Andricus nichollsi Melika & Stone, 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 : 56-59

Andricus nichollsi Melika & Stone , sp. nov.

Figs. 194–204

urn:lsid:zoobank.org:act:46627F86-0717-496A-B75A-FAE0FF6C1F3F

Type material: HOLOTYPE female “ USA, Arizona, Molino Basin campground. Santa Catalina Mnts. Leg. J. Nicholls. 2008.04.09. Code AZ1916, spAZl21; ex Quercus oblongifolia ” . PARATYPES: 3 females with the same labels as the holotype. The holotype is deposited at the USNM , 3 females at the PHDNRL .

Etymology. In recognition of the continuing contribution of Dr. James A. Nicholls (Institute of Evolutionary Biology, University of Edinburgh, UK, and Australian National Insect Collection, Canberra, Australia) to studies on oak gall wasps.

Diagnosis. The gall somewhat resembles the sexual gall of Andricus kingi Bassett, 1900 but it is larger and greenish. The entire habitus of the female is more like Dryocosmus and is quite different from that of A. kingi .

Description. Sexual female ( Figs. 194–203 ). Head and mesosoma light brown, metasoma slightly darker. maxillary and labial palpi, antennae pale yellow, legs uniformly whitish yellow.

Head alutaceous, with sparse white setae, denser on lower face, 1.2× as broad as high and as broad as mesosoma in frontal view, 2.2× as broad as long in dorsal view. Gena alutaceous, not broadened behind eye in frontal view, at least 2.5× as narrow as transverse diameter of eye in lateral view. Malar space alutaceous, glabrous, with delicate striae, radiating from clypeus and nearly reaching eye. Eyes large, occupying nearly whole length of head in frontal view, 6.6× as high as height of malar space, inner margins of eyes nearly parallel. POL 2.1× as long as OOL; OOL nearly equal in length to diameter of lateral ocellus and equal to LOL; all ocelli ovate, of same size. Transfacial distance narrower than height of eye; diameter of antennal torulus 1.9× as long as distance between them, distance between torulus and eye equal to diameter of torulus; lower face smooth, glabrous, with white setae, without striae; slightly elevated median area alutaceous, glabrous, without setae. Clypeus rectangular, slightly broader than high, smooth, glabrous, with a few long setae; ventrally rounded, not emarginate and without median incision; anterior tentorial pit large, rounded, epistomal sulcus and clypeo-pleurostomal line broad, well impressed. Frons alutaceous, without striae, with a few short setae and impressed area below central ocellus; interocellar area coriaceous, with some irregular short striae. Vertex, occiput, postgena alutaceous, with sparse white setae; postocciput smooth, glabrous; posterior tentorial pit large, ovate, area below impressed; occipital foramen higher than height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which bend outwards, postgenal bridge anteriorly broadened, as broad as width of occipital foramen. Antenna longer than head+mesosoma, with 12 flagellomeres, pedicel 1.5× as long as broad, F1 2.3× as long as pedicel and 1.4× as long as F2; F2 1.25× as long as F3; F3=F4=F5, subsequent flagellomeres shorter, nearly equal in length, F12 slightly longer than F11; placodeal sensilla on F2– F12.

Mesosoma slightly longer than high, with sparse short white setae. Pronotum smooth, glabrous, with distinct parallel rugae dorsolaterally; propleuron smooth, glabrous. Mesoscutum smooth, glabrous, with few white setae along notaulus; slightly longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus complete, deep, broad, with smooth, glabrous bottom, slightly converging posteriorly; anterior parallel, parapsidal and median mesoscutal lines absent; circumscutellar carina narrow, smooth, reaching notaulus. Mesoscutellum rectangular, with parallel sides, slightly longer than broad, centrally smooth, glabrous, with strong rugae laterally and posteriorly; posteriorly slightly rounded, overhanging metanotum. Mesoscutellar foveae in the form of a semilunar impression, with smooth, glabrous bottom, not separated. Mesopleuron and speculum uniformly smooth, glabrous, with a few setae ventrally; mesopleural triangle smooth, glabrous, with strong irregular striae in anterior half; dorsal and lateral axillar areas smooth, glabrous, with a few white short setae; subaxillular bar smooth, glabrous, with subparallel sides, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron in lower half, upper part of sulcus indistinct. Metascutellum smooth, glabrous, as high as height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous, without setae; central propodeal area smooth, glabrous, broad, with some incomplete longitudinal parallel rugae; lateral propodeal carinae strongly curved outwards at mid height; lateral propodeal area smooth, glabrous, with long dense white setae. Nucha smooth, glabrous dorsally, with numerous sulci laterally. Tarsal claws simple, without basal lobe.

Forewing longer than body, hyaline, margin with long dense cilia, veins pale yellow, radial cell open, 5.0× as long as broad, R1 and Rs reaching wing margin, areolet triangular, distinct, Rs+M inconspicuous, traceable along 1/2 of its length, its projection reaching basalis at lower half of its height.

Metasoma as long as head+mesosoma, nearly as long as high in lateral view; second metasomal tergite extending to half the length of metasoma in dorsal view, with few white setae anterolaterally; all tergites without micropunctures, smooth, glabrous. Hypopygium without micropunctures, prominent part of ventral spine of hypopygium 4.0× as long as broad in ventral view, with a few short setae ventrally which do not extend beyond apex of spine. Body length 1.8–2.1 mm (n = 4).

Male. Unknown.

Gall. ( Fig. 204 ). A small pointed unilocular leaf gall, 4–5 mm tall, 2 mm across, on edge of leaf, which causes the leaf to curve inwards at the point of gall attachment. Gall pale green with scattered brown flecks and covered with a dense coating of short hairs. Some of the hairs and the gall tip become red and then brown as the gall matures.

Biology. Only females are known. Their morphology strongly suggests that they belong to the sexual generation rather than the asexual generation. This is also suggested by the gall’s rapid development in spring. In addition, very similar galls with comparable morphology (small, unilocular, roughly conical, developing on the edge of leaves) are known from the sexual generations of some Nearctic Andricus species (see Doutt 1960, Dailey & Sprenger 1973a,b). Galls develop on Q. oblongifolia , mature in April; adults emerge soon afterwards.

Since this species induces a rather generic sexual generation gall morphology, two individuals were sequenced to confirm the morphological assessment of conspecificity. Cytb sequences were 1.15% divergent (GenBank OK346279 – OK346280 ), and ITS2sequences were 0.41% divergent ( OK 350644 – OK350645 ), matching expectations they were conspecific .

Distribution. USA, Arizona, Santa Catalina Mountains.

Figures

FIGURE 204. Andricus nichollsi Melika & Stone, sp. nov., galls.

FIGURES 194–199. Andricus nichollsi Melika & Stone, sp. nov., sexual female. 194–197, head: 194, frontal view, 195, posterior view, 196, lateral view, 197, dorsal view. 198, antenna. 199, forewing, part.

FIGURES 200–203. Andricus nichollsi Melika & Stone, sp. nov., sexual female. 200–202, mesosoma: 200, lateral view, 201, dorsal view, 202, posterodorsal view. 203, metasoma, lateral view.