Cheiloneurus lexovus, 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 : 429-431

Cheiloneurus lexovus sp.nov.

(Figs 1095-1098; Hab. E 159)

DIAGNOSIS. Female (length about 1.1mm): body mostly orange, mesoscutum posteriorly, propodeum laterally and gaster partially brown, darker areas with a weak to moderate metallic sheen; mouth margin dark brown; temple and gena with a dark brown, diagonal stripe; antenna (Fig. 1096) with scape pale orange, proximally and ventral margin brown; pedicel pale orange with a longitudinal dark brown stripe; funicle dusky pale orange mixed dark brown; clava dark brown; mesoscutum with silvery setae in posterior half; fore and hind coxae white, mid coxa pale orange; legs largely white to pale orange a few brown areas on femora and tibiae; fore wing mostly infuscate, basal cell mostly hyaline, a hyaline area at apex of venation, another opposite and apex with a relatively large, subtriangular hyaline area; head (Fig. 1097) about 6.6X as wide as frontovertex, in facial view clearly broader than long, subcircular, genae evenly curved, converging, more strongly curved inwards near mouth; frontovertex with 2 setae medially between anterior ocellus and scrobes; eye separated from scrobe by about 1.2X diameter of anterior ocellus, area between eye and scrobe completely smooth; scrobes moderately deep, not sharply margined, interantennal prominence with about 15 inconspicuous setae, dorsally with a distinct median longitudinal ridge; mandible tridentate; antenna (Fig. 1096) with scape about 3.2X as long as broad; funicle with some segments very slightly longer than broad, remaining segments transverse; clava 3-segmented, slightly shorter than F2-F6 combined; sensory area enlarged, extending ventrally about 0.3X length of clava, apex obliquely truncate; head width about equal to flagellum length; mesoscutum (Fig. 1095) anteriorly with fine, striate to striate-reticulate sculpture, posteriorly with polygonally reticulate sculpture that advances medially into anterior part; scutellum with an distinct, subapical tuft of setae; wings fully developed, fore wing about 2.5X as long as broad; parastigma weakly downcurved; costal cell dorsally with 1 or 2 apical setae, ventrally with a complete line of setae; area below proximal part of parastigma with a line of about 4 or 5 fine setae; apices of postmarginal and stigmal veins connected by a naked hyaline area that extends a little way into disc; apical bristle of postmarginal vein about 0.4X as long as marginal vein; mid tibial spur slightly longer than basitarsus; propodeum with only 2 inconspicuous setae adjacent to spiracle, side naked; syntergum about 0.9X as long as mid tibia with apex acute; ovipositor (Fig. 1098) about 3.3X gonostylus or about 1.5X as long as mid tibia; gonostylus about 1.4X as long as long mid tibial spur; exserted part of ovipositor about 0.6X as long as mid tibial spur. Male: unknown.

Female (holotype): length, including ovipositor, 1.08mm; excluding ovipositor, 1.02mm ( CPD) .

Head pale orange; frontovertex slightly dusky with a slight coppery and metallic dark blue sheen, slightly coppery between posterior ocelli; temple and gena with weak brassy and coppery sheen and a diagonal dark brown stripe from middle of posterior margin of temple to about mid way between lowest eye margin and base of mandible; scrobal area generally with a weak brassy sheen, top and outer margin of scrobe with a weak coppery sheen, lower face with a transverse, narrow, curved, dark brown line above mouth margin originating just outside torulus about midway between torulus and mouth margin and conspicuously curved upwards between lowest margins of toruli; frontovertex with a few very inconspicuous translucent setae; antenna (Fig. 1096) with radicle pale orange, apex narrowly dark brown; scape mostly pale orange, ventral margin very narrowly dark brown for most of its length on outer surface, inner surface more broadly dark brown in proximal one-half; pedicel very pale orange with a dark brown streak laterally along inner surface; F1-F3 mostly very slightly dusky pale orange but inner surface dark brown level with dark brown streak on pedicel, F4 similar but paler, F5 pale orange, F6 dark brown; clava dark brown; palpi pale orange; thorax mostly orange; pronotum with a weak brassy and coppery sheen, neck brown, posterior margin translucent, other areas orange; mesoscutum with anterior one-half orange with dark brown setae, posterior margin narrowly slightly dusky orange, remainder a moderate to strong metallic dark blue and violet band clothed with silvery setae; tegula orange with apex narrowly pale grey-brown with a slight coppery sheen; axilla and scutellum pale orange, matt, scutellum with some dark brown and translucent, golden setae, subapical tuft dark brown; metanotum dusky pale orange with a slight brassy sheen; propleuron mostly orange but with a dark brown spot immediately above fore coxa; mesopleuron with an overall slight brassy sheen, pale orange with posterior one-third dark brown with a moderate coppery sheen; prosternum and mesosternum pale orange; fore coxa white, proximal half of femur white, distal half of femur very pale orange, tibia white at extreme base, remainder pale orange, tarsus pale orange with apical tarsomere dusky; mid coxa very pale orange, slightly dusky ventrally, femur white proximally, otherwise extremely pale orange, tibia mostly very pale orange, with extreme base white and a very faint pale brown subbasal dorsal streak that is connected externally to base of tibia almost forming a Y-shaped mark, spur very pale orange, tarsus very pale orange, pretarsus brown; hind coxa white, femur very slightly dusky very pale orange, brown dorsally towards apex, tibia dark brown at extreme base, otherwise very pale orange, tarsus very pale orange; fore wing similar to that of amethes (Fig. 1139) proximally hyaline to level with base of marginal vein, very weakly infuscate at extreme base, a broadly triangular hyaline area in apical 0.15X, a narrow curved, hyaline, line connecting postmarginal and stigmal veins and extending about 0.27X into wing disc, submarginal vein mostly pale orange otherwise pale brown; propodeum medially pale orange with a weak coppery sheen, area around spiracle brown with a weak pale blue-green sheen mixed with a little purple; dorsum of gaster largely pale orange, TI-TII dark brown with a coppery and metallic dark green sheen, TIII-TV slightly dusky with coppery red, brassy and metallic green reflections, TVI and syntergum mostly pale orange with green and coppery red sheen, apex brown, side and venter of gaster dusky pale orange with brassy, coppery, coppery red and dark green reflections, apex of hypopygium dark brown; gonostylus virtually white.

Head (Fig. 1097) about 6.6X as wide as frontovertex and about 1.4X as high as deep; occipital margin sharp and without a median groove to foramen; ocelli forming an angle of about 35°; frontovertex shiny, with shallow, polygonally reticulate sculpture of mesh size about equal to diameter of eye facet or a little smaller, sculpture much shallower above scrobes; bottoms of scrobes completely smooth, other parts of scrobal area, including interantennal prominence and mouth margin with very shallow sculpture, almost smooth; temple and posterior gena completely smooth adjacent to eye margin but otherwise with shallow, irregular, longitudinally elongate polygonally reticulate sculpture; eye separated from scrobe by about 1.2X diameter of anterior ocellus, area between scrobe and eye completely smooth; scrobes moderately deep, somewhat Ʌ-shaped, not quite meeting dorsally, separated by a carinate ridge extending from dorsal part of interantennal prominence to frontovertex, interantennal prominence with a median longitudinal ridge along most of its length, dorsal margin of scrobe narrowly rounded, lateral margin weakly carinate above level of torulus; antenna as in Fig. 1096; scape conspicuously broadened and flattened, about 3.2X as long as broad; funicle with F1-F4 subequal but F1-F2 and F4 very slightly longer than broad, subquadrate, F3 quadrate, F5-F6 subequal, F5 very slightly longer than broad, F6 quadrate, linear sensilla present only on F5-F6; clava slightly shorter than F2-F6 combined, outer suture oblique, sensory area about 0.6X as long as ventral surface, forming an oblique truncation that extends about 0.3X along clava; eye very slightly overreaching occipital margin, naked; malar sulcus absent; mandible with 2 subequal acute lower teeth and very short, rounded, upper, third tooth. Relative measurements: HW 73, HH 69, FV 11, OD 4, POL 5, OOL 0, OCL 6, AOL 8, EL 53.5, EW 40, MS 34, SL 35, SW 11.

Thorax (Fig. 1095) with fairly regular, coarse, polygonally reticulate sculpture on pronotum that is slightly deeper than that in ocellar area and generally of similar mesh size; sculpture on mesoscutum of similar depth, but mostly fine, longitudinally striate to striate-reticulate in anterior half and regular polygonally reticulate in posterior half with this polygonally reticulate sculpture ending medially, in a narrow triangular area, almost to anterior margin of mesoscutum; sculpture on axilla similar to that on pronotum; scutellum mostly with relatively coarse, slightly deeper, longitudinally elongate, polygonally reticulate sculpture more or less arranged in whorls; visible part of mesoscutum about 2.5X as broad as long; scutellum about as long as broad, subapical tuft distinct, longest setae about 0.5X as long as scutellum; hind femur about 4.2X as long as broad; fore wing with venation and setation similar to that of amethes (Fig. 1139); costal cell without dorsal setae at apex, but with a complete line of setae ventrally; a naked streak connects apices of postmarginal and stigmal veins; propodeum (Fig. 1095) with only 2 setae in spiracular area, medially about 0.1X as long as scutellum and smooth. Relative measurements: FWL 80, FWW 31.5; HWL 65, HWW 16.

Gaster without “gland-like” structures on Gt1 or Gt5; hypopygium reaching about 0.4X to apex; syntergum about 0.9X as long as mid tibia, apex angular, more or less acute; ovipositor (Fig. 1098) exserted, the exserted part about 0.6X as long as mid tibial spur or about 0.2X as long as mid tibia. Relative measurements: OL 39.5, GL 12 [MT 26].

Variation. Only holotype examined.

Male. Unknown.

DISTRIBUTION. Costa Rica.

HOSTS. Unknown.

MATERIAL EXAMINED.

Type material. Holotype E: COSTA RICA, Guanacaste, PN Bosque Diría, 10°10’N 85°34’W, 200m, 14-15.ii.2011 (J.S. Noyes) . Holotype in NHMUK .

COMMENTS. As the key suggests, Cheiloneurus lexovus is close to gyges . Apart from the characters given in the key lexovus differs in having linear sensilla only on F5-F6, fine striate to striate-reticulate sculpture on the anterior part of mesoscutum and the ovipositor about 3.3X as long as the gonostylus. In gyges linear sensilla are present on F4-F6, the anterior part of the mesoscutum has coarse, longitudinally elongate lineolate-reticulate sculpture and the ovipositor is about 3.8-4.0X as long as the gonostylus. Cheiloneurus lexovus may run to fautrix if the posterior brown band on the mesoscutum is considered faint. However, in lexovus the frontovertex is about 0.15X head width, the mid tibia is about two-thirds as long as the ovipositor and hardly more than 2X as long as the gonostylus, whereas in fautrix the frontovertex is about 0.2X head width and the mid tibia is about as long as the ovipositor and more than 3X as long as the gonostylus. Cheiloneurus lexovus is also similar to omorus and might run to this species in the key if the setae on the ventral surface of the costal cell are difficult to see. In lexovus , the temple has a strong, diagonal dark brown mark nearly reaching the base of mandible, F5 is pale orange, contrasting with F6 which is dark brown, the maxillary palpi are pale orange, the hind tibia is very pale orange with some brown at its extreme base, the frontovertex is about 0.15X head width, the clava is slightly shorter than F2-F6 combined, and the exserted part of the ovipositor is about 0.6X as long as the mid tibial spur. Whereas, in omorus the diagonal brown mark on the temple is extremely faint and short, F5 is more or less concolourous with F6, the maxillary palpi are white, the hind tibia is dirty white with an external brown streak and incomplete subbasal brown ring, the frontovertex it is about 0.2X head width, the clava is about as long as the funicle and the exserted part of the ovipositor is about 0.3X as long as the mid tibial spur.