Wahnesia, Forster, 1900

Polhemus, Dan A. & Kalkman, Vincent J., 2021, Four new species of Wahnesia Förster, 1900 from the D’Entrecasteaux, Louisiade and Woodlark island groups, Papua New Guinea (Odonata: Argiolestidae), Zootaxa 5004 (3), pp. 447-464 : 463

Key to the males of the Wahnesia occurring on the Louisiade Archipelago, the D’Entrecasteaux Islands, and Woodlark Island

This key is only suited for adult males which can be recognised by the dark brown to black pterostigma and the largely dark brown to black frons.

1. Lower ridge of the cerci bearing one smoothly rounded flange ( Figs 4–7 , 13–16 ); male genital ligula with a pair of broad, apically convergent processes ( Figs 9–12 ); Woodlark Island and Lousiaide Archipelago.................................2

- Lower ridge of the cerci with one flange that is not smoothly rounded and terminates to the main axis of the cercus at a sharp angle, or bearing 2 flanges ( Figs 18–21 ); male genital ligula with a pair of narrow, apically divergent processes ( Fig. 17 ); D’Entrecasteaux Islands ( Fig. 22 )......................................................................... 5

2. Labrum with distal half to two-thirds dark; paraprocts in dorsal view either apically truncate, or with angular, interiorly-directed points at apices ( Figs 4 , 15 )............................................................................. 3

- Labrum mostly pale or with at most narrow dark margins laterally and distally; paraprocts in dorsal view with small, posteriorly-directed points apically ( Figs 6 , 13 )....................................................................4

3. Legs bright red ( Fig. 1 ); paraprocts truncate apically when viewed from above, apices forming short, upturned angles when viewed laterally ( Fig. 5 ); distal half of labrum black; Woodlark Island ( Fig. 3 ).......................... W. muyuw n. sp.

- Legs pale yellow; paraprocts with angular, interiorly-directed points at apices when viewed from above, apices elongate and tapering when viewed laterally ( Fig. 16 ); distal half of labrum metallic blue; Rossel Island ( Fig. 8 )........... W. rossel n. sp.

4. Legs medium to dark brown; apices of cerci slightly expanded and bulb-like when viewed dorsally ( Fig. 6 ); medial spine on abdominal S10 small, apex barely projecting beyond posterior margin of tergite ( Fig. 6 ); Misima Island ( Fig. 8 )................................................................................................... W. misima n. sp.

- Legs bright orange-red; apices of cerci slightly more slender and finger-like viewed dorsally, apices not expanded ( Fig. 13 ); medial spine on abdominal S10 larger, clearly projecting beyond posterior margin of tergite ( Fig. 13 ); Tagula (Sudest) Island ( Fig. 8 )................................................................................. ... W. tagula n. sp.

5. Labrum completely pale (often bluish), sometimes with very narrow dark margin; outer and inner surfaces of femora and tibiae without distinct color differences, legs entirely orange to yellow; dark bands on legs, when present, not terminating against inner side of the legs but instead forming a continuous ring.................................... W. annulipes (Lieftinck)

- Labrum cream white on basal one-third to one-half, dark metallic green on distal half to two-thirds; legs with upper surfaces dark brown to black, lower surfaces bright reddish orange; darker bands on tibiae, when present, terminating against the inner side of legs....................................................................... .. W. armeniaca (Lieftinck)

Figures

FIGURE 1. Wahnesia muyuw, n. sp., photograph of living male individual from Papua New Guinea, Woodlark Island (Stephen Richards photo).

FIGURE 3. Distribution of Wahnesia muyuw n. sp. on Woodlark Island.

FIGURE 8. Distribution of Wahnesia species occurring in the Louisiade Archipelago.

FIGURE 17. Wahnesia annulipes, scanning electron micrograph of male genital ligula.

FIGURE 22. Distribution of Wahnesia species occurring in the D’Entrecasteaux Islands.

FIGURES 4–7. Wahnesia species, male terminal anal appendages. 4. W. muyuw n. sp., dorsal view; specimen from Woodlark Island, Suloga Peninsula, CL 7217. 5. W. muyuw n. sp., right lateral view of same specimen as preceding. 6. W. misima n. sp., dorsal view; specimen from Misima Island, Yaua Creek, CL 7205. 7. W. misima n. sp., right lateral view of same specimen as preceding.

FIGURES 13–16. Wahnesia species, male terminal anal appendages. 13. W. tagula n. sp., dorsal view; specimen from Tagula Island, Kalitau Creek, CL 7190. 14. W. tagula n. sp., right lateral view of same specimen as preceding. 15. W. rossel n. sp., dorsal view; specimen from Rossel Island, Mt. Rossel. 16. W. rossel n. sp., right lateral view of same specimen as preceding.

FIGURES 9–12. Wahnesia species, scanning electron micrographs of male genital ligula. 9. W. muyuw n. sp.; 10. W. misima n. sp.; 11. W. tagula n. sp.; 12. W. rossel n. sp.

FIGURES 18–21. Wahnesia species, male terminal anal appendages. 18. W. annulipes (Lieftinck), dorsal view; specimen from Normanby Island, Yeluyelua, CL 7232. 19. W. annulipes (Lieftinck), left lateral view of same specimen as preceding. 20. W. armeniaca (Lieftinck), dorsal view; specimen from Goodenough Island, Waidala Creek, CL 7188. 21. W. armeniaca (Lieftinck), left lateral view of same specimen as preceding.