Sympycnus yakutensis, Negrobov & Grichanov & Selivanova, 2017

Negrobov, Oleg P., Grichanov, Igor Ya. & Selivanova, Olga V., 2017, Review of East Palaearctic species of Sympycnus Loew, 1857, with a key to species, Zootaxa 4277 (4), pp. 531-548 : 544-546

Sympycnus yakutensis sp. nov.

( Figs 39–44 )

Diagnosis (male). Slender species. Face narrow, at clypeus obliterated. Antenna black, with postpedicel triangular with acute apex, as long as high, and about as long as scape and pedicel combined. Stylus rather basodorsal, inserted at about basal 2/5 of upper side of postpedicel. Fore coxa pale yellow with extreme base brown. All femora pale yellow. Fore and mid femora with one rather thin preapical posteroventral bristle. Fore tibia with ventral row of elongate hairs. Mid tibia without ventral bristles. Fore tarsus with ventral row of short setae. Hind tarsus with tarsomeres 3 and 4 nearly entirely laterally flattened; tarsomere 3 practically as long as tarsomere 4, with 2–3 long posteroventral bristles at base, straight with only apex slightly curved, longer than tarsomere 3; with about 5 strong posterodorsal bristles in central part of tarsomere 3, and with several weaker erect posterodorsal and posteroventral bristles on tarsomeres 3 and 4 (MSSC).

Description. Male. Body length: 3.0 mm; wing length: 2.7 mm, wing width: 0.8 mm. Head ( Fig. 39 ): Frons bronze, dusted greyish. Occiput bronze-black, dusted grey, rather convex. Face greyish white, with shallow central furrow under antennae; narrowing below antennae, and obliterated at clypeus, bare. Palpus rather small, mostly concealed, black, with pale pubescence and without apical bristles. Proboscis short, black. Eyes red, pubescent. Antenna ( Fig. 40 ) black, with scape bare dorsally and pedicel with apical circlet of bristles; postpedicel triangular with acute apex, as long as high, and about as long as scape and pedicel combined, with distinct pubescence, especially on apical 1/2; arista-like stylus rather basodorsal, inserted at about basal 2/5, with microscopic pubescence. Length ratio of scape to pedicel to postpedicel to stylus (1st and 2nd segments) in mm, 0.05/0.06/0.13/ 0.05/0.62. About 9 uppermost postocular bristles strong and black; lower bristles rather thin, yellowish white, uniserial; a few longer yellowish white bristles posterior to postocular bristles on lower occiput. One pair of black postocellar bristles. Thorax: Mesonotum including pleura, postpronotum, scutellum and metapleura dark metallic green, with pleura slightly dusted greyish. Thoracic bristles black; 6 pairs of rather equal-sized dorsocentrals; acrostichals biserial, strong, nearly reaching 5th dorsocentral; upper proepisternum with group of about 4 small white setae in front of anterior spiracle, lower proepisternum with 2–3 white, equal-sized (prothoracic) setae. Scutellum with 2 very strong median bristles, 2 minute laterals, without white setae. Legs: Overall largely pale yellow, with mid and hind coxae and all tarsi mainly dark; with black major bristles. Fore coxa pale yellow with extreme base brown; with very dense pubescence of long white bristles and equal-sized white apical bristles. Mid coxa dark brown, yellow at apex, especially on anterior face; with pubescence of inclined white setae on anterior face, and one strong white bristle and a few setae on outer margin of anterior face. Hind coxa dark brown, yellow at apex, with one straight, white external bristle, as long as coxa. Trochanters yellow. Fore femur slightly curved; with one row of small black inclined anteroventral bristles along entire length, longest in basal 1/2, there about 1/3 times as long as width of femur; with about 3 preapical posteroventral bristles, rather thin, about as long as femur is deep. Mid femur with 1 strong anterodorsal and 1 very small anteroventral preapical bristle, and 1 posteroventral preapical bristle, rather thin, about as long as femur is deep. Hind femur with 1 strong anterodorsal, 1 small anteroventral and 1 small posteroventral preapical bristles; with one anteroventral, one ventral and one posteroventral row of short inclined black setulae along entire length. Fore tibia with anterodorsal row of 5 robust black bristles on apical 1/2, about as long as width of tibia; with dorsal and ventral rows of setae, at most as long as width of tibia. Mid tibia with 3 strong, inclined anterodorsal bristles, inserted at about basal 1/5, 1/3 and 2/3; with 2 slightly weaker posterodorsal bristles, inserted at basal 1/5 and 3/5; with 4 strong apical bristles; without ventral bristles. Hind tibia pale yellow, becoming gradually darker towards apex, with apical 1/3–1/4 brownish yellow; with 2 strong anterodorsal bristles, 3–5 distinctly stronger and many smaller dorsal bristles, 5 apical bristles; with indistinct posterodorsal pubescence along entire length. Fore tarsus pale yellow, dark brown from apex of basitarsus onwards; basitarsus with ventral row of weak setae; tarsomeres 2–5 very short; claws present; pulvilli white, half as long as segment 5. Mid tarsus mainly yellow, brown at apex of segments 1 and 2, from apical 1/2 of tarsomere 3 onwards. Hind tarsus ( Fig. 42 ) mainly brown black, brownish yellow on basal half of basitarsus, and with tarsomeres 3–4 shiny on inner (posterior) face, nearly entirely laterally flattened; tarsomeres 1–2 with one black posterior bristle at apex, with 2–3 short ventral bristles; tarsomere 3 practically as long as tarsomere 4, with 2–3 long brown posteroventral bristles at base, inserted at extreme base, straight with only apex slightly curved, longer than tarsomere 3; with about 5 strong posterodorsal bristles in central part of tarsomere 3, and with several weaker erect posterodorsal and posteroventral bristles on tarsomeres 3 and 4. Femur, tibia and tarsomere (from first to fifth) length ratio in mm: fore leg: 0.79/0.77/0.26/0.09/0.09/0.09/0.11, mid leg: 0.99/1.07/0.53/0.22/0.22/0.14/ 0.17, hind leg: 1.27/1.34/0.36/0.26/0.25/0.17/0.14. Wing ( Fig. 41 ): Hyaline, slightly smoky along costa, without anal lobe; anal vein only weakly indicated. R4+5 convex anteriorly, M1+2 with smooth bend, both parallel near wing apex. Proximal section of M1+2 (from crossvein rm to crossvein dm-cu) half as long as apical section. Proximal section of vein CuA1 1.2 times as long as apical section of CuA1. Apical section of CuA1 3.7 times longer than dmcu. Halter yellow, lower calypter yellow with white fringe. Abdomen: Six abdominal segments pubescent, with segment 6 as long as segment 5. Tergites and sternites entirely dark metallic green, with short black inclined setae on disc of tergites, with white inclined setae on sides; tergite 1 with strong bristles on posterior margin (brownblack on disc, and pale on sides; tergites 1 and 2 with erect white setae laterally. Sternites with white pubescence. Hypopygium ( Figs 43–44 ) with epandrium dark brown, with slight bronze reflection; hypandrium straight, dark brown, without serration; phallus narrow, with large lateral dens; apicoventral epandrial lobe broad, semi-rounded, with two apicoventral setae; surstylus apparently lacking; cercus rather short, rounded triangular, tapering towards apex, yellow, blackish at apex, covered with white hairs and setae; postgonites narrow, concealed, with bifurcate ventral structure arising at base, and forming two long and thin appendages, running alongside the phallus, pointed at apex; each appendage swollen at base, bearing dorsal and ventral rows of about 6 thick teeth. Female. Unknown.

Type material examined. HOLOTYPE ♂, labelled: [ Russia:] Yakutia , Lena–Amga interfluves, alas Alagar- Khoi, 18 km N Tyungyulyu vil., 21.VII.1995, Bagachanova ( ZIN) . PARATYPE: 1♂, [ Russia:] Yakutia , Kedi Lake , path to Amga River , 15.VII.1925, Yakutian Expedition, Bianki ( ZIN) .

Identification. Sympycnus yakutensis sp. nov. is very close to S. pulicarius and S. septentrionalis Pollet, 2015 ( Pollet et al. 2015). Males of the new species are most easily separated from the latter two species by the almost entirely pale yellow fore coxa and entirely pale yellow femora (partly brown in S. pulicarius and S. septentrionalis ). The absence of the posteroventral bristle on the male mid tibia is characteristic of S. septentrionalis and S. yakutensis sp. nov. (nearly always present in S. pulicarius males at apical 1/3). The chaetotaxy of legs and length ratio of tarsomeres 2 and 3 of the hind tarsus in the new species differ insignicantly from those in the other species. The inner hypopygial structures (e.g. semi-rounded apicoventral lobe of hypandrium) are rather specific for S. yakutensis sp. nov.

Etymology. The name “ yakutensis ” refers to the Russian Sakha (Yakutia) Republic.

Remarks. The S. yakutensis holotype was found among the S. changaicus material studied by Grichanov & Bagachanova (2006) as S. urgaicus Negrobov.

Distribution. Palaearctic: Russia (Yakutia).

Figures

FIGURES 39 – 44. Sympycnus yakutensis sp. nov., male holotype. 39, head, anterior view; 40, antenna, lateral view; 41, wing; 42, hind tarsus, dorsolateral view; 43, hypopygium, left lateral view; 44, hypopygium, ventral view.