Synergus flavens McCracken & Egbert, 1922

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 : 16-18

Synergus flavens McCracken & Egbert, 1922

( Figure 4 e–f)

Synergus flavens McCracken & Egbert, 1922 . Stanford Univ., Pubs., Univ. Ser. Biol. Sci. 3 (1): 55. Type material: CAS (lectotype), paralectotypes in USNM .

Synergus variegatus McCracken & Egbert, 1922 . Stanford Univ., Pubs., Univ. Ser. Biol. Sci. 3 (1): 51 syn. nov. (in part). Type material (in part): CAS (lectotype), paralectotype in CAS .

Type material of Synergus flavens McCracken & Egbert, 1922 (examined). LECTOTYPE ♀ with the following labels: ‘StanU Cal, May 1915 ’ (white label) / ‘L.S.J.U., Lot. 554, Sub. 232’ (white label) / ‘Type’ (red label) / ‘ flavens ’ (white label, handwritten) / ‘Stanford Univ., Coll. L.A.C.M., Access’d 1964’ (white label) / ‘ Synergus flavens Mc. & Eg. ’ (white label with a black frame, handwritten) / ‘ California Academy of Sciences, Type No. 5814’ (white label) / ‘ Lectotype ♀ Synergus flavens McCracken & Egbert, 1922 , IL-V desig-2019’ (red label). PARALECTOTYPES (2♀) with the following labels: ‘StanU Cal, May 1915 ’ (white label) / ‘L.S.J.U., Lot. 554, Sub. 232’ (white label) / ‘PARATYPE’ (yellow label) / ‘ Synergus flavens McC + Egb’ (white label with a black frame, handwritten) / ‘Paralectotye ♀ Synergus flavens McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♀); ‘StanU Cal, May 1915 ’ (white label) / ‘L.S.J.U., Lot. 554, Sub. 232’ (white label) / ‘PARATYPE’ (yellow label) / ‘ Synergus flavens Egbert’ (white label, handwritten) / ‘Beut. Coll, rec’d1939’ (white label) / ‘ Paratype No.52962 U.S. N.M’ (red label) / ‘Paralectotye ♀ Synergus flavens McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1♀).

Type material of Synergus variegatus McCracken & Egbert, 1922 (in part; examined). LECTOTYPE ♀ with the following labels: ‘L.S.Jr.U., Lot 554, Sub 226’ (white label) / ‘Type ♀ ’ (red label, handwritten) / ‘ variegatus ’ (white label, handwritten) / ‘Stanford Univ., Coll. L.A.C.M., Access’d 1964’ (white label) / ‘ California Academy of Sciences, Type No. 5810’ (white label) / ‘ Lectotype ♀ Synergus variegatus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) / ‘ Synergus flavens McCracken & Egbert, 1922 , IL-V det. 2019’ (white label). PARALECTOTYPE (1♂) with the following labels: ‘L.S.Jr.U., Lot 554, Sub 226’ (white label) / ‘Type ♂ ’ (red label, handwritten) / ‘ variegatus ’ (white label, handwritten) / ‘Stanford Univ., Coll. L.A.C.M., Access’d 1964’ (white label) / ‘ Synergus variegatus Mc. & Eg. ’ (white label with a black frame, handwritten) / ‘ California Academy of Sciences, Type No. 5810’ (white label) / ‘ Paralectotype ♂ Synergus variegatus McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) / ‘ Synergus flavens McCracken & Egbert, 1922 , IL-V det. 2019’ (white label).

Additional material (7♀). Non-type material deposited in USNM (examined) with the following labels: ‘HopkUS 15614ª’ (white label) / ‘Reared VII-8-18’ (white label) / ‘ Quercus chrysolepis ’ (white label) / ‘CampBaldy Calif.’ (white label) / ‘L. H. Weld Collector’ (white label) / ‘USNMENT 00960062’ (white label, QR code) (1♀); ‘HopkUS 15614ª’ (white label) / ‘Reared VI-24-18’ (white label) / ‘ Quercus chrysolepis ’ (white label) / ‘Camp-Baldy Calif.’ (white label) / ‘L. H. Weld Collector’ (white label) / ‘Ex Gall of Trichoteras coquilletti ’ (white label) / ‘ Synergus flavens McC + Egb, det. Weld 1937’ (white label with a black frame, handwritten) / ‘ Paratype No.52962, U.S. N.M.’ (red label) / ‘USNMENT 00960129’ (white label, QR code) (1♀); same as the previous one but without red label and ‘USNMENT 00960219’ (1♀), ‘USNMENT 00960371’ (1♀); ‘Hopk. U.S. 15641’ (white label) / ‘Reared Aug. 23 · 22’ (white label) / ‘ Quercus vaccinifolia ’ (white label) / ‘Tahoe City Cal’ (white label) / ‘L. H. Weld Collector’ / ‘ Synergus flavens McC + Egb, det. Weld 1937’ (white label with a black frame, handwritten) / ‘USNMENT 00960291’ (white label, QR code) (1♀); same as the previous one, but ‘USNMENT 00960051’ (1♀); ‘Tahoe City, Cal. Aug · 14’ (white label) / ‘1702’ (white label, handwritten) / ‘ vaccinifolia ’ (white label) / ‘ Synergus flavens McC + Egb’ (white label with a black frame, handwritten) (1♀).

Diagnosis. Synergus flavens is morphologically close to Synergus pacificus McCracken & Egbert, 1922 (see below), but differs from this species mainly by having the scutellar foveae large and subquadrangular (ovate to subtriangular in S. pacificus ); metasoma weakly dorsodistally incised in females (not incised in males of S. pacificus ); the last flagellar segment in females more than 4.0 times as long as wide (3.0 times in S. pacificus ); body of males almost completely yellow, with the malar space 0.7 times as long as height of compound eye and POL 1.7 times as long as OOL (males mainly black, with the malar space 0.5 times the height of compound eye and POL 2.2 times as long as OOL in S. pacificus ) (see the descriptions of both species and the identification key).

Redescription. FEMLE. Length. Body length 2.0– 2.5 mm (n = 4).

Color ( Fig. 4 e–f). Yellowish brown with some dark to black areas. Head yellowish brown, ocellar area and occiput medially dark brown to black. Antennae dark yellow to testaceous. Mesosoma yellowish brown to dark brown or blackish; pronotum anterodorsally, mesoscutum medially (a stripe between notauli), scutellum dorsally, mesopleurae basally (sometimes entirely) and metapleuron, dark brown to black (some also have propodeum black) in lighter specimens; tegulae yellow. Metasoma yellowish orange, dorsally somewhat darker. Legs yellow. Wings hyaline, veins yellow.

Head. In frontal view, almost 1.2 times as wide as high, genae not expanded behind compound eyes. Face faintly pubescent, lower face with striae radiating from clypeus. Clypeus indistinct, ventral margin very slightly projected over mandibles. Malar space about 0.5 times as long as height of compound eye. Anterior tentorial pits visible; pleurostomal and epistomal sulcus absent. Transfacial line 0.9 times as long as height of compound eye. Toruli situated mid-height of compound eye; distance between torulus and compound eye shorter than diameter of torulus; distance between toruli shorter than diameter of toruli. Frons coriaceous, with scattered small piliferous punctures; frontal carinae narrow and weak, not reaching lateral ocelli. Head in dorsal view is about 2.4 times as wide as long. Vertex coriaceous, with scattered small piliferous punctures. POL: OOL: LOL = 5: 3: 2.5 and diameter of lateral ocelli, 2. Occiput coriaceous, with scattered small piliferous punctures.

Antennae ( Fig. 4e ). 14-segmented; filiform, not broadened apically; pubescence dense and short. Scape plus pedicel about as long as F1; pedicel almost 2.0 times as long as wide; F1 about 1.2 times as long as F2, F2 and F3 subequal, the following segments progressively shorter; first flagellomeres long and thin. Last flagellar segment about 4.3 times as long as wide and about 1.6 times as long as F11.

Mesosoma. About as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 4e ). Ratio of length of pronotum medially/laterally: 0.35. Pronotal plate indistinct. Lateral pronotum ( Fig. 4e ) imbricated to very weakly wrinkled basally; lateral margins of pronotum rounded, without lateral carina. Mesoscutum ( Fig. 4f ) about as wide as long, finely coriaceous to imbricated, with very weak, discontinuous transversal elements; anterior grooves weakly impressed, almost inconspicuous. Notauli incomplete, faint in the anterior 1/3 (sometimes only visible in the distal half of the mesoscutum). Median groove absent. Parapsidal grooves weakly impressed, narrow, reaching tegulae. Scutellum ( Fig. 4f ) rounded, about as long as wide, wrinkled; circumscutellar carina weak, obscured by wrinkles; scutellar foveae subquadrangular, large, shallow, weakly sculptured, not well defined posteriorly and separated by a narrow carina. Mesopleurae ( Fig. 4e ) regularly and finely striate basally and medially, speculum smooth; little pubescent basally. Metapleural sulcus reaching 3/4 of mesopleural height. Propodeum pubescent and smooth; propodeal carinae straight and parallel. Nucha sulcated dorsally and laterally.

Legs. Tarsal claws with a small basal tooth.

Wings. Fore wings pubescent with short marginal setae, longer than body length ( Fig. 4e ). Radial cell closed, almost 2.5 times as long as wide; areolet visible, small. Rs+M visible, not reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. About as long as head plus mesosoma, about 1.2 times as long as high in lateral view ( Fig. 4e ). First metasomal segment weakly sulcated dorsally and laterally, with furrows reaching only the half of the segment. Syntergite smooth, anterolateral pubescence composed of a few setae and with a narrow band of minute micropunctures occupying the distal 1/4 of the syntergite length; weakly dorsodistally incised, not pointed ( Fig. 4f ); following segments and hypopygium also micropunctate. Hypopygial spine as long as wide and with a few lateral setae; without apical setae.

MALE. Similar to female, except for the following morphological traits: body length 1.2 mm (n = 1). Antennae 15-segmented (according to the original description of S. variegatus ; antennae of the examined male are broken); F1 strongly incised and expanded apically. Head in anterior view more quadrangular than in females; transfacial line 1.1 times as long as height of compound eye; malar space about 0.7 times as long as height of compound eye. Body color mainly yellow, except the ocellar area and the anteromedial part of pronotum, which are dark.

Distribution. USA. Different localities from the state of California ( McCracken & Egbert 1922; and in this work, see the additional material).

Biology. Synergus flavens was described from specimens bred from galls of Heteroecus flavens ( McCracken & Egbert, 1922) on Quercus vaccinifolia Kellog ( Protobalanus section) ( McCracken & Egbert 1922). Synergus flavens was also reared from galls of Trichoteras coquilletti Ashmead, 1897 on Q. chrysolepis Liebm. ( Protobalanus section), according to the labels of some of the non-type specimens found in USNM (see the additional material). Synergus variegatus was bred from galls of Heteroecus pacificus ( Ashmead, 1896) on Q. vaccinifolia ( McCracken & Egbert 1922) .

Remarks. Synergus flavens was described from 4♀ ( McCracken & Egbert 1922: 55) and S. variegatus , from 4♂ and 7♀ ( McCracken & Egbert 1922: 52). We located and examined 3♀ of S. flavens (1♀ deposited in CAS with a ‘Type’ label and 2♀ deposited in USNM) and 2♂ and 3♀ of S. variegatus (1♂ and 1♀ with a ‘Type’ label deposited in CAS, and 1♂ and 2♀ deposited in USNM) belonging to the type series of each species. The authors comment that the ‘Type’ of these species was deposited at the Stanford Entomological Museum, later absorbed by CAS; however, in the ‘Type’ section they do not specify anything else but the type depository. As a result, and since the descriptors did not designate a holotype, a lectotype for each species has been designated and deposited in CAS.

After examining the type material of S. variegatus , we noticed that its type series is composed, in fact, of two different species: while the two specimens deposited in CAS (the lectotype and a male paralectotype) are identical to S. flavens , the rest of specimens belonging to the type series that are deposited in USNM correspond to S. pomiformis ( Ashmead, 1885) (see below). The original description of S. variegatus provided by McCracken & Egbert (1922) does not give us any significant morphological clues to determine which specimens of the type series truly correspond to this species. However, both S. flavens and S. variegatus were originally described from specimens obtained from galls of Heteroecus on oaks of the Protobalanus section; so, only the two specimens of S. variegatus deposited in CAS may correspond to what McCracken & Egbert described as S. variegatus . Hence, in accordance to the above mentioned, S. variegatus (in part) is proposed as a new synonym of S. flavens . Synergus pomiformis and S. flavens were described from specimens obtained from very different gall morphotypes, so it is more than probably that the specimens composing the type series of S. variegatus were obtained from a mix of galls.

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.