Thinophilus sigwalti, Grichanov, 2023

Grichanov, Igor Ya., 2023, A review of the Afrotropical Thinophilus Wahlberg, 1844 (Diptera: Dolichopodidae), with the descriptions of ten new species, European Journal of Taxonomy 878, pp. 1-52 : 24-27

Thinophilus sigwalti sp. nov.

urn:lsid:zoobank.org:act:60A32348-A78F-4766-8A32-90FA4AEA1395

Fig. 7

Thinophilus prudens Grichanov, 1997: 137 , nec Curran, 1926.

Diagnosis

Thinophilus sigwalti sp. nov. is similar to T. prudens , differing in short cercus, about as long as surstylus, short dorsal setae on fore tibia, about as long as tibia width, yellow ventral bristles and setae on fore femur and tibia, wing with distal part of M 4 at least 2 × as long as dm-m. The male of T. prudens has a very long cercus, about 2 × as long as the surstylus, a very strong posterodorsal bristle on the fore tibia, more than 2 × as long as the tibia width, partly dark or black ventral bristles and setae on the fore femur and tibia, wing with distal part of M

4 about as long as dm-m.

Both T. sigwalti sp. nov. and T. prudens are also close to T. cilifemoratus , differing in the following characters: fore coxa mostly yellow, black at base; mid and hind coxae black, yellow at apex; male fore femur with long ventral bristles, 2 × as long as femur height; hind tibia with anterior, ventral and posterior rows of elongated setulae and 1 preapical dorsal seta. Males of Thinophilus cilifemoratus were described with all coxae yellow; fore femur with hairs (“Haaren”, nec “Borsten”), longer than femur height; fore tibia with only 2 posterodorsal bristles; mid femur ventrally with only light hairs; hind tibia with only ventral row of elongated setulae and 1 dorsal seta at basal ⅓, without apical setae; wing with distal part of M 4 about 1.5 × as long as dm-m; male cercus short, stick-shaped ( Becker 1902; Negrobov 1979).

Etymology

The specific epithet is dedicated to the collector of the holotype, the French hymenopterist, Dr B. Sigwalt (MNHP).

Material examined

Holotype SENEGAL • ♂ (with apparently washed pruinosity); “ M’Bour ; St. ORSTOM; [14°24′ N, 16°57′ W]; Piège de Malaise [Malaise trap]; 18 Dec. 1980; B. Sigwalt leg.”; MNHP.

Description

Male ( Fig. 7A )

MEASUREMENTS. Body length 2.0 mm; antenna length 0.6 mm; wing length 1.9 mm; wing width 0.6 mm.

HEAD ( Fig. 7B ). Postcranium and frons black; face and clypeus black, pollinose; face under antennae 1.4 × as wide as height of postpedicel; clypeus 0.6 × as long as epistoma, 1.4 × as wide as long; palp yellow, bearing brown bristly hairs; proboscis black; 2 diverging ocellars; 1 vertical, 1 postvertical, half as long as vertical, stronger and longer than, and not in row with upper postoculars; upper postoculars uniseriate, black; middle and lower postoculars multiseriate, white, relatively long; antennal scape, pedicel and postpedicel black dorsally, orange-yellow ventrally ( Fig. 7C ); scape small, with short inner projection; pedicel simple, convex on inner side; postpedicel apically black, rounded, with short pubescence and apicodorsal tubercle, higher than long (12/9); arista-like stylus dorsal, black, thick basally, thin distally, pubescent; length ratio of pedicel to postpedicel to stylus, 0.07/0.09/0.45.

THORAX. Bluish black; no acrostichals; 4 dorsocentrals of almost equal length; scutellum with 2 strong marginals; no laterals; 3–4 upper and 3–4 lower, white propleural bristles of different length.

LEGS. Fore coxa mostly yellow, black at base; mid and hind coxae black, yellow at apex; legs mostly yellow; fore tibia on distal half and base of basitarsus brownish; tarsi brown-black from tip of basitarsus.

FORE LEG. Coxa with white setae and bristles; femur simple, with anteroventral row of short white setae, half as long as femur height, with posteroventral row of several long white bristles, 2 × as long as femur height; tibia and tarsus simple ( Fig. 7D ); tibia with 2 anterodorsal, 2 posterodorsal bristles, short apicals, ventral row of elongated setulae; segment 5 weakly widened; length of femur, tibia and tarsal segments (in mm): 0.62/0.6/0.2/0.09/0.07/0.06/0.09.

MID LEG. Coxa with white setae; femur with anteroventral row of dark setae on distal ⅓ and posteroventral row of sparse dark setae, at most as long as femur height; tibia bearing 1 anterodorsal and 1 posterodorsal bristles at basal ¼, very short apicals; tarsal segments 3–5 inconspicuously thickened; length of femur, tibia and tarsal segments (in mm): 0.7/0.76/0.3/0.13/0.1/0.08/0.1.

HIND LEG. Coxa with 1 fine white exterior bristle; femur with several dark ventral bristles, ⅔ as long as femur height; tibia ( Fig. 7E ) with anterior, ventral and posterior rows of elongated setulae, 1 preapical dorsal seta; segment 5 inconspicuously thickened; length of femur, tibia and tarsal segments (in mm): 0.82/0.81/0.18/0.21/0.1/0.11/0.11.

WING ( Fig. 7F ). Hyaline, without darker shades; veins yellow-brown, more yellowish at base; distal part of M 1+2 straight; R 4+5 parallel with M 1+2; ratio of part of costa between R 2+3 and R 4+5 to that between R 4+5 and M 1+2 (in mm), 0.28/0.18; crossvein dm-m straight; ratio of dm-m to distal part of M 4, 0.12/0.25; anal vein distinct; halter yellow; lower calypter yellow, with white cilia.

ABDOMEN. Black; setae and hind-marginal bristles on tergites black, short; sternites with short setae. Hypopygium ( Fig. 7G–H ) black, cercus yellow; epandrial lobe at base of syrstylus, fingerlike, with strong apical bristle; hypandrium short, apically concave; phallosoma narrow, concealed; phallus simple, weakly projected distally ( Fig. 7H ); surstylus straight and narrow, with 3 long preapical bristles and several short setae at apex ( Fig. 7G ); cerci fused at base, narrow, with long marginal bristles.

Female

Unknown.

Figures

Fig. 7. Thinophilus sigwalti sp. nov., holotype, ♂ (MNHP). A. Habitus. B. Head, anterior view. C. Head and antenna. D. Fore femur, posterior view. E. Hind tibia and tarsus, dorsal view. F. Wing. G. Hypopygium after maceration, lateral view. H. Hypopygium (after Grichanov 1997: fig. 5; as in T. prudens Curran, 1926).