Andricus wugangensis Zeng, Liu, & Zhu, 2024

Duan, Yu-Bo, Liu, Luan, Zhu, Dao-Hong, Zeng, Yang & Liu, Zhiwei, 2024, Description of a new species of Andricus Hartig, 1840 (Hymenoptera: Cynipidae Cynipini) from China, Zootaxa 5474 (2), pp. 160-172 : 163-167

Andricus wugangensis Zeng, Liu, & Zhu sp. nov.

( Figs. 1–12 )

Holotype. 1♀, China, Hunan, Wugang City , 2022-V-19, reared from galls on leaves of Q. fabrei collected on 2022- IV-18, leg. Yang Zeng ; Paratypes. 7♀♀, same data as holotype, deposited in CSUFT .

Diagnosis. A. wugangensis morphologically resembles A. wuhanensis and A. xishuangbannaus in that the head is smooth and alutaceous, with some white setae on the lower face, which is flat in lateral view, but can be distinguished from the latter two species by having 1) two distinct carinae each extending from the lower rim of the antennal sockets to the clypeus, and converging at the clypeus, hence forming a large “V” shape on the lower face ( Fig. 2 ); 2) Upper face with a broad transverse depression present between the upper inner margin of the eyes ( Fig. 2 ). In addition, the mesopleuron of A. wugangensis is smooth with irregular wrinkles anteriorly. In contrast, the mesopleuron of A. wuhanensis is covered with setae anteriorly and posteroventrally and that of A. xishuangbannaus is covered with dense setae in the posteroventral quarter. Finally, delicate micro punctures are present on the metasomal tergites of A. xishuangbannaus , whereas these are absent in A. wugangensis and A. wuhanensis .

Description. Sexual Female.

Length. Body length 2.2 mm (range 2.1–2.3mm, n=8)

Color ( Fig. 1 ). Head, mesosoma and metasoma uniformly deeply dark brown to black; clypeus brown, and mandibles yellow brown; scape, pedicel, F 1– F 5 light yellow brown, subsequent flagellomeres becoming dark brown apically; tegula and legs uniformly yellow brown, ventral spine of hypopygium light brown.

Head ( Figs. 2–5 ). Smooth alutaceous, with some white setae on lower face; 1.9× as broad as long from above, 1.2× as broad as high, slightly narrower than mesosoma in anterior view. Inner margins of compound eyes almost parallel. POL 1.5 times as long as OOL; OOL 2.5 times as long as diameter of lateral ocellus and 1.5 times as long as LOL; ocelli ovate, equal in size. Gena delicately coriaceous to smooth, not broadened behind eye, malar space coriaceous, with dense white setae and irradiating striae, lower face coriaceous, with evenly dense white setae. Transfacial line slightly longer than the height of eye. Two distinct carinae, originating from lower rim of each antennal socket respectively, convergent ventrally and meeting right above clypeus, forming a distinct “ V ” shape on lower face ( Fig. 2 ). Clypeus coriaceous to smooth, rounded ventrally; epistomal sulucus and clypeo-pleurostomal line present. Upper face with a broad transverse depression spanning between upper inner margin of eyes ( Fig. 2 ). Frons smooth and glabrate; interocellar area alutaceous with sparse white setae. Vertex and occiput coriaceous, with weak rugae. Post occiput and postgena coriaceous, impressed around occipital foramen, with evenly scattered white setae; posterior tentorial pits large, obovate and deep; hypostomal carina emarginate, continuing into postgenal sulcus, not fused medially.

Antenna ( Fig. 6 ). Antenna with 13 segments, slightly longer than mesosoma; pedicel 0.8 × as long as scape except for base. F 1 1.2× as long as F 2, 2.4× as long as pedicel; F 1– F 10 progressively shorter; F 11 2.4 × as long as F 10, with blurry suture present; placoid sensilla present on F 2– F 11, absent on F 1. Relative lengths of flagellomeres 1–11: 14, 12, 11, 11, 10, 10, 9, 9, 8, 7, 17.

Mesosoma ( Figs.7–9 ). 1.1× as long as high. Pronotum coriaceous, laterally with distinctly transversal striate and dense white setae. Mesoscutum almost as long as width in dorsal view, smooth and shiny, finely coriarious, with sparse setae along notaulus; median mesoscutal lines hardly traceable; notauli complete, deeply impressed and distinct, nearly parallel in anterior 2/3 and convergent toward posterior end; parapsidal lines absent; a distinct and complete, medially strongly curved submedian depression present on each side of scutum (Figgs 7–8). Mesoscutellum overhung posteriorly, 2.0× as broad as high, coriarious, shining smooth ventrally, separated by a short median carina; scutellar foveae distinct, transversely ovate. Mesopleuron and speculum smooth, shining, without medial longitudinal strigae or setae, except for a small patch of setae on posteroventral corner of mesopleuron, and with a ventrally arched depression along entire lower part of mesopleuron; acetabular carina distinct; mesopleural triangle coriarious, with sparse setae. Axillula rough coriarious, covered with dense and short white setae; dorsal and lateral axillar area smooth, with few setae; subaxillular bar smooth and shining. Mesopleuron with numerous white setae; metapleural sulcus reaching mesopleuron in the upper 2/3 of mesopleuron height. Metanotal trough coriarious, covered with sparse short white setae. Median propodeal area alutaceous to smooth; lateral propodeal area covered with dense and short white setae; lateral propodeal carinae distinct but curved outwards in posterior half; median propodeal area rugose; ventral impressed rim of dorsellum roughly coriarious.

Metasoma ( Fig. 10, 12 ). 1.1× as long as high in lateral view; 2nd metasomal tergite occupying 3/5 of metasoma in lateral view, with a patch of setae anterolaterally; all subsequent tergites smooth and shiny, without setae or micro punctures; 2nd metasomal tergite 4.0 × as long as the 3 rd measured along dorsal line. Hypopygium with micro punctures, prominent part 4.2× as long as broad, projecting part of hypopygial spine tapered to apex in ventral view; subapical setae sparse.

Forewing ( Fig. 11 ). Longer than body, hyaline, with pale brown veins, margin with cilia; radial cell 4.6× as long as wide; R1 and Rs nearly reaching wing margin, Rs nearly straight; areolet small, triangular, closed and distinct. Rs+M distinct at distal three-fourths, meeting basalis at its middle.

Male. Unknown.

Gall ( Fig. 13 ). Single and pale green. Spherical galls form on the underside of leaves. Galls are monolocular, each measuring about 3–7 mm in diameter, with smooth surface and thin outer wall; larval chamber about 2–6 mm in height.

Biology. Galls of the new species are only known from Quercus fabrei , a common deciduous tree species in the mostly evergreen broadleaved forests of southern China. The gall appears in early May and matures later in the month. Adult wasps emerge from the galls from late May to early June. Although the male of A. wugangensis is unknown, the timing of gall formation and adult emergence suggest that the galls are likely of the sexual generation. The asexual generation remains unknown.

Distribution. Wugang City, Hunan Province.

Etymology. The specific epithet refers to the type locality. Noun in apposition.

DNA taxonomy and phylogenetic relationship. The Bayesian phylogenetic reconstruction based on COI sequences resulted in a tree ( Fig. 14 ) with weakly supported basal relationships. However, several species clusters or species pairs were well supported, including I. ( A. mairei , A. elodeoides ) (99% bootstrap value), together with A. mukaigawae, II. (( A. xishuangbannaus ), ( A. wugangensis , A. wuhanensis , )) (99%), III. (( A. mayri Mayr 1882 , A. grossulariae Giraud 1859 ), ( A. lucidus Hartig 1843 , A. cecconii Kieffer 1901 )) (99%), IV. ( A. pictus Hartig 1856 , A. quercustozer Bosc 1792 ) (98%), and V. ( A. coriarius Hartig 1843 , A. caputmedusae Hartig 1843 ) (100%). The five species from central China and the more widely distributed Eastern Asian species A. mukaigawae form two basal paraphyletic clades after A. quercusfoliatus , which is the most basal Andricus species ( Fig. 14 ). According to relationships recovered in the COI tree, A. wugangensis and A. wuhanensis form a sister species pair, which is a sister clade to A. xishuangbanaus . The genetic distance of COI sequences among the five species in central China was the smallest between A. wugangensis and A. xishuangbannaus and between A. wugangensis and A. wuhanensis , at 3.0% and 4.3%, respectively.

Figures

FIGURE 13. Oak galls: sexual young galls of Andricus wugangensis on Quercus fabrei.

FIGURE 14. Phylogenetic tree of Andricus based on COI sequences resolved using with Maximum-likelihood tree inferred under the General Time Reversible models. The bootstrap consensus tree inferred from 1000 replicates is taken to represent the evolutionary history of the taxa analyzed. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches. Plagiotrochus australis are used to root the tree. Andricus flavus Pujade-Villar, Wang, Guo & Chen, 2014= Andricus mairei Kieffer,1906 (Pujade-Villar et al. 2020b).

FIGURES 1–6. Andricus wugangensis sp. ♀. 1 general habitus; 2 head in anterior view; 3 head in posterior view; 4 head in lateral view; 5 head in dorsal view; 6 antenna.

FIGURES 7–12. Andricus wugangensis sp. ♀. 7 mesosoma in lateral view; 8 mesosoma in dorsal view; 9 propodeum in dorsal view; 10 metasoma in lateral view; 11 fore wing; 12 metasoma in posterior view.