Ecnomina radonica sp. nov.

Figures 1–5

Type material. Holotype male specimen (CT-666/DC-300). Northern Territory, Radon Springs, 12.7515°S, 132.903°E, 24 Apr 2015, P. Dostine (MVM, T-22576).

Paratypes. Northern Territory. 2 males (specimen CT-662 figured), 4 females (one figured), collected with holotype (MVM / MAGNT); 1 male, same site and collector, 19–20 May 2015; 4 males, 6 females, Leichhardt Springs, 19 May 2015, P. Dostine ; 2 males, Kubara Ck, 4 Sep 2019, P. Dostine (all MAGNT) .

Diagnosis. The male of Ecnomina radonica sp. nov. is similar to those of E. thinotes Neboiss 1979 and E. volsellus Cartwright 1990 in possessing an elongate pair of simple dorsal processes on tergum X but can be distinguished from the latter two and all other species in the genus by the distinctive, slender and incurved, pincer-like inferior appendages. The wing venation of E. radonica sp. nov. (Fig. 1) differs from those figured for E. legula Neboiss 1977 and E. scutica Cartwright 2008 (Cartwright 2008, figs 3, 5), in that forewing forks 2, 3, and 4 and hind wing fork 3 are all relatively short.

Description, male & female. Spurs: 3:4:4. Wings (slightly damaged) as in Fig. 1. Head, body, and wings light brown; wings similar to those of E. legula (Cartwright 2008, fig. 3) but most forks shorter. Length of each forewing: male 2.4–2.5 mm, female 2.8 mm. Forewing with forks 2, 3, 4, and 5 and discoidal cell; fork 2 relatively long, sessile, length of fork about 1.6–1.7 times length of fork 3; fork 3 relatively short, with long footstalk, fork about 1.7–1.8 times length footstalk, crossveins r-m and m nearly contiguous at fork 3, fork 4 about 0.8 times length of fork 3; fork 5 long, length about 1.9–2.0 times length of fork 4. Hind wing with forks 2, 3, and 5 and discoidal cell; fork 2 with short footstalk, length of fork 2 about 2.0–2.3 times length of fork 3; fork 3 shorter than its footstalk.

Male. Tergum X with one pair of relatively slender dorsal processes (Figs 2, 4), in dorsal view robust in basal third (Fig. 4). Superior appendages slender, somewhat rod-like (Figs 2, 4), in lateral view with length about 6.8 times width (Fig. 2); in dorsal view with length about 5.5 times width, each with single, robust subapical spine (Fig. 4). Phallus simple, tube-like (Figs 2, 3, 4). Inferior appendages slender, curved strongly downward and mesad like pincers, fused at base (Figs 2, 3).

Female. Genitalia with a single slender, elongate mesal process on sternite VIII; segment IX relatively long and slender, segment X relatively short and slender in ventral view (Fig. 5).

Etymology. Radonica —from the type locality (Radon Springs).

Remarks. Ten male specimens of Ecnomina radonica are recorded from three localities within Kakadu NP, NT (latitude range 12.75– 12.83°S).