Medetera iviei sp. nov.

Runyon, Justin B., 2020, The Dolichopodidae (Diptera) of Montserrat, West Indies, ZooKeys 966, pp. 57-151 : 57

Medetera iviei sp. nov. Figs 7 , 8 , 9

Type material.

Holotype, ♂ labelled: "MONTSERRAT: Woodlands/ Riverside House, 140 ft/ 16°45.985'N, 62°13.341'W / 10-12JAN2002, Malaise/ Ivie, Marske, Puliafico" "HOLOTYPE/ ♂ Medetera / iviei / Runyon [red label]" (USNM, type number USNMENT01350608).

Description.

Male (Fig. 7 ). Body length 2.2 mm, wing length 1.8 × width 0.6 mm. Head: Face (Fig. 8A ) slightly narrowed near middle, covered with dense golden-brown pruinosity; clypeus with less dense golden-brown pruinosity revealing dark metallic blue-green cuticle. Frons with dense golden-brown pruinosity. Palpus ovate, shining black with a few small pale setae. Proboscis shining black. Antenna black; first flagellomere small, oval; arista-like stylus inserted just dorsal of apex. Lower postocular setae pale yellow to white. Thorax: Scutum dorsally dark metallic green with brown pruinosity that is densest between acrostichal and dorsocentral rows of setae creating two indistinct brown stripes, scutum laterally metallic blue-green with gray pruinosity; setae on thorax light yellow; 8-10 pairs of small biseriate acrostichal setae; only posterior two pairs of dorsocentral setae noticeably enlarged; scutellum with one pair of large marginal setae and one pair of very small lateral setae. Pleuron dark metallic bluish green with gray pruinosity; with three small whitish setae on lower proepisternum. Legs: Setae and setulae pale yellow to white except setae on coxa I and lateral setae on coxae II and III light brown. Coxae wholly dark brown. Femora dark brown with tips yellow, legs otherwise yellow. Femora and tibiae I and III without distinct setae. Tibia II with paired dorsal setae near 1/3 (ad seta slightly larger than pd seta), a ventral seta at apex; tibia III with two small black hooked pd spurs at apex subtended by small yellow concavity. Tarsi plain, tarsus II with some black spicules ventrally. Ratios of tibia:tarsomeres: leg I: 24-8-8-6-4-3; leg II: 26-14-12-7-3-2; leg III: 34-7-16-9-5-4. Wing: Hyaline with brown veins, narrowly oval. R2+3 arching slightly backward; R4+5 curving more strongly backward than R2+3, approaching and becoming parallel with M near wing tip; crossvein dm-cu ca. two-thirds as long as last part of CuA1. Calypter white with white setae. Halter stem yellow-brown, knob white. Abdomen: Dark brown with dark metallic green-blue reflections and slight gray pruinosity, with small yellowish setae. Hypopygium (Figs 7 , 9 ) very large (slightly smaller than remainder of abdomen in right lateral view), fusiform, dark brown to almost black, projecting posteriorly beyond attachment to preabdomen and on a short peduncle formed by tergite VI. Hypopygial foramen left lateral near base. Epandrium dark brown to black, blunt apically, ventrally with large yellow erect seta basal to surstylus and smaller yellow seta basal to larger seta. Ventral lobe of surstylus bilobed, light brown, overlapping corner of epandrium at base, basoventral lobe large, thin, translucent, broadly rounded, and apicodorsal lobe smaller with a couple small lobes at tip and one or two small yellow apical hairs. Dorsal lobe of surstylus yellow, spatulate, with a couple small yellow hairs. Cercus brown, evenly rounded dorsally, pointed apically, with thin translucent membrane along dorsal edge, sparsely covered with short pale setae.

Female. Unknown.

Etymology.

This species is named for the coleopterist Michael A. Ivie (Montana State University) who led the invertebrate component of the Centre Hills Biodiversity Assessment project (2000-2005) and made this material available for study.

Distribution.

Montserrat.

Remarks.

Medetera iviei is most similar to M. crassicauda Robinson to which it keys in Robinson (1975), most notably in males of both possessing an extremely large hypopygial capsule that extends backwards beyond the end of the preabdomen. Males of M. iviei differ from those of M. crassicauda in the color of the face (Fig. 8 ) and in the form of the cercus (in M. iviei the cercus is pointed apically with length 2.5 × width, in M. crassicauda the cercus is blunt apically and nearly square) and the surstylus (in M. iviei the surstylus has a wide, thin translucent ventral lobe that is absent in M. crassicauda ).

Figures

Figure 7. Medetera iviei sp. nov. habitus of male holotype, left lateral. Scale bar: 1.0 mm.

Figure 8. Heads of males, showing color differences of face and frons, anterior views A Medetera iviei sp. nov. B M. crassicauda Robinson (Dominica, holotype). Scale bar: 0.5 mm.

Figure 9. Medetera iviei sp. nov. apex of male hypopygium, left lateral. Abbreviations: epand-epandrium; d sur-dorsal lobe of surstylus; v sur-ventral lobe of surstylus. Scale bar: 0.25 mm.