Pseudebenia Shima, Han & Tachi

Shima, Hiroshi, Han, Ho-Yon & Tachi, Takuji, 2010, Description of a new genus and six new species of Tachinidae (Diptera) from Asia and New Guinea, Zootaxa 2516, pp. 49-67 : 50-51

Pseudebenia Shima, Han & Tachi , gen. nov.

Type species: Pseudebenia epilachnae Shima & Han , sp. nov.

Diagnosis. Medium to small rather slender dark tachinid flies; male almost holoptic; eye with dense long hairs; parafacial bare; facial ridge with fine hairs on lower 1/2; occiput only with black hairs; arista plumose; prosternum bare; proepisternum haired; 2 postsutural intra-alar setae widely separated; scutellum with 3 pairs of long and strong marginal setae, i.e., basal, subapical and apical setae, subapical setae widely separated, apical setae strong and subequal in length to subapical setae or slightly shorter; wing with weak costal spine; mid tibia without ventral seta in male; hind tibia with 3 preapical dorsal setae and without apical posteroventral seta; abdominal syntergite 1+2 excavated only at base.

Description. Male and female. Head almost holoptic in male, frons strongly narrowed above in front of ocellar triangle, at narrowest point almost as wide as base of arista, dichoptic in female; frons about 1.5 times as long as face in profile; facial ridge wide and flattened on lower 1/2; face flat without facial carina, lower margin flat, not protruded forward; gena narrow, 1/4−1/6 of eye height, with genal dilation on lower 1/2−4/5; occiput flat. Inner vertical setae fine in male, strong in female; ocellar seta fine but distinct; frontal setae confined to lower 1/2 of fronto-orbital plate, no proclinate orbital setae in male, 1 outwardly directed prevertical and 2 proclinate orbital setae in female; parafacial bare; facial ridge without strong setae but with fine short hairs on lower 1/2; vibrissa strong, nearly level with lower margin of face; occiput only with black hairs. Base of antenna level below middle of eye height; scape short, only weakly projected; arista plumose, thickened only at base; 2nd aristomere very short. Prementum short, at most as long as antenna; labella large; palpus slender and nearly cylindrical, weakly widened apically. Eye densely haired.

Prosternum bare; proepisternum with dense fine hairs; postpronotal lobe with 3 setae, middle seta slightly set forward; 2 pre- and 3 postsutural dorsocentral setae; 0 pre- and 2 postsutural intra-alar setae, postsutural setae widely separated; 2 or 3 katepisternal setae; anepimeral seta present, not extending beyond middle of lower calypter; katepimeron bare; anatergite with several fine hairs; lateral scutellar seta absent; apical scutellar seta long and strong, longer than scutellum and basal scutellar seta, crossed; postmetacoxal area membranous; metathoracic spiracle with rounded flap.

Wing sometimes tinged with brown; tegula and basicosta black; costa with 1 or 2 long costagial setae and 1 short costal spine, the former extending beyond humeral crossvein; costa setulose below beyond subcosta; base of vein R4+5 with several fine setulae dorsally and ventrally; cell r4+5 open; vein M curved at obtuse angle, its bend much closer to wing margin than to dm-cu crossvein; vein CuA1 not reaching wing margin; lower calypter bare, rounded, inner margin well separated from scutellum; knob of halter nearly as large as metathoracic spiracle.

Fore tibia with 3 preapical dorsal setae, inner seta fine, and with 1 apical posteroventral seta; mid tibia without ventral seta in male; hind tibia with 3 preapical dorsal setae and 1 apical anteroventral seta, apical posteroventral seta absent.

Abdomen black in ground color, rather slender in shape; syntergite 1+2 excavated at most on basal 1/3; syntergite 1+2 without median marginal seta; 2nd to 4th sternites concealed under ventral margins of each tergite. Male terminalia: 5th sternite with U- or V-shaped cleft on posterior 1/3 to 2/5, bearing dense hairs on posterior lobe; 6th tergite absent, at most represented by a pair of setae; 6th sternite asymmetrical, articulated with syntergosternite 7+8 on right side; 6th abdominal spiracle on intersegmental membrane, 7th spiracle on anterior margin of syntergosternite 7+8; epandrium with 2–4 very strong setae together with many normal hairs; hypandrial arms separated; pregonite long and broad, narrowed to apex, with 2 long strong setae; postgonite narrow and long, weakly pointed at apex; cerci in lateral view narrow, flattened, at most narrowly separated on apical portion; surstylus fused at its dorsoproximal corner with epandrium; epiphallus long, arising nearly at median portion of basiphallus; distiphallus broadly membranous on dorsal portion, basal sclerotized area narrowly extending lateroventrally, ventral membrane with strong marginal spinules.

Etymology. The generic name means false Ebenia . It superficially resembles Ebenia of the subfamily Dexiinae (tribe Dufouriini ), but in reality belongs to the subfamily Tachininae .

Remarks. Pseudebenia belongs to the subfamily Tachininae ; the male terminalia have a well developed lobe-like pregonite, basiphallus and distiphallus are bridged with a narrow rigid (non-hinged) dorsal sclerite, and aedeagal guide is well developed. Among members of Tachininae , Pseudebenia resembles Macquartia Robineau-Desvoidy (Macquartiini) in general appearance, with the occiput bearing only black hairs, the hind tibia lacking apical posteroventral seta and 3 pairs of long and strong scutellar setae. The male terminalia of Pseudebenia are also similar to those of Macquartia in the structure of the phallus, i.e., long epiphallus standing nearly at mid-dorsal portion of basiphallus and distiphallus with basal sclerite narrowly extending ventrolaterally and dorsal portion broadly membranous and bearing strong ventral spinules (e.g., Figs. 3−4 ; cf. Fig. 224 of Tschorsnig 1985 & Figs. 7 & 12 of Richter & Wood 1995). However, in other features of the male terminalia it differs from Macquartia , such as in the 6th tergite absent (distinct and sometimes fused with syntergosternite 7+ 8 in Macquartia ), the surstylus fused with epandrium at base (separated in Macquartia ) and the hypandrial arms separated (usually fused in Macquartia ) (cf. Tschorsnig 1985). The female terminalia of Pseudebenia are elongate and 7th and 8th tergites are strongly reduced ( Figs. 11−15 ), in contrast to short and well sclerotized 7th and 8th tergites in Macquartia . Although the true affinity of Pseudebenia is not clearly demonstrated as yet, we at present consider it as a member of the tribe Macquartiini . Males of all species of Pseudebenia have a well developed pregonite bearing unusually long submedian and apical setae in the terminalia ( Figs. 3 , 8 , 18 , 23 , 28 , 32 ). This structure is not found in other groups of Tachinidae and considered as an autapomorphy of this genus. The surstylus of the male terminalia is characteristically fused at its dorsoproximal corner with the epandrium in this genus. This structure is also found in some members of the Tachininae , such as in Tachinini and Symmorphomyia Mesnil & Shima (Ernestiini) . However, we consider that this character state occurred independently in Pseudebenia and others, since there are no other characters to unite them in a group.

Pseudebenia may be easily distinguished from other tachinids in the combination of the following characters together with the above three macquartiine characters: male head almost holoptic, eye hairy, arista plumose, proepisternum setose, 2 widely separated postsutural intra-alar setae, abdominal syntergite 1+2 excavated only at base and abdomen with strong median discal setae. The two widely separated postsutural intra-alar setae of this genus are peculiar among Tachininae , since this character state is almost exceptionally found in Phasiinae , such as in Cylindromyiini , Leucostomatini and Parerigonini.

Figures

FIGURES 1 − 5. Male terminalia of Pseudebenia argyrosoma sp. nov. 1. Epandrium, cerci and surstylus in dorsal view. 2. Same in lateral view. 3. Hypandrium, pregonite, postgonite and phallus in lateral view. 4. Distiphallus in dorsal view. 5. 5 th sternite in ventral view. Scale, 0.1 mm.

FIGURES 6 − 10. Male terminalia of Pseudebenia epilachnae sp. nov. 6. Epandrium, cerci and surstylus in dorsal view. 7. Same in lateral view. 8. Hypandrium, pregonite, postgonite and phallus in lateral view. 9. Distiphallus in dorsal view. 10. 5 th sternite in ventral view. Scale, 0.1 mm.

FIGURES 11 − 15. Female terminalia. 11. Female terminalia of Pseudebenia argyrosoma sp. nov. in lateral view. 12. Female terminalia of P. epilachnae sp. nov. in lateral view. 13. Epiproct and cerci of P. epilachnae sp. nov. in dorsal view. 14. Epiproct and cerci of P. t ris etos a in dorsal view. 15. Female terminalia of P. trisetosa in lateral view. Scale, 0.1 mm.

FIGURES 16 − 20. Male terminalia of Pseudebenia fulvipalpis sp. nov. 16. Epandrium, cerci and surstylus in dorsal view. 17. Same in lateral view. 18. Hypandrium, pregonite, postgonite and phallus in lateral view. 19. Distiphallus in dorsal view. 20. 5 th sternite in ventral view. Scale, 0.1 mm.

FIGURES 21 − 25. Male terminalia of Pseudebenia fuscata sp. nov. 21. Epandrium, cerci and surstylus in dorsal view. 22. Same in lateral view. 23. Hypandrium, pregonite, postgonite and phallus in lateral view. 24. Distiphallus in dorsal view. 25. 5 th sternite in ventral view. Scale, 0.1 mm.

FIGURES 26 − 29. Male terminalia of Pseudebenia nepalensis sp. nov. 26. Epandrium, cerci and surstylus in dorsal view. 27. Same in lateral view. 28. Hypandrium, pregonite, postgonite and phallus in lateral view. 29. Distiphallus in dorsal view. Scale, 0.1 mm.

FIGURES 30 − 34. Male terminalia of Pseudebenia trisetosa sp. nov. 30. Epandrium, cerci and surstylus in dorsal view. 31. Same in lateral view. 32. Hypandrium, pregonite, postgonite and phallus in lateral view. 33. Distiphallus in dorsal view. 34. 5 th sternite in ventral view. Scale, 0.1 mm.