Synergus distinctus 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 : 37-39

Synergus distinctus McCracken & Egbert, 1922

( Figure 12 )

Synergus distinctus McCracken & Egbert, 1922 . Stanford Univ., Pubs., Univ. Ser. Biol. Sci. 3 (1): 58. Type material: CAS (lectotype), paralectotypes in CAS and USNM .

Type material (examined). LECTOTYPE ♀ with the following labels: ‘L.S.Jr.U., Lot. 554, Sub. 22’ (white label) / ‘ ♀ Type’ (red label) / ‘ California Academy of Sciences, Type No. 5806’ (white label) / ‘ Lectotype ♀ Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label). PARALECTOTYPES (2♂ & 4♀) with the following labels: ‘L.S.Jr.U., Lot. 554, Sub. 22 ♂’ (white label) / ‘♂ Type’ (red label) / ‘ Synergus distinctus McC & Eg’ (white label with a red frame, handwritten) / ‘ California Academy of Sciences, Type No. 5806’ (white label) / ‘ Paralectotype ♂ Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♂, deposited in CAS); ‘L.S.Jr.U., Lot. 554, Sub. 22’ (white label) / ‘I. McCracken Col.’ (white label) / ‘Paratype’ (yellow label) / ‘Ex gall of Cynips canescens ’ (white label, handwritten) / ‘ Paratype No. 24502 U.S. N.M’ (red label) / ‘ Synergus distinctus McC & Eg’ (white label with a red frame, handwritten) / ‘ Paralectotype ♀ Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♀, deposited in USNM); ‘L.S.Jr.U., Lot. 554, Sub. 22’ (white label) / ‘I. Mc-Cracken Col.’(white label) / ‘Paratype’(yellow label) / ‘ Paratype No. 24502 U.S. N.M’(red label) / ‘ Paralectotype ♀ Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♀, deposited in USNM); ‘ Mar1915, Stan U Cal’ (white label) / ‘L.S.Jr.U., Lot. 554, Sub. 22 ♀ ’ (white label) / ‘Paratype’ (yellow label) / ‘Beut. Coll, rec’d1934’ (white label) / ‘ Paralectotype ♀ Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♀, deposited in USNM); ‘ Mar1915, Stan U Cal’ (white label) / ‘L.S.Jr.U., Lot. 554, Sub. 22 ♀ ’ (white label) / ‘Paratype’ (yellow label) / ‘Beut. Coll, rec’d1934’ (white label) / ‘ Synergus distinctus Egbert’ (white label, handwritten) / ‘USNMENT 00960442’ (white label, QR code) / ‘ Paralectotype Synergus distinctus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♂ & 1♀, deposited in USNM)

Diagnosis. Along with Synergus atripennis (see above), S. distinctus differs from the rest of species known within this genus from the New World by having smoky wings (commonly hyaline in Synergus ). The main differences between these two species have already been treated (see the diagnosis of S. atripennis and the identification key).

Redescription

FEMALE. Length. Body length 4.0– 4.5 mm (n = 5).

Color ( Fig. 12 ). Black and amber. Head black. Antenna amber, scape dark brown. Mesosoma black; tegulae yellowish orange. Metasoma amber, the first metasomal segment, black. Legs amber; coxae and trochanters (except distally), black. Wings slightly smoky, veins brown.

Head. In frontal view trapezoid, 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 slightly projected over mandibles. Malar space about 0.5 times as long as height of eye. Anterior tentorial pits visible; pleurostomal and epistomal sulcus absent. Transfacial line about as long as 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 between frontal carinae coriaceous to reticulated, with some punctures, and wrinkled outside carinae; frontal carinae well-marked and thick, branched before reaching lateral ocelli. Head in dorsal view is about 2.3 times as wide as long. Vertex wrinkled and with some punctures. POL: OOL: LOL = 10: 9: 5 and diameter of lateral ocelli, 6. Occiput dorsally with some wrinkles, the rest coriaceous, without punctures.

Antenna ( Fig. 12b ). 14-segmented; long, filiform, not broadened apically; pubescence dense and short. Scape plus pedicel shorter than F1; pedicel about 1.2 times as long as wide; F1 about as long as F2, F2 just slightly longer than F3; the following segments progressively shorter. Last flagellar segment about 4.5 times as long as wide and almost 2.0 times as long as F11.

Mesosoma. About 1.2 times as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 12b ). Ratio of length of pronotum medially/laterally: 0.4. Pronotal plate indistinct. Lateral pronotum strongly carinated; lateral carina absent, lateral margins of pronotum rounded seen from above. Mesoscutum ( Fig. 12c ) about 1.2 times as wide as long, with dense discontinuous carinae; anterior parallel lines weakly impressed, reaching 1/3 of the mesoscutum; notauli complete and visible in their whole length, somewhat interrupted by carinae anteriorly; median mesoscutal line absent; parapsidal lines shallowly impressed, reaching tegulae. Mesoscutellum ( Fig. 12c ) rounded, about as long as wide, strongly wrinkled; circumscutellar carina inconspicuous; scutellar foveae more or less ovate, large, well defined but shallow, weakly sculptured bottom and separated by a narrow carina. Mesopleuron ( Fig. 12b ) with regular, widely spaced and well-marked striae. Metapleural sulcus reaching about 3/4 of mesopleural height. Propodeum pubescent and weakly sculptured; propodeal carinae almost straight and parallel. Nucha sulcate dorsally and laterally.

Legs. Tarsal claws with a small basal lobe.

Wings. Fore wing pubescent with short marginal setae, as long as body length ( Fig. 12b ). Radial cell closed, about 2.7 times as long as wide; areolet visible, all veins well pigmented. Rs+M visible, almost reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. About as long as head plus mesosoma and almost 1.2 times as long as high in lateral view ( Fig. 12b ). First metasomal segment sulcate dorsally and laterally. Syntergum smooth, anterolateral pubescence composed of a few setae and posteriorly with an incomplete narrow band of micropunctures ( Fig. 12a ); weakly to not dorsodistally incised ( Fig. 12a ), not pointed. 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 3.5 mm (n = 2). Antenna 15-segmented; F1 just slightly longer than F2; F1 long, straight, almost not incised medially, very slightly broadener apically than basally, the distal part, longer. Metasoma shorter than head plus mesosoma, the band of micropunctures more widespread. Metasoma dark brown.

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

Biology. Reared from galls of Disholcaspis canescens (Bassett, 1890) on Q. douglasii ( McCracken & Egbert 1922) .

Remarks. Synergus distinctus was described from an unstated number of specimens ( McCracken & Egbert 1922: 58, 59). We located and examined 2♂ and 5♀ belonging to the type series: 1♂ and 1♀ deposited in CAS with a ‘Type’ label and 1♂ and 4♀ deposited in USNM. The authors stated that the ‘Types’ were deposited at the Stanford Entomological Museum (later absorbed by CAS) and the ‘Paratypes’, in USNM; however, in the ‘Type’ section they do not specify any details besides the type location of this species. As a result, it has been impossible to determine which of the specimens deposited in CAS is the holotype, necessitating that all the specimens needed to be considered as syntypes. Hence, a lectotype has now been designated from one of the syntype specimens deposited in CAS.

According to the original description, both metasoma and legs of females are reddish brown, but all the examined specimens have the metasoma amber probably due to the passing of time.

Figures

FIGURE 12. Synergus distinctus (female paralectotype, Paratype No. 24502 USNM): a) detail of the metasomal punctuation; b) lateral habitus; c) mesosoma in dorsal view.