Stigmatodipogon Ishikawa, 1965

Shimizu, Akira, Lelej, Arkady S., Loktionov, Valery M., Nishimoto, Yutaka & Endo, Tomoji, 2018, Revision of the subgenus Stigmatodipogon Ishikawa of the genus Dipogon Fox (Hymenoptera: Pompilidae: Pepsinae), Zootaxa 4514 (1), pp. 1-22 : 2-3

Subgenus Stigmatodipogon Ishikawa, 1965

Stigmatodipogon Ishikawa, 1965: 98 (as subgenus of Dipogon Fox, 1897 ). Type species: Dipogon (Deuteragenia) macrostigmatus Ishikawa, 1959 , by original designation.

Stigmatodipogon : Lelej & Loktionov 2012a: 414 (as genus); 2012b: 11 (as genus); Loktionov & Lelej 2012a: 251 (as genus); 2014: 157 (as genus).

Species included. The genus includes six species, which are distributed in Eastern Russia, Japan, and Laos: Dipogon (Stigmatodipogon) budrisi ( Loktionov & Lelej, 2014) , comb. nov., D. (S.) kurokawai Shimizu , sp. nov., D. (S.) lao Loktionov & Lelej , sp. nov., D. (S.) macrostigmatus Ishikawa, 1959 , D. (S.) petiolatus Lelej, 1986 , and D. (S.) tanakai Ishikawa, 1965 .

Diagnosis. This genus differs from other groups of Dipogon by the following combination of characters: (1) the pterostigma is large, its length 1.6–2.6 × SMC 2 length, its width 0.7–1.1 × SMC 2 width; (2) the setae on the propodeum and coxae are few and short; (3) the spines on the mid and hind tibiae are few, weak, and rudimentary in both sexes; and (4) metasomal tergum I is distinctly petiolate in the female.

Description (for additional characteristics, see the generic characteristics of Dipogon provided by Shimizu and Ishikawa (2002)).

FEMALE. Small-sized, body length 4–8 mm. Body mostly black. Maxillary beard dark brown. Wings hyaline and iridescent with veins and pterostigma dark brown ( Figs 1F, 1G , 3D , 6E , 7C , 9F ). Fore wing bifasciate without subapical white spot; inner fascia along second abscissae of vein M and of vein Rs (basal vein) and crossvein cu-a; outer fascia occupying basal third or basal half of marginal cell, SMC1 apically, SMCs 2 and 3 and apical half of discal cell2.

Body covered with short grayish- to brownish-white pubescence. Setae on body sparse; a few erect setae on vertex and dorsa of pro- and mesonota; clypeus and mandible with long bristles arising from pores. Metasomal sterna and tergum V sparsely and tergum VI densely bristly.

Head and mesosoma densely punctate or shagreened. Side of metanotum obliquely striate, interspaces of striae alutaceous anteriorly. Metapostnotum with few transverse striae. Upper metapleuron finely and obliquely striate and punctate. Metasoma impunctate and alutaceous with minute setiferous pores.

Mandible with two teeth on inner margin. Eye narrower than half of MID. Antennal socket separated from frontoclypeal sulcus by about half its diameter. Flagellomere X pointed at apex. Clypeus with setiferous pores preapically.

Pronotum with anterior declivity not or feebly differentiated from dorsum. Lateral face of pronotum with deep, circular depression anterior to pronotal tubercle. Mesoscutum slightly convex with parapsidal sulcuses divergent anteriorly; posterolateral rim raised. Metapostnotum short, its length 0.1–0.2 × metanotum length at midline, slightly depressed between metanotum and propodeum, arcuately emarginate posteromedially. Propodeum with declivity not differentiated from dorsum.

Fore wing vein Rs strongly angulate at juncture with crossvein 2rs-m ( Figs 1F , 3D , 6E , 7C , 9F ). Crossvein cu- a originating a little posteriorly to separation of vein M+CuA (postfurcal), almost vertical to vein A. Hind wing crossvein cu-a confluent with vein A ( Fig. 6E ) or somewhat angulate at juncture with it ( Figs 1G , 3D , 9F ), forming sinuate line.

Fore femur slightly thicker than mid femur. Outer apicoventral corner of hind femur triangularly produced into sharp point. Tarsi slender; tarsomeres V more or less enlarged, compared with tarsomeres IV. Tarsal claws with small acute tooth preapically.

Metasomal tergum I petiolate, i.e., the tergum narrowed immediately behind articulation with propodeum ( Figs 1I , 3C , 6G , 7F ). Sternum I alutaceous except for smooth posterior margin, with short lateral carina basally and a few short erect setae. Sternum II with transverse groove. Sternum VI carinate apicomedially.

MALE. Similar to female but smaller and slenderer. Antenna with flagellomeres II–XI triangularly produced subbasally below, weakly concave above ( Fig. 4G ). Mandible with tooth on its inner margin, that being as stout as apical point. Metapostnotum subtriangularly emarginate posteromedially.

Fore wing fasciae rudimentary ( Figs 2F , 4F , 5G , 8A ). Hind wing crossvein cu-a forming distinct angle with vein A, shorter than in female, slightly sinuate ( Figs 2G , 4F ).

Fore femur slightly thicker than mid femur. Outer posterior margin of hind femur truncate, not triangularly produced into sharp point below.

Exposed portion of subgenital plate small and stubbed apically with apical margin roundly convex ( Fig. 2H ), triangularly produced ( Figs 4H , 8E ) or truncate ( Fig. 5K ). Genitalia: basal hooklets double ( Figs 2I , 4J , 5M , 8F ).

Distribution. Russia (Eastern Siberia, Far East), Japan (Hokkaido, Honshu), and Laos.

Biology. Nesting record is available only for D. (S.) kurokawai sp. nov. This species nests in bamboo cane trap nests. The nest structure is similar to that of other Dipogon species nests. The prey of D. (S.) macrostigmatus Ishikawa, 1965 and D. (S.) petiolatus Lelej, 1986 consists of small spiders of Araneidae and Thomisidae . More detailed information is summarized under the corresponding species.

Figures

FIGURE 1. Dipogon (Stigmatodipogon) budrisi, holotype, ♀. A. Head and pronotum, dorsal view. B. Head, frontal view. C. Whole body, lateral view. D. Head and pronotum, lateral view. E. Head, pro-, meso- and metanota, dorsal view. F. Fore wing. G. Hind wing. H. Mesosoma anteriorly, lateral view. I. Metasomal tergum I basally, dorsal view. Scale bars: 1 mm for C, 0.1 mm for I, 0.5 mm for others.

FIGURE 2. Dipogon (Stigmatodipogon) budrisi, paratype, ♂. A. Head, pronotum and scutum, dorsal view. B. Metasomal tergum I basally, dorsal view. C. Whole body, lateral view. D. Head, frontal view. E. Head and pronotum, lateral view. F. Fore wing. G. Hind wing. H. Metasomal sternum VII and SGP, ventral view. I. Genitalia, ventral view. Scale bars: 1 mm for C, 0.1 mm for B, 0.2 mm for H, I, 0.5 mm for others (H, I from Loktionov & Lelej 2014).

FIGURE 3. Dipogon (Stigmatodipogon) kurokawai, sp. nov., holotype, ♀. A. Head, frontal view. B. Whole body, lateral view. C. Mesosoma and metasomal tergum I basally, dorsal view. D. Wings. E. Head, lateral view. F. Head, dorsal view and pronotum, dorsolateral view. Scale bars: 1 mm for B, 0.5 mm for others.

FIGURE 4. Dipogon (Stigmatodipogon) kurokawai, sp. nov., paratype, ♂ from Yamagata Pref., Honshu, Japan. A. Metasomal tergum I basally, dorsal view. B. Head, frontal view. C. Head, pronotum and scutum, dorsal view. D. Head and pronotum anteriorly, lateral view. E. Head and mesosoma, lateral view. F. Wings. G. Flagellomeres III–XI, lateral view. H. Metasomal sternum VI and SGP apically, ventral view. I. Genitalia, dorsal view. J. Same, ventral view. Scale bars: 0.1 mm for A, H–J, 0.5 mm for others.

FIGURE 5. Dipogon (Stigmatodipogon) lao, sp. nov., holotype, ♂. A. Head, mesosoma and metasoma anteriorly, dorsolateral view. B. Head, frontal view. C. Head and pronotum, dorsal view. D. Head, pro-, meso- and metanota and metapostnotum, dorsal view. E. Head and pronotum, lateral view. F. Metasomal tergum I, dorsal view. G. Fore wing. H. Scutellum, metanotum, metapostnotum and propodeum, dorsal view. I. Metasomal sternum VI, ventral view. J. Same, lateral view. K. Metasomal sternum VII and SGP, ventral view. L. Same, lateral view. M. Genitalia, ventral view. Scale bars: 0.2 mm for A–H, 0.1 mm for I–M.

FIGURE 6. Dipogon (Stigmatodipogon) macrostigmatus, holotype, ♀. A. Head, frontal view. B. Head and pronotum, dorsal view. C. Head, mesosoma and metasoma except posterior part, dorsal view. D. Mesosoma, dorsal view. E. Wings. F. Head and mesosoma, lateral view. G. Propodeum posteriorly and metasomal tergum I anteriorly, dorsal view. Scale bars: 1 mm for C, E, 0.1 mm for G, 0.5 mm for others.

FIGURE 7. Dipogon (Stigmatodipogon) petiolatus, holotype, ♀. A. Head, frontal view. B. Head and pronotum, dorsal view. C. Whole body, lateral view. D. Head and pronotum, lateral view. E. Pro- and mesonota, dorsal view. F. Metasomal tergum I, dorsal view. Scale bars: 1 mm for C, 0.1 mm for F, 0.5 mm for others.

FIGURE 8. Dipogon (Stigmatodipogon) petiolatus, paratype, ♂. A. Fore wing. B. Metasomal tergum I, dorsal view. C. Head, dorsal view. D. Mesosoma and metasoma, lateral view. E. Metasomal sterna VII and SGP, ventral view. F. Genitalia, ventral view. Scale bars: 1 mm for D, 0.1 mm for B, 0.25 mm for E, 0.5 mm for others (E, F from Loktionov & Lelej 2014).

FIGURE 9. Dipogon (Stigmatodipogon) tanakai, holotype, ♀. A. Head, frontal view. B. Mesosoma, lateral view. C. Whole body, lateral view. D. Head, lateral view. E. Head, dorsal view and pronotum, dorsolateral view. F. Wings. Scale bars: 1 mm for C, 0.5 mm for others.