Cerroneuroterus yukawamasudai Pujade-Villar & Melika, 2020

Pujade-Villar, Juli, Wang, Yiping, Guo, Rui, Sala-Nishikawa, Alba, Cuesta-Porta, Victor, Arnedo, Miquel A. & Melika, George, 2020, A new species of Cerroneuroterus Melika & Pujade-Villar from the Eastern Palaearctic (Hymenoptera, Cynipidae, Cynipini), Zootaxa 4869 (4), pp. 515-528 : 518-522

Cerroneuroterus yukawamasudai Pujade-Villar & Melika , sp. nov.

( Figs 1–3 )

urn:lsid:zoobank.org:act:B8F23FF3-50B2-4CC5-8DBE-B7FD8662BEA2

Type material. HOLOTYPE female: “ Mian Hua community, Xi Fu Town, Cheng Yin District , Qingdao City , Shandong Province ” (white label); “ Q. acutissima (17.xi.2018) 15-31.i.2019 (col. Zhao Haiyan)” (white label); “ Holotype ♀, Cerroneuroterus yukawamasudai sp. nov. (desig. J. P-V)” (red label). Paratypes: 33 females: 11 with the same labels as holotype; 22 idem but emerged in ii.2019. The holotype and 33 female paratypes are deposited in the J.P-V collection at the University of Barcelona (Catalonia) , 22 female paratypes in Zhejiang Agricultural and Forestry University, China ( ZAFU) .

Additional material: 3 asexual females (with the same data as the holotype), 2 females used for preparing SEM pictures and 1 female for the DNA extraction. The sequences are deposited in the GenBank database ( Benson et al. 2012), under accession numbers: MT 250550 for the COI, MT 252990 for the cytb, and MT 252624 for the 28s sequences respectively .

Etymology. The species is named in honor of Prof. J. Yukawa and Prof. H. Masuda for their essential contribution to the knowledge of the Japanese oak gall wasp fauna and for documenting the lifecycles of numerous cynipid species, supported by excellent photos of the galls ( Yukawa & Masuda 1996).

Diagnosis. Cerroneuroterus yukawamasudai sp. nov. most closely resembles C. vonkuenburgi and C. folimargo by having F1 at least 1.3x as long as F2 and the metasoma distinctly longer than head+mesosoma. In C. yukawamasudai sp. nov. the notaulus is incomplete or complete, deeply impressed only in the posterior half of mesoscutum, the propodeum is smooth and the mesosoma is black, while in C. vonkuenburgi the notaulus is deeply impressed along the entire length, the propodeum sculptured between propodeal carinae and the mesosoma with more or less extended light brown areas. In Cerroneuroterus yukawamasudai sp. nov. the mesoscutum is longer than broad, the mesoscutellum inclined in lateral view, and median mesoscutal sulcus present, very short, while C. folimargo the mesoscutum as long as broad, the mesoscutellum more or less flat, not inclined in lateral view, median mesoscutal sulcus always absent. Finally, C. yukawamasudai sp. nov. differs from C. folimargo and C. vonkuenburgi in the structure and appearance of their respective galls.

Description. Asexual female.

Length. 2.3–3.0 mm (n = 7).

Color ( Fig. 3e ). Body black; antennae, legs, tegula and hypopygium dark brown; tips of mandibles black. Forewing uniformly hyaline, without smoky spots and venae brown to dark brown.

Head ( Figs 1 a–c). Transversally oval in frontal view, around 1.4x as broad as high; next to 3.0x as broad as long from above. Lower face smooth to alutaceous next to compound eyes, with sparse white setae and piliferous punctures, with coriaceous central elevated area going from toruli to the base of clypeus. Clypeus rectangular, delicately coriaceous, incised ventrally; anterior tentorial pits distinct, epistomal sulcus not impressed or only few impressures in the center, clypeo-pleurostomal lines present. Gena alutaceous, slightly broadened behind eye, 0.8 times as broad as cross diameter of eye in lateral view; malar space delicately coriaceous, without sulcus, 0.3–0.4 times as long as height of eye. Transfacial distance 1.3–1.4 times as broad as eye height; diameter of torulus equal than distance between them and shorter than distance between torulus and inner margin of eye. Frons alutaceous to weak coriaceous, glabrous, with impression under the frontal ocellus. Vertex and occiput delicately coriaceous to alutaceous, postocciput delicately coriaceous, without piliferous punctures. POL 1.9x to OOL, 2.9 as long as LOL; diameter of lateral ocellus subequal as LOL; POL: OOL: LOL relation is 43: 23: 15. Postocciput around occipital foramen alutaceous; posterior tentorial pits deep, shiny, smooth, enlarged; gular sulcus present but unconspicous; gula nearly as broad as high, shorter than length of occipital foramen length; hypostomal carina present and emarginated, and area close to it carinated-rugose.

Antenna ( Fig. 1d ). Slightly longer than half length of body, with dense white setae, 14-segmented (suture between F13 and F14 indistinct); pedicel as long as broad, F1 1.4x as long as F2, 2.0x as long as scapus, 2.8x as long as pedicel; F2 slightly longer than F3; the ratio of scapus, pedicel and F1–F11 as follows: 14:10:28:20:17:16:16:16:15:15:14:15:14:25 (13+12). Placodeal sensilla on F3–F12.

Mesosoma ( Fig. 2 ). Around 1.3x as long as high; black, glabrous, with very few short white setae. Pronotum smooth and shining, with some delicate parallel carinae along the ventrolateral edge, visible dorso-laterally; anterior rim of pronotum, narrow, delicately coriaceous to smooth, without striae; propleuron black, smooth and shining (delicately alutaceous basally and coriaceous anterocentrally), glabrous with few sparse white setae laterally, strongly concave in mediocentral part. Mesoscutum smooth, shining, notaulus deeply impressed in posterior half of mesoscutum, reaches pronotum or not but always with visible anterior depression, without setae; distance between notauli at the posterior end of mesoscutum shorter than distance between notaulus and lateral edge of mesoscutum; anterior parallel lines, parapsidal lines absent; median mesoscutal sulcus very short, always visible; parascutal carina reaches notaulus. Mesoscutum 1.2x as long as broad in dorsal view (largest width measured across mesoscutum on the level of the base of tegulae); emarginate on lateral sides and slightly elevated posteriorly, along dorsoaxillar area; transscutal articulation absent. Mesoscutellum smooth, shining, with few sparse white setae laterally, emarginate, laterally alutaceous with some piliferous punctures; rounded, slightly longer than broad in dorsal view, convex dorsally, slightly overhanging metanotum; mesoscutellar foveae in a form of transverse impression, not separated by a median carina, with smooth, shining bottom. Mesopleuron smooth, shining without pilosity; mesopleural triangle alutaceous with some very weak carinae, sparsely pubescent; acetabular carina narrow laterally; lateral axillar area shining, alutaceous or nearly smooth; axillula alutaceous to smooth, with sparse setae; subaxillular bar triangular, glabrous and slightly projected dorsally; metapleural sulcus reaches mesopleuron in the lower half. Metascutellum rectangular, with few carinae, shining; metanotal trough smooth, shining, without setae; ventral impressed area of dorsellum smooth, shining, around 1/2 of dorsellum height; central propodeal area smooth, shining; lateral propodeal area weakly delimited, alutaceous to smooth, with few short setae.

Forewing ( Fig. 3f ). Hyaline, longer than body, without smoky spots, with long cilia on margin, radial cell 4.0x as long as broad; R1 straight, nearly reaches margin, 2r curved and Rs straight reaches wing margin; areolet triangular, closed and distinct; Rs+M curved, reaches below the mid-height of basal vein.

Legs. Tarsal claws simple, without basal lobe.

Metasoma ( Fig. 3e ). Uniformly black, longer than head+mesosoma, strongly compressed laterally, 1.4–1.5x as high as long; all tergites smooth, glabrous, without or with very inconspicuous micropunctures; metasomal tergite 2 occupying nearly 1/2 of metasoma length in dorsal view. Ventral spine of hypopygium stout, prominent part short, nearly 2.0x as long as broad, with very few sparse white setae.

Gall ( Figs 3 a–d). A densely pubescent spangle gall, in groups (up to 500 galls) on the upper side of the leaf lamina (sometimes also underside), located between the lateral veins and attached to the leaf through a short petiole. On the upper part there is a glabrous red navel impressed in the center, covered distally by short and applied pale silk delimiting a circular mound; at the basis there are long reddish hair bundles, which turn brown to whitish distally. The gall is flat, 3.0– 5.5 mm in diameter, 2.0–3.0 mm high; if the pubescence is eliminated the lenticular gall is around 2.5–3.5 mm in diameter, brown with a coriaceous surface. The larval chamber is large (2.0 mm in diameter), occupying the entire center of the gall; the parenchima around the central larval chamber near 0.6 mm thick, spongy, not very hard.

Comments. Yukawa & Masuda (1996: Fig. C-91) provided images for galls of C. yukawamasudai sp. nov., collected on Q. acutissima and Q.variabilis Blume , however, Yukawa & Masuda (1996) erroneously determined the galls as those of Neuroterus nawai (Asmead) . In the revision of the genus Latuspina, Ide & Abe (2016) transferred N. nawai to Latuspina and depicted the sexual and asexual galls of L. nawai . According to these images, the gall depicted in Yukawa & Masuda (1996: Fig. C-91) is not that of L. nawai , but is actually the asexual gall of Cerroneuroterus yukawamasudai sp. nov. Yukawa & Masuda (1996) also experimentally documented the life cycle of this species and matched the asexual (Fig. C-91) and the sexual (Fig. C - 98) generation galls, which they described, however, they did not describe the adults of both generations. The asexual generation galls of C. yukawamasudai sp. nov. are also depicted in Fig. C-47 and C-92 (right image) in Yukawa & Masuda (1996).

Distribution. China, Shandong Province. Probably distributed in all areas where the host occurs. Similar galls have been collected in Korea on Q. acutissima and on Q. variabilis in Japan ( Yukawa & Masuda 1996; Figs C-91, C-92 (right image) and C-47).

Biology. Alternate sexual and asexual generations are known to occur on Q. acutissima and Q. variabilis ( Yukawa & Masuda 1996) . Asexual galls appear in early September; the central part of the gall is formed first and then expands laterally as the gall develops. In November the galls mature, and fall to the ground along with the leaves; larvae pupate in November-December and the adults emerge the following year in late March (under laboratory conditions the adults appear by the end of January into February); females lay eggs into the floral buds. Sexual galls are on catkins, 1–4 galls in one group; they are unilocular, 1.2–1.8 mm long, with short white pubescence; the wall is thin, hard, yellowish-green, turning reddish pink, later to lilac-red, and when mature the gall is lilac-black; the gall formation is rapid, maturing by the end of April, or beginning of May; adults emerge in mid-May, and females oviposit directly into young leaves of Q. variabilis ( Yukawa & Masuda 1996) .

Figures

FIGURE 1. Cerroneuroterus yukawamasudai Pujade-Villar & Melika, sp. nov.: (a–c) head: (a) frontal view, (b) dorsal view, (c) posterior view; (d) antenna and detail of last flagellomeres.

FIGURE 2. Cerroneuroterus yukawamasudai Pujade-Villar & Melika, sp. nov., mesosoma: (a–b) dorsal view, (c) lateral view, (d) posterior view.

FIGURE 3. Cerroneuroterus yukawamasudai Pujade-Villar & Melika, sp. nov.: (a-d), asexual galls: (a) general view, (b) individual gall, dorsal view, (c) individual gall, ventral view, (d) dissected gall, (e) habitus, asexual female, (f) forewing, asexual female.