Feron crystallinum ( Bassett, 1900 ) Cuesta-Porta & Melika & Nicholls & Stone & Pujade-Villar, 2023

Cuesta-Porta, Victor, Melika, George, Nicholls, James A., Stone, Graham N. & Pujade-Villar, Juli, 2023, Re-establishment of the Nearctic oak cynipid gall wasp genus Feron Kinsey, 1937 (Hymenoptera: Cynipidae: Cynipini), including the description of six new species, Zootaxa 5366 (1), pp. 1-174 : 51-59

Feron crystallinum ( Bassett, 1900) comb. nov.

Figs 124–149

Andricus crystallinus Bassett, 1900: 319 , female, gall.

Type examined. Asexual female. A type female No. 10488 is deposited in the Entomology Type Collection at the Academy of Natural Sciences of Philadelphia, not examined by the authors. We have examined several pictures from several sexual specimens (females coded 1332063, and 1332065; males coded 1132047, and 1132055) made by Peter T. Oboyski .

Additional material. Three asexual females “ USA, CA, Salt Springs , ex Q. douglasii , coll. 2004.02.29., leg. K. Schick ”; 2 asexual females “ USA, CA, Diablo, ex Q. douglasii , 1925.10.15, leg. A. Kinsey ”; 2 asexual females “ USA, CA, 30km SW of Williams, CA2 , galltype165, ex Q. douglasii , 2007.11.02., leg. J.A. Nicholls ”; 2 asexual females “ USA, CA, Copperopolis, CA969 , galltype165, ex Q. douglasii , 2007.11.06., leg. J.A. Nicholls ”; 1 sexual female “ USA, CA, Dye Creek Preserve, CA1042 , spCAl6_1, ex Q. douglasii , coll. 2008.03.30., leg. J.A. Nicholls ”. In the general collection of the USNM there are specimens with Bassett handwriting labels (not type material) and our asexual females are conspecific with those of Bassett .

Diagnosis. Asexual females belong to the Feron species group in which the pronotum is without carinae, with dense setae and piliferous points; the mesoscutum is dark brown between notauli in anterior 1/3 length of the mesoscutum; as in F. pattersonae (asex) and F. sulfureum (asex). Differs from F. pattersonae in the trapezoid head in frontal view (ovate in F. pattersonae ) and the mesoscutellar foveae divided by a central carina (fused in F. pattersonae ). Morphologically most similar is F. sulfureum but in F. crystallinum the pronotum is coriaceous, with piliferous points and distal flagellomeres broader than basal; for other characters see couplet 26 in the key. Sexual females are brown to chestnut brown, rarely darker; inner margins of eyes are parallel or only slightly converging ventrally, the frons is flat, not or only slightly bulging in frontal view; the mesoscutum is smooth, glabrous or alutaceous anteriorly; the mesoscutellum with irregular rugae at least in lateral and posterior parts, sometimes dorsocentral part is smooth, shining, without piliferous points; these characters are shared with F. amphorus (asex), F. clarkei (sex) and F. dumosae (sex). Differs from F. amphorus and F. clarkei in the transfacial distance which is as long as or slightly shorter than the height of the eye, the eye more than 3.6× as high as length of the malar space; the pronotum laterally with short carinae only along posterior margin. Differs from F. dumosae by characters mentioned at couplet 19 in the key. Males are different from all other Feron males in the inner margins of eyes which are slightly diverging ventrally, the notaulus is complete, mesoscutellar foveae absent, present in the form of a transverse smooth anterior impression, continuing into smooth mesoscutellar disc.

Re-description. Asexual female ( Figs 124–134 ). Head chestnut brown, posteriorly darker, clypeus darker, mandibles and palpi chestnut brown, antenna chestnut brown, with darker F4–F12; mesosoma predominantly brown; pronotum brown with darker anterolateral part, propleuron dark brown; mesoscutum brown with black marks between notauli in anterior half and next to lateral lines; mesoscutellum uniformly brown; mesopleuron brown, ventrally dark brown to black; propodeum dark brown to black; metasoma uniformly dark brown; legs chestnut brown, with darker coxae.

Head with sparse setae, denser on lower face, 1.2× as broad as high and slightly broader than mesosoma in frontal view; 2.1× as broad as long in dorsal view. Gena reticulated, not broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space reticulate, with striae radiating from clypeus and not reaching eye; eye 2.7× as high as length of malar space; malar sulcus absent. Inner margins of eyes parallel. POL 1.7× as long as OOL, OOL 1.9× as long as diameter of lateral ocellus and slightly longer than LOL, all ocelli ovate, of same size. Transfacial distance slightly longer than height of eye; toruli located in the upper half of head and frons definitely shorter than lower face, diameter of antennal torulus 1.3× as long as distance between them, distance between torulus and eye 1.2× as long as diameter of torulus; lower face smooth with white setae; slightly elevated median area coriaceous, with few setae. Clypeus quadrangular, slightly broader than high, smooth, with a few long setae scattered all over; ventrally rounded, emarginate, without median incision; anterior tentorial pit small, rounded, distinct, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons, interocellar area, vertex uniformly reticulate, without striae and setae; area under central ocellus impressed, smooth, glabrous; occiput and postocciput alutaceous; postgena reticulate, with a few setae; posterior tentorial pit large, elongated, area below impressed; occipital foramen as high as height of postgenal bridge; hypostomal carina emarginate, continuing into strong postgenal sulci which strongly diverge toward occipital foramen, postgenal bridge anteriorly slightly broader than occipital foramen. Antenna longer than head+mesosoma, with 12 flagellomeres; F6–F12 about 2.0× broader than F1–F5; pedicel 1.7× as long as broad; F1 1.8× as long as pedicel and slightly longer than F2; F2 slightly longer than F3; all subsequent flagellomeres shorter, F12 as long as F11; placodeal sensilla on F5–F12.

Mesosoma as long as high, with a few white setae, denser along propleura and on lateral propodeal area. Pronotum coriaceous in posterolateral area, with dense setae laterally with piliferous points; propleuron smooth, glabrous. Mesoscutum slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae), rugose-reticulate between notauli in anterior half and laterad to notauli, smooth and glabrous in between notauli in posterior half; entirely and uniformly with dense long white setae and some distinct piliferous points. Notaulus complete, shallow, posteriorly converging and broader than anteriorly, with smooth, glabrous bottom; in most posterior part distance between notauli shorter than distance between notaulus and side of mesoscutum; anterior parallel line distinct, elevated or impressed, smooth, glabrous, reaching to half-length of mesoscutum; parapsidal line marked with broad smooth, glabrous stripe; median mesoscutal line indistinct, very short, present at the most posterior end; parascutal carina broad, reaching notaulus. Mesoscutellum ovate, slightly longer than broad, broadest part posteriorly, circumscutellar carina complete; uniformly rugoso-coriaceous, overhanging metanotum, with sparse long setae. Mesoscutellar foveae quadrangular, as broad as high, with smooth, glabrous bottom, divided by a rugose elevated triangular area. Mesopleuron entirely smooth, with setae only along ventral edge; mesopleural triangle coriaceous, with dense white setae; dorsal and lateral axillar areas smooth, glabrous, without setae; axillula with delicate parallel longitudinal striae; subaxillular bar smooth, glabrous, triangular, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron at half of its height; lower part separating smooth, glabrous area, with dense setae, upper part of sulcus also distinct. Metascutellum coriaceous, as high as height of smooth, glabrous ventral impressed area; metanotal trough smooth, with few setae; central propodeal area lyre-shaped, smooth, with a few strong short longitudinal rugae; lateral propodeal carinae strong, broad and high, bent outwards in posterior 1/3; lateral propodeal area smooth, with long white setae, each seta with piliferous point at the base. Nucha with numerous irregular rugae. Tarsal claws with basal lobe.

Fore wing longer than body, hyaline, with short dense cilia on margin, veins brown, radial cell open, 3.8× as long as broad; Rs and R1 not reaching wing margin; areolet small, triangular, closed and distinct. Rs+M distinct in 2/3 of its length, its projection reaching basalis at half of its height.

Metasoma longer than head+mesosoma, longer than high in lateral view; 2nd metasomal tergum smooth, extending to 5/6 length of metasoma in dorsal view, with patch of dense white setae anterolaterally, without micropunctures; all subsequent terga and hypopygium smooth, with fine micropunctures; prominent part of ventral spine of hypopygium 6.8× as long as broad in ventral view, with short white setae ventrally, which do not extend beyond apex of spine.

Body length 2.1–2.3 mm (n = 3).

Sexual generation. According to Doutt (1960), specimens used for the description of the sexual females and males were housed in the University of California, Albany. Currently they are deposited in the Essig Museum (University of California, Berkeley, Peter T. Oboyski pers. comm.). These specimens were not examined by the authors; however, photos were taken from females and males by Peter T. Oboyski and sent to authors. For material examined by the authors, see above in Additional material.

Sexual female ( Figs 136–145 ). Head, mesosoma dark brown to black; scape, pedicel and F1 light brown, all subsequent flagellomeres uniformly dark brown; legs yellowish-brown, except dark brown to black coxae; metasoma chestnut brown.

Head slightly transverse, with sparse setae, denser on lower face and along inner margins of eyes, 1.2× as broad as high and as broad as mesosoma in frontal view; 2.1× as broad as long in dorsal view. Gena reticulated, not broadened behind eye in frontal view, 2.7× narrower than transverse diameter of eye in lateral view. Malar space alutaceous, with striae radiating from clypeus and reaching eye; malar sulcus absent; eye 3.8× as high as length of malar space. Inner margins of eyes parallel or very slightly converging ventrally. POL 2.2× as long as OOL, OOL 1.5× as long as diameter of lateral ocellus and slightly shorter than LOL, all ocelli ovate, of same size. Transfacial distance as long as height of eye or slightly longer; toruli located in the upper half of head and frons definitely shorter than lower face, diameter of antennal torulus 1.6× as long as distance between them, distance between torulus and eye 1.2× as long as diameter of torulus; lower face coriaceous with white setae, above malar space smooth and glabrous; slightly elevated median area coriaceous, with few setae. Clypeus rectangular, around 1.6× as broad as high, coriaceous, with long setae along ventral edge; ventrally rounded, emarginate, without median incision; anterior tentorial pit small, rounded, distinct, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons, interocellar area, vertex uniformly alutaceous, without striae and setae; area under central ocellus impressed, smooth, glabrous; occiput and postocciput alutaceous, postgena alutaceous, with few setae; posterior tentorial pit large, elongated, area below impressed; occipital foramen as high as height of postgenal bridge; hypostomal carina emarginate, continuing into strong postgenal sulci which diverge strongly toward occipital foramen, postgenal bridge anteriorly slightly broader than occipital foramen. Antenna longer than head+mesosoma, with 12 flagellomeres; all flagellomeres nearly equal in width, F1 narrower than F2; pedicel longer than broad; F1 1.4× as long as pedicel, shorter than scape+pedicel and nearly equal in length to F2; F2 longer than F3, F3 longer than F4; all subsequent flagellomeres shorter and nearly equal in length; F12 slightly longer than F11; placodeal sensilla on F2–F12.

Mesosoma slightly longer than high, with a few white setae along propleura and on lateral propodeal area. Pronotum smooth with sparse setae laterally, with parallel short delicate wrinkles along posterior edge; propleuron smooth, with scattered white setae. Mesoscutum slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae), entirely smooth and glabrous without setae. Notaulus complete, deep, posteriorly converging, with smooth, glabrous bottom; at posterior end the distance between notauli just shorter than distance between notaulus and side of mesoscutum; anterior parallel line impressed, smooth, glabrous, extending to 1/3 length of mesoscutum; parapsidal line marked with impressed smooth, glabrous stripe; median mesoscutal line absent; parascutal carina broad, complete. Mesoscutellum trapezoid, slightly longer than broad, broadest part posteriorly, uniformly rugoso-coriaceous, overhanging metanotum, with sparse long setae. Mesoscutellar foveae ovate, broader than high, with smooth, glabrous bottom, divided by a smooth elevated triangular area. Mesopleuron entirely smooth, with setae only along ventral edge; mesopleural triangle rugose, with dense white setae; dorsal and lateral axillar areas smooth, with some sparse setae; axillula with delicate parallel longitudinal striae; subaxillular bar smooth, glabrous, triangular, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron in lower 1/3 of its height; lower part separating smooth, glabrous area with dense setae, upper part of sulcus indistinct. Metascutellum smooth, glabrous, slightly higher than height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous, without setae, with some irregular rugae; central propodeal area smooth, glabrous, without rugae; lateral propodeal carinae strong, broad and high, bent outwards in mid-height of propodeum; lateral propodeal area smooth, with long white setae, each seta with piliferous point at the base. Nucha with some irregular rugae. Tarsal claws with basal lobe.

Fore wing longer than body, hyaline, with short dense cilia on margin, veins brown, radial cell open, 4.1× as long as broad; Rs and R1 not reaching wing margin; areolet small, triangular, closed and distinct. Rs+M distinct in 1/3 of its length, its projection reaching basalis at half of its height.

Metasoma longer than head+mesosoma, higher than long in lateral view; 2nd metasomal tergum smooth, extending to half-length of metasoma in dorsal view, with patch of dense white setae anterolaterally, without micropunctures; all subsequent terga and hypopygium smooth without micropunctures; prominent part of ventral spine of hypopygium 3.7× as long as broad in ventral view, with short white setae ventrally, which do not extend beyond apex of spine.

Body length 1.9 mm (n = 1).

Male ( Figs 146–147 ). Body yellowish to amber; eyes bigger, transfacial distance much shorter than height of eye; height of eye 4.3× as high as length of malar space; ocelli much bigger, POL 6.0× as long as OOL, OOL 0.5× as long as diameter of lateral ocellus and much shorter than LOL, all ocelli ovate, of same size; antenna with 13 flagellomeres, longer than body, F1 slightly curved, not excavated laterally; placodeal sensilla on all flagellomeres; mesoscutum glabrous, scarcely pubescent on pronotum, along notaulus, along ventral edge of mesopleuron, mesopleural triangle and side of propodeum; mesosoma smooth and shiny, pronotum laterally and anterior part of mesoscutum alutaceous; mesoscutellar foveae absent; metasoma with long petiole, shorter than mesosoma.

Gall. Asexual galls ( Fig. 135 ). Bristly-haired gall masses 35 mm long by 25 mm wide on the underside of leaves composed of small, individual, elliptical or spherical, monothalamous galls, 12–14 mm high, 7 mm in diameter. Each gall usually with a slightly curved beak at the apex and a sparse coating of crystalline white, rose pink, red, or brown hairs ( Russo 2021). Sexual galls ( Fig. 148–149 ) monolocular, they are mostly on the upper surface of leaves, singly or in small groups, green with straw coloured apex, conical, slightly curved. The gall has numerous long cottony, white hairs projecting laterally, which are longer than the greatest width of the gall. The gall is 2.5 mm in length, with the base 1.0 mm tapering to the tip. The position of the gall is indicated on the opposite (usually lower) side of leaf by a pale coloured elliptical swelling ( Doutt 1960). The gall is difficult to distinguish from other similar sexual galls such as F. comatum , F. dumosae and F. kingi .

Biology. Alternate asexual and sexual generations were matched by Doutt (1960). Alternate sexual and asexual generations are also confirmed herein using DNA data, with four individuals (three asexual females, one sexual female) sequenced for cytb and three individuals (two asexual females, one sexual female) sequenced for cytb. Cytb sequences grouped into two haplotypes that were 0.23% divergent (GenBank accessions KX683596, MZ030743, OQ446195–OQ446196) and ITS2 sequences were identical among the three individuals (GenBank accessions OQ448237–OQ448239).

Asexual galls in autumn on leaves, adults emerge in January–February; sexual galls in spring, adults emerge in March. Both generations develop on oaks from section Quercus , subsection Dumosae: Q. douglasii , Q. dumosa and Q. garryana .

Distribution. USA: California.

Comments. The sexual males and females from the experimental material deposited in the Essig Museum by Doutt all have an amber body colour which differs from the chestnut brown sexual females collected by JN and examined by GM, and also from the colour Doutt described for sexual generation adults. We consider this simply to represent within-species chromatic variation (as is known for other Feron species) since the remainder of the diagnostic characters, host plant, and distribution are consistent with Doutt’s description.

Figures

FIGURES 124–129. Feron crystallinum, comb. nov., asexual female. 124–127, head: 124, frontal view, 125, dorsal view, 126, lateral view, 127, posterior view. 128, antenna. 129, mesosoma and propleura, frontal view.

FIGURES 130–133. Feron crystallinum, comb. nov., asexual female. 130, mesosoma, lateral view. 131, mesoscutum, dorsal view. 132, mesoscutellum, dorsal view. 133, metascutellum and propodeum, posterodorsal view.

FIGURES 134–135. Feron crystallinum, comb. nov., asexual generation. 134, metasoma, lateral view. 135, asexual gall.

FIGURES 136–141. Feron crystallinum, comb. nov., sexual female. 136–138, head: 136, frontal view, 137, dorsal view, 138, lateral view. 139, antenna. 140, mesosoma and propleura, frontal view. 141, mesoscutellum and propodeum, dorsal view.

FIGURES 142–145. Feron crystallinum, comb. nov., sexual female. 142, mesosoma, lateral view. 143, mesoscutum, dorsal view. 144, mesoscutellum, dorsal view. 145, metasoma, lateral view.

FIGURES 146–147. Feron crystallinum, comb. nov., male. 146, habitus, dorsal view, 147, habitus, lateral view (pictures taken by Peter Oboyski from the holotype deposited at the Essig Museum).

FIGURES 148–149. Feron crystallinum, comb. nov.. 148–149, sexual galls.