Stipulosina Yau & Marshall, 2021

Yau, Tiffany & Marshall, Stephen A., 2021, Stipulosina new genus (Diptera: Sphaeroceridae: Limosininae) from bamboo (Chusquea scandens stipules in Ecuador, Zootaxa 5072 (3), pp. 255-277 : 261-262

Stipulosina Yau & Marshall new genus

Type species: Stipulosina amphibarba new species

Generic diagnosis. Stipulosina species are characterized by two pairs of cruciate interfrontal setae, two pairs of dorsocentral setae, four scutellar setae, sexually dimorphic mid tibia, and the costa extending far beyond the apex of R 4 +5. Males have a characteristic sternite 5 (S5) with a trifid posteromedial margin, and stout, bilaterally symmetrical hypandrial arms separate from both the epandrium and the central part (anterior apodeme) of the hypandrium.

Generic description. Antenna to wing tip length 1.8–2.8 mm; wing fully developed, extending far beyond tip of abdomen and twice as long as wide. General color brown, legs mostly pale brown to yellowish (hind femur brown).

Head: Face broad and flat, lunule broadly rounded and as wide as distal margin of pedicel. Clypeus narrow, strap-like. Palpus short, pale, with one or more preapical ventral setae. Eye 2.5–5× as high as gena; vibrissa long; gena with 1–3 upturned setae in addition to the small marginal setae, anterior genal seta longer than genal height. Antenna yellowish brown, margin of pedicel with long setae, arista long-pubescent and almost twice as long as head height. Frons with dark stripes surrounding base of interfronal setae, forming a M pattern more or less interrupted anteromedially. Interfrontal area broad, flanked by two pairs of cruciate interfrontal setae and a pair of small lower setulae. Fronto-orbital setae large and lateroclinate, lower pair about 0.7× upper pair, small exclinate orbital setulae present. Ocellar and outer vertical setae large and subequal; inner vertical seta very large; postocellar setae very small, inner and outer occipital setae large.

Thorax: Prosternum linear, bare. Fore femur with several long, thin posterodorsal and ventral setae. Mid tibia of both sexes with a distinct ventral seta before middle and a long apicoventral seta; male mid tibia with a row of stout ventral setae on distal half and corresponding enlarged setae in the basal half of the femur. Hind leg with first tarsomere swollen, less than half as long as second, first and second tarsomeres densely golden setulose ventrally; hind tibia with neither a distinct apical spur nor enlarged dorsal setae; hind femur slightly to strongly swollen. Scutum pruinose, with two strong postsutural dorsocentral setae; prescutellar acrostichal setulae twice as long as other acrostichals. Postpronotal lobe with a single very large outer seta and a small inner seta; notopleural, supraalar and postalar setae strong, intra-alar slightly enlarged. Scutellum wider than long, with four long marginal setae. Katepisternum with one large dorsal seta and one or two very small setae.

Wings with white to pale brown veins and a small, narrow, apically rounded alula. Vein R 2+3 weakly sinuate, apex strongly curving up to costa; R 4+5 evenly curved up to meet costa well before wing tip, costa extending far beyond apex. Ventral costagial seta long.

Male abdomen: Sternite 5 short to long but always with a strongly developed tripartite posterior margin with a small, dark central process flanked by two larger setose lobes. Sternite 8 (S8) very short, fused to sternite 6+7 (S6+7) on right side. Subepandrial sclerite well developed, functionally replacing weak subanal plate. Cercus variable, short and fused to epandrium or sometimes more separate and elongate, but always with strong setae. Surstylus highly variable between species. Hypandrial arm free from main (medial) part of hypandrium and from epandrium. Phallic complex compact and heavily sclerotized.

Female abdomen (female unknown for S. curvistylus ): Tergite 7 (T7) half as wide as and slightly shorter than tergite 6 (T6), sometimes posteriorly emarginate. Tergite 8 (T8) entire, approximately equal in width to T7. Epiproct weakly sclerotized, bare. Cercus elongate, apically long-setose. Sternite 7 (S7) very large and well sclerotized, at least 1.5× length of sternite 6 (S6) and normally concealing S8. S8 short, strap-like with four setae. Hypoproct separated, on each side ventral to cerci and posterior to margins of T8. Three (2+1) small, short spermathecae, bodies no longer than wide.

Etymology: The generic name is derived from a combination of the name of the structure in which these flies occur and the “-sina” suffix that has become usual for generic names in the Limosininae . The gender is feminine.