Irwinus irwini Grichanov, 2023

Irwinus irwini Grichanov View in CoL , sp.n.

Figs 1–15 View Figs 1–6 View Figs 7–10 View Figs 11–15 .

MATERIAL. Holotype ♂, South Africa: [Northern] Cape Prov., Hondeklipbaai, [27°24´70´´N, 052°40´9.0´´E], 8.IX.1972, sea level, coastal dunes, 3017Ad, M.E & B.J. Irwin leg. ( NMSA) . Paratype: 1 ♀, same data as for holotype ( NMSA) .

DESCRIPTION. Male ( Fig. 1 View Figs 1–6 ). Body length 1.5 mm; wing 1.3 x 0.3 mm; antenna 0.5 mm. Head ( Figs 2–3 View Figs 1–6 ). Postcranium, vertex, frons and face black, covered with grey pruinosity; head (excluding proboscis) distinctly wider than high in anterior view; all setae white; postoculars forming single row of setae around posterior orbit; uppermost seta longer; lower postoculars about as long as lateral setae; ventral postcranium with few sparse setae; face concave, almost parallel-sided; clypeus flat, short, 3 times wider than high, as wide as face under antennae (14/13); palpus small, rounded, black, with short setae; proboscis brown-black; antenna black; postpedicel rounded, haired, slightly wider than long (4/3); arista-like stylus long, filiform, lateroapical, bare, bi-segmented, with segment 1 very short; length (mm) of scape, pedicel, postpedicel, stylus, 0.02/0.02/0.06/0.42. Thorax. Mesonotum, scutellum, and pleura dark bluish black, covered with grey pruinosity; all setae white; mesonotum without acrostichals, with 4 strong dorsocentrals slightly decreasing in size anteriorly; scutellum with pair of strong marginal bristles and pair of minute setae laterally; proepisternum with 2–3 lower strong setae and 1–2 minute upper setae. Legs. Fore and mid coxae black, brownish apically, hind coxa black, and femora mostly black-brown, yellow in distal 1/2 or 1/3, tibiae and tarsi yellow with last 2–3 tarsomeres brown; fore and mid coxae with white setae anteriorly, longer on mid coxa; hind coxa with short white bristle at middle; legs covered with yellow-brown bristles and white setulae, without black vestiture; fore femur simple, with 2 ventral rows of short white semi-erect setae, at most 1/3 as long as femur height; fore tibia simple, with few short apicals; fore tarsomeres 1–4 each with 1–2 short apical setae; fore tarsomere 5 with small pulvilli and claws; mid femur simple, ventrally bare, with short preapical anterior bristle, as long as femur height; mid tibia with pair of strong antero- and posterodorsals at base, 3–4 times as long as tibia width, 1 anterodorsal bristle, 4 strong apical bristles; tarsomeres 1–4 each with 2 apical setae; tarsomere 5 with small pulvilli and claws; hind femur simple, slightly curved, without strong ventral setae, with short preapical anterior bristle, as long as femur height; hind tibia with pair of strong antero- and posterodorsals at base, about 2 times as long as tibia width, 1 anterodorsal bristle in middle, with few short apicals; tarsomeres 1–4 each with 1–2 short setae; tarsomere 5 with small pulvilli and claws; femur, tibia and tarsomere (from first to fifth) length ratio (mm): fore leg: 0.49/0.49/0.29/0.14/0.11/0.07/0.07, mid leg: 0.78/0.78/0.39/0.19/0.16/0.11/0.07, hind leg: 0.84/0.87/ 0.24/0.32/0.17/0.11/0.09. Wing ( Fig. 4 View Figs 1–6 ). Grey, with hyaline windows at base and at middle as figured, veins brown, cross-vein dm-m white; wing plate widest at distal 3/4; ratio of parts of costa between R 2+3 and R 4+5 to this between R 4+5 and M 1 (in mm), 0.18/0.13; cross-vein dm-m weak, straight; ratio of dmm to apical part of M 4, 0.04/0.22; anal lobe absent; anal vein reduced; posterior wing margin between base and M 4 without hairs; lower calypter yellow, with very short white cilia; haltere pale yellow. Abdomen ( Figs 5–6 View Figs 1–6 ). Broad and strongly flattened dorso-ventrally, about 1.2 times longer than wide, bluish black, with weak pruinosity, with only short white setae; tergites 1–3 wide; tergites 4–6 gradually narrowed; tergite 6 hardly visible, haired; only tergite 8 and dorsal side of epandrium visible partly in dry specimen under tergites 3– 6; tergite 8 covered with very short sparse white setae; sternites 1 and 6 absent; sternites 2–5 ( Fig. 6 View Figs 1–6 ) as 2 rows of sclerites along tergal margins, strongly decreasing in size caudally; sclerites of sternite 2 rounded-triangular, touching each other; sclerites of sternite 3 semicircular; sclerites of sternite 4 small, fingerlike; sclerites of sternite 5 very small, rounded; tergum 7 hidden, semicircular, small and narrow; epandrium rounded-ovate (lateral view; Fig. 7 View Figs 7–10 ), slightly longer than high; hypopygial foramen dorso-lateral in position ( Fig. 8 View Figs 7–10 ); hypandrium asymmetrical, broad, narrow and curved at apex, with long spine-like straight process raising from middle of hypandrium (ventral view; Fig. 10 View Figs 7–10 ); phallus narrow, slightly curved, simple; ventral lobe of surstylus articulated, long, fingerlike, with 2 ventral rows of long curved setae ( Fig. 9 View Figs 7–10 ); dorsal lobe of surstylus long and wide, widest at middle (lateral view), with some outer setae and row of short dense setae along distal margin; cercus short and narrow, and covered with setulae and some short setae, 1 long apical seta ( Fig. 8 View Figs 7–10 ).

Female ( Fig. 11 View Figs 11–15 ). Body length 1.7 mm; wing 1.4 x 0.3 mm; antenna 0.6 mm. Similar to male except lacking male secondary sexual characters. Head. ( Figs 12–13 View Figs 11–15 ). Legs. Lighter, with femora mostly brown, yellow in distal 1/2 or 1/3; fore femur with very short ventral setulae; femur, tibia and tarsomere (from first to fifth) length ratio (mm): fore leg: 0.54/ 0.51/0.29/0.14/0.12/0.08/0.08, mid leg: 0.79/0.89/0.39/0.22/ 0.17/0.11/0.07, hind leg: 0.81/0.92/0.25/0.33/0.21/0.13/0.09. Wing ( Fig. 14 View Figs 11–15 ). Ratio of parts of costa between R 2+3 and R 4+5 to this between R 4+5 and M 1 (in mm), 0.19/0.12; ratio of dmm to apical part of M 4, 0.04/0.23. Abdomen. Flattened dorso-ventrally, concave ventrally; with 5 visible tergites; tergite 6 small; sternites entire, undivided; oviscapt concealed; terga 9+10 divided medially into two broad hemitergites, each bearing 3 thick pointed spines and 2 simple setae ( Fig. 15 View Figs 11–15 ); cercus short, non-extending beyond hemitergites.