Pristonesia nyamuragira ( Benoit, 1957 )

Azevedo, Celso O. & Colombo, Wesley D., 2022, Revision of Pristonesia (Hymenoptera, Bethylidae, Pristocerinae), an endemic Afrotropical genus, Zootaxa 5124 (3), pp. 321-340 : 323-324

Pristonesia nyamuragira ( Benoit, 1957)

Figs 1A–C , 4A–C

Diagnosis. This species differs from the others of the genus by having the posterior hypopygeal margin forming two angulated lobes and the apical set of setae of the aedeagus very dense and long.

Redescription. Male. Body 4.3–4.8 mm long. Forewing 3.5–4.3 mm long. Antenna 1.5–2.0 mm long. Color. Head, mesosoma, and clypeus almost black; antenna castaneous; palpi light castaneous; mandible castaneous with dark castaneous margins; legs castaneous; metasoma dark castaneous; wings hyaline, veins castaneous, pterostigma darker.

Head. Heptagonal, slightly longer than wide. Mandible with five teeth, two ventral most sharpened and large, otherwise rounded and short, progressively increasing in length ventrad. Clypeus with median lobe angulate; median carina complete, high and straight in lateral.Antenna with dense suberect pubescence, longer than half flagellomeral diameter, with some outstanding erect setae on first five flagellomeres; first four antennomeres in a ratio of about 3:1:2:2. Vertex crest mostly straight. Temple evenly little outcurved, progressively divergent anterad. Antennal rim about as long as wide, inter-torular space about 2 × torular diameter. Frons polished, with very few small punctures. Ocellar triangle with frontal angle about right, anterior ocellus fully posterior to supra-ocular line. Occipital carina partially visible on dorsal view.

Mesosoma . Dorsal pronotal area polished, with few irregularly sized large punctures, almost as long as anteromesoscutum, posterior area wider than anterior one, surface slightly depressed anterad, transverse pronotal carina crossing all anterior border, somewhat high and straight; cervical pronotal area vertical, polished. Notauli well impressed, reaching anterior margin of anteromesoscutum and almost reaching posterior one, straight, almost evenly wide, converging posterad. Parapsidal signums well impressed, but missing anteriorly, very poorly S-shaped. Mesoscutum-mesoscutellar sulcus with anterior margin incurved posterad, posterior margin angularly arched anterad medially, very narrower medially. Metascutellum polished, lateral margin angularly incurved, surface transversally sulcate; metascutellar foveae fused forming transverse sulcus, metanotal fovea well-delimited, scalenetriangular; carinae of metanotal trough weak. Metapectal-propodeal disc weakly striate on metapostnotal area, and mostly polished on propodeal area, 1.2–1.3 × as long as wide, surface of posterior area depressed and subvertical, metapostnotal median carina complete, narrow but well-impressed, bifurcated very anteriorly, lateral marginal carina little distinguishable from background texture, transverse posterior carina complete but weak, strongly arched ventrad. Propodeal declivity weakly striate. Lateral surface of metapectal-propodeal complex strigulate on extreme anterior, polished medially, weakly striate posteriorly. Mesopleuron sparsely foveolate on polished background, callus contrastingly smooth, posterior oblique sulcus not delimited. Mesodiscrimen with surface concave, median carina bifurcated anteriorly. Metasternum with somewhat high posterior margin and with median pair of dentiform projection.

Wings and legs. Forewing with poststigmal abscissa of radial 1 about half length of pterostigma, 2r-rs&Rs vein evenly arched, not notched where 2r-rs sector connects to Rs sector; anterior medial and posterior medial 1 flexions lines long, m-cu flexion line straight, cubital flexion line somewhat straight; claval flexion line strong, r-m flexion line very slightly S-shaped, almost straight. Hind wing with two basal hamuli, and four equidistant distal hamuli. Claws bifid, teeth sharp and curved, basal one smaller.

Metasoma. Opening of spiracle of metasomal segment I eye-shaped and subdorsal. Tergum I 2.4 × as long as tergum II. Sternum II ecarinate, but finely longitudinally strigate. Epipygium somewhat wide, but not such an extent to its lateral margins touch each other ventrally, posterior margin straight, without median emargination, not excavated where epipygium folds ventrad. Hypopygium with spiculum short and tip, sharp, anteromedial apodeme absent, anterolateral apodeme short, sharp spine-shaped and somewhat inclined mesad, anterior margin weakly double u-shaped, posterior margin strongly excavated forming two round lobes, excavation about half as long as hypopygeal plate, each lobe without any spine; thick median area of inner surface large and evenly wide.

Genitalia. Harpe with apical margin with two expansions, dorsal one long and conical, much longer than ventral one, its apex sharpened, ventral expansion very short with rounded apex, dorsal margin evenly incurved, wide basally, ventral predominantly straight; inner margin of ventral side of gonostipes with median small sharp median callus, and with few medioapical setae; apical basivolsellar expansion absent; cuspis angled medially, very wide basally, cross-section flat, outer surface convex and smooth, apex somewhat sharpened, without any membranous extension; digitus with cross-section subcylindrical, base strongly angled, otherwise mostly straight, apex dilated and rounded, apex squamate and not membranous; aedeagus cylindrical in dorsal profile, ventral valve membranous, very short, apex wide and aligned with base of basivolsella, apical margin truncate, dorsal valve much longer ventral one, its apical membranous extension longer than wide, cat whisker-shaped set of setae long and somewhat dense; aedeagal apodeme arched mesad, ergot short as stub and sharp; genital ring strongly incurved ventrally.

Material examined. Holotype, ♂, Congo Belge: P. N. A., Nyasheke (Vol. Nyamuragira), 1820 m., 14au 26-vi-1935, G.F. de Witte: 1486 ( MRAC) . Paratypes: 1♂, Congo Belge: P. N. A., Mayumby ( Volc. Nyamuragira ), 2100 m., 14au 26-vi-1935, G.F. de Witte: 1501 ( MRAC) ; 1♂, Congo Belge: P. N. A., Gibete ( Volc. Nyamuragira ), 2324 m., 14au 26-vi-1935, G.F. de Witte: 1514 ( MRAC). New material. Uganda , 1 ♂, Kibale National Park, Kanyawara, Makerere University Biological Field Station , 1495m, 0º33.996’N 30º21.262’E, 29-31.vii.2005, S. van Noort, UG05 - M02, Malaise trap, secondary mid-altitude rainforest ( SAMC) .

Remarks. It was not possible to measure the length of the hypopygeal spiculum because it was not fully preserved during the process of dissection.

Distribution. Democratic Republic of Congo, Uganda.

Figures

FIGURE 1. A–C. Pristonesia nyamuragira Benoit; D–F. Pristonesia oracil sp. nov.; G–I. Pristonesia parcetil sp. nov.. A, D, G. Habitus, lateral view; B, E, H. Head, dorsal view; C, F, I. Mesosoma dorsal view. Scale bars = 100 µm.

FIGURE 4. A–C. Pristonesia nyamuragira Benoit; D–F. Pristonesia oracil sp. nov.; G–I. Pristonesia parcetil sp. nov., J-L. Pristonesia querfil sp. nov.. A, D, G, J. Hypopygium, external view; B, E, H, K. Genitalia, dorsal view; C, F, I, L. Genitalia, ventral view. Black = cupula; dark grey = ventral valvae; light grey = apical membranous bubble. Scale bars = 100 µm.