supra-anal plate (Fig. 105) yellowish-brown to brown depending on angle of light; ovipositor sheaths mostly brown but lighter apically. Ovipositor sheaths brown, projecting only slightly beyond supra-anal plate.
MALE (habitus: Figs 106, 107). Length = 3.2 mm. Head (Figs 108, 109) dark with slight bluish-green to bluish lusters under some angles of light, most conspicuously on frontovertex (Fig. 109); interantennal region and scrobal depression except narrowly above each torulus distinctly meshlike reticulate, but lower face meshlike coriaceous to coriaceous-imbricate, and frontovertex more finely meshlike coriaceous to very shallowly coriaceous-reticulate, most distinctly along inner orbits and on vertex, and with oblique sulcus extending between lateral ocellus and upper inner orbit (Fig. 109); with comparatively long and conspicuous brown setae, the setae on frons originating from tiny pin-prick like punctures; scrobal depression shallow with indistinct margins, the reticulation laterally extending over slightly convex, setose parascrobal region between torulus and inner orbit, and without evident pit above interantennal prominence; OOL: POL: LOL: MPOD = 0.8: 1.6: 0.7: 1.0; frontovertex 0.58× head width. Antenna (Fig. 110) with scape yellow except for dark brown setae dorsally and on inner surface, flagellum dark brown, and pedicel slightly paler brown than flagellum; scape compressed-tubular with subparallel dorsal and ventral margins, about 3.9× as long as wide; combined length of pedicel + flagellum about 3.2× as head width; fl1 strongly transverse, anelliform; f2–clava each with short pedicel basally (pedicels becoming more distinct apically), with semierect, apically slightly curved setae longer than width of flagellomere, and with obscure, very sparse mps apically; fl2–fl8 all much longer than wide, elongate-tubular, and clava with clavomeres separated by distinct sutures [length(medial width) of pedicel and flagellomeres excluding pedicels = 18(12), 2(8), 58(8), 50(8), 44(8), 41(8), 37(8), 34(8), 31(7), 70(8)]. Eye (Fig. 108) very sparsely and inconspicuously setose with very short setae; EH: EL: MS = 53: 44: 37. Labiomaxillary complex yellowish.
Mesosoma (Figs 106, 107) dark with obscure metallic lusters under some angles of light similar to head, except propodeum lighter brown medially and posterolaterally above metacoxa. Pronotum with collar covered by head, but at least extensively setose with dark setae. Mesonotum (Fig. 112) with mesoscutal medial lobe variably meshlike reticulate, with mediolongitudinal band of comparatively small reticulations extending much of length, obviously larger reticulations paramedially, smaller, more punctate-reticulate sculpture anterolaterally in posteriorly tapered region, and more effaced meshlike sculpture posteriorly near transscutal articulation, but with dark setae similar to head; lateral lobe with more minutely sculptured, bare parapsidal band, but otherwise similarly setose as medial lobe, with dorsal part mesal to parapsidal band finely meshlike coriaceous and lateral of parapsidal band more strongly coriaceous-reticulate with some setiferous punctures; scutellar-axillar complex with axillae and scutellum laterally anterior to frenum similarly setose as mesoscutum, and frenum with single seta laterally on either side, with axillae meshlike coriaceous, scutellum mostly coriaceous but slightly coriaceous-imbricate laterally and coriaceous-reticulate dorsomedially, and frenum finely coriaceous-reticulate. Fore wing (Fig. 113) with slight but distinct brownish infuscation, most conspicuously basally on disc and along mediocubital fold; length about 2.9× as long as maximum width and length of marginal vein equal to wing width; cc: mv: stv: pmv = 3.8: 3.9: 1.0: 2.0; stigmal vein variably developed between wings but extending at least for distance about equal with distance between stv and pmv; costal cell dorsally with line of setae along about apical half of leading margin and ventrally setose along length; disc entirely and uniformly as setose as basal cell. Metapleuron (Fig. 111) setose with long white setae in ventral half and distinctly though finely meshlike reticulate; extending dorsally as very slender angle to near level of anterior margin of propodeum conspicuously anterior to level of propodeal spiracle, and abutting posterior margin of acropleuron over most of height, but posterodorsal margin of acropleuron slightly separated from and lying above dorsal-most slender region. Propodeum (Fig. 114) with median length about 0.6× distance between transscutal articulation and posterior margin of dorsellum; with comparatively high median carina and transverse, crenulate furrow along anterior margin lateral of dorsellum, but otherwise plical region mostly meshlike coriaceous except more coriaceous-reticulate to transversely strigose along median carina and callus more distinctly reticulate, particularly posteriorly; callus with transverse line of white setae anterior of spiracle to about mid-way between spiracle and median carina, and with similar setae lateral of spiracle posteriorly to recurved margin over metacoxa, with spiracle conspicuously closer to anterior than posterior margin. Legs (Figs 106, 107), including coxae, mostly yellowish but tarsi and meso- and metatibiae extensively darker brown; metacoxa bare except for band of white setae ventrolaterally and dorsolongitudinally.
Metasoma with petiole yellow, longer than wide with sides divergent over about basal half and subparallel over about apical half, and smooth and shiny except for median carina (Fig. 114). Gaster mostly dark but Gt2 dorsally narrowly yellow apically, and Gt1–Gt4 yellow laterally and ventrally (Fig. 114); Gt1 and Gt2 compressed (Fig. 106), smooth, shiny, and bare except laterally, but subsequent tergites finely coriaceous and more extensively setose.
Distribution. AFROTROPICAL: Kenya.
Hosts. Unknown.
Remarks. Putative relationships and differentiation of females of M. reticulatus from those of M. speculum, M. micropterus and M. distigma are discussed under the latter species. The unique male has the gaster compressed basally (Fig. 106), which was described for males of three of five species of R. (Hirticauda) described by Fusu (2013). As discussed within the section on generic limits and relationships, this does not appear to be an artefact of preservation.
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 45-49, DOI: 10.5281/zenodo.556479