Synergus reniformis 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 : 85-89

Synergus reniformis McCracken & Egbert, 1922

( Figures 33–34 )

Synergus reniformis McCracken & Egbert, 1922 . Stanford Univ., Pubs., Univ. Ser. Biol. Sci. 3 (1): 53. Type material: CAS (lectotype), paralectotypes in CAS and USNM .

Synergus magnificus Weld, 1957 . Proc. U. S. Nat. Mus. 107: 107 syn. nov. Type material: USNM (holotype), paratypes in USNM, CAS, AMNH , and FMNH.

Type material of Synergus reniformis McCracken & Egbert, 1922 (examined). LECTOTYPE ♀ with the following labels: ‘L.S.Jr.U., Lot. 554, Sub. 251’ (white label) / ‘Type ♀ ’ (red label) / ‘reniformis’ (white label, handwritten) / ‘Stanford Univ. Coll. L.A.C.M, Access’d 1964’ (white label) / ‘ Lectotype ♀ Synergus reniformis McCracken & Egbert, 1922 , IL-V desig-2019’ (red label). PARALECTOTYPES (3ϐ) with the following labels: ‘L.S.Jr.U., Lot. 554, Sub. 251’ (white label) / ‘Type ϐ’ (red label) / ‘ reniformis ’ (white label, handwritten) / ‘Stanford Univ. Coll. L.A.C.M, Access’d 1964’ (white label) / ‘ California Academy of Sciences, Type No. 5812’ (white label) / ‘ Paralectotype ϐ Synergus reniformis McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1ϐ, deposited in CAS); ‘L.S.Jr.U., Lot. 554, Sub. 251’ (white label) / ‘ϐ’ (white label, handwritten) / ‘I. McCracken col.’ (white label) / ‘Paratype’ (yellow label) / ‘Ex. gall of Andricus reniformis ’ (white label, handwritten) / ‘ Paratype No. 24998 U.S. N.M’ (red label) / ‘ Synergus reniformis McC & Eg’ (white label with a red frame, handwritten) / ‘ Paralectotype ϐ Synergus reniformis McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1ϐ, deposited in USNM); ‘L.S.Jr.U., Lot. 554, Sub. 251’ (white label) / ‘ϐ’ (white label, handwritten) / ‘Paratype’ (yellow label) / ‘ Synergus reniformis Egbert’ (white label, handwritten) / ‘Beut. Coll. Rec’d1939’ (white label) / ‘ Paralectotype ϐ Synergus reniformis McCracken & Egbert, 1922 , IL-V desig-2019’ (red label) (1ϐ, deposited in USNM).

Type material of Synergus magnificus Weld, 1957 . HOLOTYPE ♀ (examined) with the following labels: ‘Oregon Caves, Ore. el. 6000’ (white label) / ‘ chrysolepis ’ (white label) / ‘Ex 1822’ (white label, handwritten) / ‘Type No 63004 U.S. N.M’ (red label) / ‘ Synergus magnificus Weld’ (white label with a black frame, handwritten) / ‘ USNMENT 00802168’ (white label, QR code) / ‘ Holotype ♀ Synergus magnificus Weld, 1957 ’ (red label). PARATYPES (7ϐ & 6♀) (examined) with the following labels: ‘Idyllwild, Cal.’ (grey label) / ‘1622’ (white label, handwritten) / ‘ Paratype No. 63004 U.S. N.M.’ (red label) / ‘USNMENT 00960804’ (white label, QR code) / ‘ Paratype Synergus magnificus Weld, 1957 ’ (red label) (6ϐ & 3♀, deposited in USNM); same data, but without the QR code label: 2♀ (deposited in USNM); ‘Mill Valley Marin Co. Cal.’ (white label) / ‘H. B. Leech Collector’ (white label) / ‘Emerged from cynipid gall on Quercus chrysolepis ’ (white label) / ‘Paratype’ (red label) (1ϐ & 1♀, deposited in CAS). Eighty-eight more paratypes (sex unknown, not examined) are deposited in CAS ( R. Zuparko pers. comm.).

Other material examined (2ϐ & 7♀). Material deposited in USNM with the following labels: ‘Kyburz, Cal.’ (grey label) / ‘ Quercus chrysolepis ’ (white label) / ‘1622’ (white label, handwritten) / ‘ Synergus reniformis McC & Egb’ (white label with a black frame, handwritten) (1♀); ‘Tahoe City Cal., Aug. 38’ (grey label) / ‘vaccinifolia’ (grey label) / ‘1622’ (white label, handwritten) / ‘ Synergus reniformis Mc +E, det. Weld’ (white label with a black frame, handwritten) (2ϐ & 3♀). New material reared from galls collected in Mexico with the following location data: MEX: P393, Sierra de San Pedro Mártir (B.C.), Andricus ? truckeensis, Q. chrysolepis , (07.iv.2018) 03.v.2018, S. Ordaz leg. (3♀).

Diagnosis. Synergus reniformis can be easily separated from other species by having tarsal claws simple, without a basal lobe, and a large size, with females ranging from 3.0 to 6.0 mm in length and males, from 2.0 to 5.0 mm. It is also characterized by having the mesopleuron entirely sculptured, including the speculum; hyaline wings and radial cell of fore wing at least 2.7 times as long as wide; F1 as long as F2; POL longer than OOL; notauli complete, reaching the posterior margin of pronotum; first metasomal segment dorsally with striae reaching the half of its length, anterior half smooth (sometimes completely smooth); and syntergum posteriorly with or without punctures, if present then forming either a patch or a band.

Redescription

FEMALE. Length. Body length 3.0–6.0 mm (n = 15).

Color ( Fig. 33a, c, d, g, h, i ). Lower face and gena yellow, except for a black stripe that sometimes appears running from toruli to the oral fovea ( Fig. 33h ); frons, vertex and occiput, black. Antenna testaceous to dark brown. Mesosoma mainly black; pronotum from almost completely yellow (only with some black spots laterally and dorsally) to black; mesopleuron from almost completely yellow (only tinged with black posteriorly and ventrally) to black; mesopleural triangle and tegulae always yellow; mesosoma dorsally and propodeum always black. Metasoma reddish brown to chestnut, with the basal edge and the hypopygium yellowish, to dark yellow laterally and ventrally, only infuscate anterodorsally. Legs yellow, basal half of hind and mid coxae (rarely the first pair), black. Wings hyaline, veins dark brown.

Head. In frontal view ( Fig. 33c, d ) 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 midheight of eye; distance between torulus and eye shorter than diameter of torulus; distance between toruli clearly shorter than diameter of toruli. Frons ( Fig. 33c, d ) coriaceous with scarce small punctures and weak wrinkles; frontal carinae narrow and weak, branched before reaching lateral ocelli. Head in dorsal view is about 2.3 times as wide as long. Vertex ( Fig. 33i ) coriaceous with small punctures and weak wrinkles. POL: OOL: LOL = 8.5: 6.5: 4 and diameter of lateral ocelli, 5. Occiput coriaceous with some small punctures.

Antenna ( Fig. 33f ). 14-segmented; filiform, not broadened apically; pubescence dense and short. Scape plus pedicel about as long as F1; pedicel almost 1.3 times as long as wide; F1 about as long as F2 or F1 slightly longer than F2, F2 and F3 subequal; the following segments progressively shorter. Last flagellar segment about 4.0 times as long as wide and almost 2.0 times as long as F11.

Mesosoma. About 1.1 times as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 33a, f ). Ratio of length of pronotum medially/laterally: 0.26. Pronotal plate indistinct. Lateral pronotum coriaceous, basally with some weak wrinkles; lateral carina absent, lateral margins of pronotum rounded seen from above. Mesoscutum ( Fig. 33d, i ) about 1.2 times as wide as long, coriaceous with very delicate discontinuous transversal elements not forming true carinae; anterior parallel lines shallow, reaching 1/3 of the mesoscutum; notauli complete, but shallowly impressed and less visible in the anterior 1/3, interrupted by the sculpture, wider and convergent posteriorly; median mesoscutal line inconspicuous or at most visible as a small triangular incision; parapsidal lines weakly impressed, narrow, surpassing tegulae. Mesoscutellum ( Fig. 33d, i ) about 1.2 times as long as wide, wrinkled, interspaces coriaceous; circumscutellar carina weak but visible, obscured by wrinkles; scutellar foveae ovate to subtriangular, moderately large, shallow, weakly sculptured bottom, the posterior margin not well defined and separated by a narrow carina. Mesopleuron ( Fig. 33a, f ) finely, regularly and densely striated, interspaces smooth. Metapleural sulcus reaching 3/4 of mesopleural height. Propodeum pubescent and alutaceous; propodeal carinae slightly curved outwards. Nucha sulcate dorsally and laterally.

Legs. Tarsal claws simple, without a basal lobe (in some specimens, with an inconspicuous tooth) ( Fig. 33b, g ).

Wings. Fore wing pubescent with short marginal setae, slightly longer than the body length ( Fig. 33a, f ). Radial cell closed, about 2.7–2.9 times as long as wide; areolet visible, well pigmented. Rs+M visible, well pigmented, not reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. Slightly longer than head plus mesosoma and almost 1.4 times as long as high in lateral view ( Fig. 33a, f ). First metasomal segment sulcate dorsally and laterally but sulci incomplete, not reaching the anterior margin of the segment (in some specimens, completely smooth). Syntergum smooth, anterolateral pubescence composed of a few setae and posteriorly usually with an incomplete band of micropunctures extended laterally about 1/3 of its length, less extended dorsally (with very few or without micropunctures, smooth, in some specimens); strongly dorsodistally incised ( Fig. 33d ), not pointed; following segments with minute micropunctures. Hypopygial spine almost 2.0 times as long as wide and with a few lateral setae; without apical setae.

MALE ( Fig. 33e, j ). Similar to female, except for the following: body length 2.0–5.0 mm (n = 12). Antenna 15-segmented; F1 slightly curved, almost not incised medially nor broadened, longer apically after the incision than basally. Malar space 0.6 times as long as height of eye. Metasoma shorter than head plus mesosoma. Antenna yellow; pronotum almost completely yellow; metasoma dorsally black, ventrally yellow; sometimes only hind coxae, black.

Distribution. USA: California and Oregon ( Weld 1957; McCracken & Egbert 1922; authors). First time recorded from Mexico: Baja California (authors).

Biology. Originally reared from galls of Disholcaspis ? reniformis ( McCracken & Egbert, 1922) on Q. vaccinifolia ( McCracken & Egbert 1922) , and from galls of Andricus ? truckeensis ( Ashmead, 1896) on Q. chrysolepis ( Weld 1957) . The new material found in Mexico was reared from galls of Andricus ? truckeensis on Q. chrysolepis (authors). Also collected from unknown galls on Q. chrysolepis and Q. vaccinifolia in the USA (authors).

Remarks. Synergus reniformis was described from 7ϐ and 1♀ ( McCracken & Egbert 1922: 54). We located and examined 3ϐ and 1♀ belonging to the type series: 1♀ and 1ϐ deposited in CAS with a ‘Type’ red label, and 2ϐ deposited in USNM with a ‘Paratype’ yellow label. As we cannot know which of the specimens deposited in CAS is the holotype, since it is not stated in the original description, we designated as lectotype of the type series the female deposited in CAS.

Synergus magnificus was described from about 120 specimens ( Weld 1957: 108). We located and examined 7ϐ and 7♀ belonging to the type series: 6ϐ and 6♀ deposited in USNM, and 1ϐ and 1♀ deposited in CAS, as well as eighty-eight more paratypes deposited in CAS that were not examined .

The type specimens of S. magnificus are generally darker than those of S. reniformis , even though specimens within both type series show a moderate degree of color variability. Despite this, both species share all other diagnostic morphological traits, including having the tarsal claws simple or with an inconspicuous tooth. Furthermore, they were obtained from similar galls (as stated by Melika & Abrahamson (2002), McCracken & Egbert (1922) suggest that reniformis might be a variety of truckeensis, both probably belonging to a still undescribed genus, according to Dailey & Menke 1980) on oaks from the Protobalanus section in California and its surroundings. Hence, we propose here Synergus magnificus Weld, 1957 as a synonym of Synergus reniformis McCracken & Egbert, 1922 .

This species shows a high degree of variability in the metasomal punctuation. Weld (1957: 108) recorded that while some specimens show a conspicuous punctuation on the syntergum posteriorly, others have it almost smooth. Both the types of S. magnificus and S. reniformis examined have the syntergum micropunctate ( Fig. 34a, b ), whereas the specimens found in Baja California ( Mexico) have the syntergum smooth ( Fig. 34c ).

Figures

FIGURE 33. Synergus reniformis. Lectotype of S. reniformis (female): a) lateral habitus and head in frontal view; b) tarsal claw; d) dorsal habitus. Paralectotype of S. reniformis (male): c) head in frontal view; e) lateral habitus. Holotype of S. magnificus (female, USNMENT 00802168): f) lateral habitus; g) tarsal claw; h) head in frontal view; i) head and mesosoma in dorsal view. Paratype of S. magnificus (male): j) lateral habitus.

FIGURE 34. Variability of the metasomal punctuation of Synergus reniformis: a) S. magnificus (holotype); b) S. reniformis (lectotype); c) S. reniformis (additional material from Mexico).