Gynacantha apiaensis Fraser, 1927

Theischinger, Gunther, Marinov, Milen, Bybee, Seth, Jensen, Colin, Theuerkauf, Jörn & Rashni, Bindiya, 2020, The genus Gynacantha Rambur, 1842 in the South Pacific (Odonata: Anisoptera: Aeshnidae), Zootaxa 4778 (1), pp. 171-195 : 188

Gynacantha apiaensis Fraser, 1927

( Figs 2 , 11 , 21 , 33c , 36e, 36f, 36k )

Gynacantha apiaensis Fraser, 1927: 35 .

Distribution. Hitherto known only from Samoa.

Holotype: ♂ ( BMNH), West Samoa, Apia; detailed high-resolution photographs studied.

Diagnostic characters: Postfrons apparently without T-mark. Both Hw with space between CuP and A1 basally expanded and with several double cells in proximal half. Denticles along posterior portion of genital fossa reduced almost to a single row, occasional single or paired denticles present in anterior part. Superior anal appendages sinuous, basally rather narrow, continuously widening for whole length and with apex blunt and not extended into a distinct point; inferior appendage about 1/3 the length of superiors, with lateral margins only slightly sinuous and apex rather narrow.

The only species of Gynacantha known from Samoa. Distinguished from all species of the group by (1) lacking a dark T-mark on the postfrons, (2) by having more double cells in proximal half of the space between CuP and A1 of Hw, (3) by the narrower (almost a single row) patch of denticles along posterior portion of genital fossa, (4) by markedly more sinuous and less pointed superior anal appendages and (5) by the subtriangular shape of the inferior appendage.

Figures

FIGURE 2. Gynacantha apiaensis, male, Holotype; insert: S2, ventral; S2–3, ventral; anal appendages, dorsal.

FIGURE 33. Gynacantha sp. with superior anal appendages not sharply pointed: (a) G. rosenbergi; (b) G. amphora; (c) G. apiaensis.

FIGURE 36. Key structures of males of Gynacantha species. (a, c, e) S2 and S3, ventral, (b, d, f) anal appendages, dorsal: (a, b) G. rosenbergi; (c, d) G. dobsoni; (e, f) G. apiaensis; (g, i) part of hindwing, (h, j) S2 and S3, dorsal: (g, h) G. amphora; (i, j) G. dobsoni; (k, l) head: (k) G. apiaensis; (l) G. cf. stevensoni; (m–p) genital fossa, (q–t) anal appendages: (m, q) G. vanuatua; (n, r) G. vitiana; (o, s) G. koroana; (p, t) G. sp. cf. stevensoni.

FIGURES 3–11. Gynacantha species, male S2, ventral (to show arrangement of denticles along genital fossa): (3) G. rosenbergi; (4) G. dobsoni; (5) G. amphora; (6) G. vanuatua; (7) G. vitiana; (8) G. koroana; (9) G. stevensoni; (10) Gynacantha cf stevensoni; (11) G. apiaensis.

FIGURES 12–21. Gynacantha species, male anal appendages dorsal (to show differences between width of S10 and length of superior anal appendages): (12) G. rosenbergi; (13) G. dobsoni; (14) G. amphora; (15, 16) G. vanuatua; (17) G. vitiana; (18) G. koroana; (19) G. stevensoni; (20) G. cf stevensoni; (21) G. apiaensis.