Sympotthastia, Pagast, 1947

Fang, Xiangliang, Shangguan, Jingru & Fu, Yue, 2025, Sympotthastia annularis sp. nov. from Oriental China (Diptera: Chironomidae: Diamesinae) with a worldwide key, Zootaxa 5717 (4), pp. 571-578 : 576-577

Key to known species for adult males* of Sympotthastia worldwide (based on Liu et al. 2016)

1. Anal point absent..................................................................................... 2

- Anal point present..................................................................................... 4

2. Anal lobe of wing reduced, megaseta absent ( Liu et al. 2016: Figs. 10–15)........... S. wuyiensis Liu, Ferrington & Wang

- Anal lobe of wing well developed, megaseta present......................................................... 3

3. Phallapodeme curved, S-shaped; gonostylus gradually expanded anteriorly ( Ghaderi et al. 2024: Figs. A–E).............................................................................. S. golalae Ghaderi, Namayandeh & Karimian

- Phallapodeme boot-shaped, distal end extending downwards to the middle of gonocoxite; gonostylus widest in the middle and narrower towards the apex........................................................... S. annularis Fu , sp. nov.

4. Anal point sclerotized, narrow, long and slender............................................................. 5

- Anal point tubercle-like; apex of tubercle with or without strong setae........................................... 9

5. Aedeagal lobe distally expanded, reniform or knob-like....................................................... 6

- Aedeagal lobe not distally expanded, sigmoid or straight...................................................... 8

6. Median volsella bare, apical margin finely serrated ( Tuiskunen 1986: Figs. 2–3 )................... S. huldeni Tuiskunen

- Median volsella spiniferous............................................................................. 7

7. AR 3.38–4.26; prealars 14; aedeagal lobe distally knob-like ( Makarchenko 1994: Figs. 10–13)..... S. takatensis (Tokunaga)

- AR 2.90–3.10; prealars 23–31; aedeagal lobe distal reniform ( Makarchenko 1985: Fig. 228)...... S. repentina Makarchenko

8. Scutellum with 48 setae; prealars 15; aedeagal lobe distally sigmoid ( Doughman 1985: Figs. 1–3 )..... S. diastena (Sublette)

- Scutellum with 24 setae; prealars 4; aedeagal lobe distally straight ( Doughman 1985: Fig. 13; Makarchenko 1985: Fig. 227)..................................................................................... S. fulva (Johannsen)

9. Aedeagal lobe very broad, converging to point distally; phallapodeme short, not extending beyond aedeagal lobe ( Makarchenko 1994: Figs. 1 –4)............................................................... S. gemmaformis Makarchenko

- Aedeagal lobe not as above; phallapodeme long, extending much beyond aedeagal lobe............................ 10

10. Anal point tubercle-like, without strong setae ( Serra-Tosio 1968: Fig. 2 ).............................. S. zavreli Pagast

- Anal point reduced to a simple seta or consists of two strong setae arising at the tip................................ 11

11. AR higher, ca. 3.0; clypeus with 11 setae ( Doughman 1985: Figs. 11–12)...................... S. macrocera Serra-Tosio

- AR lower, ca. 1.60–1.75; clypeus with 4–5 setae ( Doughman 1985: Figs. 7–10).................. S. spinifera Serra-Tosio

Figures

FIGURE 1. Sympotthastia annularis sp. nov., male imago (A–G). A. adult male habitus (Scale bars = 2 mm). B. head. C. apex of antenna. D. maxillary palp. E. thorax. F. wing. G. hind tibial comb (Scale bars = 0.5 mm).

FIGURE 2. Sympotthastia annularis sp. nov., male imago (A–E).A. image of hypopygium, ventral view (Scale bars = 0.2 mm). B. image of the dorsal part of the hypopygium showing absence of anal point (Scale bars = 0.5 mm). C. hypopygium, dorsal view. D. hypopygium, ventral view. E & F. sclerotized structures of the hypopygium (AL: aedeagal lobe; SVo: superior volsella; MAL: median aedeagal lobe; Pha: phallapodeme).

FIGURE 3. A Neighbor-Joining (NJ) tree of Sympotthastia Pagast, 1947 species, and one outgroup Potthastia gaedii (Meigen, 1838) inferred from the COI nucleotide sequence data (658 bp). Numbers below the branches represent bootstrap values (>70).