Georynus, 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 : 163-165

Genus GEORYNUS gen.nov.

Type species: Georynus aitne sp.nov. Gender masculine.

Female. Overall length about 1.7-1.8mm.

Body generally dark brown to black with a metallic sheen; maxillary palpus off-white; antenna pale orange with clava orange-brown to brown; tegula dark brown; mesoscutum and scutellum contrasting in colour with scutellum more metallic; all coxae white, remainder of legs pale white to orange; fore wing hyaline or weakly infuscate below marginal vein, venation pale orange; gonostylus at leat partly pale orange.

Head about 8X as wide as frontovertex, in profile about 1.6X as high as deep, anteriorly quite evenly and strongly curved from occipital margin to top of scrobes, more strongly curved at top of scrobes and from there quite straight to mouth margin, with interantennal prominence hardly protuberant; occipital margin rounded; frontovertex narrowest about midway between anterior ocellus and top of scrobes, shiny, mainly with shallow, fairly fine, polygonally reticulate sculpture of mesh size generally less than diameter eye facet; piliferous punctures on frontovertex shallow; eye slightly overreaching occipital margin, with very conspicuous pale setae, each much longer than diameter of facet; scrobes very shallow, narrowly ∩-shaped, meeting dorsally, with shallow sculpture, weakly margined dorsally and laterally; interantennal prominence distinct, clearly reaching past toruli, dorsally acute; antenna with scape hardly broadened about 4-5X as long as broad; funicle segments varying from all slightly longer than broad to some distinctly transverse, becoming slightly wider distad; linear sensilla absent on proximal funicle segments; clava slightly wider than F6, shorter than funicle, three segmented, apex strongly obliquely truncate; malar sulcus absent; clypeal margin weakly concave; mandible with 3 acute teeth, without a ventral peg; palp formula 4-3.

Thorax with pronotum short, but visible behind head and with imbricate-reticulate to polygonally reticulate sculpture that is about as deep as that on frontovertex below anterior ocellus; notaular lines absent; mesoscutum with polygonally reticulate sculpture that is about as deep as that on pronotum; axilla with polygonally reticulate sculpture that is conspicuously finer and deeper than that on mesoscutum; scutellum dorsally weakly convex and with regular, fine, punctate-reticulate, honeycomb-like sculpture that is much finer and deeper than that on mesoscutum or axillae, apex and side almost vertical and completely smooth and shiny; scutellum apex, in dorsal view, broadly rounded; mid tibial spur slightly shorter than basitarsus; fore wing about 2.4-2.5X as long as broad, with linea calva entire; basal cell fairly evenly setose; costal cell with a line of setae dorsally in apical half and 1 or 2 lines of setae ventrally in apical half or so; submarginal vein with parastigma hardly swollen, with a very weak triangular expansion, not downcurved; marginal vein at least about 4X as long as broad, hardly longer than postmarginal vein, stigmal vein longer than postmarginal vein; uncus of stigmal vein with 3 campaniform sensilla arranged in almost a straight; posterior margin of mesopleuron reaching level with posterior margin of propodeum; propodeum medially about 0.16X as long as scutellum, with some shallow, irregular sculpture medially; about 4-8 setae anterior to and outside spiracle.

Gaster about as long as head and thorax combined; Gt2 with a conspicuous, subspherical, gland-like structure anterolaterally, of about the same diameter as width of cercal plate, in addition to an area of strong reticulate sculpture (clearly visible on slide-mounted material); syntergum at least about as long as mid tibia, its apex acute; hypopygium reaching about 0.5X along gaster, about 2X as broad as long, anteriorly biconcave, with distinct median and anterolateral projections, posteriorly moderately biconvex with a moderate median invagination that is at least 0.2X as deep as hypopygium length; ovipositor 1.5X as long as mid tibia, slightly exserted with exserted part at least about half as long as mid tibial spur; second valvifer without subapical setae; gonostylus freely articulated with second valvifer, about 0.25-0.35X as long as ovipositor and up to about 2.5X as long as mid tibial spur.

Male. Unknown.

DISRIBUTION. Costa Rica.

HOSTS. Unknown.

COMMENTS. The habitus of species of Georynus is very similar to those of Mahencyrtus Masi and the two species described below were initially included in the latter genus as aberrant species. However, the presence of the unusual, spherical gland-like structures anterolaterally on the second gastral tergite immediately separates Georynus from Mahencyrtus . Georynus also differs from Mahencyrtus in the scutellum having a broadly rounded apex, fine punctate sculpture and very smooth and shiny vertical sides as well as a very weakly expanded parastigma and hyaline fore wings. In Mahencyrtus the scutellum is shield-shaped and has coarse longitudinally elongate polygonally reticulate sculpture, the sides are rounded and generally shiny but with shallow sculpture and the fore wing has a conspicuously swollen parastigma and usually has a median infuscate streak in its apical half.

Georynus may be close to Casus Noyes & Woolley. Species of both genera have a sharply tridentate mandible, the clava with an oblique apical truncation, similar wing venation with a long marginal vein and only three campaniform sensilla at the apex of the stigmal vein, an acutely angled apex of the syntergum, similarly structured ovipositor and similar hypopygium. However in Casus the scutellum has shallow, longitudinally elongate imbricate-reticulate sculpture, the mesopleuron clearly does not reach level with the posterior margin of the propodeum, the propodeal spiracle is separated from the anterior margin of propodeum by at least 2X its own diameter and there are no spherical gland-like structures on the second gastral tergite. In Georynus the scutellum has deep, regular, polygonally reticulate (honeycomb-like) sculpture, the mesopleuron reaches level with the posterior margin of the propodeum and the propodeal spiracle is separated from the anterior margin of the propodeum by at most its own diameter.

It is possible that Georynus is related to two species currently placed in combination with Tyndarichus Howard (clavicornis Cameron and orarius Annecke & Mynhardt) and which appear to uniquely share these round, gland-like structures. It is very likely that these two species are misplaced in Tyndarichus . However, Georynus can be distinguished from clavicornis and orarius (and other species currently placed in Tyndarichus , but which lack these structures) by the lack of a strong triangular expansion of the parastigma, marginal vein at least 4X as long as broad and the scutellum having fine, punctate-reticulate sculpture with the sides and apex near vertical and completely smooth and shiny. In Tyndarichus the parastigma has a very strong, triangular expansion, the marginal vein is not more than 3X as long as broad and the scutellum is evenly convex, usually with relatively shallow sculpture.

It seems likely that Georynus and Mahencyrtus belong to the tribe Cheiloneurini (mainly associated with Hemiptera ) and Tyndarichus (s.s.) belongs to the Bothriothoracini, subtribe Syrphophagina (mainly associated with Holometabola). The phylogenetic relationships of the scale insect parasitoids, previously placed in Parechthrodryinus Girault , and now included in Tyndarichus (see Hayat, 2012) need to be reassessed using a holistic approach.

See also comments under Strigenia (p. 172).