Hercostomus koshelevae, Grichanov, 2020

Grichanov, Igor Ya., 2020, New species of Hercostomus Loew, 1857 from Afrotropics (Diptera: Dolichopodidae) and key to Afrotropical fauna, European Journal of Taxonomy 722, pp. 16-36 : 25-28

Hercostomus koshelevae sp. nov.

urn:lsid:zoobank.org:act:FE2253FC-4CDF-4E22-880A-463F75F070B2

Fig. 4

Diagnosis

The new species is sister species to H. sanipass sp. nov., differing distinctly in its smaller size, narrower face, lighter colored legs, weakly widened fore tarsomere 3. The hypopygia are rather similar in the two species. Nevertheless, the proximal arm at apex of ventral lobe of postgonite in H. koshelevae sp. nov. is always thinner than that in H. sanipass . The long basolateral cercal lobe in males of both species is very peculiar, being much shorter in males of close species with modified fore tarsus.

Etymology

The species is named for the Russian entomologist, Dr. Oksana Kosheleva (VIZR, St. Petersburg).

Material examined

Holotype

SOUTH AFRICA • ♂; KwaZulu-Natal, Balgowan , “Yellowoods”; 29°24′′ S, 30°03′′ E; 1300 m a.s.l.; 31 Dec. 1982; J. Manning leg.; high forest, deeply shaded stream herbs; NMSA.

Paratypes

SOUTH AFRICA – KwaZulu-Natal • 4 ♂♂, 1 ♀; same data as for the holotype • 1 ♂; Pietermaritzburg, Town Bush, 2930Cb; Nov. 1971; M.E. Irwin leg.; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA • 1 ♀; Richmond District, Pateni, 2930Cc; 30°09′′ S, 29°56′′ E; 18 Nov. 1971; B. and P. Stuckenberg leg.; temp. forest; NMSA • 1 ♂; Deepdale, Umkomaas Valley ; 29°48′ S, 29°58′ E; May 1959; B. and P. Stuckenberg leg.; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA • 1 ♂, 1 ♀; Royal Natal National Park, Forest stream rocks ; 1828.8 m a.s.l. [alt. 6000’]; 19 Jan. 1987; J. Manning leg.; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA • 1 ♂; Cathedral Peak Natural Reserve, Rainbow Gorge ; 1480 m a.s.l.; 28°57.6′ S, 29°13.61′ E; 29 May – 21 Sep. 2006; Mostovski leg.; malaise trap; NMSA . – Eastern Cape • 1 ♂, 1 ♀; Storms River Pass , Tsitsikama Range ; 33°59′ S, 23°55′ E; 12–13 Oct. 1959; B. and P. Stuckenberg leg; indigenous forest; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA • 1 ♀; Hogsback, 3226Db; 32°35′ S, 26°57′ E; 13–16 Dec. 1985; J. and B. Londt leg.; forest and forest margins; NMSA . – Western Cape • 1 ♂; Groeneweide Forest, Saasweld Forest margin ; 33°57′ S, 22°32′ E; ca 150 m a.s.l.; 9 Sep. 1993; D. and C. Barraclough leg.; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA . – Mpumalanga • 1 ♂; E. Transvaal , Marieskop [Forest Reserve]; Oct. 1956; B. Stuckenberg leg.; terminalia dissected and stored in glycerin in microvials pinned with the specimen; NMSA .

Description

Male ( Fig. 4 )

Similar to H. sanipass sp. nov. in all respects except as noted.

MEASUREMENTS (in mm). Body length 3.6–4.1; antenna length 1; wing length 3.9; wing width 1.4 ( Fig. 4A ).

HEAD. Face gradually narrowed towards palpi, 4.9 × as high as wide in middle, under antennae 1.5 × as wide as width of postpedicel, at clypeus half as wide as width of postpedicel. Antennal postpedicel 1.3 × longer than high ( Fig. 4B ). Length ratio of scape to pedicel to postpedicel to stylus (1 st – 2 nd segments), 23/10/23/15/50. Palpus, proboscis moderately small, yellow, with short black setae; palpus with 1 black bristle.

THORAX. Mostly greenish-black, greyish pollinose; metepimeron dirty yellow.

LEGS. including coxae mostly light yellow; mid coxa brownish laterally; hind femur brownish at extreme apex; tarsi black from tip of basitarsus, fore tarsomere 5 yellow. Fore tarsomere 3 flattened and slightly widened, with dorsal comb of short black setulae; tarsomeres 4–5 with semi-accumbent dorsal hairs, tarsomere 4 with black hairs, tarsomere 5 with white hairs ( Fig. 4C ). Length of fore femur, tibia and tarsomeres 1–5 = 1.15 mm, 1.29 mm, 0.65 mm, 0.53 mm, 0.33 mm, 0.14 mm, 0.16 mm. Length of mid femur, tibia and tarsomeres 1–5 = 1.38 mm, 1.8 mm, 1.01 mm, 0.49 mm, 0.4 mm, 0.22 mm, 0.16 mm. Length of hind femur, tibia and tarsomeres 1–5 = 1.75 mm, 2.16 mm, 0.58 mm, 0.74 mm, 0.5 mm, 0.26 mm, 0.2 mm.

WINGS. simple, greyish, almost hyaline, veins brown. Ratio of part of costa between R 2+3 and R 4+5 to between R 4+5 and M 1+2, 24/7. Ratio of dm-m to distal part of M 4, 39/60.

GENITALIA. ( Fig. 4D ) with epandrium mostly yellow, brown at base. Hypandrium mid-ventral, with short base, 4 long thin lobes of different lengths, widths. Phallus thin, projected. Distoventral epandrial lobe as short rounded prominence, fused to epandrium, with 1 short and 1 long seta. Surstylus yellow, bilobate; ventral lobe broad, simple, ¾ length of dorsal lobe, with 1 subapical seta; dorsal lobe of surstylus widened in distal half, with short narrow process at apex, several subapical setulae, 1 strong mid-dorsal seta. Distal lobe of postgonite as long as ventral lobe of surstylus, narrow, broad and pointed at apex. Ventral lobe of postgonite ( Fig. 4E ) strongly sclerotized, with 2 long arms (anterior, posterior) at apex forming letter V, 2 short symmetrical processes between them, covered with denticles on ventral side. Cercus ( Fig. 4F ) broad, light yellow, densely covered with short light hairs, longer at apex; cercus with basolateral lobe, longer than cercus, densely covered with long setae, with distolateral narrow process bearing 3 thick hook-tipped setae at apex; 2 strong setae proximal to process, 3 strong setae at apex of cercus.

Female

Similar to male except lacking male secondary sexual characters.

Ecology

According to type specimen labels, imagos inhabit rocks in mountain streams, being common in forests.

Distribution

South Africa.

Figures

Fig. 4. Hercostomus koshelevae sp. nov., ♂, holotype (MNSA; A–C); ♂, paratype, Town Bush (MNSA; D–F). A. Habitus. B. Antenna. C. Fore tarsus. D. Hypopygium, right lateral view. E. Distoventral appendages of epandrium. F. Cercus.