Grahamstoneia humboldti Melika & Nicholls, 2021

Melika, George & Nicholls, James A., 2021, A new genus of Nearctic oak gall wasp, Grahamstoneia Melika & Nicholls, gen nov. (Hymenoptera: Cynipidae, Cynipini), Zootaxa 4999 (5), pp. 456-468 : 462

Grahamstoneia humboldti Melika & Nicholls , sp. nov.

Figs 1–12

urn:lsid:zoobank.org:act:C5846E88-9A98-4027-A91D-09710919E90D

Type material: HOLOTYPE female „ USA, California, Berry summit, Arcata, leg. J. Nicholls, 2007.11.04. Code CA10 , spCAb8; ex Quercus vacciniifolia ”. Five female paratypes: four with the same labels as the holotype and one female „ USA, Arizona, Oak Creek Canyon, S of Flagstaff, AZ800, Quercus chrysolepis , leg. J.A. Nicholls, 2007.11.01 ”. The holotype and two female paratypes are deposited at the USNM, 3 female paratypes at the PHD- NRL.

Etymology. Named after Humboldt County, California, where it was first found.

Diagnosis. The gall somewhat resembles that of Andricus projectus Weld, 1952b although is more slender and green when young rather than red. However, morphologically the adults are very different. In G. humboldti sp. nov. the tarsal claws lack a basal lobe, while in A. projectus the tarsal claws have a basal lobe. No other Andricus or Callirhytis species are known to have the entire head and mesosoma uniformly reticulate or have such an unusually broad incomplete notaulus, the bottom of which has the same reticulate sculpture as the mesoscutum.

Description. See the description of the genus.

Gall. ( Fig 12 ). A bud gall on terminal or axillary buds, up to 8mm long and 2–3mm in diameter. Smooth conical gall with a pointed tip, emerging from bud scales. Young galls are green with a slight pubescence at base that rubs off easily; mature galls are a rich dark brown colour.

Biology. Only the asexual generation is known, which induces galls on Q. vacciniifolia and Q. chrysolepis within Quercus section Protobalanus – the golden cup or intermediate oaks ( Denk et al. 2017, Govaerts & Frodin 1998). Mature galls were collected in early November, and adults emerged soon afterwards.

Distribution. USA: California (three locations: Berry summit, ~ 25km E of Arcata; a site 30km NE of Arnold; and Irvine Lodge rest area on route 101, ~ 20km N of Willits); Arizona (Oak Creek Canyon, 15km N of Sedona).

Figures

FIGURE 12. Grahamstoneia humboldti Melika & Nicholls, sp. nov., asexual generation, galls.

FIGURES 1–6. Grahamstoneia humboldti Melika & Nicholls, sp. nov., asexual generation, female: 1–4, head: 1, frontal view, 2, posterior view, 3, dorsal view, 4, lateral view. 5, antenna. 6, forewing, part.

FIGURES 7–11. Grahamstoneia humboldti Melika & Nicholls, sp. nov., asexual generation, female: 7, mesosoma, lateral view, 8–9, mesosoma, dorsal view, 10, metascutellum and propodeum, posterodorsal view, 11, metasoma, lateral view.