Robustagramma setosum Cui and Marshall, 2005

Marshall, Stephen A. & Cui, Yongsheng, 2005, Systematics of Robustagramma, a new genus of New World Sphaeroceridae (Diptera), Zootaxa 1026 (1), pp. 1-122 : 34-35

Robustagramma setosum Cui and Marshall , new species

( Figs. 56–59 )

As described for Robustagramma robustinervus except as follows.

Body length 1.3 mm, general color reddish to brown. Face, gena, antenna and lower frons reddish yellow. Interfrontal bristles in 3 or 4 pairs. Ocellar bristle, inner and outer vertical bristle, and inner and outer occipital bristles well developed. Postvertical bristles ca. 2/3 as long as inner occipital bristles. Eye height ca. 2.1 times genal height. Preapical palpal bristles slightly longer than maximum width of palpus.

Acrostichal setulae in 6–8 irregular rows between anterior dorsocentral bristles. Wing very lightly, uniformly pigmented; First costal sector distinctly thicker than second costal sector. Length ratio of second to third costal sector ca. 0.42; R 4+5 and costa ending together before wing apex; discal cell with a long, 3–4 vein widths, stump of vein CuA 1. Tarsi and fore tibiae yellow. Mid tibia also with an apicoventral and 4 or 5 short ventral bristles on distal third. Mid femur with an anterior preapical bristle and 5 ventral proximal bristles.

Sternite 5 twice as long as sternite 4, with two dark processes near posterior margin and a bare, pale central area. Dorsomedial length of epandrium ca. 0.33X length of sternite 8. Surstylus densely covered with long bristles, posteroventral lobe tapering in lateral view. Cercus narrow, similar in length to surstylus. Distiphallus with a pair of large, dark ventral sclerites. Postgonite with a straight distal half. Ejaculatory apodeme small.

Holotype (♂, NHRS): ECUADOR: Napo. Lumibaqui , 10–11.iii.1983, L. Huggert.

Etymology: The specific epithet refers to the densely setose surstylus.

Comment: A male specimen (labeled: Venezuela, Aragua, Maracay, Rancho Grande Biol. Stn., 27.ii.1995, 1400m, Portachuelo Pass, S. A. Marshall) is almost identical to R. setosum in genitalia and most external characters, but differs from the latter in that the mid femur has 10 (not 5) ventral proximal bristles, the ratio of second to third costal sector is about 0.52 (not 0.42), and the discal cell lacks a long stump of vein CuA 1.

Figures

FIGURES 56–59. Robustagramma setosum sp. nov.: 56, posterior view of male terminalia; 57, lateral view of male terminalia; 58, lateral view of male internal genitalia; 59, male sternite 5.