Peltopsilopa Hendel

Genus Peltopsilopa Hendel

Peltopsilopa Hendel 1914: 156. Type species: Peltopsilopa aspistes Hendel 1914 (= Peltopsilopa anisotomoides (Karsch)), original designation.— Malloch 1941: 125 ‒126 [review].— Wirth 1968: 12 [Neotropical catalog].— Mathis & Zatwarnicki 1995: 37 [world catalog].

Diagnosis. Peltopsilopa is distinguished from other genera of Psilopini by the following combination of characters: Small to moderately small shore flies, body length 1.75‒2.25 mm; scutellum greatly enlarged, extended over abdomen; microtomentum generally sparse or lacking, appearing subshiny to shiny; mostly black species. Head: Head in lateral view with antenna inserted at dorsal 1/3; frons conspicuously wider than long; fronto-orbital setae reclinate and proclinate but sometimes weakly developed; pseudopostocellar setae well developed, subequal to lateral vertical seta, orientation mostly proclinate and slightly divergent; both medial and lateral vertical setae well developed; vertex acutely creased; posterior ocelli situated immediately before creased vertex, these in isosceles triangle. Antenna with basal flagellomere longer than pedicel; scape not exerted; arista with 7‒11 dorsal rays. Facial vestiture variable, surface mostly flat and plain, lacking pits and transverse microrugosity or striae; 1 strong facial seta, mesoclinate; palpus black; proboscis normally developed, not elongate. Thorax: Generally black to deep bluish black, microtomentum sparse to lacking; supra-alar seta absent; prescutellar acrostichal seta well developed; scutellum greatly enlarged, much longer than wide, extended over abdomen; basal scutellar seta over 1/ 2 length of apical seta; anepisternum with 2 large setae. Wing mostly hyaline to faintly yellowish except for blackish base; crossveins not darkened; vein R2+3 extending normally to costal margin, lacking a stump vein; R stem vein bare of setulae dorsally. Knob of halter black. Femora black; forebasitarsomere whitish yellow to yellow, only apical 1‒2 tarsomeres blackish. Abdomen: Generally bare of microtomentum, shiny, blackish; tergites 3‒4 long, 5th tergite very short and lacking prominent, dorsally erect setae along posterior margin. Male terminalia: epandrium in posterior view as an inverted, rounded U (open ventrally), in lateral view wider subventrally; cerci lunate to rod-like, narrower dorsally, sometime with a mediodorsal point; presurstylus much longer than wide, setulose; postsurstylus longer than wide; subepandrial plate wider than long, usually narrowed medially and with each lateral extension slightly enlarged; pregonite bearing 2‒4 setulae; aedeagus longer than wide, wider basally in ventral view; phallapodeme in lateral view more or less triangular, keel sometimes irregular, asymmetrical; hypandrium U-shaped, open posteriorly, in lateral view shallow to moderately deep, pocket-like.

Discussion. Peltopsilopa is similar and evidently is closely related to Cressonomyia, as Mathis & Zatwarnicki (2004) suggested. Both genera share at least three synapomorphies: 1. base of wing darkened; 2. knob of halter blackish brown to black; and 3. postsurstylus angulate, L-shaped. Peltopsilopa differs from Cressonomyia in having a greatly enlarged, dome-like scutellum that extends posteriorly over most of the abdomen or beyond. Both genera are also only known from the New World, especially tropical areas. Although Peltopsilopa is distinctive and readily distinguished from other genera of the tribe Psilopini (enlarged scutellum and setulose gonite that bears setulae in addition to the three long, apical setulae), it should perhaps be recognized as a derived and included lineage within Cressonomyia, closely related to the aciculata group. This relationship is also evident in the shape of structures of the male terminalia, which are very similar to those of Cressonomyia, and appear to represent a variation on a single theme.