Nyssonini

Schmid-Egger, Christian & Al-Jahdhami, Ali A., 2025, Nyssonini of the Arabian Peninsula with description of six new species (Hymenoptera, Spheciformes, Bembicidae), Zootaxa 5696 (2), pp. 247-259 : 249-250

Identification key to males and females of Nyssonini from Arabian Peninsula

The females of Brachystegus nemkovi , B. schneideri , Synnevrus arabicus and the males of Nysson waleedi and N. woodi are unknwon.

1. Hindtibia irregulary serrate on dorsal surface. Median vein of hindwing starts behind submedial cell ( Fig. 1 ) Male S 2–5 medially with row of long white bristles ( Fig. 7 )......................................... 3 ( Brachystegus A. Costa)

– Hindtiba with simple spines only. Median vein of hindwing starts inside submedial cell ( Fig. 2 ). Male sterna simple...... 2

2. Mesoscutum with fine punctation, interspaces at least as large as puncture diameter (figs 15, 18). Apical margin of T 1–3 simple. [Clypeus without transverse carina]................................................. 5 ( Nysson Latreille )

– Mesoscutum with deep, comb-like punctation, punctures larger than interspaces, interspaces dull or finely micropunctured ( Fig. 8 ). Apical margin of T 1–3 with obliquely protruding lamella above tergite edge, creating double edge .....................................................................................................6 ( Synnevrus A. Costa)

3. Clypeus evenly rounded, yellow ( Fig. 5 ). Band of T2 continuous ( Fig. 3 ). Median tooth of male T7 pointed, T6 yellow ( Fig. 6 ). 10.2 mm. Saudi Arabia. (Female unknown).............. Brachystegus nemkovi Schmid-Egger & Al Jahdhami sp. nov.

– Clypeus with transverse conspicous edge along its whole width, roof like seen in profile, black ( Fig. 10 ). Band of T2 interrupted ( Fig. 8 , 11 ). Male: Median tooth of T7 rounded or truncate, T6 black or reddish (fig. 14)............................. 4

4. Pronotum with yellow lateral spots, scutellum black ( Figs 8 , 11 ). Antenna black, with apex red in male. T 1–4 with lateral yellow spots, in male also T5, black space between spots at least as large as yellow spots ( Figs 8 , 11 ). 8.0– 8.5 mm. Northern Oman.................................... Brachystegus samadashanensis Al-Jahdhami & Schmid-Egger sp. nov.

– Pronotum and parts of scutellum red ( Fig. 12 ). Antenna red ( Fig. 13 ). Only T1 with lateral yellow spots, T 2–6 with yellow band, medially shortly interrupted in T2-3 (or T2-T4), continuous at least in T6 ( Fig. 14 ). 8.5–10.0 mm. (Female unknown). Northern Oman................................. Brachystegus schneideri Schmid-Egger & Al Jahdhami sp. nov.

5. Mesoscutum shiny, with scattered fine punctation. Head and mesosoma red ( Fig. 15 ). T 1–3 with thin continuous yellow bands. Northern Oman. 3.5 mm. (Male unknown).................... Nysson waleedi Al-Jahdhami & Schmid-Egger sp. nov.

– Mesoscutum dull, with denser and larger punctation, punctures approximately a diameter apart. Head and mesosoma black, pronotum and scutellum with yellow spots and some red, propodeum laterally red. T 1–5 with large lateral spots or continuous bands ( Fig. 18 ). 4.5 mm. (Male unknown). Northern Oman, Saudi Arabia................................................................................................ Nysson woodi Al-Jahdhami & Schmid-Egger sp. nov.

6. Clypeus with sharp transverse lamella, indistinct in male, ACM with two medial teeth ( Fig. 28 ). Pronotum laterally rounded or with obtuse angle. [Pronotum red, remaining mesosoma black. Only T 1–2 with yellow band or spots.] 6.0- 6.5 mm. Saudi Arabia.......................................... Synnevrus mekkahensis Schmid-Egger & Al Jahdhami sp. nov.

– Clypeus flat or with rounded transverse step. ACM different. Pronotum laterally rectangular or pointed................. 7

7. Mesosoma all or largely red ( Figs 22, 24 ). Clypeus forming rounded step just before apex. ACM without teeth. 4.5–6.0 mm. Oman, Saudi Arabia, UAE................................................. ... Synnevrus barrei Radoszkowski

– Mesosoma all or largely black, or with withish spot or band ( Figs 21 , 25, 31, 32 ). Clypeus flat, ACM with teeth.......... 8

8. Pronotum black with some red only ( Fig. 21 ). Scutellum black, basally red. T 1–6 with lemon yellow bands or spots. Larger, 6.0 mm. Male T7 with medial tooth larger and as long as lateral teeth, apex without long pilosity. (Female unknown). Saudi Arabia................................................................ Synnevrus arabicus Gadallah & Edmardash

– Pronotal collar whitish ( Fig. 31, 32 ). Scutellum basally with white spot. Only T 1–3 with whitish yellow spots or bands. Smaller, most specimens between 4.5–6.0 mm. Oman, Saudi Arabia, UAE............... Synnevrus ohli Schmid-Egger

Figures

FIGURES 1–8. 1. Brachystegus spp. hindwing. 2. Synnevrus decemmaculatus, hindwing. 3–7. Brachystegus schneideri ♂ holotype. 3. Dorsal view. 4. Lateral view. 5. Face. 6. Last terga. 7. Metasoma, ventral view. 8. Brachystegus samadashanensis, ♀ holotype, dorsal view.

FIGURES 9–16. 9–11. Brachystegus samadashanensis,. 9. ♀ holotype, face. 10. ♀ holotype, clypeus. 11. ♂ dorsal view. 12–14. Brachystegus nemkovi ♂ holotype. 12. Dorsal view. 13. Face. 14. Last terga. 15–16. Nysson waleedi ♀ holotype. 15. Dorsal view. 16. Last terga.

FIGURES 17–24. 17. Nysson waleedi ♀ holotype, face. 18–20. Nysson woodi ♀ holotype. 18. Dorsal view. 19. Face. 20. Last terga. 21. Synnevrus arabicus ♂ from Abu El-Ghiet et al. (2023). A. Dorsal view. B. Lateral view. 22–24. Synnevrus barrei from Oman. 22. ♀ dorsal view. 23. ♀ face. 24. ♂ dorsal view.

FIGURES 25–32. 25–28.Synnevrus mekkahensis ♀ holotype. 25. dorsal view. 26. Face. 27. Last terga. 28. Clypeus, dorsolateral view. 29–30. Synnevrus mekkahensis ♂ paratype 29. dorsal view. 30. Last terga. 31–32. Synnevrus ohli from Oman: 31. ♀ dorsal view. 32. #, dorsal view