Neboissomina topendica sp. nov.

Figures 6–9

Type material. Holotype male (CT-807), Northern Territory, Umbrawarra Gorge, 21 May 2015, P. Dostine (MVM, T-22578).

Paratypes. Northern Territory. 1 male (CT-667/DC-312 figured), collected with holotype (MVM); 7 males, collected with holotype (MAGNT) .

Other material examined. Northern Territory. 1 male, Blackmore R., 14 May 2015, P. Dostine; 2 males, same loc. and coll., 17 Jun 2015; 1 male, same loc. and coll., 13 Aug 2015; 1 male, same loc. and coll., 3 Aug 2016; 1 male, same loc. and coll., 31 Aug 2016; 1 male, same loc. and coll., 28 Nov 2016; 1 male, Sandy Billabong, Kakadu N.P., 26 May 2017, P. Dostine (all FFD) .

Diagnosis. The male of Neboissomina topendica sp. nov. is most similar to those of N. jardinei, N. kuranya Cartwright 2011, N. riyala, and N. philsuteri Cartwright 2011 in possessing inferior appendages which are fused to form a single large sub-rectangular plate, but it is distinguished by the three, minute, acute projections apicolaterally and apicomesally on each inferior appendage, in ventral view.

Description, male. Spur formula: 3:4:4. Head, body, and wings light brown, abdomen paler ventrally; wings (Fig. 6) similar to those of N. jardinei (Cartwright 2011, fig. 2), length of each forewing: male 2.3–3.1 mm, female 2.8–3.1 mm, length about 3.0 times width; length of each hind wing 3.2–3.3 times width. Wing venation: Each forewing with forks 2, 3, 4, and 5 present; fork 2 sessile, length about 1.5 times length of fork 3; fork 3 with length of fork about twice length of footstalk, fork 4 about 0.8 times length of fork 3, fork 5 about 1.6–1.7 times length of fork 4. Hind wings each with forks 2, 3, and 5 present; fork 2 sessile, its length about 1.7 times length of fork 3.

Male. Tergum X membranous, with pair of long, slender dorsal sclerotized processes converging near middle and diverging posteriorly (Fig. 9). Superior appendages short and robust (Figs 7, 9), in lateral view appearing subrectangular, very slightly tapered posteriorly, length about 2.8 times width, apices slightly rounded (Fig. 7), in dorsal view slightly dilated in posterior third (Fig. 9); pair of long, slender curved processes (mesal processes of tergum X) ventral to superior appendages. Phallus simple, tube-like (Figs 7, 8) with elongate, slender process partly embedded and emergent posteriorly (Fig. 7). Inferior appendages slightly longer than superior appendages, fused (Figs 7–9), in ventral view large, subrectangular shield, truncate posteriorly, length about 1.5 times width, with acute apicolateral corners and acute apicomesal projection (Fig. 8), in lateral view robust, tapered basally, very slightly tapered posteriorly, appearing sub-trapezoidal, length about 3 times width (Fig. 7).

Female. Unknown.

Etymology. Topendica —based on the colloquial regional name for the locality (Top End of the NT).

Remarks. At least thirty males of N. topendica have been collected from 3 localities in the Top End (latitude range 12.80– 14.59 °S), including sites in Kakadu NP and in the greater Darwin area.