Hercostomus albicoxa Pollet & Kazerani

Kazerani, Farzaneh, Khaghaninia, Samad, Talebi, Ali Asghar, Persson, Magnus & Pollet, Marc, 2017, Eight new species of Dolichopodinae (Diptera: Dolichopodidae) from northern Iran, Zootaxa 4242 (1), pp. 111-141 : 127-130

Hercostomus albicoxa Pollet & Kazerani sp. nov.

( Figs 20–22)

Hercostomus convergens of authors, not Loew, 1857: 17. Kazerani et al. 2014a: 269; Grichanov 2016: 13.

Diagnosis. Male. Moderate-sized rather robust species. Face silvery white. Uppermost postoculars black, lower yellow. Antenna mainly reddish yellow with postpedicel triangular, 1.2 x as long as wide, with apical ½ brown. Legs nearly entirely whitish yellow including coxae; only coxa II with a distinct spot on lateral face and apical tarsomeres infuscate. Hypopygium large and robust, with epandrium blackish brown, slightly projecting beyond abdomen posteriorly; hypandrium elongate triangular, symmetrical, reddish yellow on ventral face, transparant on sides; cercus moderate-sized, circular, white with broad black apical margin, with thin black outer and thin yellow inner curved bristles on margin. Distinct MSSCs lacking.

Description. Male. Body: 4.1 mm; wing length: 3.7 mm (n=1). Head. Face silvery white, with shallow furrow along entire length, slightly narrowing below antennae, parallel-sided at clypeus, at narrowest width about 0.8 x as wide as postpedicel (length), bare. Frons metallic green, strongly dusted whitish. Occiput metallic green, slightly convex. Palpus rather small, about 1/6 of eye, rounded ovoid, reddish yellow, with less than basal 1/2 dark brown, with black pubescence and 1 strong black apical bristle. Proboscis brownish yellow. Eyes red, with green reflection in frontal view, especially in dorsal half, with short pale pubescence. Postocular bristles rather strong, with uppermost 1/3 black, and lower 2/3 yellow. Two pairs of black postocellar bristles. Antenna mainly reddish yellow, with scape brown on less than basal 1/2 and postpedicel brown on apical ½; postpedicel triangular, 1.2 x as long as deep, and 0.9 x as long as scape and pedicel combined; stylus dorsal, inserted at about apical 1/3, about 1.4 x as long as first three antennal segments combined, with distinct pubescence, especially on 2nd aristal segment. Thorax. Mesonotum entirely metallic green, bluish green on dorsum; pleura metallic green, with small yellow spot posteriad of coxa I, and yellow zone dorsad of coxa II, with greyish dusting; scutellum bronze, metallic green in centre, with 2 large median and 2 smaller, thin lateral bristles, bare on dorsum. Thoracic bristles black. Six dc; 9 strong ac, biserial, reaching beyond 5th dc, at least 2.5x as long as distance between rows; 1 large and at least one minute ant pprn, 1 internal and 1 external bas pprn, 1 psut ial, 1 equal-sized sut ial, 2 npl, 2 spal, and 1 pal bristles. Upper proepisternum with 2 black minute setae, and sparse pubescence of pale minute setae, lower proepisternum with 1 strong black bristle and a group of thin pale setae. Wing. Hyaline, very slightly and evenly infuscate. Vein R4+5 slightly curved, M1+2 with smooth but distinct bend, both converging towards wing apex, parallel at apex. Proximal section of M1+2 as long as apical section. Proximal section of CuA1 2.3 x as long as apical section. CuA x ratio: 1.8. Halter white, calypteral fringe black. Legs. Nearly entirely whitish yellow including coxae, with only coxa II with brown spot on lateral face and apical tarsomeres infuscate. Bristles black. Coxa II whitish yellow, with brown spot on basal 1/2 on lateral face, with some erect bristles at basis on anterior face. Coxa III with black external bristle, inserted at middle. Femur I with 1 small but distinct pv preapical bristle. Femur II with 1 ad and pv preapical bristles, latter nearly as strong as ad bristle. Femur III with one strong ad preapical bristle at apical ¼, and with short inclined ds bristles in basal 1/2. Tibia I with 2 ad bristles at about basal 1/4 and 1/3, and 2 pd bristles at about basal 1/4 and beyond 1/2, with basalmost pair smaller, and strongest bristles 3 x as long as tibia is deep; with strong ad serration on apical 2/3, not as long as tibia is deep; with 3 ap bristles (incl. 1 pd bristle). Tibia II with 4 strong ad and 3 strong pd bristles, with basalmost pair distinctly smaller, strongest bristles 4.5 x as long as tibia is deep; with 5 equally strong ap bristles; with 1 strong av bristle at 1/2, about 4.5 x as long as tibia is deep, and 1 smaller pv bristle at apical 1/3, 3 x as long as tibia is deep. Tibia III with 4 strong ad and 5 strong pd (incl. 1 preapical ds bristle), with basal pair distinctly smaller, most bristles 4.5 x as long as tibia is deep; with pd serration and distinct pd pubescence on about apical 1/3; with 1 av bristle at apical 1/3, and 3 rather erect bristles in basal 3/5, all 1.5 x as long as tibia is deep; with 2 strong and 1 smaller ap bristles. Tarsus I hardly infuscate towards apex. Tarsus II gradually infuscate towards apex, with taII4-5 brown; taII1 with some short vt bristles. Tarsus III darker than taI–II, gradually infuscate towards apex, with taIII4-5 dark brown; taIII1-2 with dense ventral pubescence, some basal bristles on taIII1 about 1.5 x as long as taIII1 is deep; taIII1 with brown crescent-shaped tooth at extreme basis posteriorly. Length ratios of femur/tibia/tarsomeres 1–5 in leg I: 9.5/9.5/5/2/1.5/1/1.3, in leg II: 8.2/9.2/4.2/2.6/2.2/ 1.6/1, and in leg III: 6.6/7.8/2,5/3.1/2.5/1.6/1. Abdomen. With 5 pubescent segments, T6 short, brown, about 0.4 x as long as T5. Tergites greenish bronze, with strong black bristles on posterior margin. Sternites S2-4 dark brown, unmetallic, with sparse, short pale pubescence, only S4 with some short black setae at upper margin. Hypopygium with epandrium blackish brown, slightly projecting beyond abdomen posteriorly; hypandrium elongate triangular, symmetrical, reddish yellow on ventral face, and transparant on sides; bv epandrial lobe indistinct, apv lobe reddish yellow, with rather large, rounded triangular apex, with one large bristle on shaft and two smaller bristle on apex; cercus moderate-sized, circular, white with broad black apical margin, with thin black outer and thin yellow inner curved bristles on margin. Female. Unknown.

Type material. HOLOTYPE ♂, IRAN: Mazandaran, Tangevaz, Sisangan National Forest (sampling site: Mazandaran _3), 36˚21.917′N, 52°06.179′E, 692 m, 16.viii–5.ix.2011, MT, leg. Mohammad Khairandish & Ahmad Nadimi ( TMUC).

Distribution and ecology. This species is only known from its holotype specimen collected in Mazandaran province ( Iran). Its ecology remains unknown. Previously, this species has erroneously been recorded from Iran as H. convergens Loew, 1857 by Kazerani et al. (2014a).

Etymology. The name “ albicoxa ” refers to the whitish yellow colour of coxa I–III in this species.

Remarks. This species is very closely related to Hercostomus convergens . In fact, the key by Stackelberg (1933) directly leads to the couplet of H. convergens and H. insularum , but decisive differences were noticed between H. convergens and the new species. Moreover, the Iranian Malaise trap survey in Guilan (2010) yielded fresh specimens of H. convergens and also the holotype of this species (in ZMHB) was examined. Both species can be easily separated on the basis of the following features:

1 Coxa II with distinct brown spot on lateral surface. Postpedicel ( Fig. 21) triangular, 1.2 x as long as deep, reddish yellow with apical ½ dark brown. Cercus ( Fig. 22) circular with broad black margin, bearing stronger curved bristles................................................................................ Hercostomus albicoxa sp. nov. ( Iran) ( Fig. 20)

- All coxae entirely whitish yellow. Postpedicel ( Fig. 24 ) elongate triangular, 1.5 x as long as deep, reddish yellow and only slightly infuscate on apical ½. Cercus ( Fig. 25 ) circular with very narrow black margin, bearing short straight bristles.............................................................. Hercostomus convergens (western Palaearctic) ( Fig. 23 )

Figures

FIGURES 23 – 25. Hercostomus convergens, holotype. (23) habitus; (24) head; (25) hypopygium.