Thitena cadaverina, 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 : 51-52

Thitena cadaverina n.sp.

Figs. 29–32

Type material. HOLOTYPE 3 Australia, Western Australia “ Barrow Island / W. Australia / 12.ii.1977 H. H. 75 / H.

Heatwole / W.H. Butler // On dead turnstone / 12 Feb. 1977 / Beach / Barrow Is. W.A. / H. H. 75. // HOLOTYPUS / Thitena cadaverina / gen. n., sp. n. 3 / L. Munari des.” AM K186744 . The specimen is in fairly good condition (many setae missing, posterior edge of both the wings a little damaged), and is double mounted (glued on the tip of a triangular card label); abdomen, including terminalia, in situ. PARATYPES Australia, Western Australia: same data as holotype, 433 7♀♀. The holotype and most of the paratypes are deposited in AM , a couple of paratypes is preserved in MCV .

Description. Size. Body length 4.1 mm (3.3–4.1), wing length 2.7 mm (2.2–2.7), wing width 1.0 mm (0.8–1.0).

Habitus ( Fig. 29). Robust, yellowish brown species with legs bearing strong setae and long and thick villosity. Wings brownish yellow. Head. Frons brownish yellow to brown, with very narrow, whitish orbital vittae; ocellar triangle and postcranial surface covered with dark grey microtomentum; antenna yellow, distinctly infuscated; face, parafacial, and gena pale yellowish, latter homogeneously microtomentose; frons without golden patch lateral to ocellar triangle, only with slight infuscation; paravertical setae strongly developed, cruciate at apex; inner vertical seta inclinate, strong, about as long as lateroclinate outer vertical seta; postocular and postgenal setae arranged in several irregular rows; 2 upper postocular setae inclinate towards paraverticals, external seta distinctly longer; ocellar triangle bearing pair of well-developed pseudopostocellar setae, distinctly longer than half of strong ocellars; a few very short setulae between ocellars and pseudopostocellars, and behind latter setae; 3 strong, lateroclinate orbital setae; several additional setulae between orbitals and frontals, distinctly more numerous between two anterior orbitals and anterior pairs of frontal setae; 3–4 pairs of strong, frontal setae intercalated with 3 pairs of shorter and weaker setae, all setae and setulae inclinate; antenna with postpedicel bearing microscopically pubescent arista; eye roundish, with strongly impoverished micropubescence formed by very few, sparse interfacetal setulae; longest diameter of eye 2.8– 3.3× as long as genal height; 7 strong peristomal setae (including vibrissa) decreasing in length posteriad; very narrow, glossy stripe along peristomal edge, between this one and peristomal setae, ending above vibrissal angle to form foldlike, shining facial tubercle; face depressed, without median carina; mouth parts yellow, with labellum shorter than length of buccal cavity, and palpus long, slender, slightly clavate, bearing scattered, golden brown setulae. Thorax. Brownish, covered with dark grey microtomentum; postpronotal lobe yellowish, faintly shining, distinctly contrasting with rest of brown thoracic surface; setae of mesonotum brownish to black, noticeably thinner than those in all other Tethininae species; 1+3 dorsocentral setae; 8–9 rows of acrostichal setulae on anterior half of scutum, otherwise arranged in 6 rows; prescutellar acrostichals long; postpronotal lobe bearing 3 setae, each with different inclination, posterior seta very long, anterior setae shorter, remaining surface with numerous strong setulae; 1 presutural seta; 2 notopleurals subequal in length; 1 supraalar, below it 1 shorter seta; 2 postalars, external one slightly, even though distinctly, longer; scutellum with 4 long marginal setae and many additional setulae on discal surface ( Fig. 30); proepisternal and proepimeral setae subequal in length and strength; anepisternum with pubescence almost fully covering entire surface, bearing 3 long, posteriorly directed, posteromarginal setae, mid one long and strong, and 1–2 erect, thin setae at posterodorsal margin; katepisternum very poorly pubescent on mid and upper parts, but with dense and very long brown villosity on lower surface, bearing long, erect seta on posterodorsal margin; anepimeron, katatergite, and meron without setae and setulae. Legs. Ventral and posteroventral sides of all legs, in particular of forelegs, strongly shaggy in male and with rows of long and robust setae present in both sexes; foreleg having yellow coxa bearing several, long, black setae; ventral and posteroventral surfaces of both fore femur and tibia of male covered with thick, very long and rather ruffled, golden villosity; fore tibia with row of posterodorsal black setae; fore femur bearing few setae dorsally and row of several, long, posteroventral setae; ctenidium absent, only short row of long, thin, golden setae in its place; mid leg with more or less bristly femur, and with tibia bearing antero- and posterodorsal rows of strong and long setae on distal two thirds of its length; hind leg with femur distinctly swollen in male, and with tibia bearing anteroventral and antero- and posterodorsal rows of long and strong setae (in variable number) on distal two thirds of its length; tarsi of male stumpy, with tarsomeres noticeably short (in particular basitarsomeres), setulose, and flattened; all legs brownish, with last tarsomeres darker. Wing. Veins light brownish to yellowish, membrane brownish yellow; alula with fringe formed by several, erect, golden brown setae; costal vein reaching end of M 1, with apex of first section, just above subcostal break, bearing long and strong spine-like seta; dorsal and ventral surfaces of costal vein with hardly discernible, microscopic setulae; R 2+3 almost straight to perceptibly bisinuate, slightly, even though distinctly, 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 about as long as half of last section of CuA 1; halter pale yellow. Abdomen. In male, with tergites and sternites well sclerotized, former rather broad, with narrow, yellowish, marginal stripes, and covered with several brownish to black setulae as well as with moderately long, golden brown, marginal setae which are longer on postabdominal segments; epandrium of male terminalia distinctly exposed. Male terminalia ( Figs. 31–32). Entire surface of epandrium bearing numerous, short setae; cercus tiny, dorsally covered with microscopic hairs and with long setae; anterior surstylus very long and slender, about as long as posterior surstylus, narrow, slightly bent forwards, bearing very long, spaced, thin setae on inner side; posterior surstylus large, bent forwards, distinctly tapered and pointed apically (in lateral view), externally covered with dense microtrichia, bearing several thin setae and short, stout tubercles on inner side of posterior margin; aedeagal apodeme relatively short, sinuated medially; ejaculatory apodeme with distal fan poorly developed, having regular, subtriangular, unindented margin; distiphallus stumpy, short, ribbon-like, covered with dense micropubescence.

Female. All legs distinctly setulose, but without remarkable long villosity; for the rest, external morphology and chaetotaxy similar to male, except for slight sexual dimorphism; abdominal sternites well developed and distinctly sclerotized; 6th tergite and sternite large, latter with roundish margin; both tergites and sternites brown, bearing several marginal setae and setulae. Female terminalia. Cerci small, relatively short, setulose; spermathecae spherical, smooth.

Distribution. Australia (WA).

Remarks. More material of this interesting species is desirable as most of the type series is damaged. Many specimens have a collapsed thorax and many setae and setulae are missing.

Etymology. From the Latin cadaverinus meaning of dead body, corpse, carcass. The specific epithet refers to the substrate upon which the new species was collected: a dead Turnstone (a migratory shorebird of the genus Arenaria ) possibly washed up on the beach.