Merostenus (Merostenus) congoensis 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 congoensis

description: M. (Merostenus) congoensis n. sp.
Figs 22–30
Type material. Holotype ♀ (HNHM). [Democratic Republic of the Congo] “149 [blue label] / Kindamba, Meya, settl. | Louolo river | 10.XII.1963 | leg. BALOGH / ZICSI | Congo-Exped. d. Inst. | Syst. Zool. Budapest | 16.X.63. – 21-I.64. | Fundort No.: 149 / HOLOTYPE ♀ | M. (Merostenus) | congoensis | Gibson”. Glued on rectangular card by venter, with glue concealing some structures; entire except clava of left antenna and apical three tarsomeres of left front leg missing, and right leg beyond coxa detached and glued separately to card; uncontorted.
Etymology. Based on the type locality.
Description. FEMALE (habitus: Fig. 22). Length = 2.1 mm. Head (Fig. 23) mostly brown but under some angles of light with some violaceous to purple lusters on frons and scrobal depression lighter, orangish-brown; in frontal view subquadrate, approximately 1.2× as wide as high (lower face in glue), but in lateral view only about 1.3× as high as long with highly convex frontal surface; smooth and shiny except vertex very finely and inconspicuously meshlike coriaceous and likely lower face finely sculptured (not clearly visible); scrobal depression, dorsal surface of interantennal prominence above level of toruli, and frontovertex bare except for line of dark setae along inner orbit (ventrally where scrobal depression touches lower inner orbit to upper inner orbit behind ocelli) and transversely on vertex posteriorly, but lower face uniformly setose with short white setae; scrobal depression quite strongly inclined above dorsal surface of interantennal prominence and transversely Πshaped between inner orbits, the lateral margin directed obliquely from torulus to lower inner orbit where slightly undulate, and broadly convex dorsal margin separated from anterior margin by about 3× LOL; ratio of OOL: POL: LOL: MPOD = 1.4: 2.0: 1.1: 1.0. Antenna (Figs 22, 24) with scape yellow apically to brownish-yellow basally, pedicel to fl2 brown to yellowish-brown depending on angle of light, fl3 and fl4 white, fl5 varying in color from whitish or at least paler basally to yellowish-brown to dark brown apically, and fl6 to clava dark brown; scape slender, about 6× as long as apical width but broadest within basal half such that only about 4.2× as long as greatest width; flagellum clavate with fl1 about as long as wide, subsequent funiculars all longer than wide with fl2 longest and funiculars decreasing in length apically [length(width) of pedicel–fl8 (left antenna) and clava (right antenna) = 16(9), 7(7), 25(8), 21(10), 19(11), 18(11), 17(11), 16(11), 15(12), 37(15)]. Color of labiomaxillary complex and mandibles hidden by glue.
Mesosoma (Fig. 25) mostly brown but scutellar-axillar complex (Fig. 28), and under some angles of light mesoscutum, lighter, more orangish-brown. Pronotum divided mediolongitudinally (Fig. 26); collar shiny, virtually smooth and with line of setae along lateral margin, the dorsal surface otherwise bare but with 3 or 4 setal pores visible on either side indicating dorsal setae abraded. Mesoscutum (Fig. 26) with lateral lobes strongly angulate from midline, ^-like, carinately margined dorsolongitudinally, with angulations connected anteriorly by slightly curved, transverse carina differentiating shallowly concave, transverse region along anterior margin of mesoscutum; shiny and almost smooth but very finely meshlike coriaceous under indirect light, with 3(?) setal pores in row along inner inclined surface and line of setae along outer inclined surface. Scutellar-axillar complex (Figs 25, 26, 28) with scutellum and axillae bare and similarly longitudinally strigose except for smooth frenum; scutellum elongate-oval, similarly lowly convex as, but obviously longer and larger than axillae, and extending almost to transscutal articulation; axillae anterior to scutellum separated by only tiny depression between strigose sculpture. Fore wing (Fig. 28) extending flat over mesosoma to base of gaster; disc elongate-slender, about 3.4× as long as greatest width, slightly brownish basally and apically but more hyaline subapically, smooth, and with setose submarginal vein extending almost three-quarters length to differentiate bare costal cell and subequally broad part of wing, but continued distally within apically tapered part of wing as narrower vein to slightly curved, acutely angled apex, with 1 somewhat longer seta basally and 2 setae apically on vein plus setae on membrane and along posterior margin of apically narrowed portion. Mesopleurosternum with mesopectus mostly concealed by glue; acropleuron slightly angulate posteriorly near ventral margin of metapleuron (Fig. 25), meshlike coriaceous anteriorly but mostly longitudinally coriaceous-alutaceous. Metanotum with dorsellum vertically raised over apex of scutellum, smooth and shiny (Figs 25, 28). Metapleuron (Fig. 25) bare, meshlike coriaceous to coriaceousimbricate; anterior margin straight and reflexed into slender but distinct smooth band behind posterodorsal margin of acropleuron, and curved along ventral margin as flange above metacoxa to segregate small ventral region between acropleuron and anteroventral margin of metacoxa, the ventral region obscured by glue but apparently bare or only sparsely setose. Legs (Fig. 22) with coxae and femora brown but tibiae and tarsi yellow (Figs 22, 27); mesotibia with 4 apical pegs (Fig. 27); metacoxa with single white seta dorsobasally, a couple of long white setae dorsoapically, and with white setae on outer surface basally continued in a line ventrolaterally along length. Propodeum (Fig. 28) long, medial length about 0.4× distance between transscutal articulation and posterior margin of dorsellum; posterior margin shallowly, broadly incurved, and anterior margin broadly V-like behind dorsellum; carinate margin of foramen reflexed anteriorly near midline to differentiate small, triangular region posteromedially behind high median carina formed by strongly inclined part of plical region, the inclined surface obliquely strigose but meshlike coriaceous mesal to spiracle; callus lowly convex anteriorly to flat posteriorly, apparently once with line of long white setae along lateral margin (?) though most setae now missing, and with spiracle only narrowly separated from lateral margin by distance obviously less than own diameter.
Metasoma with petiole transverse-quadrangular (Fig. 28). Gaster (Fig. 29) with Gt1 comparatively lightbrownish and almost smooth, Gt2 hyaline, and subsequent tergites dark brown and comparatively distinctly meshlike coriaceous, the basal tergites setose only laterally but more apical tergites also with transverse line of setae dorsally; syntergum in dorsal view shallowly incurved (Fig. 29) and in posterior view (Fig. 30) with strongly transverse supra-anal plate under apical margin of syntergum and larger subanal plate faced ventrally; ovipositor sheaths somewhat lighter yellowish-brown than gaster apically, rigid and short, extending beyond syntergum by almost 0.2× length of gaster excluding sheaths.
MALE. Unknown.
Distribution. AFROTROPICAL: Democratic Republic of the Congo.
Hosts. Unknown.
Remarks. Females of this non- excavatus group species are most readily differentiated from other brachypterous Merostenus by flagellar color pattern, with at least fl3 and fl4 being white (Fig. 24). Color of fl5 indicates this flagellomere likely is variably extensively white to dark. Females also differ from other brachypterous Merostenus by their lowly convex and longitudinally strigose scutellar-axillar complex (Figs 26, 28). However, they share a modified mesoscutal structure with females of all excavatus -group species except possibly M. mexicanus (exact structure uncertain for M. mexicanus, see description). However, in M. congoensis the upcurved anterior part of the mesoscutum is uniquely differentiated posteriorly by a transverse carina that extends between the two dorsolongitudinally carinate lateral lobes (Fig. 26). When the mesonotum is arched the pronotum likely is pulled over the reflexed portion of the mesoscutum, and the transverse carina likely limits the extent to which this is possible. Females of M. congoensis also share entirely dorsolongitudinally carinate mesoscutal lateral lobes with four excavatus -group species, M. excavatus (Fig. 41), M. micropterus (Fig. 86), M. platyscapus (Fig. 93) and M. speculum (Fig. 118), which in the last two species are less highly angulate than in the first two species. Their short and rigid ovipositor sheaths are associated with an only slightly incurved posterior margin of the syntergum (Fig. 29).
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 23-25, DOI: 10.5281/zenodo.556479