Andricus chapmanii Melika & Abrahamson, 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 : 18-21

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Andricus chapmanii Melika & Abrahamson

sp. nov.

Andricus chapmanii Melika & Abrahamson , sp. nov.

Figs. 46–56 View FIGURES 46–51 View FIGURES 52–55 View FIGURE 56

Type material: HOLOTYPE female “ USA, Florida., Highlands Co., Lake Placid, Archbold Biological Station , coll. G. Melika , 28 November 1994, adults cut out on 17-19 March 1995, ex Quercus chapmani . PARATYPE: One female with the same labels as the holotype. The holotype female and the female paratype are deposited at the USNM .

Etymology. The species is named after its host oak, Q. chapmani .

Diagnosis. The galls of A. chapmanii resemble the account of the gall accompanying the original description of Zopheroteras vaccinii ( Ashmead, 1887) (see also Weld 1959, Fig. 203 View FIGURES 200–203 ), but the adults of Z. vaccinii are easily distinguishable as they are apterous (reflected by the original placement of this species in the genus Acraspis ). However, Weld (1922b) noted that the gall Ashmead described is actually induced by the winged species Andricus impositus Beutenmueller, 1918 (originally described based on asexual females and galls), meaning the gall of Z. vaccinii remains unknown. Later Weld (1926) correctly synonymised A. impositus with Callirhytis lustrans (Beutenmueller, 1913) , and re-iterated Ashmead’s error regarding assignment of the gall. In his original description of A. impositus (= C. lustrans ), Beutenmueller (1918) also mentioned the mature galls of this species resemble those of Andricus vacciniiformis (Beutenmueller, 1913) .

The new species A. chapmanii can be distinguished from either C. lustrans or A. vacciniiformis as follows. In C. lustrans the head is micropunctate, the mesoscutum punctuate, notaulus incomplete, extending to the half the length of the mesoscutum, anterior parallel line distinct, extending to half the length of the mesoscutum, the mesopleuron partially punctate, metasomal tergites smooth, while in A. chapmanii the head is alutaceous, the mesoscutum alutaceous, notaulus complete, anterior parallel line indistinct and hardly visible, the mesopleuron is smooth and glabrous, metasomal tergites with micropunctures. In A. vacciniiformis the length of OOL is equal to POL, the mesoscutum has dense white setae, thus the sculpture is not or hardly visible, the mesoscutellum has a transverse semilunar impression at the base with the same sculpturing pattern on the bottom as on the mesoscutellar disk, while in A. chapmanii the OOL in females is distinctly longer than POL, the mesoscutum has sparse setae and the sculpture of the mesoscutum is distinct, the mesoscutellar foveae are small and deep with a smooth glabrous bottom, separated by an elevated central carina.

Description. Asexual female ( Figs. 46–55 View FIGURES 46–51 View FIGURES 52–55 ). Head, metasoma dark brown; mesosoma black; antennae light brown, darkened at the distal end; coxae, femorae and tibiae dark brown, tarsi light brown.

Head delicately alutaceous, with white setae, denser on lower face, 1.3× as broad as high and slightly broader than mesosoma in frontal view, 2.2× as broad as long in dorsal view. Gena alutaceous, broadened behind eye, slightly broader than transverse diameter of eye. Malar space alutaceous, with delicate parallel striae radiating from clypeus and not reaching eye; eye 2.3× as high as length of malar space. Eyes slightly converging ventrally. POL 1.4× as long as OOL, OOL 2.65× as long as diameter of lateral ocellus, 1.3× as long as LOL; ocelli ovate, all equal in size. Transfacial distance 1.3× as long as height of eye and 2.0× as long as height of lower face (distance between antennal rim and ventral margin of clypeus); diameter of antennal torulus 1.2× as long as distance between them, distance between torulus and eye 1.5× as long as diameter of torulus. Lower face smooth, glabrous, without striae, with elevated median area. Clypeus rectangular, flat, 2.0× as broad as high, smooth, glabrous; ventrally rounded, not emarginated, without median incision; anterior tentorial pit deep, epistomal sulcus and clypeo-pleurostomal line distinct. Frons and interocellar area delicately alutaceous, with few setae; vertex, occiput alutaceous. Postgena smooth, glabrous, postocciput around occipital foramen impressed, smooth, glabrous, with delicate parallel striae; posterior tentorial pit large, deep, elongate; hypostomal carina emarginate, continuing into postgenal sulci, postgenal bridge broader toward occipital foramen; occipital foramen as high as height of postgenal bridge.Antenna shorter than head+mesosoma, with 12 flagellomeres; pedicel 1.3× as long as broad, F1 1.9× as short as length of scape+pedicel and 1.5× as long as F2, F2 1.25× as long as F3, F3–F5 equal in length, subsequent flagellomeres shorter, broader and equal in length, F12 2.0× as long as F11; placodeal sensilla in numerous rows on F4–F12.

Mesosoma nearly as high as long in lateral view. Pronotum smooth, glabrous, with white setae, without striae, emarginate along anterolateral rim. Mesoscutum alutaceous, with some white setae, nearly as long as broad (width measured across base of tegulae). Notaulus complete, deeply impressed in posterior 2/3 of mesoscutum length, with smooth, glabrous bottom, posteriorly broad and converging; anterior parallel line indistinct, hardly traceable; median mesoscutal line absent; parascutal line broad, smooth, reaching base of tegula. Transscutal articulation deep, distinct. Mesoscutellum longer than broad, with subparallel sides; shorter than mesoscutum, coriaceous, with smooth glabrous mesoscutellar disk, overhanging metanotum; mesoscutellar foveae rounded, with smooth, glabrous bottom, divided by narrow median carina. Mesopleuron and speculum smooth, glabrous, with few setae; mesopleural triangle smooth, glabrous, with a few white setae. Metapleural sulcus reaching mesopleuron in upper 1/3 of its height, upper part of sulcus indistinct; dorsal and lateral axillar areas smooth, glabrous, with setae; axillar carina broad, with longitudinal striae; subaxillular bar broad, smooth, glabrous, as high as height of smooth, glabrous metanotal trough. Metascutellum coriaceous, shorter than height of smooth, glabrous ventral impressed area. Central propodeal area smooth, glabrous, without striae; lateral propodeal carinae distinct, broad, subparallel, slightly curved outwards in posterior 1/3; lateral propodeal area smooth, glabrous, with a few long white setae; nucha short, without sulci dorsally, with delicate sulci laterally.

Forewing slightly longer than body, hyaline, veins pale brown, margin with long, dense cilia; radial cell opened, 3.3× as long as broad; R1 and Rs nearly reaching wing margin; areolet triangular, well-delimited by distinct veins; Rs+M projection reaching basalis at mid-height. Tarsal claws simple, without basal lobe.

Metasoma nearly as long as head+mesosoma, longer than high in lateral view, glabrous, with a few white setae anterolaterally; second metasomal tergite smooth, occupying more than half length of metasoma dorsally; subsequent tergites and hypopygium with dense micropunctures; prominent part of ventral spine of hypopygium 5.4× as long as broad in ventral view, with short white setae ventrally. Body length 2.6–2.8 mm (n = 2).

Gall ( Fig. 56 View FIGURE 56 ). The unilocular gall is shaped like a tall cup or wine glass, 5–6 mm long, 2–3 mm in diameter, with delicate longitudinal surface grooves. The gall is slightly broader distal to the point of attachment to the leaf and the apex of the gall is truncate and depressed centrally. The gall is green to brown, develops on the underside of leaves, typically in clusters of 3–10 galls.

Biology. Only an asexual generation is known, which induces galls on Q. chapmanii . The galls mature in October–November, at which stage the galls fall easily from the leaves. The larvae overwinter in the gall and the adults probably emerge in March–April. Rare.

Distribution. USA, Florida, Highlands Co., Lake Placid, Archbold Biological Station.


Smithsonian Institution, National Museum of Natural History