Synergus laeviventris ( Osten-Sacken, 1861 ), 1865

Lobato-Vila, Irene, Equihua-Martínez, Armando, Estrada-Venegas, Edith G., Cibrián-Tovar, David, Barrera-Ruíz, Uriel M. & Pujade-Villar, Juli, 2020, Synergus Hartig species group (Hymenoptera: Cynipidae: Synergini) with partially smooth mesopleurae from the New World, Zootaxa 4822 (1), pp. 1-38 : 19-21

Synergus laeviventris ( Osten-Sacken, 1861)

( Figure 4 g–h)

Synophrus laeviventris Osten Sacken, 1861 . Proc. Entomol. Soc. Phil. 1: 57. Type material: MCZ.

Synergus laeviventris: Osten-Sacken (1865) . Proc. Entomol. Soc. Phil. 4: 375.

Type material (examined). HOLOTYPE ♀ with the following labels: ‘Gall of C. confluens Harris’ (white label, handwritten) / ‘ S. laeviventris O.S.’ (white label, handwritten) / ‘Osten Sacken Coll.’ (white label) / ‘Type 13972’ (red label) / ‘ MCZ Image Database’ (white label) / ‘ MCZ-ENT 00013972’ (white label, QR code) / ‘ Holotype ♀ Synophrus laeviventris Osten-Sacken, 1861 , IL-V desig-2019’ (red label) / ‘ Synergus laeviventris (Osten-Sacken) Osten-Sacken, 1865 , IL-V det. 2019’ (white label).

Diagnosis. Synergus laeviventris is morphologically close to S. cibriani , S. citriformis (see above), S. longimalaris Pujade-Villar & Lobato-Vila, 2017 and S. longiscapus Pujade-Villar & Lobato-Vila, 2017 (see below), but differs from them mainly by having the mesoscutum with weak, discontinuous transversal elements (without transversal elements in the above-mentioned species); the notauli complete (incomplete in the above-mentioned species); the scutellar foveae small, circular, shallow, separated by a wide septum (shallowly impressed and almost inconspicuous or absent in the above-mentioned species); and the metasoma without punctures (with a few punctures in the above-mentioned species) (see the descriptions of all these species and the identification key).

Redescription. FEMALE. Length. Body length 1.8 mm (n = 1).

Color ( Fig. 4 g–h). Brown. Head, mesosoma and metasoma brown; tegulae yellow. Antennae and legs, yellow; metacoxae somewhat darker basally. Wings hyaline, veins light yellow.

Head. In frontal view, about 1.1 times as wide as high, genae just slightly expanded behind compound eyes. Face faintly pubescent, lower face with striae radiating from clypeus. Clypeus indistinct, ventral margin slightly projected over mandibles. Malar space about 0.6 times as long as height of compound eye. Anterior tentorial pits visible; pleurostomal and epistomal sulcus absent. Transfacial line slightly longer than height of compound eye. Toruli situated slightly under mid-height of compound eye; distance between torulus and compound eye about as long as diameter of torulus; distance between toruli slightly shorter than diameter of toruli. Frons coriaceous, without punctures; frontal carinae absent. Head in dorsal view about 2.0 times as wide as long. Vertex coriaceous, without punctures. POL: OOL: LOL = 12: 7.5: 5.5 and diameter of lateral ocelli, 3.5. Occiput coriaceous, without punctures.

Antennae. 14-segmented, according to the original description (antennae of the type are broken, Fig. 4g ); pubescence dense and short. Scape plus pedicel about 1.4 times as long as F1; pedicel 2.0 times as long as wide; F1 about 1.4 times as long as F2, F2 slightly longer than F3, the following segments progressively shorter. Last flagellar segment is somewhat less than 1/5 the length of the preceding, according to Osten-Sacken (1865: 375).

Mesosoma. About 1.2 times as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 4g ). Ratio of length of pronotum medially/laterally: 0.28. Pronotal plate indistinct. Lateral pronotum ( Fig. 4g ) finely coriaceous; lateral margins of pronotum rounded, without lateral carina. Mesoscutum ( Fig. 4h ) as wide as long, alutaceous to finely coriaceous, with some weak, discontinuous transversal elements; anterior grooves inconspicuous. Notauli complete and narrow. Median groove absent. Parapsidal grooves very narrow, almost inconspicuous. Scutellum ( Fig. 4h ) about 1.5 times as long as wide, finely coriaceous to alutaceous; circumscutellar carina well-defined, somewhat upturned and projected; scutellar foveae small, circular and very shallow, not well defined posteriorly and separated by a wide septum. Mesopleurae ( Fig. 4g ) finely striate medially and basally, speculum smooth; little pubescent basally. Metapleural sulcus reaching 3/4 of mesopleural height. Propodeum pubescent and weakly sculptured, almost smooth; propodeal carinae straight and parallel. Nucha sulcated dorsally and laterally.

Legs. Tarsal claws with a basal tooth.

Wings. Fore wings pubescent with short marginal setae, slightly longer than mesosoma plus metasoma. Radial cell closed and 2.4 times as long as wide; areolet inconspicuous. Rs+M inconspicuous, not reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. About as long as head plus mesosoma, about 1.5 times as long as high in lateral view ( Fig. 4g ). First metasomal segment sulcated dorsally and laterally. Syntergite smooth, anterolateral pubescence composed of a few setae and without punctures; not dorsodistally incised, pointed. Hypopygial spine about as long as wide and with a few lateral setae; without apical setae.

MALE. Unknown.

Distribution. USA. State of Washington D.C., according to the original description and Burks (1979); Colorado and Michigan, according to Gillette (1896).

Biology. Originally reared from Amphibolips confluenta (Harris, 1841) on Quercus rubra L. (Lobatae section) ( Osten-Sacken 1861). Some years later, Osten-Sacken (1865) reared four more females from the galls of Amphibolips quercusspongifica (Osten Sacken, 1862) and Atrusca quercuscentricola (Osten Sacken, 1861) , as well as from an unnamed gall on Quercus falcata Michx. (Lobatae section) which was described by Osten-Sacken (1861), according to Osten-Sacken (1865). Gillette (1896) also bred some specimens of this species from Disholcaspis rubens (Gillette, 1893) and D. quercusglobulus (Fitch, 1859) .

Remarks. Synergus laeviventris was originally described from a single female ( Osten-Sacken 1861: 57). Its description was later improved by the same author after obtaining four more females from different galls (Osten-Sacken 1865: 375).

According to both the original description ( Osten-Sacken 1861) and the notes provided by the same author some years later ( Osten-Sacken 1865), S. laeviventris has the mesosoma black and the metasoma black or chestnut; however, the specimen examined has the body entirely brown. Osten-Sacken (1865: 375) says ‘mesosoma in older specimens often become brownish or reddish-brown’, so we think the color differences observed in the type specimen are the same observed by its descriptor.

Figures

FIGURE 4. Synergus campanula: a) lateral habitus; b) dorsal view. Synergus confertus: c) lateral habitus; d) dorsal view. Synergus flavens: e) lateral habitus; f) dorsal view. Synergus laeviventris: g) lateral habitus; h) dorsal view.