Synergus nigroornatus McCracken & Egbert, 1922

Lobato-Vila, Irene & Pujade-Villar, Juli, 2021, The genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) in the New World: a complete taxonomic revision with a key to species, Zootaxa 4906 (1), pp. 1-121 : 67-69

Synergus nigroornatus McCracken & Egbert, 1922

( Figure 25 )

Synergus nigro-ornatus McCracken & Egbert, 1922 . Stanford Univ., Pubs., Univ. Ser. Biol. Sci. 3 (1): 57. Type material: CAS. Synergus nigroornatus: Burks in Krombein et al. (1979) . Smith. Inst. Press 1: 1062.

Type material (examined). LECTOTYPE ♀ with the following labels: ‘ L.S.Jr. U., Lot 554, Sub 95’ (white label) / ‘ ♀ Type’ (red label) / ‘ Synergus nigro-ornatus Mc & Eb’ (white label with a red frame, handwritten) / ‘ California Academy of Sciences , Type No. 5804’ (white label) / ‘ Lectotype ♀ Synergus nigro-ornatus McCracken & Egbert, 1922 , IL-V desig-2018’(red label). PARALECTOTYPE (1♂) with the following labels: ‘ L.S.Jr. U., Lot 554, Sub 95’ (white label) / ‘♂ Type’ (red label) / ‘ California Academy of Sciences , Type No. 5804’ (white label) / ‘ Paralectotype ♂ Synergus nigro-ornatus McCracken & Egbert, 1922 , IL-V desig-2018’ (red label).

Diagnosis. Synergus nigroornatus belongs to a group of species characterized by having the mesopleuron entirely sculptured, covered with parallel and fine transverse striae; hyaline wings and radial cell of fore wing at most 2.5 times as long as wide; POL longer than OOL; OOL 1.2–1.3 times as long as diameter of lateral ocelli; gena not broadened behind eye; F1 as long as F2 and female antenna with 14 segments; lateral pronotum wrinkled or carinated, at least ventrally; mesoscutum with transversal carinae, interspaces sculptured, rarely strongly coriaceous with weak discontinuous transversal elements; notauli complete, reaching the posterior margin of pronotum; tarsal claws with a distinct basal lobe; first metasomal segment completely sulcate dorsally and laterally; syntergum with a posterior band of micropunctures; and body of females with some dark surfaces, never completely yellow. Synergus nigroornatus differs from the species sharing these traits ( S. oneratus and S. rutulus , see below) by having the malar space 0.4 times as long as height of eye (0.6 in these species); transfacial line slightly shorter than height of eye ( Fig. 25d ) (as long as height of eye in these species); head in dorsal view 1.8 times as wide as long (2.1 in these species); tarsal claws with a very small, almost inconspicuous, basal lobe (conspicuous in these species); syntergum posteriorly with an incomplete band of micropunctures extended laterally about 1/4 of its length, almost 1/ 3 in males (wide band extended more than 1/ 3 in both sexes in these species); and, in females, syntergum strongly dorsodistally incised ( Fig. 25b ) (weakly to not incised in these species).

Redescription

FEMALE. Length. Body length 3.0 mm (n = 1).

Color ( Fig. 25 ). Yellow, with some brownish black areas. Head yellow, except for a black spot in the ocellar area. Antenna yellow. Mesosoma mainly yellow; dorsomedial pronotum, mesoscutum between notauli, mesoscutellum medially, metanotum, propodeum and mesosoma basally between coxae, black; tegulae pale yellow. Metasoma yellow, dorsally with a black stripe that not reaches the tip of the syntergum. Legs pale yellow. Wings hyaline, veins yellow.

Head. In frontal view trapezoid, about 1.2 times as wide as high, gena not broadened behind eye. Face faintly pubescent, lower face with striae radiating from clypeus. Clypeus indistinct, ventral margin straight, not projected over mandibles. Malar space about 0.4 times as long as height of eye. Anterior tentorial pits visible; pleurostomal and epistomal sulcus absent. Transfacial line slightly shorter than height of eye. Toruli situated mid-height of eye; distance between torulus and eye shorter than diameter of torulus; distance between toruli shorter than diameter of toruli. Frons ( Fig. 25d ) coriaceous, without punctures; frontal carinae narrow, branched, reaching lateral ocelli. Head in dorsal view is about 1.8 times as wide as long. Vertex ( Fig. 25d ) coriaceous, with some punctures and weak wrinkles. POL: OOL: LOL = 6: 4.5: 3.5 and diameter of lateral ocelli, 3.5. Occiput weakly wrinkled and with some punctures.

Antenna. 14-segmented according to the original description (the tip of both antennae is broken); filiform, not broadened apically; pubescence dense and short. Scape plus pedicel longer than F1; pedicel 1.5 times as long as wide; F1 about as long as F2, F2 and F3 subequal; the following segments progressively shorter.

Mesosoma. About 1.3 times as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 25a ). Ratio of length of pronotum medially/laterally: 0.31. Pronotal plate indistinct. Lateral pronotum weakly wrinkled; lateral carina absent, lateral margins of pronotum rounded seen from above. Mesoscutum ( Fig. 25c ) about 1.2 times as wide as long, with weak and dense discontinuous carinae, interspaces alutaceous; anterior parallel lines shallow, reaching somewhat more than 1/3 of the mesoscutum; notauli complete and visible in their whole length, somewhat interrupted by carinae and slightly convergent posteriorly; median mesoscutal line absent; parapsidal lines inconspicuous. Mesoscutellum ( Fig. 25c ) about 1.2 times as long as wide, weakly wrinkled, interspaces alutaceous; circumscutellar carina visible but weak, obscured by wrinkles; scutellar foveae ovate, shallow, weakly sculptured bottom, the posterior margin not well defined and separated by a narrow carina. Mesopleuron finely, regularly and densely striated, interspaces smooth ( Fig. 25a ). Metapleural sulcus reaching 3/4 of mesopleural height. Propodeum pubescent and alutaceous; propodeal carinae straight and convergent posteriorly. Nucha sulcate dorsally and laterally.

Legs. Tarsal claws with a very small basal tooth.

Wings. Fore wing pubescent with short marginal setae, about as long as the body length ( Fig. 25a ). Radial cell closed, about 2.5 times as long as wide; areolet visible, small, the basal vein not well pigmented. Rs+M visible, the last third not well pigmented but reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. About as long as head plus mesosoma and about 1.2 times as long as high in lateral view ( Fig. 25b ). First metasomal segment sulcate dorsally and laterally. Syntergum smooth, anterolateral pubescence composed of a few setae and posteriorly with an incomplete narrow band of minute micropunctures extended at most 1/4 of its length; dorsodistally incised, not pointed; following segments and hypopygium also with minute micropunctures. Hypopygial spine about as long as wide and with a few lateral setae; without apical setae.

MALE. Similar to female, except for the following: body length 2.5 mm (n = 1). Antenna 15-segmented; F1 straight, weakly excavated and slightly broadened apically and basally, longer apically after the incision than basally. Metasomal punctuation extended 1/3 of the syntergum length. Mesoscutellum completely black; the black stripe of the mesoscutum expands outside notauli.

Distribution. USA: California ( McCracken & Egbert 1922).

Biology. Reared from galls of Heteroecus pacificus ( Ashmead, 1896) (= Andricus pacificus ) on Q. chrysolepis ( McCracken & Egbert 1922) .

Remarks. Synergus nigroornatus was described from 1♂ and 1♀ ( McCracken & Egbert 1922: 57), which have been located and examined. The female has been designated as lectotype of the type series and deposited in CAS.

Figures

FIGURE 25. Synergus nigroornatus (lectotype, Type No. 5804): a) lateral habitus; b) lateral metasoma; c) mesosoma in dorsal view; d) head in anterodorsal view.