Raquanus, Noyes, 2023

Noyes, John Stuart, 2023, ENCYRTIDAE OF COSTA RICA (HYMENOPTERA: CHALCIDOIDEA), 4 Subfamily Encyrtinae: tribes Arrhenophagini, Habrolepidini, Cerapterocerini, Cheiloneurini, Trechnitini, Cercobelini, Polaszekiini, Protyndarichoidini, Gahaniellini and Syrphophagini (part), mainly primary parasitoids and hyperparasitoids of Coccoidea and Psylloidea (Hemiptera), Taxonomic Monographs on Neotropical Hymenoptera (Oxford, England) 2 (11), pp. 1-921 : 671-672

Genus RAQUANUS gen.nov.

Type species: Raquanus hades sp.nov. Gender masculine.

Female. Length about 1.2-1.4mm.

Body robust, generally dark with a weak to moderate metallic sheen; funicle with unicolourous pale segments; dorsum of thorax with dark setae; legs generally dark with pale areas; wings hyaline, sometimes with a small infuscate area below marginal and stigmal veins; propodeum dark with a weak metallic sheen, side more strongly metallic, some silvery setae near spiracle; gaster dark with a metallic sheen.

Head in profile about 1.7X as high as deep, anteriorly fairly evenly curved from occipital margin to top of scrobes, more strongly curved at top of scrobes and virtually straight to mouth margin, interantennal prominence hardly protuberant; occipital margin carinate; frontovertex about one-third head width and with irregular, polygonally reticulate sculpture and sparse, shallow piliferous punctures; ocelli forming an acute to a slightly obtuse angle; temple and gena with conspicuous, longitudinally elongate, polygonally reticulate sculpture; eye nearly reaching occipital margin, with fairly conspicuous setae; scrobes shallow, ∩ -shaped; antenna attached well below lower eye margin, much closer to mouth margin; scape broadened and flattened, a little less than 3X as long as broad, about 0.4X as long as head width; funicle segments transverse, broader towards apex, linear sensilla only on distal segments; clava shorter than funicle, 3-segmented, sutures subparallel, sensory area slightly enlarged and extending a little way along ventral surface, giving apex of clava a slight, obliquely truncate appearance; malar sulcus absent; mouth about 0.4X head width, clypeal margin convex, very slightly produced medially; mandible with two teeth and a broadly truncate upper tooth; palp formula 4-3.

Thorax with pronotum short; mesoscutum without notaular lines; scutellum convex, with deeper sculpture than mesoscutum, extreme apex and side completely smooth and shiny; mid tibia without a minute elongate invagination on its external surface about mid-way along its length, spur slightly longer than basitarsus; fore wing fully developed; about 2.4X as long as broad; costal cell with only 1 line of setae ventrally and a line of setae dorsally in apical half or so; submarginal vein with an apical hyaline break; marginal vein about 3X as long as broad, subequal stigmal vein and about 1.5X as long as postmarginal vein; linea calva open; filum spinosum present, consisting of 1-2 lines consisting of a total of about 4-7 peg-like setae; posterior margin of mesopleuron not reaching level with posterior margin of propodeum, falling short by distance equivalent to about half to two-thirds diameter of propodeal spiracle; propodeum short, with some shallow, irregular sculpture posteriorly, side rounded above hind coxa, with a minute posterolateral tooth behind spiracle; about 20 setae near spiracle, not extending part way towards hind coxa.

Gaster with hypopygium not reaching more than about 0.8X to apex; paratergites absent; syntergum shorter than mid tibia, apex weakly angular; ovipositor not exserted, shorter than mid tibia, outer plates narrow, elongate and subtriangular; second valvifer without a subapical seta, proximally knob-like with posterior semicircular sheet virtually absent, outer posterior margin short and almost straight; hypopygium transverse with posterior margin almost semicircular and anterior margin virtually straight with a pair of short anterolateral lobes.

Male. Length about 0.9mm.

Very similar to female but for wider frontovertex, filiform antenna with unsegmented clava and genitalia.

DISTRIBUTION. Known only from Costa Rica, but probably more widespread in the Neotropics.

HOSTS. Unknown.

COMMENTS. The strongly reduced semicircular sheet of the proximal part of the second valvifer (see comments under Polaszekius ) of the female suggest that Raquanus may be closest to Polaszekius . However, Raquanus has a tridentate mandible with the upper tooth truncate, palp formula 4-3, lacks an elongate invagination on the external surface of the mid tibia, has the ovipositor hidden and the hypopygium is transverse and more or less semicircular. In Polaszekius the mandible basically has only one tooth and a broad truncation, the palp formula is 3-3, the mid tibia has a minute, elongate invagination on its external surface, the ovipositor is strongly exserted and the hypopygium is elongate and subtriangular with a trident-like posterior margin. The combination of the obliquely truncate clava, mandibular structure, scutellum with deep sculpture and elongate marginal vein suggest that Raquanus may be close Alkonia and other genera (e.g. Hebynthus , Alkonia , Mendisa , Caldencyrtus , etc., see comments under Alkonia , p. 708). It can be distinguished from these genera by having the truncation of the clava not extending as much as one-third along the ventral surface of the clava, having the funicle unicolourous with all segments transverse and the hypopygium bowl-shaped with a weakly concave anterior margin and evenly convex posterior margin.