Platypalpus septentrionalis Shamshev & Sinclair & Khruleva 2020, sp. nov.

Platypalpus septentrionalis Shamshev & Sinclair sp. nov.

(Figs 69–72)

urn:lsid:zoobank.org:act: 67F5F184-B4CB-4F4E-895D-491D576A1A5E

Type material. HOLOTYPE ♂, labelled: [RUSSIA. Chukotka AO (Wrangel Island)] “bukh. [=bukhta, bay] Somnitelnaya,/ south o. [=ostrov, island] Wrangel/ Gorodkov 22.vii.[1966]”; “dol. r. [=dolina reki, valley of river] Somnitelnaya,/ Mineev Mountains, 150 m,/ shingle”; “on flower of Potentilla emarginata ”; “ Holotypus / Platypalpus / septentrionalis / Shamshev, Sinclair sp. nov. [red label]” (INS_DIP_0000619, ZIN, pinned on one pin with a female).

PARATYPES. RUSSIA. Chukotka AO (Wrangel Island): Pinned on one pin with the holotype male (1 ♀, ZIN); same data as holotype (1 ♂, 4 ♀, ZIN; 1 ♂, 1 ♀, CNC); same data as holotype, 19.vii.1966 (1 ♀, ZIN).

Diagnosis. Small robust blackish species of the P. longicornis group; 2 pairs of black vertical setae; postpedicenearly 2.5X longer than wide and 2X longer than stylus; legs extensively dark brown, mid tibia with very short apical spur; halteres brown.

Description. Body holotype 1.9 mm, wing 2.0 mm. Male (Fig. 69). Head black. Occiput entirely densely greyish pollinose; with 2 pairs of long, black vertical setae (inner pair proclinate and slightly inclinate; outer pair lateroclinate); very short dark setae on upper part and longer pale setae on lower part. Ocellar tubercle concolorous with occiput, with 2 long, black lateroclinate anterior setae and 2 minute posterior setae. Frons broad on upper part, narrowed toward antennae, below ocellar tubercle broader than distance between outer margins of posterior ocelli; densely greyish brown pruinose (anterior view). Face rather broad, nearly as broad as frons above antennae, concolorous with frons; clypeus shiny.Antenna uniformly dark brown; postpedicel conical, moderately long, nearly 2.5X as long as basal width; stylus short, nearly 2X shorter than postpedicel. Gena very narrow, shiny. Proboscis dark brown, short. Palpus black, small, oval, pale pubescent, with 2 pale setae apically.

Thorax black, almost entirely uniformly greyish tomentose; katepisternum almost entirely shiny, only narrowly tomentose along upper margin and anteriorly. Postpronotal lobe with 1 long black seta and some minute setulae. Mesonotum with main setae black to brown; 2 long npl (with additional pale setulae), 2 pal (1 much longer), 4 sctl (apical pair long, lateral pair short); acr very short, fine, arranged in 2 broad irregular rows; dc mostly arranged in 2 irregular rows and almost similar to acr anteriorly (some setae very slightly longer), 2 prescutellar pairs long.

Legs extensively dark brown, subshiny; fore femur narrowly yellowish brown apically, mid and hind femora reddish brown on extreme apex; fore tibia mostly yellowish brown, somewhat paler closer to base, mid and hind tibiae reddish brown near extreme base. Coxae broadly shiny laterally, otherwise faintly greyish pruinose; fore coxa with pale setae anteriorly; hind trochanter with fine setulae. Fore femur strongly thickened; pilose ventrally; with anteroventral and posteroventral mostly minute fine setae becoming slightly longer toward base. Mid femur slightly stouter than fore femur; with double row of blackish short spine-like setae ventrally, without row of posteroventral setae. Hind femur slender, with minute anteroventral setae. Fore tibia slightly uniformly thickened; with simple setulae dorsally. Mid tibia slightly arcuate; with row of ventral dark spinule-like setulae; apical spur very short, shorter than apical width of tibia. Hind tibia slender, straight, with simple setulae. Tarsi of all legs unmodified.

Wing faintly infuscate, with pale brownish veins. Basal costal seta long, blackish. Veins R 4+5 and M 1+2 parallel near wing margin; CuA slightly recurrent; anal vein very faint; crossveins m-cu and r-m somewhat contiguous. Calypter brown, pale fringed. Halter brown.

Abdomen entirely dark brown to black, almost entirely shiny, only tergites 1 and 2 laterally faintly greyish pruinose (tergite 2 only narrowly anteriorly); covered with scattered pale setulae.

Terminalia (Figs 70–72) small, subglobular, concolourous with abdomen, epandrium mostly shiny. Right cercus (Fig. 71) digitiform with somewhat pointed apex, short, with small internal projection slightly beyond middle; covered with short simple setae. Left cercus of similar shape to right cercus viewed dorsally, broadly ovate viewed laterally, nearly as long and as broad as right cercus (dorsal view); with small internal projection slightly beyond middle; covered with short simple setae. Hypoproct subtriangular (dorsal view), with somewhat pointed apex. Right epandrial lamella (Fig. 70) subglobular viewed laterally, with row of several short to moderately long subapical setae; right surstylus hardly differentiated from apex of epandrial lamella, short, rounded apically. Left epandrial lamella (Fig. 72) rather subtriangular but with small rounded projection about mid-dorsally; with scattered short setae along ventral margin and some setulae ventrally.

Female. Similar to male. Visible parts of tergites 7 and 8 densely greyish pruinescent; cercus long, slender.

Distribution. Palaearctic: Russia (Chukotka Autonomous Okrug, Wrangel Island).

Etymology. The specific name is from the Latin septentrionalis (north, northern), in reference to the distribution of this species.

Remarks. This new species can be readily distinguished from all other species of Holarctic Platypalpus by brown halteres. In having small body size, two pairs of vertical setae, very short midtibial spur and lacking posteroventral setae on the mid femur, the new species resembles P. vegrandis Frey, 1943 known from Europe (Chvála 1989). However, P. vegrandis has partly yellow antennae and legs. In addition, hind trochanters in the male of this species bear three black spine-like setae. It is interesting to note that both species are found on flowers and may have similar hunting behaviour (Grootaert et al. 2012).

Also, the new species could be compared with P. palmeni Frey, 1943 known from the Alps (Chvála 1989). Both species are similar in body size, have two pairs of vertical setae and lack posteroventral setae on the mid femur. However, P. palmeni can be readily distinguished from the new species by pale yellow palps and extensively yellow legs.

In addition, the new species was compared with the syntypes (currently in CNC) of the following species known from subarctic areas of North America in order to confirm its status (especially since the Nearctic fauna is not as well diagnosed in comparison to the Palaearctic): Platypalpus arcticus Melander, 1928, P. diversipes Coquillett, 1900, P. gilvipes Coquillett, 1900, P. lateralis Loew, 1864, P. vittiger Melander, 1928 (described as var. of P. flavirostris Loew, 1864). All these species differ from the new species primarily by a combination of characters noted in the diagnosis.