Coprosylia bisetosa Marshall & Yau, 2019

Marshall, Stephen A. & Yau, Tiffany, 2019, Coprosylia bisetosa, a new genus and species of limosinine sphaerocerid (Diptera: Sphaeroceridae) phoretic on dung beetles in Borneo, Raffles Bulletin of Zoology 67, pp. 183-188 : 183-185

Coprosylia bisetosa Marshall & Yau , new genus and new species

Type of genus (by current designation): Coprosylia bisetosa Marshall , new species

Material examined. Holotype male ( DEBU), two male paratypes ( DEBU, ZRC) and one female paratype ( DEBU): Malaysia. Sarawak, Bau , “Mendung Escape”, 1°31′15.09″N 110°9′59.06″E, August 30, 2018, S.A. Marshall.

Diagnosis. Small Limosininae with conspicuously large presutural dorsocentral bristles, small eyes, subequal second and third costal sectors with the latter not overlapped by the costa, and mid tibial chaetotaxy including apicoventral, midventral, preapical anterior, and multiple dorsal bristles ( Fig. 2 ).

Generic and specific description. Body length (front of head to abdominal tip) 1.6 mm. Colour brown with heavy

pruinosity; lower half of frons, face, first flagellomere, tibiae and tarsi yellowish.

Head: One strong posterior lateroclinate orbital bristle, a minute anterior orbital bristle and 2–4 anterior orbital setulae; ocellar and outer vertical bristles large and subequal; inner vertical bristle very large; postocellar bristles very small, inner and outer occipital bristles small.

Interfrontal bristles small, in 4 equal pairs with a small outer setula beside lower interfrontal; interfrontal area subequal in width to orbital plate. Arista long-pubescent, 1.1× as long as head height. Face broad and centrally flat. Vibrissa strong, subtended by a small subvibrissa, gena otherwise with only 1 or 2 small setae in addition to small marginal setae. Eye small, 2× genal height.

Thorax: Scutum pruinose; dorsocentral bristles in 2 very long pairs, presutural pair as long as prescutellar pair; prescutellar acrostichal setulae not enlarged. Postpronotal lobe with a single large bristle; notopleural, supra-alar and postalar bristles strong, intra-alar slightly enlarged. Scutellum wider than long, with 4 long marginal bristles. Propleuron with two strong setulae. Katepisternum dorsally with a large bristle and one or two very small setae. Fore tarsus conspicuously longer than fore tibia, tarsal claws cultriform, larger and more strongly curved than tarsal claws of other legs; pulvilli of all legs very broad and strongly developed. Fore femur with 2–3 anterodorsal bristles just beyond midpoint. Mid tibia of both sexes with strong midventral and apicoventral bristles; proximal half of dorsal surface of mid tibia with a weak proximal anterodorsal bristle followed by a very strong posterodorsal bristle and a more distal strong anterodorsal; distal half with 3 bristles (anterior, anterodorsal, and posterodorsal); apex with a small anterior bristle in addition to the apicoventral. Hind leg with first and second tarsomeres swollen, first tarsomere broader, half as long as second, densely golden setulose ventrally; hind tibia with no trace of an apical spur.

Wing with a small, pointed alula. Vein R 2+3 evenly curving up to costa; R 4+5 almost straight, apex not bypassed by costa, second and third costal sectors subequal. Crossvein dm-cu about twice as long as r-m, separated from r-m by about 7 times the length of r-m; posterior corner of cell dm slightly rounded, CuA 1 not developed. Anal vein short, slightly arched.

Abdomen: Pleuron with sclerotised patches and conspicuous short, stout setae.

Abdomen abruptly tapered (telescoped) at segment 6; tergites and sternites 6, 7, and 8 much narrower than T5 and S5. T6 generally uniformly but lightly sclerotised, with several setae at posterior margin. T7 well sclerotised only on outer strip, with several setae at posterior margin. T8 weakly sclerotised, with single row of setae at posterior margin. Epiproct shield-like with a pair of setae. S7 sclerotised only at four corners in triangular patches, with setal cluster at posterior margin. S8 bell-shaped, with setae on posterior half. Hypoproct anteromedially desclerotised, with single row of setae at posterior margin. Cercus simple with several long wavy setae. Two (1+1) spermathecae, both dorsoventrally slightly compressed, apically invaginated. Spermathecal duct smooth, without swelling, diameter gradually increasing from bursa copulatrix to spermatheca. Apex of bursa copulatrix mushroomed and bilobed, dorsally along length with heartshaped sclerotised patch; ventral receptacle apparently absent.

Etymology. The generic name is an adaptation of the Greek term nekrosylia, defined in Brown (1954) as “robbery of the dead”. The gender of the name is feminine. The altered prefix “ copro ” (dung) reflects the assumption that the larvae of this species develop as robbers of the dung transported by scarabaeine beetles. The specific name refers to the strikingly large anterior dorsocentral bristles.

Figures

Figs. 1, 2. Coprosylia bisetosa. 1A, B, Male and female flies on host Paragymnopleurus maurus; 2A, Male paratype, right wing; 2B, Male holotype, left lateral; 2C, Male paratype, left mid tibia and tarsomere one.