Irwinus Grichanov, 2023

User, GBIF. Org, 2023, Occurrence Download, Russian Entomological Journal 32 (1), pp. 83-88 : 84

Genus Irwinus Grichanov , gen.n.

Type species. Irwinus irwini Grichanov sp.n., here designated.

DESCRIPTION. This generic description is based on one species and emphasizes characters considered to be of generic importance. Body length 1.5–1.7 mm, wing 1.3–1.4 x 0.3 mm. Head. Distinctly wider than high in anterior view; occiput concave; pair of short postvertical setae on dorsal postcranium, half as long as verticals and not in line with postocular setae; pair of strong verticals at level of ocellar bristle pair present; face as wide as small flat clypeus, concave, almost parallel-sided, and fronto-clypeal suture distinct laterally; labella with 6 pseudotracheae; eyes with microscopic hairs; eye facets uniform; palpus small; scape small, simple, bare; pedicel simple, with corona of short setae; postpedicel small, rounded, haired, with lateroapical arista-like stylus comprised of 2 segments. Thorax. Mesonotum convex posteriorly, flattened immediately anteriad of scutellum; acrostichal setae absent; 4 strong dorsocentrals present in almost parallel rows, slightly decreasing in size anteriorly; 1 strong postalar, 1 strong supraalar, 1 strong sutural, 1 strong humeral, 1 strong and 1 hair-like notopleurals; scutellum with pair of strong marginal bristles and pair of minute setae laterally; proepisternum with 2–3 simple setae; postnotum short. Legs. Coxae with short white bristles; legs simple; fore leg without strong bristles; mid and hind femora each with short anterior preapical bristle; mid and hind tibiae each with pair of strong antero- and posterodorsals at base and 1 anterodorsal bristle in middle; only mid tibia with rather strong apical bristles. Wing. Short and narrow; membrane grey, with hyaline windows at base and at middle; R 1 short, reaching costa at basal 1/3 of wing length; R 2+3 and R 4+5 weakly convex, subparallel, diverging at wing apex; M 1 weakly convex, parallel apically with R 4+5, and joining costa at wing apex; cross-vein dm-m straight and weak, much shorter than apical part of M 4; anal lobe absent. Abdomen. Broad and flattened dorso-ventrally; tergites without strong marginal bristles; male sternites 2–5 as 2 rows of sclerites along tergal margins, strongly decreasing in size caudally; tergite 6 haired; male tergite 8 large; segment 7 reduced; epandrium rounded-ovate (lateral view); hypopygial foramen dorso-lateral in position; hypandrium fused to epandrium; phallus simple; epandrial lobes absent; surstylus well developed; cercus short; female oviscapt with tergites 9+10 divid- ed medially into two broad hemitergites, each bearing 3 thick pointed spines.

DIAGNOSIS. The genus Irwinus gen.n. described here is believed to be closest to the genus Campsicnemus Haliday in Walker, 1851 in the subfamily Sympycninae and can be distinguished from the latter by use of the following key (both sexes):

1. Face almost parallel-sided with fronto-clypeal suture distinct laterally; arista-like stylus latero-apical; body with only white setae; wing narrow and maculated; abdomen broad and strongly flattened dorso-ventrally; female cercus short, not extending beyond hemitergites ................ ................................................................ Irwinus gen.n.

— Face narrowest near middle with indistinct fronto-clypeal suture; arista-like stylus usually distinctly dorsal; body with black setae; wing rarely narrow and maculated; abdomen moderately broad and flattened dorso-ventrally; female cercus elongated, extending beyond hemitergites ................................................................ Campsicnemus ETYMOLOGY: The name of the new genus and new

species is dedicated to the collector of the type series, Dr.

M.E. Irwin (Emeritus, University of Illinois, Urbana-Cham-

paign, Illinois, USA, and University of Arizona, Tucson ,

USA). The gender is masculine.