Loxaulus virginianae Melika & Buss, 2021

Melika, George, Nicholls, James A., Abrahamson, Warren G., Buss, Eileen A. & Stone, Graham N., 2021, New species of Nearctic oak gall wasps (Hymenoptera: Cynipidae, Cynipini), Zootaxa 5084 (1), pp. 1-131 : 87-90

Loxaulus virginianae Melika & Buss , sp. nov.

Figs. 317–328

urn:lsid:zoobank.org:act:A7C8E359-5013-4D15-B686-02589B18F2CB

Type material: HOLOTYPE female “ USA, Alabama, Grand Bay, Oak Hill Tree Farm , coll. 18-26 May 2013, leg. Albert van Hoogmoed; ex galls in twigs of Quercus virginiana ” ; PARATYPES: 4 females with the same labels as the holotype. The holotype is deposited at the USNM , 4 females at the PHDNRL .

Etymology. Named after the host plant, Q. virginiana .

Diagnosis. A key to all 14 Loxaulus species known from America north of Mexico was published by Melika & Abrahamson (2000). There are two species of Loxaulus , L. pattersoni ( Kinsey, 1922) and L. virginianae , which are associated with Q. virginiana . Loxaulus pattersoni , known from Texas, induces galls on roots of Q. virginiana . In L. pattersonae the forewing margin has dense cilia, antenna with 13 flagellomeres, while in L. virginianae the forewing margin is without cilia, antenna with 12 flagellomeres. Loxaulus virginianae somewhat resembles L. laeta Pujade-Villar, 2014 described from Mexico (Pujade-Villar et al. 2014b), but the latter has antennae with only 10 flagellomeres, the forewing with cilia on the margin and the body is dark brown to black, while L. virginianae has antennae with 12 flagellomers, the forewing without cilia on margins, and the body is uniformly reddish brown.

Description. Asexual female ( Figs. 317–327 ). Head, mesosoma, metasoma, antennae, mouthparts, legs all uniformly reddish brown.

Head delicately reticulate, with a few white setae, 1.2× as broad as high and slightly broader than mesosoma in frontal view, 2.0× as broad as long in dorsal view. Gena reticulate, broadened behind eye in frontal view, broader than transverse diameter of eye in lateral view. Malar space reticulate, with malar sulcus, eye 3.2× as high as length of malar space. Inner margins of eyes parallel. POL 2.0× as long as OOL, OOL 1.8× as long as diameter of lateral ocellus, 1.2× as long as LOL, all ocelli ovate, of same size. Transfacial distance as long as height of eye, diameter of antennal torulus 1.9× as long as distance between them, distance between torulus and eye 1.2× as long as diameter of torulus; lower face and slightly elevated median area alutaceous, with a few short white setae, without striae. Clypeus trapezoid, slightly broader than high, smooth, glabrous; ventrally rounded, not emarginate, without median incision and with a few long setae; anterior tentorial pit large, deep, rounded, epistomal sulcus and clypeo-pleurostomal line distinct. Frons and interocellar area reticulate, without setae. Vertex and occiput reticulate, postocciput smooth, glabrous, postgena reticulate, with a few setae; posterior tentorial pit large, ovate, area below impressed, occipital foramen 1.6× as high as height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which are not united, running parallel to half the length of postgenal bridge, diverge in anterior half; anterior half of postgenal bridge as broad as occipital foramen. Antenna slightly longer than head+mesosoma, with 12 flagellomeres (in some paratypes suture between F11 and F12 indistinct), pedicel 1.8× as long as broad, F1 1.6× as long as pedicel and equal to F2; F2=F3=F4; F4 to F11 equal in length, slightly shorter than F3; F12 slightly shorter than F11; placodeal sensilla on F3–F12.

Mesosoma longer than high, with rare short white setae. Pronotum uniformly reticulate, invaginated anterior margin of pronotum foveolate, dorsally with a few sparse setae. Propleuron delicately coriaceous, glabrous. Mesoscutum uniformly reticulate, longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus incomplete, deep, with smooth, glabrous bottom in posterior 1/3 of mesoscutum, hardly traceable in anterior 2/3, converging posteriorly; anterior parallel line indistinct, extends to 1/4 of mesoscutum length; parapsidal line visible in posterior 2/3 of mesoscutum, marked with smooth, glabrous areas; median mesoscutal line absent or in the form of a short triangle posteriorly; circumscutellar carina narrow, reaching slightly above tegula. Mesoscutellum rounded slightly longer than broad, with net of irregular rugae, posteriorly rounded. Mesoscutellar foveae not separated medially, in the form of a transverse anterior impression, with smooth glabrous bottom and parallel longitudinal rugae. Mesopleuron and speculum glabrous, uniformly delicately reticulate, without setae; mesopleural triangle glabrous, with some transverse delicate rugae; dorsal and lateral axillar areas reticulate; subaxillular bar smooth, glabrous, narrow, with subparallel margins, at posterior end slightly shorter than height of metanotal trough; metapleural sulcus delimiting broad rugose, glabrous area, reaching mesopleuron in upper 1/3, upper part of sulcus indistinct. Metascutellum coriaceous, 2.0× as high as height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous, without setae, with distinct longitudinal parallel rugae; central propodeal area smooth, glabrous, without setae, broader anteriorly, narrowing posteriorly, with strong complete central longitudinal carinae and numerous transverse rugae dividing central propodeal area into rectangular units; lateral propodeal area glabrous, without setae, with net of irregular rugae. Nucha with net of short irregular delicate sulci dorsally and laterally. Tarsal claws simple, without basal lobe.

Forewing longer than body, hyaline, with dark brown veins, margin without cilia, with dark brown stripe going across radial cell and extend to Cu1b, radial cell open, 3.5× as long as broad, R1and Rs nearly reaching wing margin, areolet triangular, well-delimited, Rs+M distinct along full length, reaching basalis at mid height.

Metasoma longer than head+mesosoma, slightly longer than high in lateral view; second metasomal tergite extending to 1/4 length of metasoma in dorsal view, with a few white setae anterolaterally, without micropunctures, subsequent tergites glabrous, with few rare indistinct micropunctures. Hypopygium with delicate dense micropunctures, prominent part of ventral spine of hypopygium narrowing slightly towards apex, more than 2.0× as long as broad in ventral view, with few long setae extend beyond apex of spine. Body length 2.7–3.1 mm (n = 5).

Gall. ( Fig. 328 ). Galls are tiny cryptic cells hidden under the bark of twigs, with little or no visible swelling of the twig. The galls are 2 mm long and consist only of the larval chamber. The galls are commonly induced in a longitudinal cluster and are most easily detected by the emergence holes in the bark.

Biology. Only an asexual generation is known, which induces stem galls in twigs of Q. virginiana . Galls mature in May, adults emerge soon afterwards.

Distribution. USA, Alabama, Grand Bay.

Figures

FIGURES 317–322. Loxaulus virginianae Melika & Buss, sp. nov., asexual generation, female. 317–320, head, female: 317, frontal view, 318, dorsal view, 319, posterior view, 320, lateral view. 321, antenna. 322, forewing, part.

FIGURES 323–328. Loxaulus virginianae Melika & Buss, sp. nov., asexual generation, female and gall. 323–324, mesosoma: 323, lateral view, 324, dorsal view. 325, mesoscutum, dorsal view. 326, metascutellum and propodeum, posterodorsal view. 327, metasoma, lateral view. 328, gall.