Amphibolips quercuspomiformis Cuesta-Porta & Equihua-Martínez & Estrada-Venegas & Cibrián-Tovar & Barrera-Ruíz & Silva & Sánchez & Melika & Pujade-Villar 2020, comb. nov.

Amphibolips quercuspomiformis (Bassett) comb. nov.

Cynips q. pomiformis Bassett, 1881: 74.

Andricus (Andricus) pomiformis (Bassett) Ashmead, 1885: 295

Callirliytis rossi Kieffer, 1903: 84. Synonymy in Weld, 1951: 652

Callirhytis maculipeunis Kieffer, 1904: 131. Synonymized by Kinsey, 1922: 36

Andricus yosemite Beutenmuller, 1911: 211. Synonymy in Weld, 1951: 652

Callirhytis pomiformis (Bassett) Mayr, 1902: 289

Andricus pomiformis var maculipennis (Kieffer) in Kinsey, 1922: 36

Callirhytis quercuspomiformis (Bassett), Weld, 1951: 652

Type material. Asexual females. Deposited in AMNH: 4 pins (insects in a good condition); 3 pins with white redletter label “ Type ”, 1 pin with red label “ Type ”, all with printed labels “ California ”, “ Am. Mus. Nat. Hist. Dept. Invert. Zool. No. 24651.”; one pin with Bass. handwritten label “ Andricus pomiformis B. Type ”.

Material examined. 7ǒ (deposited in UB) with the following label: “MEX-453, MEXICO, Ejido Uruapan, Ensenada, Baja California Q. agrifolia, (19.x.2018) 1–10.xi.18, 17ǒ (7ǒ UB), leg. S. Ordaz Silva & I. V. López Sán-chez”; same data, extraction 19.x.2018: 20ǒ.

Additional material. Deposited in UB with the following labels: “P037, MEXICO, Cerro del Cubilete, Silao, Guanajuato, only galls without data, leg. JP-V, A. Equihua & E. Estrada”.

Sexual females and males. We were unable to get specimens of the sexual generation and thus we follow the description of adults and galls given by Lyon (1959).

Diagnosis. The asexual female of this species is characterized by a mesoscutum with sparse long white setae and discontinuous transversal carinate sculpture in anterior half. Most closely resembles A. salicifoliae for its glabrous shining, smooth speculum, simple tarsal claws, posterior scutellar depression absent, and forewing almost hyaline except for the infuscate margins of R1 and 2r veins. Amphibolips quercuspomiformis comb. nov. differs from A. salicifoliae by its colouration (black head, mesosoma and metasoma in dorsal view, but rufous metasoma laterally in A. quercuspomiformis comb. nov. while entirely brownish-rufous in A. salicifoliae; head faintly rugate dorsally and striae radiating from clypeus on lower face (coarsely rugate in A. salicifoliae); notauli shallow and entirely rugate (posteriorly smooth in A. salicifoliae) and ventral spine of hypopygium 2.2x as long as broad (0.8x in A. salicifoilae). Forewing colour pattern also resembles those of A. aliciae and A. kinseyi n. sp. but can be differenti-ated for tarsal claws with basal lobe (simple in A. quercuspomiformis comb. nov.); speculum sculptured in A. aliciae and A. kinseyi n. sp. (smooth and glabrous in A. quercuspomiformis comb. nov.), a less infuscate basal margin of radial cell (extended to basal third of radial cell in A. aliciae and A. kinseyi n. sp.); notauli deep and emarginate dorsally and with transverse carinae along sulci in A. aliciae and A. kinseyi n. sp. Galls of A. quercuspomiformis comb. nov. are similar to other species with galls that have a large globular shape and without a mottled surface; nevertheless, they are differentiable from all of these in colour (surface yellowish to orange-magenta when mature, turning to brownish orange when dry) and by being multilocular; it is the only Amphibolips multilocular gall so far known in the studied area. In USA (Arizona), A. ruginosus (Bassett, 1890) galls are also multilocular, but in this case, the larval chambers are not detachable from the host tissue (easily detachable in A. quercuspomiformis comb. nov.), 2.5 mm in diameter (longer in A. quercuspomiformis comb. nov.) with the surface rough and blackened and deeply and irregularly fissured (never in A. quercuspomiformis comb. nov.); adults with hyaline wings and metasoma yellowish brown (with a dark patch next to the basal part of radial cell and metasoma brownish-rufous in A. quercuspomiformis comb. nov.).

Redescription. (Figs 7 A–7F, 8A–D).

Asexual female. Body length: 3.4–3.6 mm. (N=5)

Colour. Head black, except chestnut brown maxillary and labial palpi; antennae light brown, mesosoma black; forelegs light brown and ambarine distally, median and hind legs darker basally and progressively lighter on distal end; coxae black, femora chestnut to light brown, tibiae and tarsi light brown; metasoma dorsally black with rufous stripes around margin of metasomal terga II and III, brownish-rufous on lateral view.

Head (Figs 7 B–7D) quadrangular in anterior view, frons dull rugose, with sparse short white setae, 2.4x as broad as long from above, 1.4x as broad as high in anterior view and as broad as mesosoma; lower face alutaceous with striae radiating from clypeus, with denser white setae and narrow elevated rugose median area. Gena dull rugose, slightly broadened behind eye, hardly visible in anterior view behind eye, as broad as cross diameter of eye; malar space striate, smooth on lower margin of eye; height of eye 2.0x as long as length of malar space. POL 1.4x as long as OOL; diameter of lateral ocellus equal to LOL; ocelli ovate. Transfacial distance 1.2x as broad as height of eye; diameter of antennal torulus 1.7x as long as distance between toruli, distance between torulus and inner margin of eye 1.6x as long as diameter of torulus. Clypeus smooth, ventrally projected and slightly sinuate, with median incision; anterior tentorial pits deep, epistomal sulcus inconspicuous, clypeo-pleurostomal line distinct. Frons, vertex, interocellar area and occiput uniformly dull rugose. Occiput with conspicuous carina dorsally. Labial palpus 3-segmented, maxillary palpus 5-segmented.

Antenna (Fig. 8B) with 12 flagellomeres; slightly longer than head+mesosoma, scape 2.2x as long as pedicel; pedicel subglobose, slightly longer than broad; F1 equal to scape+pedicel and 1.3x as long as F2; F2 as long as F3; F3 nearly equal in length to F4, subsequent flagellomeres shorter, F12 1.8x as long as F11; placodeal sensilla visible on F4–F12, absent on F1–F3.

Mesosoma (Figs 7C, 7E) only slightly longer than high. Pronotum smooth dorsally, with numerous faint irregular rugae laterally. Mesoscutum dull rugose, with transversal interrupted carinae in anterior half; dull rugose in posterior half; subequal, nearly as long as broad in dorsal view (largest width measured across mesoscutum on the level of tegulae base). Notauli distinct under dull rugose sculpture; anterior parallel lines extending to anterior third of mesoscutum, slightly elevated, mesoscutum impressed along both sides of lines; parapsidal lines distinct, originating from posterior margin and extending to nearly half length of mesoscutum; median mesoscutal line absent; parascutal carina short, extending to level of tegula only. Mesoscutellum 0.4x as long as mesoscutum, uniformly dull rugose, quadrangular, 1.4x as broad as long, slightly overhanging metanotum; scutellar foveae triangular, shallow, smooth, with distinct complete elevated narrow median carina; lateral sides of foveae with strong narrow carinae, separating them from dorsoaxillar area. Mesoscutellum without posteromedian depression. Mesopleuron, except speculum, uniformly dull rugose; speculum shiny, smooth, dorsal third glabrous and sparsely pubescent ventrally, ventral rugae orientated into transverse faint subparallel striae. Mesopleural triangle rugose; dorsoaxillar area with faint rugae; lateral axillar area and axillula coriaceous, with few short, white setae; subaxillular bar smooth, shining, with parallel sides, its height less than height of metanotal trough, most posterior part extending to half height of mesoscutellum; postalar process long, with parallel striae; metapleural sulcus hidden under dull rugose sculpture. Metascutellum uniformly coriaceous, metanotal trough coriaceous, with dense white setae; ventral impressed area smooth, slightly shorter than height of metascutellum; central propodeal area faintly rugate; lateral propodeal carinae strong, high, converge in anterior margin, slightly curved outwards medially; lateral propodeal area with faint rugae and dense white setae; nucha short, smooth.

Legs (Figs 7A, 8 C–D) with dense short white setae; tarsal claws simple.

Forewing (Fig. 8A) longer than body, mostly hyaline, with short dense cilia on margin, heavy dark stripe on basal part of radial cell, veins dark brown, Rs+M vein faintly pigmentated; radial cell narrow, long, opened on margin, 3.5 times longer than broad; R1 and Rs nearly reaching wing margin; areolet small, triangular, closed but posterior margin indistinct; Rs+M reaching basalis at its half height.

Metasoma (Figs 7A, 7F) as long as head+mesosoma, slightly longer than high in lateral view; 2nd metasomal tergum occupying nearly 4/5 of metasoma length, smooth, shining, with sparse setae laterally; posterior third conspicuously finely punctate laterally, posterior margin with a very narrow smooth band, without punctures; all subsequent terga dorsally and laterally uniformly and entirely micropunctate, with a narrow smooth band posteriorly on each tergum. Ventral spine of hypopygium robust, short, needle-like, prominent part 2.2x as long as broad, with two rows of white setae each side, extending beyond apex of spine.

Sexual female. Similar to the asexual females, but differs in the following characters: antenna with 11–12 flagellomeres; body uniformly yellowish-brown; all the legs yellowish-brown; mesoscutum and mesoscutellum less pubescent; metasomal terga sometimes smooth, without micropunctures, body length 2.3–3.1 mm.

Male. Similar to the sexual females except that they are smaller; antenna with 13 flagellomeres; body reddish-brown, except for the two basal terga which are yellowish. Mesoscutum only sparsely pubescent. Body length 2.1–2.6 mm.

Gall. Asexual galls (Figs 16 A–D). A large multilocular subglobose bud gall, up to 40 mm in diameter. The body of the gall is spherical (rarely flattened or ovate), with greatest diameter near the middle of the gall; surface sometimes with low tubercles radiating more or less from the slightly pointed tip of the gall. The gall is hard-walled, yellowish to rufous-magenta when mature and turning to brownish orange when dry, with smooth and naked surface; spongious internally, with hard filaments connecting the larval chambers with the base of the gall; up to 50 hardwalled larval chambers clustered in the center of the gall, easily separable from the firm; sometimes resembling the inquiline larval chambers; each larval chamber around 2.0–4.0 mm in diameter.

Sexual galls. A toadstool-shaped gall arising singly, or occasionally in groups of two or three from the lamina of the underside of the leaves. Galls are tinged with rose or pink when young, although most are light-green in colour. Galls are monolocular, with the single cell occupying the space below the flared top of the gall. The elongated stem of the gall is solid.

Hosts. Quercus agrifolia, Q. wislizenii, for both generations.

Biology. Alternate sexual and asexual generations are known (Lyon 1959). Sexual galls appear from February to early April, mature in early May; adults emerged from mid-May to the first week of June. Asexual galls mature in October; adults emerged in November.

Distribution. USA (California) and México (Baja California and Guanajuato states).

Remarks. Kinsey (1922) named this species as Andricus pomiformis and described five varieties, considering Callirhytis maculipennis Kieffer 1904 one of them: A. pomiformis var descansonis (Kinsey 1922), A. pomiformis distinctus (Kinsey 1922), A. pomiformis pomiformis (Basset, 1881), A. pomiformis var maculipennis (Kieffer) and A. quercuspomiformis provincialis (Kinsey 1922). Later, Weld (1951), following Mayr’s work (1902), transferred this species to the genus Callirhytis and recognised only three of Kinsey’s varieties (var. descansonis, var distincta and var. provincialis). Later, Melika & Abrahamson (2002) concluded that this species belongs to the genus Amphibolips but did not formalize the nomenclatorial act for species transfer. Herein this nomenclatorial act is completed.

According to Kinsey (1922), the morphological differences of these varieties included the notauli (from mostly indistinguishable within the mesosomal sculpture with notaular furrow rugose, to distinct with notaular furrow smooth posteriorly, and to distinct but shallow and furrow rugose); mesosoma with median sulci (absent except in var. distinctus); anterior parallel lines on the mesosoma (mostly continuous to discontinuous); lateral lines of the mesosoma (from prominent to fine and narrow); scutellar foveae (divided by a rugose and elevated area in all, or with median area also rugose but low); scutellar posteromedian depression (from absent to present, but variable in depth, deepest in var. provincialis); speculum (from glabrous and smooth to not completely smooth, with scattered punctuations and sometimes setae); areolet ranging from small to large, prolonged on the cubitus; forewing infuscation around the base of radial cell; and gall surface (present several projections on the surface, each ending in a short filament in var. distinctus and surface smooth and naked in the rest). Several characters are roughly differentiable or shared between the varieties such as the anterior parallel lines, the speculum, but others such as the median carina or the posteromedian depression of the mesoscutellum may be unique to a variety. Among the varieties, the most deviant is var. distinctus based on the distinct notauli, median sulci visible and the surface of the galls with projections. However, Kinsey (1922) comments that some var. distinctus specimens share characters of var. maculipennis (as well as var. provincialis had specimens similar to var. maculipennis). Similarly, the new material from Baja California present distinct notauli, smooth notaular furrow posteriorly as in var. distinctus, but the median sulci and scutellar posteromedian depression are absent, and the speculum is completely smooth and glabrous. The distribu-tion of the varieties is limited to California (USA) and range from the central to southern regions. All varieties have overlapping, or nearly so, distributions with at least another variety. The range of var. maculipennis includes localities from the range of var. descansonis, var. distinctus and var. provincialis, which occur almost exclusively in the southern regions. The variety pomiformis is limited to central California (San Francisco, Mount Diablo, Gilroy, and Salinas) and the closest known varieties are var. maculipennis and var. distictus (Yosemite Park and Merced Falls). Most of these characters also follow a continuous variation, and the distributions overlap in the southern regions for all, except var. pomiformis. Thus, there are not conspicuous character states to support these varieties as independent entities. Also, the host plant is Q. agrifolia in three of the varieties and Q. wislizenii in var. provincialis and var. distinctus. Both oaks are closely related and often form hybrids (Brophy & Parnell 1974). We consider all these varieties as intraspecific variations of Amphibolips quercuspomiformis comb. nov.