Stipulosina amphibarba 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 : 262-266

Stipulosina amphibarba Yau & Marshall n. sp.

( Figs. 6a–e , 7a–d , 8a–d )

Description: Body length 2.0– 2.8 mm, males and females similar in size. General color brown but leg parts other than hind femur yellow. Eye height 5× genal height. Mid tibia with a pair of equal setae at basal quarter with posterodorsal seta at least half as long as anterodorsal seta; anterodorsal, dorsal and smaller posterodorsal setae at distal 3/4. Wing veins pale, whitish. Third costal sector subequal to second.

Male abdomen: Sternite 5 with a prominent trifid posteromedial area made up of a small, distally bilobed central piece with a cluster of dense setae on each side; flanked by longer processes with a narrow, pointed outer margin; inner margin of process with a long-setose lobe. Sternite 5 length anterior to trifid posteromedial area subequal to length of S4. Epandrium with uniform setae. Cercus robust and conspicuously long-setose at apex, length 1.2–1.3× surstylus length. Surstylus stout and triangular; ventral lobe densely setose, dorsomedial lobe with thick tuft of setae (often hidden between/ behind posteromedial lobe of S5). Basiphallus broadly cylindrical; distiphallus very short and broad, mostly sclerotized except at apex. Postgonite stout, broad basally and tapered apically.

Female abdomen:Tergite 8 desclerotized medially or just posteromedially; tergite length at margins 1.25× medial length of tergite. Epiproct half as long as cercus. Spermathecae smooth except few creases on dorsal surface.

Type material: Holotype (♂, QCAZ): ECUADOR: Napo: SierrAzul Reserve , 14 km W Cosanga, 2200 m, in bamboo stipules, 11.v.2002, S.A. Marshall debu00195517.

Paratypes: Same as holotype (9♂, 9♀, DEBU); Yanayacu Biological Station , 0°36’S, 77°53’W, 2000–2500 m, 25.ix–13.x.2019, T . Yau and S.A. Marshall (6♂, 8♀, QCAZ) .

Etymology: The specific name refers to the bearded surstylus and cercus.

Comments: Males of S. amphibarba and S. barbistylus are easily differentiated by the relative lengths of the large, heavily setose cerci and surstyli, which are usually visible even in dried specimens. Females of these two species are similar, but females of the closely related S. barbistylus (taken in copula with the easily identified male) have a T8 with dilated lateral margins. The remaining female specimens, with subequal medial and lateral lengths of T8, are assumed to be S. amphibarba .

Figures

FIGURES 6a–e. Stipulosina amphibarba sp. n. male habitus. 6a, lateral; 6b, dorsal; 6c, head; 6d, wing against white background; 6e, mid tibia dorsal.

FIGURES 7a–d. Stipulosina amphibarba sp. n. male abdomen. 7a, terminalia left ventrolateral; 7b, terminalia ventral; 7c, epandrium posterior; 7d, phallus and associated structures left dorsolateral.

FIGURES 8a–d. Stipulosina amphibarba sp. n. female abdomen. 8a, terminalia dorsal; 8b, terminalia ventral; 8c, terminalia lateral; 8d, spermathecae.