Dasyrhicnoessa ciliata, Munari, 2004

Munari, L., 2004, Beach Flies (Diptera: Tethinidae: Tethininae) From Australia and Papua New Guinea, with Descriptions of Two New Genera and Ten New Species, Records of the Australian Museum 56 (1), pp. 29-56 : 34-36

Dasyrhicnoessa ciliata n.sp.

Figs. 5–6

Type material. HOLOTYPE 3, Australia, Northern Territory “NT: Buffalo Ck, / Darwin; 2–5 Mar. / 1996; D.K. McAlpine, / G. R. Brown” // “ HOLOTYPUS / Dasyrhicnoessa / ciliata sp.n. 3 / L. Munari des”, AM K186736 . The specimen is in excellent condition, and is double mounted (glued on the tip of a triangular card label); abdomen dissected, stored in glycerol in a small plastic tube, and pinned below the specimen . PARATYPES 2♀♀ same data as holotype. One paratype has an additional, orange label with handwritten “Laboulb.” The holotype and one paratype are deposited in AM , the second paratype is preserved in MCV .

Description. Size. Body length 2.3 mm (2.1–2.3), wing length 1.9 mm (1.8–1.9), wing width 0.7 mm (0.67–0.72).

Habitus.Yellow species with setal vestiture of thorax black. Head yellow with antenna bearing very long-haired arista. Wings yellowish grey. Head. Entirely yellow; frons, including orbital vittae, homogeneously yellow, except for usual golden yellow patch on both sides of ocellar triangle; paravertical setae well developed, inclinate; inner vertical seta slightly inclinate, strong, about as long as lateroclinate outer vertical seta; postocular and postgenal setae somewhat long, former setae in 1–2 rows; upper postocular seta long, inclinate towards inner vertical seta; ocellar triangle bearing pair of long, thin pseudopostocellar setae in addition to pair of strong ocellars; 2–3 very short, thin setulae between ocellars and pseudopostocellars; 3 strong, lateroclinate orbital setae; row of long, thin, inclinate setulae on orbital vitta between two anterior orbitals and frontals; 3 pairs of frontal setae, anterior one short and thin in male holotype, plus 2 pairs of thin setulae, all setae and setulae inclinate, mid pair with setae distinctly cruciate at apex; antenna with large and pubescent postpedicel, bearing blackish, very long-haired arista ( Fig. 8); eye micropubescent, very large, distinctly oblong vertically, its longest diameter 5× as long as genal height; 6–8 blackish peristomal setae, three anteriors, including vibrissa, very strong and long; mouth parts pale yellow, with labellum shorter than length of buccal cavity, and palpus long, slightly clavate, bearing scattered setulae. Thorax. Entirely yellow, slightly translucent, with setal vestiture black; 1+3 long dorsocentral setae; 4 rows of acrostichal setulae on anterior half of scutum, otherwise arranged in 2–3 rows; posterior surface of scutum mostly bare (holotype); prescutellar acrostichals very long and strong; postpronotal lobe bearing 3 setae, each with different inclination, posterior seta long and strong, anterior setae shorter and weaker; 1 long presutural seta; 2 notopleurals about subequal in length; 1 supra-alar, below it 1 shorter and weaker seta; 2 postalars, external one distinctly longer and stronger; scutellum with 4 long marginal setae; both proepisternal and proepimeral setae present; anepisternum with scattered pubescence, bearing 3 long, posteriorly directed, posteromarginal setae, middle one longer and stronger, and 1 erect, thin seta at posterodorsal margin; katepisternum with few scattered setulae and bearing long posterodorsal seta; anepimeron, katatergite and meron without setae and setulae. Legs. Evenly setulose, bearing short blackish to yellowish setae and setulae, except for foreleg having coxa with long, black setae, and femur with a few posterodorsal setae and remarkable row of very long, slightly curved, posteroventral setae; fore femur with ctenidium formed by long, strong, black spinulae (in female distinctly weaker); mid femur of male with row of long, spaced, spine-like, posteroventral black setae evenly arranged on entire length of femur; all legs, including coxae, yellow; last tarsomere slightly infuscate. Wing. Veins brownish yellow, membrane yellowish grey; alula with fringe formed by erect, black setae; costal vein reaching end of M 1, bearing several, spaced, microscopic setulae on dorsal and ventral surfaces; R 2+3 slightly bisinuate, diverging from R 4+5 distally; R 4+5 and M 1 parallel; crossvein r-m ending before middle of cell dm; crossvein dm-cu distinctly shorter than one third of last section of CuA 1; halter yellowish. Abdomen. Brown, bearing several thin setae and setulae; transverse stripes at posterior edge of tergites narrow, whitish. Male terminalia ( Figs. 5–6). Epandrium bearing two pairs of very long setae dorsally, and several short setae on remaining posterior surface; cercus moderately long, pubescent, covered with microscopic hairs and with long setae dorsally; anterior surstylus small, simple, with sparse, thin setae on both outer and inner sides; posterior surstylus rather broad, with anterior outline markedly sinuous, lobe-shaped; inner side of posterior surstylus with many setae and apical cluster of short, stout tubercles; aedeagal apodeme long and straight; distal fan of ejaculatory apodeme poorly developed; distiphallus long, ribbon-like, bearing long micropubescence.

Female. Similar to male, except for slight sexual dimorphism. Abdomen pale reddish yellow, marked by medial, longitudinal, brown stripe, and with transverse stripes at posterior edge of tergites hardly discernible; apex of postabdomen with segments telescopically retractile. Female terminalia. Cerci moderately long, straight, setulose; spermathecae spherical, smooth.

Distribution. Australia (NT).

Remarks. This new species is characterized by a longhaired arista (an apomorphic character state with respect to the ground plan of the Tethinidae , Figs. 7–8) as well as by the very enlarged posterior surstylus of the male terminalia ( Fig. 5). Both these peculiar features, in addition to the yellow body and legs, and the characteristic slender habitus of the flies, are also found in D. longisetosa and D. priapus (see below). In my opinion, these three species form a taxonomic group, named here “the Dasyrhicnoessa ciliata - group”, in which D. ciliata would seem to be the sister species of the monophyletic clade D. longisetosa plus D. priapus , the latter two species additionally sharing a peculiar cluster of thin setulae arising from the medial side of posteromarginal surface of the posterior surstylus ( Figs. 11– 12, 20–21) as well as sharing the lack of a true ctenidium which is well developed in D. ciliata .

Etymology. From the Latin ciliatum meaning bearing eyelashes. The specific epithet refers to the long-haired arista of the antennal postpedicel.