Parydra kahanpaai, Stuke, 2025

Parydra kahanpaai spec. nov.

( Figs. 10 View FIGURE 10 , 66–70 View FIGURES 66–70 )

Holotype: 1 ♂ with these labels: (1) “Fennia [crosswritten] / Helsingin ymp. / 28.iv.1946 / L. Tiensuu “; (2) “barcode & http://id.luomus.fi/ GV.19145 / Parydra / nigritarsis ♂ / Strobl, 1893 / J. Kahanpää det.”; (3) „ Holotypus / Parydra kahanpaai / spec. nov. ♂ / Stuke det. 2025“. The specimen is pinned using a minuten and is in excellent condition. The abdomen is dissected, macerated and stored in a glycerine microvial pinned underneath the specimen. The holotype will be preserved in the collection of the Finnish Museum of Natural History, Helsinki ( MZH).

Paratypes: FINLAND: 1♂, 31.vii.2022, Bodominjärvi , Oitviken [60.240°N 24.662°E], coll. PJHS GoogleMaps ; 2♂♂, 28.iv.1946, Helsingin ymp. [60.2°N 24.91°E], leg. L. Tiensuu, coll. MZH & PJHS GoogleMaps ; 1♂, 12.v.1945, Herttonieme [60.192°N 25.038°E], leg. L. Tiensuu, coll. MZH GoogleMaps ; 1♂, 15.viii.2022, Rukajärvi 6 km se Ruka [66.133°N 29.229°E], coll. PJHS GoogleMaps ; 1♂, 6.viii.–2.ix.2021, Talaskangas , Kajaani, Sopenjoki [48.717°N 8.400°E], yellow tray, leg. I. Immonen, coll. PKW GoogleMaps .

Additional material examined: FINLAND: 1♀, 15.viii.2022, Rukajärvi 6 km se Ruka [66.133°N 29.229°E], coll. PJHS GoogleMaps ; 1♀, 16.v.1945, Herttonieme [60.192°N 25.038°E], leg. L. Tiensuu, coll. MZH GoogleMaps ; 1♀, Kuusamo [65,96°N 29,16°E], no date, leg. Frey, coll. MZH GoogleMaps .

Description Holotype (♂):

Length about 4.1 mm. Wing length = 2.9 mm. Head height = 0.7 mm.

Head black. Gena-eye-ratio (in lateral view genal height measured at the maximum eye height: eye height) = 0.3. Antenna black. Ocelli black-brown, forming an almost equilateral triangle. Frontal triangle and frontorbital plate subshining, frontal vita densely dusted. Frontal triangle broad, reaching to ptilinal suture. Face straight in lateral view, dusted with brown to golden microtrichia. Ocellar seta and two lateroclinate fronto-orbital setae about as large as inner and outer vertical setae; 1 prominent facial seta with 4 minute setae below; 3 inconspicuous genal setae. Scutellum without any process. Scutum and scutellum subshining. Scutum with indistinct submedial light dusting stripes only. Pleurae grey to brown dusted. Two rows of acrostichal setae. Only prescutellar dorsocentral seta distinct. No prescutellar seta; 2 notopleural setae, anterior one smaller; 1 postalar seta; 1 large apical and 1 smaller sublateral scutellar setae; 1 seta at posterior margin of anepisternum. Wing brown infuscate with conspicuous white spots anterior and posterior to crossveins dm-cu and crossvein r-m but not darker brown around veins and crossveins. Veins brown. Knob of haltere and stem light brown. Legs with tarsi black. Legs grey dusted except for the posterior surface of hind femur and the posterior surface of apical hind tibia which are mainly shining. Coxae with black to brown setulae only. Middle coxa with an outstanding black seta, middle tibia without any obvious setae or setulae. Hind femur with a row of inconspicuous brown setulae posteroventrally. Hind tibia in the apical half with long ventral setae. Tergites 4 and 5 without long setulae. Tergite III–IV-ratio (length tergite 3 medially: length tergite 4 medially) = 0.9. Tergite IV–V-ratio (length tergite 4 medially: length tergite 5 medially) = 1.1. Sternites 3–4 as Fig. 70 View FIGURES 66–70 , sternite 5 not recognised due to lacking sclerotization or being fused with the hypandrium. Sternites 3–4 equally sclerotised. Sternites with scattered, inconspicuous setulae only. Epandrium without obvious characters. Subepandrial plate not developed. Hypandrium as shown in Fig. 67 View FIGURES 66–70 . Postgonite as shown in Fig. 66 and 69 View FIGURES 66–70 : base with a distinct broad, rounded tip. Phallus as shown in Figs. 66 and 68 View FIGURES 66–70 : narrow and with distinct apical notch in dorsal view; not curved tip in lateral view. Phallus apodeme as shown in Figs. 66 and 68 View FIGURES 66–70 : fused with phallus, short, broad at its junction with phallus. Lateral arms of phallus apodeme inconspicuous in dorsal view ( Fig. 66 View FIGURES 66–70 ).

Females: Agreeing with the description of the holotype with the exception of the genus specific characters of the postabdomen. Tergite 6 can usually be seen in dried specimens and is about 1 / 3 as long as tergite 5.

Diagnosis: The main characters of P. kahanpaai are (i) strongly dusted face, (ii) broad gena, (iii) knob of the haltere light and (iv) wing brown infuscated without obvious wing markings nor additional vein stump. Together with P. arctica and P. nigritarsis it belongs to a group of similar species which share these characters. Contrary to P. nigritarsis it has (v) no medial dusting stripe on scutum and (vi) the crossveins are slightly darker infuscated than the remaining wing membrane. Additionally P. kahanpaai is separated from P. arctica by the subshining frontal triangle. The male terminalia of P. kahanpaai are characterized by the broad and rounded postgonite and a phallus that is not obviously curved.

Derivatio nominis: This species is dedicated to the Finnish entomologist Jere Kahanpää (Helsinki), who has significantly advanced Finnish Diptera research. The author is indebted to him for his patient support of his work with Finnish shore flies.

Biology: The only specimens collected by the author were swept along a lakeshore. Parydra kahanpaai is polyvoltine and has been recorded from April to August.