Formosargus melanogrammus Lessard & Woodley, 2020

Lessard, Bryan D., Yeates, David K. & Woodley, Norman E., 2020, Review of Australian Sarginae Soldier Fly Genera (Diptera: Stratiomyidae), with First Records of Cephalochrysa, Formosargus and Microchrysa, Records of the Australian Museum 72 (2), pp. 23-43 : 27-30

Formosargus melanogrammus Lessard & Woodley , sp. nov.

http://zoobank.org/NomenclaturalActs/ 05C4A849-BD02-4618-AF2C-2CE8CE515DD5

Fig. 4

Holotype ♀, “Middle Claudie R. / Iron Range N. Qld / 12 Oct.1974 / G. Daniels ”; “ HOLOTYPE ♀ / Formosargus melanogrammus / Lessard & Woodley, 2020 ” AMS K.478681. The specimen is in excellent condition . Paratype ♀, same data as holotype: “ PARATYPE ♀ / Formosargus melanogrammus / Lessard & Woodley, 2020 ” AMS K.478682. The specimen is in excellent condition .

Diagnosis. A small (length 5–7 mm), pale yellowish brown species, with frons wide, parallel-sided, upper half black and lower half pale yellowish cream in the females, and thorax with a distinct dark brownish black medial stripe. It can be distinguished from Formosargus kerteszi James, 1939 , by the wings with R 2+3 arising directly in line with crossvein r-m (distinctly proximal in F. kerteszi ), antennal flagellum with a more rounded apical margin of the basal complex and larger fourth flagellomere, scutum and scutellum with a relatively weakly defined black medial stripe (sharply delineated in F. kerteszi ), and entirely yellowish pleura (a black spot is present on the anepisternum near the notopleural suture in F. kerteszi ). Formosargus melanogrammus is extremely similar to F. lineata , differing mainly by having the scutal vitta widened posteriorly and occupying more than one-third of the width of the scutellum (narrower and more sharply defined in F. lineata , occupying one-fourth or less of the width of the scutellum). Regarding the Australian sargines, it could possibly be confused with Ptecticus , but can be readily distinguished by the generic characters.

Description. Male. Unknown.

Female. Length 5–7 mm. Head. Rectangular in dorsal view, about 0.4 times as long as wide. Eyes dichoptic, ommatidia uniform in size. Frons wide (index 1.4–1.5), margins parallel-sided, cuticular surface shining, upper half black, slightly raised medially with a linear pale yellowish marking, bare, with moderately long, dense, hair-like setae at lateral margins, lower half pale yellowish cream, cuticular surface relatively convex, bare; ocellar tubercle black, ocelli in the form of an equilateral triangle, hair-like setae moderately long and dense, golden yellow. Occiput not visible in lateral view, occipital plate covered in moderately long, dense, golden yellow hair-like setae. Face with cuticular surface shining, with some sparse, moderately long, hair-like setae at lower margins, oral margin with dense, relatively short, golden yellow hair-like setae. Antennae long, scape+pedicel+flagellum about 1.6 times as long as head, pedicel about 0.4 times as long as scape at outer surface, apically expanded and evenly rounded on inner surface, both segments pale yellow, with short, golden brown hair-like setae; flagellum about 1.8 times as long as scape+pedicel, basal complex yellow, apical margin covered with short, relatively dense, yellowish hair-like setae, apical flagellomere long, about 3 times as long as scape+pedicel. Palpi yellow, with tomentum. Proboscis yellowish, with moderately long, dense, yellowish hair-like setae.

Thorax. Scutum pale yellowish brown, with a distinct dark brownish black medial line, hair-like setae moderately long, dense, erect, golden yellow, becoming darker brown dorsomedially; scutellum in same plane as scutum, dark brownish black on more than medial third, pale yellowish brown at lateral margins, hair-like setae moderately long, brown, more yellowish at margins; mediotergite same colour as scutum, with relatively long, erect, golden hair-like setae; pleura pale yellow, shining, hair-like setae relatively long, sparse, golden yellow. Legs pale yellow with yellowish hair-like setae. Wings hyaline; discal cell elongate, about 1.5 times as long as wide; all four medial veins issued from discal cell, terminating just before margin; CuA curved; alula about 6 times as long as wide, surface bare of microtrichia, marginal hair-like setae about equal to width of alula; posttegula with small dorsal tuft of dense, orangey yellow hair-like setae.

Abdomen. Elongate ovoid, about 1.2 times as long as wide, widest at tergite 4, yellowish brown, with darker brown infuscation becoming more prominent from tergites 3 onwards, hair-like setae relative long, dense, appressed golden yellow, becoming longer and more erect at lateral margins. Sternites pale yellowish brown, hair-like setae relatively long, appressed, golden yellow. Terminalia cuticular surface and hair-like setae yellowish brown, cerci with both segments about equal in length, second segment parallel-sided and tapering apically.

Distribution. Known only from the type locality of Kutini- Payamu (Iron Range) NP, northern Qld ( Fig. 2 ).

Etymology. This specific name is derived from the Greek, melan, black, and gramme, line, referring to the distinctive black medial stripe on the scutum.

Remarks. The face is slightly anteroventrally produced to form a beak-like protuberance, similar to Hermetia Latreille, 1804 , but not as distinct.

This species is very similar to F. lineata (New Guinea), differing mainly in the form of the thoracic vitta. Unfortunately, the wings in the holotype female of F. lineata are mostly destroyed, so comparisons of wing characters cannot be made. Also, only females are known for both species so male terminalia characters are also unavailable.

One additional specimen from the Mt Lamond track (♀, “beginning of Mt Lamond track / Iron Range Nat. Park, Qld / 12°43'34"S 143°17'06"E / 3 Jan 1996 20 m / G. and A. Daniels ” AMS K.478680) most likely represents an undescribed species as it is larger in size (length 7 mm), and has an incomplete thoracic vitta that is mostly absent anterior to the transverse suture, and abdomen with more defined, almost black markings predominantly on tergites 2 and 3 .

Figures

Figure 2. Distribution of the Sarginae from Australia, including the first records of Formosargus James, 1939 and Microchrysa Loew, 1855.ACT, Australian Capital Territory; NSW, New South Wales; NT, Northern Territory; Qld, Queensland; SA, South Australia; Tas, Tasmania; Vic, Victoria; WA, Western Australia.

Figure 4. Formosargus melanogrammus Lessard & Woodley, sp. nov. holotype ♀ (AMS K.478681): (a) dorsum; (b) lateral; (c) head, frontal; (d) head, anterolateral.