Leptopilina Foerster , 1869

Lue, Chia-Hua, Driskell, Amy C., Leips, Jeff & Buffington, Matthew L., 2016, Review of the genus Leptopilina (Hymenoptera, Cynipoidea, Figitidae, Eucoilinae) from the Eastern United States, including three newly described species, Journal of Hymenoptera Research 53, pp. 35-76 : 38-46

Leptopilina Foerster, 1869

Leptopilina Förster, 1869: 342, 348 (original description. Type: Cothonaspis longipes Hartig, by monotypy and original designation); Forshage & Nordlander, 2008: 350 (keyed); Novković, Mitsui, Suwito & Kimura, 2011: 337 (phylogenetic relationships of Japanese species); Forshage, Nordlander & Buffington, 2013: 233 (catalog of species of North America); Wachi, Nomano, Mitsui, Kasuya & Kimura, 2015: 48 (phylogenetic relationships); van Noort, Buffington & Forshage, 2015: 64, 73, 90 (diagnosis, keyed, new distribution record for Botswana, Burkina Faso, Burundi, Central African Republic, Ethiopia, Gabon, Ghana, Malawi, Rwanda, Tanzania and Yemen).

Diagnosis.

Leptopilina are typically small wasps, less than 2mm in length, rather stout when compared with other eucoiline taxa, and have a worldwide distribution. Many species within this genus are easily confused with those in other genera, such as Ganaspis , Kleidotoma , Rhoptromeris , and Trybliographa . However, Leptopilina possess some unique morphological characteristics that allow them to be distinguished from other eucoiline genera. Generally speaking, in Leptopilina , the head narrows ventrally at the bottom of the eyes and forms a triangle. The petiole is enlarged posteriorly, and the broad posterior rim has varying sculptural patterns. The hairy ring at the base of the metasoma is more or less reduced in density with various lengths of setae, but there is no connection dorsally, leading to the common state of 'hairy ring broken’. The mesoscutum lacks notauli, and the subalar pits are moderately developed.

In Leptopilina , as in all other Eucoilinae , the scutellum is surmounted by a disc with a glandular pit close to the posterior margin of the disc. The posterior margin of the scutellum is usually rounded with punctate sculpture, reticulate sculpture, striate sculpture or a combination of these three. In some species of Leptopilina , the scutellum has ridges radiating from the scutellar disc; this state is similar to some species of Hexacola Föerster, but these Leptopilina can be differentiated by having an incomplete hairy ring on the metasoma (complete hairy ring in most Hexacola ) and a glabrous postero-lateral corner of the metapleuron (setose posterolateral corner of metapleuron in Hexacola ). Compared to Rhoptromeris , the basal part of the pronotal plate of Leptopilina is distinct and foveae on the pronotal plate are open laterally; by contrast, in Rhoptromeris , but the lateral foveae are closed. Compared to Ganaspis , males have the antennal F1 distinctly modified, whereas the F1 of Leptopilina is shorter than the F2, and F2 is distinctly modified by being curved outward and elongate. This flagellomere character is one of the main characteristics used to separate Leptopilina from Ganaspis . Another important characteristic used to distinguish between Leptopilina and Ganaspis is their metapleural corners: in Leptopilina , the corner is hairless (glabrous), and in Ganaspis , the corner is hairy (setose). Wing morphology can also be helpful in separating other genera from Leptopilina . Leptopilina wings are always covered with short hair, rounded apically, and typically have a long hair fringe on wing tip; the marginal cell is quadrangular in shape and may or may not be closed completely along the anterior margin. In Rhoptromeris the cell is always closed, and more triangular in shape: in Kleidotoma the cell is always open and apical margin is typically emarginate.

Description.

Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Sculpture on vertex, lateral surface of pronotum and mesoscutum absent, surface smooth.

Head, in anterior view, broadly triangular. Pubescence on head sparse setae scattered over face. Sculpture along lateral margin of occiput absent. Gena (measured from compound eye to posterolateral margin of head) short, ratio of length of gena to length of compound eye in dorsal view <0.3. Sculpture of gena absent, smooth. Lateral margin of occiput evenly rounded, not well defined. Occiput (except extreme lateral margin) smooth. Carina issuing from lateral margin of postocciput absent. Ocelli small, ratio of maximum diameter of a lateral ocellus to shortest distance between lateral ocelli 0.2-0.4. Anterior ocellus far from posterior ocelli, clearly separate anterior ocelli to anterior margins of posterior ocelli. Relative position of antennal sockets intermediate, ratio of vertical distance between inner margin of antennal foramen and ventral margin of clypeus to vertical distance between anterior ocellus and antennal rim 2.0-4.0. Median keel absent. Vertical carina adjacent to ventral margin of antennal socket absent but present in Leptopilina decemflagella . Facial sculpture absent, surface smooth. Facial impression absent, face flat. Antennal scrobe absent. Anterior tentorial pits small. Vertical delineations on lower face absent. Ventral clypeal margin laterally, close to anterior mandibular articulation straight. Ventral clypeal margin medially with spatulate projection. Clypeus smooth with slight central spatulate projection. Malar space adjacent to anterior articulation of mandible evenly rounded, smooth. Malar sulcus present. Eye removed from ocelli, ratio of distance between compound eye and posterior mandibular articulation to distance between posterior ocellus and compound eye <1.2. Compound eyes, in dorsal view, not distinctly protruding from the surface of the head. Pubescence on compound eyes present, short. Orbital furrows absent. Lateral frontal carina of face absent. Dorsal aspect of vertex smooth. Posterior aspect of vertex smooth. Hair punctures on lateral aspect of vertex absent. Posterior surface of head deeply impressed around postocciput.

Apical segment of maxillary palp with pubescence, consisting one long erect setae. Apical seta on apical segment of maxillary palp longer than twice length of second longest apical seta. Maxillary palp composed of four segments. Last two segments of maxillary palp (in normal repose) straight. Apical segment of maxillary palp more than 1.5 times or 1-1.5 times as long as preceding segment.

Terminal flagellomere with one to three basiconic sensillae. Basiconic sensillae present between F5-F11 and also on F1, F2 in Leptopilina maia . Articulation between flagellomeres in antenna moniliform, segments distinctly separated by narrow neck-like articulation. Female antenna composed of 11 flagellomeres, 10 flagellomeres in Leptopilina decemflagella . Male antenna composed of 13 flagellomeres. Female F1 longer than F2. Flagellomeres of female antenna cylindrical, distinctly widened towards apex, semi-clavate. Placoidal sensilla present between F5-11. Last antennal flagellomeres of female antenna not conspicuously enlarged compared to adjacent flagellomeres.

Macrosculpture on lateral surface of pronotum absent dorsally and laterally, in Leptopilina decemflagella with longitudinal ridge ventrally. Anteroventral inflection of pronotum narrow. Pubescence on lateral surface of pronotum present, sparse long hair. Number of ridges on pronotal plate in lateral view between 2 to 4. Anterior flange of pronotal plate distinctly protruding anteriorly, transversely strigate. Ridges extending posteriorly from lateral margin of pronotal plate distinct but short, not extending to the dorsal margin of pronotum; present. Lateral pronotal carina absent. Crest of pronotal plate absent. Dorsal margin of pronotal plate (in anterior view) spatulate. Submedian pronotal depressions open laterally, deep. Lateral margin of pronotal plate defined all the way to the dorsal margin of the pronotum. Width of pronotal plate narrow, not nearly as wide as head.

Mesoscutal surface convex, evenly curved. Sculpture on mesoscutum absent, entire surface smooth, shiny, with sparse long hairs. Notauli absent. Median mesoscutal carina absent. Anterior admedial lines absent. Median mesoscutal impression absent. Parascutal carina nearly straight.

Mesopleuron entirely smooth. Subpleuron entirely smooth, glabrous. Lower pleuron entirely smooth, glabrous. Epicnemial carina absent. Lateroventral mesopleural carina present, not marking abrupt change of slope of mesopectus. Mesopleural triangle absent. Subalar pit present, located under subalar area obscure to see. Speculum absent. Mesopleural carina present, complete, composed of one complete, uninterrupted carina. Anterior end of mesopleural carina inserting above notch in anterior margin of mesopleuron.

Dorsal surface of scutellum foveate-areolet, areolet - rugulose or irregularly striate. Circumscutellar carina present, complete, delimiting dorsal and ventral halves of scutellum, or incomplete, posteriorly. Posterior margin of axillula marked by distinct ledge, axillula distinctly impressed adjacent to ledge. Latero-ventral margin of scutellum posterior to axillula, smooth or with weakly rugulose. Dorsoposterior part of scutellum rounded. Transverse median carina on scutellar plate absent. Dorsal part of scutellum entirely rugose, foveate, or areolate. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Scutellar fovea present, two, distinctly margined posteriorly. Longitudinal scutellar carinae absent. Single longitudinal carina separating scutellar foveae present, short, ending at posterior margin of foveae. Postero-lateral margin of scutellum rounded. Lateral bar smooth, narrow.

Posterior impression of metepimeron absent or present. Metapectal cavity anterodorsal to metacoxal base present, well-defined. Anterior margin of metapectal-propodeal complex meeting mesopleuron at same level at point corresponding to anterior end of metapleural carina. Posteroventral corner of metapleuron (in lateral view) not extended posteriorly. Anterior impression of metepimeron absent. Posterior margin of metepimeron distinct, separating metepimeron from propodeum. Subalar area broad ened anteriorly, narrowed posteriorly. Prespiracular process present, blunt, lobe-like, polished. Dorsellum absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present. Pubescence consisting of few hairs on posterior part of metepisternum, few or dense hair on propodeum.

Pubescence posterolaterally on metacoxa, present, small, rounded, with adjacent sparse pubescence. Microsculpture on hind coxa absent. Longitudinal ridge on the posterior surface of metatibia absent. Metafemoral tooth present, elongate, with adjacent serrate ridge posteriorly. Ratio of first metatarsal segment to remaining 4 segments greater than 1.0.

Wing vein M absent or present but not well defined. Pubescence of fore wing present, long, dense on most of surface. Apical margin of female fore wing rounded. Rs+M of forewing defined but nebulous at point of origin from basal vein at posterior third. Mesal end of Rs+M vein situated closer to anterior margin of wing, directed towards middle of basalis. Vein R1 forming marginal cell completely. Basal abscissa of R1 (the abscissa between 2r and the wing margin) of fore wing as broad as adjacent wing veins. Coloration of wing absent, entire wing hyaline. Marginal cell of fore wing membranous, similar to other wing cells. Areolet absent. Hair fringe along apical margin of fore wing present, long or very long.

Propodeal spurs absent. Lateral propodeal carinae present, not reaching scutellum. Ventral end of lateral propodeal carina reaching nucha, carinae separated from each other. Inter propodeal carinae space lightly setose, or too dense to see underlying surface, in Leptopilina boulardi with a horizontal carina. Petiolar rim of uniform width along entire circumference. Petiolar foramen removed from metacoxae, directed posteriorly. Horizontal carina running anteriorly from lateral propodeal carina present, or not visible, setae too dense. Lateral propodeal carina, straight, sub-parallel, in Leptopilina boulardi distinctly angled. Calyptra, in lateral view, rounded. Propodeum neck-like, drawn out posteriorly. Calyptra, in posterior view, dorsoventrally elongate or rounded.

Petiole about as long as wide. Surface of petiole longitudinally costate, ventral keel absent. Posterior part of female petiole abruptly widened. Ventral and lateral parts of petiolar rim broad.

Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally. Tergum 3 indistinct, fused with syntergum. Posterior margin of tergum 3 indistinct, fused with tergum 4 in syntergum. Posterior margin of tergum 4 evenly rounded. Sternum 3 encompassed by syntergum. Sculpture on metasomal terga absent. Syntergum present with terga 3 to 5 fused, ventral margin rounded. Peglike setae on T6-T7 absent. Postero-ventral cavities of female metasoma T7 present, glabrous save for few, long setae. Female postero-ventral margin of T6-T7 straight, parallel. Terebrum and hypopygium (in lateral view) curved, pointing upward. Ovipositor clip, present.

Comments.

It was difficult to locate type specimens before the revision of Nordlander (1980). Only one European species of Leptopilina ( Cothonaspis longipes Hartig, 1841) was placed in this genus by Weld (1952). Nordlander (1980) suggested Cothonaspis longipes (Hartig, 1841) should be maintained as type species, and included a taxonomic history of Leptopilina . Many species belonging to this genus have also been treated under various generic names for decades. Meanwhile, the true Leptopilina species had been assigned to other genera such as Erisphagia and Cothonaspis ( Nordlander 1980).

Distribution.

This genus has a worldwide distribution and is known from Europe, Africa, Asia, Australia, North America and South America.

Key to Eastern North American Leptopilina species

1	Female with 10 flagellomeres on the antenna (Fig. 1 ); vertical carina present adjacent to ventral margin of antenna socket (arrow, Fig. 2 ); hypopygium pointing ventrally in lateral view (arrow, Fig. 3 )	Leptopilina decemflagella Lue & Buffington, sp. n.
-	Female with 11 flagellomeres (Fig. 4 ); no obvious carina adjacent to margin of antenna socket (Fig. 5 ); hypopygium pointing dorsally (arrow, Fig. 6 )	2
2	Mesoscutal hair absent (Figs 7 -8 )	3
-	Mesoscutal hair present, sometimes reduced (arrow, Figs 9-10 )	5
3	Scutellum with semi-parallel to slightly radiating ridges running the length of the dorsal surface of the scutellum, totally lacking foveate-areolet or rugulose pattern (Fig. 11 ); metasomal hairy ring scarce and only has few long hairs (arrow, Fig. 12 ); propodeal carinae angled and with horizontal carinae in between (when viewed from postero-dorsal angle) (arrow, Fig. 13 )	Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault, 1979)
-	Scutellum with foveate-areolet or rugulose pattern on the dorsal surface of the scutellum (Fig. 14 ); metasomal hairy ring dense (Fig. 15 ); propodeal carinae sub-parallel and without a horizontal carina in between propodeal carinae (when viewed from postero-dorsal angle) (arrow, Fig. 16 )	4
4	Scutellar cup large, covering most of the surface of the scutellum, rhomboid shaped (arrow, Figs 17-18 ); metasomal hairy ring dense and long (Fig. 19 )	Leptopilina heterotoma (Thomson, 1862)
-	Scutellar cup smaller, exposing more than half of the dorsal surface of the scutellum, tear-drop in shape (Figs 20-21 ); metasomal hairy ring thinner, hairs shorter, composed by one or two rows of hairs, narrowly broken dorsally (Fig. 22 )	Leptopilina victoriae Nordlander, 1980
5	Metapleuron, posteriorly, with a deep depression that is continuous with propodeum (arrow, Fig. 23 ); wing vein M without clear trace line on fore wing (Fig. 24 )	Leptopilina clavipes (Hartig, 1841)
-	Metapleuron, posteriorly, not continuous with propodeum but with distinct posterior border (arrow, Fig. 25 ); wing vein M with or without a clear trace line on fore wing (Figs 27 , 26 )	6
6	Metapleuron, posteriorly, without a deep depression (arrow, Fig. 28 ); in flagellomeres F5-F10, the length is twice the width of each flagellomere (Fig. 29 ); hairy ring is widely broken dorsally, not directly connected to anterior margin of metasoma (arrow A, Fig. 30 ), dense and long ventrally (arrow B, Fig. 30 ); wing vein M without a clear trace line (Fig. 26 )	Leptopilina leipsi Lue & Buffington, sp. n.
-	Metapleuron, posteriorly, with a deep depression (arrow, Fig. 31 ); in flagellomeres F5-F10, the length is 1 to 1.5 times longer than width of each flagellomere (Fig. 32 ); hairy ring is widely or slightly broken dorsally, and all hairs are about equal in length, directly attached to anterior margin of metasoma (arrow, Fig. 33 ); wing vein M present, with a clear trace line (arrow, Fig. 27 )	Leptopilina maia Lue & Buffington, sp. n.

Figures

Figures 1 - 6.

Figures 7 - 10.

Figures 11 - 16.

Figures 17 - 22.

Figures 23 - 27.

Figures 28 - 33.