Periclistus orientalis Pang, Liu & Zhu, 2020

Pang, Yin, Liu *, Zhiwei, Su, Cheng-Yuan & Zhu, Dao-Hong, 2020, A new species of Periclistus Foerster, 1869 from China and review of the tribe Diastrophini (Hymenoptera, Cynipoidea, Cynipidae), ZooKeys 964, pp. 109-126 : 109

Periclistus orientalis Pang, Liu & Zhu sp. nov. Figures 1-6 , 7-11

Type materials.

Holotype: ♀ (CSUFT), China, Hunan Province, Zhuzhou City, 27.83N, 113.13E, reared in 2011-V-10-20 from galls collected in 2011-IV, leg. Xiao-Hui Yang; Paratypes: 4♀♀, 2♂♂ (CSUFT), collection data and locality same as holotype.

Etymology.

The species epithet is derived from Latin orient, meaning east, to suggest the type locality from the Oriental region.

Diagnosis.

Periclistus orientalis can be distinguished from the other congeneric species in the Eastern Palearctic using the taxonomic key provided herein. Below we provide more detailed comparison of the new species with the two very similar species, i.e., P setosus and P capillatus .

Periclistus orientalis sp. nov. is similar to P setosus , but differs from the latter in the lower face with striae radiating from clypeus reaching eyes and antennal socket in the new species, whereas in P setosus striae of lower face not reaching eyes and antennal socket (Fig. 5 ); notauli distinctly present in posterior one third of scutum and medial sulcus absent in the new species, whereas complete and distinctly in P setosus ( Wang et al., 2012) (Fig. 7 ); lateral surface of pronotum entirely coriaceous with evenly distributed dense setigerous punctures (Fig. 8 ) in the new species, but in the latter lateral surface of pronotum glabrous, with sparse setigerous punctures ventrolaterally. The new species is also similar to P capillatus Belizin, 1968. It differs from P capillatus in the mesoscutum glabrous with piliferous punctures and dense appressed pubescence in the new species, whereas with piliferous points and sparse pubescence in P capillatus (Fig. 7 ); notauli distinctly present in posterior one third of scutum and medial sulcus absent in the new species, whereas incomplete or very weakly impressed anteriorly in P capillatus (Fig. 7 ); fused metasomal tergites T2+T3 anterolaterally with a patch of sparse white setae, mostly smooth except for minute punctures on laterally posterior half and a narrow band of punctures along posterior margin, whereas in the latter metasomal tergites fused (T2+T3) smooth, with an anterolateral patch of white setae, and the subsequent segments glabrous with micropunctures (Figs 1 , 9 ).

Description.

Female: Body length 2.7-2.8mm (N = 5).

Coloration. Head completely black. Antenna uniformly light brown. Front and middle legs reddish brown, except coxa and claw black; hind legs black, except tarsomeres 1 and 5 reddish brown. Mandible and maxilla reddish brown, labial palpi light brown. Mesosoma black; metasoma mostly reddish brown in anterior half, and dark in dorsal half. Ventral spine of hypopygium reddish brown.

Antenna filiform with ten flagellomeres, slightly tapering toward apex; pedicel 1.67 times as long as broad; relative lengths of scape, pedicel and F1-F10: 9:5:10:10:10:9:8:8:7:6:6:13 (Fig. 3 ).

Head coriaceous, with sparse setae, 2.0 times as broad as long in dorsal view, 1.24 times as wide as high and slightly broader than mesosoma in dorsal view. Gena delicately coriaceous and not broadened behind eyes. Malar space 0.27 times as high as height of eye. Lower face with striae radiating from clypeus and reaching eyes and antennal socket, entirely densely punctate with white, long, and appressed setae; median area slightly elevated, delicately coriaceous, lateral carinae bordering median area complete from clypeus to antennal socket and about as strong as radiating striae on lateral areas of lower face. Clypeus inversely trapezoid, ventral margin straight, and delicately coriaceous with dense long setae; anterior tentorial pits indistinct; epistomal sulcus and clypeo-pleurostomal lines indistinct. Transfacial distance longer than height of eye; distance between inner margin of eye and outer rim of antennal torulus slightly longer than distance between antennal toruli, all larger than diameter of torulus (Fig. 5 ). Ratios of POL/OOL, POL/LOL, and LOL/OOL1.3, 1.8 and 0.7, respectively. Frons, vertex and gena behind eyes, and postgena with sparse setigerous punctures; setae long and white. Frons coriarious and smooth, with scattered punctures. Vertex smooth and evenly punctate with long setae (Fig. 7 ).

Mesosoma longer than high in lateral view and with white setae. Pronotum median length nearly one third of length of outer lateral margin; anterior lateral depressions medially separated broadly from each other, laterally open, continuing to a distinct furrow; posterior rim of anterior lateral depressions extending dorsally to reach posterior margin of pronotum, distinctly separating anterior plate from lateral pronotal areas. Anterior plate of pronotum delicately coriaceous, posteriorly with shallowly punctate and sparsely setose (Fig. 7 ); lateral pronotal areas coriaceous, entirely densely punctate with appressed long setae, without glabrous ventral nude area (Fig. 8 ). Mesoscutum smooth and shiny, slightly broader than long, distinctly depressed anteriorly, with evenly dispersed piliferous punctures; anteroadmedian signum absent, notauli distinctly present in posterior one third of scutum, medial sulcus absent, parapsidal signa present in posterior half and absent anteriorly (Fig. 7 ). Scutellar foveae large, deeply impressed, glabrous, separated by a broad median carina (Fig. 7 ). Mesoscutellum about as broad as long, rugose and foveolate with sparse, appressed setae (Fig. 7 ). Mesopleuron distinctly higher than broad, glabrous and shining, devoid of striation and pubescence, except for pubescence along ventral margin (Fig. 8 ); mesopleural triangle glabrous, not separated from rest of mesopleuron by a ventral carina. Metapleural sulcus reaching mesopleuron in upper one fourth of its height; metapleuron rugulose with long setae; metanotum slightly overhanging. Lateral propodeal carinae distinct and evenly curved outwards; median propodeal area rugose foveolate; lateral propodeal areas with dense setae (Fig. 10 ).

Forewing with distinct veins R+Sc, R1+Sc, R1, M, M+Cu1, Cu1, Cu1b, Cu1a, 2r and Rs+M; areolet distinct and large; radial cell closed, 3.3 times as long as wide; all visible veins dark brown (Fig. 1 ).

Metasoma nearly as long as head and mesosoma combined, distinctly longer than height in lateral view, distinctly punctate posteriorly. Metasomal tergites 2+3 with some setae ventrally. Prominent part of ventral spine of hypopygium very short (Fig. 9 ).

Male: Similar to female, but different as follows. Antenna with 12 flagellomeres, pedicel 2.5 times as long as broad. F1 strongly curved medially. Relative lengths of scape, pedicel and F1-F12: 7:5:13:12:7:7:6:6:5:5:5:5:4:7 (Fig. 4 ). Second and third metasomal tergites not fused, separated by a suture (Fig. 2 ).

Biology.

All specimens were reared from galls collected from Rosa multiflora , and the galls were very similar in morphology to those made by Diplolepis japonica : fleshy and spherical with pointed spikes on top, pinkish green to greenish yellow in color, and located on rachis or central vein of leaflets of both upper and under sides (Fig. 20 ). Nonetheless, the identity of the host gall maker remains reclusive since our rearing yielded no specimen of the putative gall maker. The galls were collected from April through August, and specimens of P. orientalis emerged in early May from galls collected in April.

Distribution.

Known from Zhuzhou City, Hunan Province, China.

The known species of Periclistus in the Eastern Palearctic can be identified using the following taxonomic key modified from Pujade-Villar et al. (2016) to accommodate the new species.

Figures

Figure 20. Galls on Rosa multiflora, from which specimens of Periclistus orientalis were reared.

Figures 1 - 6. Periclistus orientalis sp. nov. 1 general habitus (♀) 2 general habitus (♂) 3 antenna (♀) 4 antenna (♂) 5 head in anterior view (♀) 6 head in anterior view (♂).

Figures 7 - 11. Periclistus orientalis 7 head and mesosoma in dorsal view (♀, similar in ♂) 8 mesosoma in lateral view (♀) 9 metasoma in lateral view (♀) 10 propodeum in dorsal view (♀) 11 propodeum in dorsal view (♂).