Albistyla occulta, Marshall, Stephen A., 2014

Marshall, Stephen A., 2014, Albistyla, a new genus of Neotropical Limosininae (Diptera: Sphaeroceridae), Zootaxa 3793 (2), pp. 257-264 : 261

Albistyla occulta n.sp.

Figs. 6 –9.

Description. Abdomen: Syntergite 1+2 very large, 4X length of T3, with a large pale anteromedial area and a dark posterior margin.

Male abdomen ( Figs. 6–8 ): Posterior margin of S5 complex, each side with a single large bristle and a trilobed spatulate process, outer lobes dark, cup-shaped and widely separated; middle lobes elongate, tuberculate, setose and projecting ventrally; inner lobes shallowly fimbriate. Epandrium and surstylus as described for A. spatulisterna . Basiphallus with a prominent and apically rounded posterior process (epiphallus); distiphallus very short, tubular; lightly sclerotized but setulose along broadly expanded flanged distal margin. Postgonite with a large anterobasal tubercle articulating with a bisetose pregonite, distal part of postgonite strongly tapered and curved anteriorly ( Fig. 8 ).

Female abdomen: T7 and T8 complete, only slightly shortened dorsomedially, with only a few small bristles on posterior margin. T10 greatly reduced, bare. Posterior margin of S7 convex and weakly bilobed; S8 hyaline, transverse and with a transverse row of 4 small equal bristles. S10 densely setulose, without bristles. Cercus very short and rounded, no longer than broad, with 4 short bristles. Spermathecae with a funnel-shaped base and a ridged, tire-shaped distal part; ducts with a U-shaped bend just beyond base, sclerotized part as long as spermathecal body (Fig. 9).

Type material. Holotype (♂, ROME) and 3 paratypes (1♂, 1♀, DEBU): ECUADOR. Napo Prov., Baeza, 1700m, Malaise head wet, montane forest/pasture nr. small creek. 16–19.v.1987, ROM 870009, L.D. Coote and B.V. Brown.

Additional paratypes: ECUADOR. Napo, Baeza, 1500 m, wet montane rain forest, malaise trap, 16–19.May.1987, 16–19.May.1987, Coote & Brown (2♂, DEBU).

Etymology. The specific name is from the Latin for concealed, and refers to the way the distinctive characters of the male sternite 5 are normally concealed beneath sternite 4.

Comments. Albistyla occulta , currently known only from Ecuador, shares several distinctive synapomorphies with the Central American A. spatulisterna . The single large bristles overlapping the lateral lobes of sternite 5, the general structure of the sternal lobes, and the general form of the distiphallus and postgonite suggest that these species are closely related although they differ markedly in detail of the posterior margin of sternite 5.

Figures

FIGURES 6 – 8. Albistyla occulta male abdomen. 6, ventral; 7, sternite 5; 8, phallus and associated structures left lateral, with hypandrium. Figs. 9 – 10: Albistyla females, spermathecae. 9, A. occulta; 10, A. spatulisterna. Abbreviations: S 3 – 5, sternites 3 – 5.