New species of oak gallwasps from Taiwan (Hymenoptera: Cynipidae: Cynipini)

ZOOTAXAISSN 1175-5326 (print edition)

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Zootaxa 2865: 37–52 (2011) www.mapress.com/zootaxa/ Article

New species of oak gallwasps from Taiwan (Hymenoptera: Cynipidae: Cynipini)

CHANG-TI TANG1, GEORGE MELIKA2,4, MAN-MIAO YANG1,JAMES A. NICHOLLS3 & GRAHAM N. STONE3

1Department of Entomology, National Chung Hsing University, Taichung, 40227 Taiwan. E-mail: [email protected]; [email protected] Diagnostic Laboratory, Plant Protection & Soil Conservation Directorate of County Vas, Ambrozy setany 2, 9762 Tanakajd (Hungary). E-mail: [email protected] 3Institute of Evolutionary Biology, University of Edinburgh, King’s Buildings, West Mains Road, Edinburgh EH9 3JT, Scotland, U.K. E-mail: [email protected]; [email protected] author. E-mail: [email protected]

Abstract

Three new species of oak gallwasps from Taiwan are described: Andricus songshui and Andricus pseudocurvator, both known to induce integral leaf galls on Quercus serrata, and Plagiotrochus glaucus which induces stem swelling-like galls on Quercus glauca. Galls and adults of new species are described; data on the diagnosis, distribution and biology of the new species and a key to the Taiwanese Andricus species are also given.

Key words: Andricus, Plagiotrochus, taxonomy, distribution, biology

Introduction

The cynipid gallwasp fauna of the Eastern Palaearctic and Oriental region is poorly known: only 35 valid species are recognised from the Eastern Palaearctic, mostly from Japan and the Russian Far East. Only few oak gallwasp species from the Oriental region have yet been described or mentioned as “cynipid gallwasp” (Kovalev 1965; Mani 2000; Abe et al. 2007; Melika et al. 2010), most of which are from Taiwan (Tang et al. 2009; Melika et al. 2010)In Taiwan the plant family Fagaceae is represented by 3 genera which serve as hosts for oak gallwasps (Cynipini): Castanopsis (D.Don) (8 species); Lithocarpus Blume (=Pasania (Miq.)) (15 species); Quercus L. subgenus Cyclo-balanopsis Oerst. (13 species), and Quercus subgenus Quercus (10 species in two sections, Cerris and Quercus) (Govaerts & Frodin 1998; Lu et al. 2006). To date, eleven gall morphotypes attributed to cynipids have been described from Taiwan (Yang & Tung 1998; Yang et al. 2000), from which only three valid species are known: Andricus formosanus Tang & Melika (Tang et al. 2009), Trichagalma formosana Melika & Tang (Melika et al.2010), and Cerroneuroterus vonkuenburgi (Dettmer) (Melika et al. 2010). Here we describe three new oak gall-wasp species from Taiwan which are associated with either the subgenus Cyclobalanopsis or Quercus.

Material and methods

We follow the current terminology of morphological structures and surface sculpturing (Ronquist & Nordlander 1989; Liljeblad & Ronquist 1989; Melika 2006; Harris 1979). Abbreviations for fore wing venation follow Ron-quist & Nordlander (1989), cuticular surface terminology follows that of Harris (1979). Measurements and abbre-viations used here include: F1–F12, 1st and subsequent flagellomeres; POL (post-ocellar distance) is the distance between the inner margins of the posterior ocelli; OOL (ocellar-ocular distance) is the distance from the outer edge of a posterior ocellus to the inner margin of the compound eye; LOL, the distance between lateral and frontal ocelli. The width of the forewing radial cell is measured from the margin of the wing to the Rs vein. In cynipoid literature

Accepted by M. Buffington: 29 Mar. 2011; published: 3 May 2011 37

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(Ronquist & Nordlander 1989; Melika 2006; Liljeblad et al. 2008) the postgenal bridge was termed as gula and the postgenal sulcus as gular sulcus; the setaceous median sulcus of the postgenal bridge was named as the median membranous strip of gula (Liljeblad et al. 2008). The term gula, which, by definition, is a sclerotisation between the foramen magnum and the posterior tentorial pits and as such is rare in Hymenoptera (Vilhelmsen 1999), thus we prefer to use the terms “postgenal bridge” and “postgenal sulcus”.

Images of wasp anatomy were produced with a digital Nikon Coolpix 4500 camera attached to a Leica DMLB compound microscope, followed by processing in CombineZP (Alan Hadley) and Adobe Photoshop 6.0.

The type material (wasps and galls) is deposited in the following institutions: NMNS, National Museum of Natural Science, Taichung, Taiwan (curator Mei-Ling Chan); PDL, Pest Diagnostic Laboratory (the former Sys-tematic Parasitoid Laboratory, SPL), Tanakajd, Hungary (curator G. Melika); NCHU, collection of the Department of Entomology, National Chung Hsing University, Taichung, Taiwan (curator Chang-Ti Tang); USNM, National Museum of Natural History, Smithsonian Institution, Washington, DC, U.S.A. (curator Matthew Buffington); AMNH, American Museum of Natural History, New York City, U.S.A. (curator James Carpenter).

Andricus songshui Tang & Melika, new speciesFigs 1–19

Type material. HOLOTYPE female: TAIWAN, Nantou County, Renai Township, ex Quercus serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 10.III.2010. PARATYPES: 26 females and 19 males: 3 female paratypes with the same labels as the holotype; 1 female paratype: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 08.III.2010; 1 female paratype: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 09.III.2010; 5 female and 3 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 09.III.2010; 4 female paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 11.III.2010; 1 female paratype: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 12.III.2010; 7 female and 9 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 18.III.2010. adult em. 21.III.2010; 1 female and 4 male paratypes: TAIWAN, Nan-tou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 18.III.2010. adult em. 22.III.2010; 2 male para-types: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 18.III.2010. adult em. 23.III.2010; 2 female and 1 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 18.III.2010. adult em. 24.III.2010. The female holotype, 9 female and 7 male paratypes are deposited in NMNS, 5 female and 4 male paratypes in PDL, 2 female and 2 male in USNM, 10 female and 6 male paratypes in NCHU.

Etymology. The species named after the mountain, Mt. Song-Shu, where it was collected for the first time.Diagnosis. Andricus songshui resembles the only known Taiwanese Andricus species, A. formosanus and the

herein described new species, A. pseudocurvator. In Andricus songshui, at least anterior half of the mesoscutum distinctly sculptured, delicately coriaceous to alutaceous; F1 of male antenna slightly curved and swollen apically and 1.8 times as long as pedicel, while in A. formosanus and A. pseudocurvator mesoscutum alutaceous to smooth, glabrous, without distinct strong surface sculpture anteriorly, F1 of male antenna strongly curved, swollen apically and 2.8–3.0 times as long as pedicel.

Description. SEXUAL FEMALE. Head dark brown to black; antenna brown dorsally, yellow ventrally; meso-soma and metasoma dark brown, legs uniformly dark yellow.

Head alutaceous, with some white setae, more dense on lower face; 2.0 times broader than long from above, 1.25 times broader than high,as broad as mesosoma in anterior view. Gena alutaceous, not broadened behind eye, 0.5 times cross diameter of eye; malar area alutaceous, with delicate striae extending to eye margin, 0.4 times height of eye. Compound eyes converging ventrally. POL nearly 1.2 times broader than OOL; OOL 3.0 times length of lateral ocellus and 1.75 times LOL; all ocelli of same size and shape. Transfacial distance only 1.2 times wider than height of eye; diameter of antennal toruli 1.4 times distance between them, distance between torulus and inner margin of eye 1.4 times diameter of torulus; lower face alutaceous, with dense white setae, small area under antennal torulus and median elevated area coriaceous. Clypeus rounded, emarginate, without median incision ven-trally, alutaceous to glabrous, with very small elevated central area; anterior tentorial pits distinct, epistomal sulcus

TANG ET AL.38 · Zootaxa 2865 © 2011 Magnolia Press

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and clypeo-pleurostomal line distinct, deep. Frons alutaceous, with small smooth shiny impression below median ocellus, with some white setae; interocellar area delicately coriaceous. Vertex and occiput delicately coriaceous to alutaceous. Postocciput and postgena smooth, shiny, without setae; posterior tentorial pit large, ovate, deep, area below not impressed; height of occipital foramen nearly equal to height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulcus. Antenna with 11 flagellomeres; slightly longer than mesosoma; pedi-cel longer than broad; F1 1.3 times longer than F2, 2.3 times longer than pedicel; F2–F10 progressively shorter; F11 2.0 times longer than F10; placodeal sensilla present on F3–F11, absent on F1–F2.

FIGURES 1–8. Andricus songshui, new species: 1–4, head, female: 1, anterior view, 2, dorsal view, 3, posterior view, 4, lateral view. 5–6, head, male: 5, anterior view, 6, dorsal view. 7–8, antenna: 7, female, 8, male.

Zootaxa 2865 © 2011 Magnolia Press · 39NEW OAK GALLWASP SPECIES FROM TAIWAN

FIGURES 9–13. Andricus songshui, new species, female: 9, clypeus and lower face, anterior view, 10, mesoscutum, dorsal view, 11, mesoscutellum, dorsal view, 12, mesosoma, lateral view, 13, metascutellum and propodeum, posterodorsal view.

Mesosoma 1.2 times longer than high. Pronotum coriaceous to smooth, shiny, with delicate parallel striae later-ally, with dense white setae; propleuron light brown, alutaceous, shiny, with smooth area centrally. Mesoscutum alutaceous to delicately coriaceous in anterior half, smooth or delicately alutaceous in posterior half, especially in area between notauli, shiny, with some white setae; slightly wider than long (largest width measured across mesoscutum at level of base of tegulae). Notauli complete, deep, distinctly impressed, slightly converging and broadened at posterior and anterior ends; anterior parallel, parapsidal, median mesoscutal lines absent. Mesoscutel-lum quadrangular, uniformly dull rugose, with irregular strong rugae, longer than broad, overhanging metanotum; scutellar foveae distinct, transversely ovate, nearly 2.0 times wider than high, with smooth, shining bottom, with distinct elevated narrow smooth median carina, separating foveae. Mesopleuron and speculum darker than rest of mesosoma, smooth, shining, without setae, except dense patch of setae on posteroventral quarter of speculum; with impressed foveae along acetabular carina; dorsal axillar area smooth, shining, with dense white setae; lateral axillar area alutaceous, with some setae; subaxillular bar dark brown, smooth, shiny, the most posterior part broader than height of metanotal trough; postalar process with parallel delicate striae; metapleural sulcus reaching mesopleuron at upper 1/3 of its height. Metascutellum uniformly coriaceous, metanotal trough smooth, shiny, with some short


white setae; ventral impressed area nearly as high as height of metascutellum, smooth, with distinct longitudinal striae; central propodeal area smooth, shiny, with some irregular wrinkles and rugae, lateral propodeal carinae strong, high, curved outwards in posterior third; lateral propodeal area rugose, with dense long, white setae. Nucha with irregular wrinkles and rugae, brown.

Tarsal claws with basal lobe. Forewing longer than body, hyaline, with distinct long, dense cilia on margin, radial cell 3.9 times longer than wide; R1 reaching wing margin, Rs nearly straight, reaching wing margin; areolet small, triangular, closed and distinct. Rs+M distinct at 2/3 of distance to basalis and its projection reaching basalis at middle.

FIGURES 14–19. Andricus songshui, new species: 14, forewing, female, 15, metasoma, female, lateral view, 16, ventral spine of hypopygium, lateral view, 17, metasoma, male. 18–19, gall (Fig. 18 by Chang-Ti Tang, Fig. 19 by Chang-Fu Wu).


Metasoma slightly shorter than head+mesosoma, higher than long in lateral view; 2nd metasomal tergite occu-pying nearly half length of metasoma in dorsal view, with some white setae laterally, all subsequent tergites without setae, smooth, shiny. Ventral spine of hypopygium short, prominent part nearly as long as broad, with some white subapical setae extending beyond apex of spine; 4–5 long white setae located along ventral part of hypopygium. Body length 1.7–2.0 mm (n=5).

MALE. 1.7–1.8 mm (n=4), similar to female but head and mesosoma black, metasoma very dark brown to black; antenna with 13 flagellomeres, slightly longer than body length, F1 only slightly curved and swollen api-cally, 1.3 times longer than F2 and nearly 1.8 times longer than pedicel; F13 nearly equal in length to F12; placo-deal sensilla present on all flagellomeres.

Gall (Figs 18–19). Swelling, occurring on both unfolded young leaves and base of midrib, 1.8–2.5 mm long (n = 10). Galls located at the base of a leaf midrib are usually yellowish and single; galls on unopened young leaves are green and in clusters of 1–3, multilocular. The two gall morphotypes can be found in the same month.

Biology. Only the sexual generation is known, inducing integral leaf galls on Quercus serrata Murray (=Q. glandulifera Blume) (section Quercus sensu stricto). Mature galls were collected in early March, adults emerging immediately after the galls were collected, in mid to late March.

Distribution. Currently known only from Taiwan: Nantou County, Renai Township (Fig. 57). It is possible that this species is also distributed in continental China and Japan where Q. serrata occurs. Further research is neces-sary to establish the distribution of this species.

Andricus pseudocurvator Tang & Melika, new speciesFigs 20–38

Type material. HOLOTYPE female: TAIWAN, Nantou County, Renai Township, ex Quercus serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 11.III.2010. PARATYPES: 12 females and 18 males: 5 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 08.III.2010; 6 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 09.III.2010; 4 female and 2 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 10.III.2010; 1 female paratype: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 01.III.2010. adult em. 12.III.2010; 6 female and1 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 12.III.2010; 4 male paratypes: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 04.III.2010. adult em. 14.III.2010; 1 female paratype: TAIWAN, Nantou County, Renai Township, ex Q. serrata, leg. Chang-Ti Tang, 18.III.2010. adult em. 24.III. The female holotype, 4 female and 7 male paratypes are deposited in NMNS, 3 female and 3 male paratypes in PDL, 1 female and 1 male in USNM, 4 female and 7 male paratypes in NCHU.

Etymology. The shape, structure and location of the gall is very similar to that induced by a Western Palaearc-tic species, Andricus curvator Hartig, thus the species was named as “curvator-like” -- pseudocurvator.

Diagnosis. Andricus pseudocurvator most closely resembles A. formosanus. In Andricus pseudocurvator head anteriorly black, malar area with striae, frons smooth shiny or very delicately alutaceous, distance between anten-nal toruli slightly larger than diameter of torulus; 2nd metasomal tergite in females occupying 1/3–1/2 length of metasoma in dorsal view, prominent part of ventral spine of hypopygium 6.0 times longer than broad; male pre-dominantly black, while in A. formosanus head anteriorly, especially lower face, brown, malar area without striae, frons with distinct alutaceous sculpture, distance between toruli distinctly shorter than diameter of torulus; 2nd metasomal tergite occupying 2/3 length of metasoma in dorsal view, prominent part of ventral spine of hypopy-gium around 3.0 times longer than broad; male light brown. Andricus pseudocurvator also differs distinctly from A.moriokae Monzen, known from Japan, which more closely resembles A. formosanus.

Description. SEXUAL FEMALE. Head black (in some paratypes very dark brown); antenna yellowish brown, with dark brown F8–F11; mandibles, palpi labialis and maxilaris dirty yellow; mesosoma black, metasoma dark brown, legs light brown, with basally darker coxae.

Head alutaceous, with some white setae, more dense in lower face; 2.0 times broader than long from above, 1.3 times broader than high and as broad as mesosoma in anterior view. Gena alutaceous, not broadened behind eye, nearly 0.5 times cross diameter of eye; malar area alutaceous, with some delicate striae extending to eye margin,


FIGURES 20–27. Andricus pseudocurvator, new species: 20–23, head, female: 20, anterior view, 21, dorsal view, 22, poste-rior view, 23, clypeus and lower face, anterior view. 24–25, head, male: 24, anterior view, 25, dorsal view. 26–27, antenna: 26, female, 27, male.

0.4 times height of eye. Inner margins of compound eyes nearly parallel. POL nearly 1.4 times OOL; OOL 2.5 times length of lateral ocellus and 1.5 times LOL; all ocelli ovate, same size and shape. Transfacial distance 1.3 times height of eye; diameter of antennal toruli nearly equal to distance between them, distance between torulus and inner margin of eye 1.2 times diameter of torulus; lower face alutaceous, with dense white setae, median ele-


vated area alutaceous. Clypeus quadrangular, nearly 2.0 times broader than high, slightly emarginate, without median incision ventrally, alutaceous to glabrous, with very small elevated central area; anterior tentorial pit dis-tinct, large, epistomal sulcus and clypeo-pleurostomal line distinct, deep. Frons smooth, shiny, delicately aluta-ceous, with small smooth shiny impression below median ocellus, with some white setae; interocellar area with stronger surface sculpture. Vertex and occiput delicately alutaceous to smooth, shiny. Postocciput and postgena smooth, shiny, with some setae; posterior tentorial pit large, ovate, deep; height of occipital foramen nearly equal to height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulcus. Antenna with 11 flagellomeres (in some paratype females indistinct suture present and antenna seems to be with 12 flagellomeres); slightly longer than mesosoma; pedicel slightly longer than broad; F1 1.2 times F2, 2.0 times longer than pedicel and nearly equal to length of scape; F2–F8 progressively shorter; F8–F10 nearly equal in length; F11 2.2 times lon-ger than F10 (if a suture present, than F12 equal to F11); placodeal sensilla present on F3–F11, absent on F1–F2.

FIGURES 28–32. Andricus pseudocurvator, new species, female: 28, head, lateral view, 29, mesoscutellum, dorsal view, 30, mesoscutum, dorsal view, 31, mesosoma, lateral view, 32, metascutellum and propodeum, posterodorsal view.


FIGURES 33–38. Andricus pseudocurvator, new species: 33, forewing, female, 34, metasoma, female, lateral view, 35, ven-tral spine of hypopygium, lateral view, 36, metasoma, male. 37–38, gall (photos by Chang-Ti Tang).

Mesosoma 1.2 times longer than high. Pronotum coriaceous to alutaceous, with parallel, very delicate striae posterolaterally, with dense white setae; propleuron brown, alutaceous, shiny, with smooth area in center, concave in mediocentral part. Mesoscutum smooth, shiny, delicately alutaceous in anterior third, with some white setae; slightly broader than long (largest width measured across mesoscutum at the level of the base of tegulae). Notauli complete, deep, distinctly impressed, slightly converging and broadened at posterior and anterior ends; anterior parallel and parapsidal lines inconspicuous; median mesoscutal line absent, parascutal carina broad. Mesoscutel-lum trapezoid, broader posteriorly, slightly longer than broad, overhanging metanotum, uniformly dull rugose, with irregular strong rugae, areas between rugae smooth, shiny; scutellar foveae distinct, deep, transversely ovate, broader than high, with smooth, shiny bottom, with distinct elevated narrow smooth median carina, separating foveae. Mesopleuron and speculum smooth, shiny, without setae, except dense patch of setae on posteroventral quarter of speculum; with impressed, transverse foveae along acetabular carina; dorsal axillar area smooth, shiny,


with dense white setae; lateral axillar area smooth, shiny, with some setae; subaxillular bar smooth, shiny, poste-riormost part narrower than height of metanotal trough; postalar process with parallel delicate striae; metapleural sulcus reaching mesopleuron slightly above half its height. Metascutellum uniformly delicately coriaceous, metan-otal trough smooth, shiny, with some short white setae; ventral impressed area nearly 2.0 times height of metas-cutellum; central propodeal area smooth, shiny, without or with very few irregular delicate wrinkles, lateral propodeal carinae distinct, curved outwards in posterior 1/4; lateral propodeal area coriaceous, with dense long, white setae. Nucha with irregular wrinkles and rugae.

Tarsal claws with basal lobe. Forewing longer than body, hyaline, with distinct, long dense cilia on margin, radial cell 3.3 times longer than broad; R1 and Rs nearly reaching wing margin; areolet small, triangular, closed and distinct. Rs+M distinct for 2/3 of distance to basalis and its projection reaching basalis at middle.

Metasoma slightly longer than head+mesosoma, nearly as high as long in lateral view; 2nd metasomal tergite occupying 1/3–1/2 length of metasoma in dorsal view, with some white setae laterally, all subsequent tergites with-out setae, smooth and shiny. Ventral spine of hypopygium long, prominent part 6.0 times longer than broad, with some white subapical setae not extending beyond apex of spine, with numerous long setae ventrally. Body length 1.9–2.1 mm (n=3).

MALE. 1.8–1.9 mm (n=3), similar to female but compound eye slightly larger and malar area shorter; ocelli slightly larger; antenna with 13 flagellomeres, slightly longer than body length, F1 curved and swollen apically, 1.2 times longer than F2 and nearly 2.5 times longer than pedicel; F13 equal in length to F12; placodeal sensilla pres-ent on all flagellomeres.

Gall (Figs 37–38). Individual galls approximately spherical, 2.4–3.6 mm in height (n=9), and integral to leaf lamina. Galls appear as yellowish or brownish dots on leaves, cause swelling on both upper and lower surfaces of leaf, each contains single thin-walled larval chamber, 1.6–2.3 mm in diameter (n=9). Outer wall of larval chamber attached to inner wall of surrounding gall tissue in both growing and mature galls. Galls usually occur separately on leaf and do not aggregate together. Young galls fleshy, yellowish to brownish, remaining soft as they mature.

Biology. Only the sexual generation of this species is known, inducing integral leaf galls on Q. serrata. Mature galls were collected in early March, adults emerged immediately after the galls were collected, in mid and late March.

Distribution. Currently known only from Taiwan: Nantou County, Renai Township and Taichung County, Heping Township (Fig. 57). In Taichung County, galls have been observed but no adults have been reared. It is pos-sible that this species also occur in continental China and Japan, where Q. serrata occurs. Further research is neces-sary to establish the distribution of this species.

Comments. The gall of this species occurs and develops at the same time as A. songshui, on the same organ of Q. serrata. Preliminary molecular data suggest this species is allied to the Eastern Palaearctic species A. symbioti-cus and the Western Palaearctic species A. inflator (J.Nicholls, unpublished data).

Key to Andricus species of Taiwan

1 Anterior half of mesoscutum distinctly sculptured, delicately coriaceous to alutaceous; F1 of male antenna slightly curved and swollen apically, 1.8 times longer than pedicel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . songshui

- Mesoscutum alutaceous to smooth, glabrous, without distinct surface sculpture anteriorly; F1 of male antenna stronly curved and swollen apically, 2.8–3.0 times longer than pedicel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Head black anteriorly, malar area with striae; frons smooth shiny or very delicately alutaceous; distance between antennal toruli slightly larger than diameter of torulus; prominent part of ventral spine of hypopygium 6.0 times longer than broad; male predominantly black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pseudocurvator

- Head brown anteriorly, especially lower face; malar area without striae, frons with distinct alutaceous sculpture; distance between toruli distinctly shorter than diameter of torulus; prominent part of ventral spine of hypopygium around 3.0 times lon-ger broad; males light brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . formosanus

Plagiotrochus glaucus Melika & Tang, new speciesFigs 39–56

Type material. HOLOTYPE female: TAIWAN, Nantou County, Lienhuachih Forest Research Centre, ex Quercus


glauca, 23.X.2008. leg. J. Nicholls. Thirty-four female PARATYPES with the same labels as the holotype. The female holotype and 5 paratypes are deposited in NMNS, 15 female paratypes in PDL, 4 female paratypes in USNM, 4 female paratypes in AMNH, 5 female paratypes in NCHU.

Etymology. The species is named after the host plant, Quercus glauca Thunb. on which it induces galls.Diagnosis. There are no Plagiotrochus species known from the Far East of Russia, Japan and China, thus no

obvious species to compare with P. glaucus. More details are presented in Comments below. But the species does possess the diagnostic characters of Plagiotrochus: malar sulcus absent, lower face with few striae radiating from clypeus; mesoscutum transversely rugose, 1.3-2.0 times longer than broad; central propodeal area broad, delimited by strongly outwards curved lateral propodeal carinae; median longitudinal carina present; forewing margin always with long cilia.

FIGURES 39–44. Plagiotrochus glaucus, new species, female: 39–43, head: 39, anterior view, 40, dorsal view, 41, posterior view, 42, clypeus and lower face, anterior view. 43, mouthparts and postgenal bridge, posterior view. 44, antenna.


Description. ASEXUAL FEMALE. Entire body uniformly chestnut reddish brown, with slightly lighter genae, antennae and legs; metasoma slightly darker dorsally and laterally.

Head massive, rounded in anterior view, dull, rugose, with some white setae, more dense setation in lower face; 1.9–2.0 times broader than long from above, 1.2 times broader than high and slightly broader than mesosoma in anterior view. Gena uniformly and delicately coriaceous to reticulate, broadened behind eye, nearly as broad as cross diameter of eye; malar area coriaceous, with some striae extending to eye margin, 0.4 times height of eye. Inner margins of compound eyes slightly converging ventrally. POL 0.8 times OOL; OOL 3.6 times longer than lateral ocellus and 2.7 times LOL; all ocelli elongated, ovate, of same size and shape. Transfacial distance 1.2 times height of eye; diameter of antennal toruli 2.2 times larger than distance between them, distance between torulus and inner margin of eye 1.2 times diameter of torulus; lower face coriaceous, with dense white setation; rugae irradiat-ing from clypeus extending into area between eye and torulus; median elevated area of lower face coriaceous. Clypeus rounded, nearly as broad as high, emarginate, without median incision ventrally, alutaceous to glabrous, with small elevated rugose central area; anterior tentorial pit distinct, large, epistomal sulcus and clypeo-pleuros-tomal line distinct, deep. Frons rugose, shiny, with small smooth, shiny impression below median ocellus, with some white setae; interocellar area with strong rugae. Vertex and occiput uniformly coriaceous. Postocciput and postgena reticulate, shiny, impressed around occipital foramen, with some setae; posterior tentorial pit large, ovate, deep; height of occipital foramen nearly equal to height of coriaceous postgenal bridge; hypostomal carina emar-ginate, continuing into postgenal sulcus, not united medially. Antenna with 12 flagellomeres, slightly longer than mesosoma; pedicel longer than broad; F1 1.2 times longer than F2, 1.7 times longer than pedicel and nearly equal to length of scape; F2–F4 progressively shorter; F5–F11 nearly equal in length; F12 1.7 times longer than F11; pla-codeal sensilla present on F3–F12, absent on F1–F2.

Mesosoma elongate, 1.3 times longer than high. Pronotum dull, rugose, with some white setae, rugae with anastomoses, area between rugae smooth, shiny; propleuron brown, delicately coriaceous to alutaceous, shiny, con-cave in medio-central part. Mesoscutum uniformly dull, rugose, with rugae orientated mainly transversely, with numerous anastomoses; slightly longer than broad (largest width measured across mesoscutum on the level of the base of tegulae), with very few short, white setae. Notauli complete, deep, distinctly impressed, slightly converging at posterior end, with transverse rugae on bottom; anterior parallel and parapsidal lines hardly traceable in polished smooth areas; median mesoscutal line as short as longitudinal impression (sometimes hardly traceable); parascutal carina narrow. Mesoscutellum quadrangular, broader in posterior 1/4, longer than broad, only very slightly over-hanging metanotum, uniformly dull, rugose, with irregular strong rugae, areas between rugae smooth, shiny; scutellar foveae slightly ovate or transverse, occupying 1/3–1/5 length of mesoscutellum, with smooth, shiny bot-tom, with elevated narrow, smooth median carina, separating foveae; foveae absent or very indistinct in some para-types. Mesopleuron reticulate in upper half, with numerous transversely orientated delicate striae (rugae) medially, especially in anterior half; mesopleuron coriaceous ventrad to median transverse rugae, with more dense white setation; acetabular carina delimiting very narrow area; dorsal axillar area narrow, coriaceous to rugose, with some setae; lateral axillar area smooth, shiny, with some setae and rugae; subaxillular bar smooth, shiny, posteriormost part narrower than height of metanotal trough; postalar process with parallel delicate striae; metapleural sulcus reaching mesopleuron in upper third of its height. Metascutellum uniformly coriaceous, metanotal trough smooth, shiny, with some short, white setae; ventral impressed area nearly as high as height of metascutellum, smooth, with distinct longitudinal striae; central propodeal area smooth, shiny, without or with very few irregular, delicate wrin-kles, lateral propodeal carinae distinct, curved outwards in posterior third; lateral propodeal area rugose, with dense, long, white setation. Nucha very short, smooth, shiny, without irregular wrinkles and rugae.

Tarsal claws simple, without basal lobe. Forewing longer than body, hyaline, with distinct, long, dense ciliation on margin, radial cell 3.7 times longer than broad; R1 nearly straight, Rs reaching wing margin and for a short dis-tance following margin; areolet large, triangular, closed and distinct. Rs+M distinct throughout, reaching basalis somewhat posterior to middle.

Metasoma as long as head+mesosoma or slightly shorter, slightly longer than high in lateral view; 2nd meta-somal tergite occupying more than half length of metasoma in dorsal view, without setae laterally, all subsequent tergites without setae, smooth, shining. Narrow posterior band on 2nd metasomal tergite and all subsequent tergites entirely uniformly, densely, minutely punctured. Ventral spine of hypopygium very short, prominent part as long as broad, with sparse, long white subapical setation, extending far beyond apex of spine, with many long setae ven-trally. Body length 2.3–2.8 mm (n=20).


FIGURES 45–50. Plagiotrochus glaucus, new species, female: 45, mesoscutum, dorsal view, 46, mesoscutellum, dorsal view, 47, pronotum and propleuron, anterior view, 48, mesosoma, lateral view, 49, metascutellum and propodeum, posterodorsal view, 50, hind tarsal claw.


FIGURES 51–56. Plagiotrochus glaucus, new species, female: 51, forewing, 52, metasoma, female, lateral view, 53, ventral spine of hypopygium, lateral view. 54–56, gall (photos by J. Nicholls).

Gall (Figs 54–56). The gall is a swelling of branches and twigs, usually located in middle of twig, not apically; sometimes swellings at joints of twigs; up to 6.0 cm long, 1.2–1.5 cm in diameter, coloured the same as the bark of twigs. When the gall mature, tissues hard, lignified. Larval chambers (up to 14 mm in length and 3–5 mm in diam-eter) arranged perpendicularly to main axis of gall, radiating from center of twig toward gall surface, reaching to 2–3 mm from surface (Fig. 56).

Biology. Only the asexual generation is known, inducing stem swelling-like galls on Quercus glauca. Mature galls were collected in late October, adults emerged under laboratory conditions the following spring.


FIGURE 57. Current distribution of Andricus songshui, A. pseudocurvator and Plagiotrochus glaucus (figure from http://www.google.com/earth/,). The white dot represents the location where A. songshui and A. pseudocurvator occur together (Renai Township, Nantou County), the blue dot represents another site where A. pseudocurvator is known to occur (Heping Township, Taichung County), and the red dot shows the type locality of P. glaucus (Nantou County, Lienhuachih Forest Research Centre).


Distribution. Taiwan: currently known from Nantou County, Lienhuachih Forest Research Centre only (Fig. 57).

Comments. The genus Plagiotrochus includes 15 Western Palaearctic species (Pujade-Villar & Ros-Farré 1998; Pujade-Villar et al. 2000; Nieves Aldrey 2001; Melika et al. 2010). Only three Eastern Palaearctic species have been described: P. semicarpifoliae (Cameron) from the NW Himalayas, known to induce acorn galls on Q. semicarpifolia Smith (Bellido et al. 2000), and P. smetanai Melika & Pujade-Villar and P. follioti Pujade-Villar & Melika, both from Nepal (Melika et al. 2009). Plesiomorphic traits of P. semicarpifoliae (Cameron), known from the Himalayan area, and the herein described new species from Taiwan, suggest a Southeast Asian origin for Pla-giotrochus, with species from the Mediterranean region probably being derived and representing a secondary radi-ation (Melika et al. 2010). On the basis of molecular data, Plagiotrochus glaucus does not seem to form a monophyletic group with Western Palaearctic Plagiotrochus species but rather appears plesiomorphic relative to the Mediterranean species (J. Nicholls, unpublished data).

References

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New species of oak gallwasps from Taiwan (Hymenoptera: Cynipidae: Cynipini)