Procladius tenebricosus Brodin & Hellberg, 2025

Procladius tenebricosus Brodin & Hellberg , new species

P. choreus — Ratnasingham et al. (2024), Germany, adult male.

P. cf. cinereus — Ratnasingham et al. (2024), Norway, adult male, photo.

P. sp.— Ratnasingham et al. (2024), Germany, adult males.

Material examined (n = 19). FRANCE, 1 adult male (as P. choreus, LHST ), River Truyère, Entraygues, 44.65°N 2.57°E, 238 m a.s.l., +12 °C m.a.t., 22.ix.1977, leg. H. Laville.— GERMANY, 1 adult male (as P. sagittalis, ZSMG ), Tegel small lake, Berlin, 52.57°N 13.28°E, 38 m a.s.l., +8 °C m.a.t., 1932, leg. D. Scheer; 1 adult male (as Procladius sp. , ZSMG), Überlingen, Andelshofen Neuweiher Reservoir, 47.8°N 9.2°E, 450 m a.s.l., +9 °C m.a.t., 8.viii.1964, leg. F. Ringe; 1 adult male (Paratype of P. tenebricosus , as Procladius sp. , ZFMK), Winningen, 50.31°N 7.51°E, 66 m a.s.l., +10 °C m.a.t., 20.ix.2012, leg. B. Rulik [Barcode GBMWN 627-15]; 1 adult male (Holotype of P. tenebricosus , as P. choreus, ZFMK ), Meyenburg, Fleet, wet meadow, 52.51°N 9.38°E, 37 m a.s.l., +10 °C m.a.t., 21.vi.2017, leg. E. Resendiz and H.-G. Rudzinski [Barcode GBOL-2596807].— GREECE, 1 adult male (as Procladius sp. , HCMR), River Pamisos, Vrachopanagista, 37.24°N 21.91°E, 90 m a.s.l., +17 °C m.a.t., 30.vi.2002, leg. I. Karaouzas.— NORWAY, 1 adult male (as P. cf. cinereus, NTNU ), Lake Jonsvatn, near Flaten, 63.40°N 10.55°E, 150 m a.s.l., +4 °C m.a.t., 14‒28.viii.2014, leg. E. Stur [Barcode CHMNO 293-15].— PORTUGAL, 1 adult male (as Procladius sp. , DEBE), Albureira do Arade Reservoir, 37.24°N 8.37°W, 41 m a.s.l., +17 °C m.a.t., 10.v.1996, leg. M. Rieradevall.— SPAIN, 1 adult male (as Procladius sp. , DEBE), Gabriel Y Galan Reservoir, 40.13°N 6.06°W, 388 m a.s.l., +16 °C m.a.t., 25.vii.1965, leg. N. Prat; 3 adult males (as Procladius sp. , DEBE), Guadalajara, Entrepenas Reservoir, 40.29°N 2.43°W, 723 m a.s.l., +14 °C m.a.t., 9.xi.1974, leg. N. Prat; 2 adult males (as P. culiciformis, DEBE ), Cuenca, Contreras Reservoir, 39.27°N 1.38°W, 669 m a.s.l., +14 °C m.a.t., 7.xi.1974, leg. N. Prat.— SWEDEN, 1 adult male (as Procladius sp. , NHRS), Lake Boren, Borenshult, 58.57°N 15.10°E, 74 m a.s.l., +6 °C m.a.t., 11.vi.1980, leg. Y. Brodin; 1 adult male (as P.? pruinosus, NHRS ), Lake Vänern, Sjötorp boat harbour, 58.84°N 13.97°E, 44 m a.s.l., +6 °C m.a.t., 16.vi.1987, leg. Y. Brodin; 1 adult male (as Procladius sp. , NHRS), Mattön torrents, 60.27°N 16.91°E, 64 m a.s.l., +5 °C m.a.t., 24.vi.2007, leg. Y. Brodin; 1 adult male (as Procladius sp. , NHRS), River Dalälven, Tyttbo torrents, 60.19°N 16.68°E, 64 m a.s.l., +5 °C m.a.t., 7‒15.vii.2007, leg. Y. Brodin; 1 adult male (as Procladius sp. , NHRS), Gysinge torrents, 60.28°N 16.91°E, 63 m a.s.l., +5 °C m.a.t., 2.viii.2007, leg. Y. Brodin.

Diagnostic characters. Figs. 6 View FIGURE 6 , 12 View FIGURES 11‒12 , 34 View FIGURES 32‒35 , 89‒91 View FIGURES 89‒91 , key couplet 17. P. tenebricosus has a medium long gonostylus process with a GspR that overlaps that of eight other species of Procladius in Europe. Of these, P. culiciformis , P. lugubris P. frigidus , P. ferrugineus and P. floralis are distinctly separated from P. tenebricosus by more than one mostly non-overlapping other morphological character in the key and the helpdesk.

P. tenebricosus males can be distinguished morphologically from P. islandicus , P. pruinosus and P. longistilus by the dark marked wing (anal cell patch distinct to very distinct versus absent to faint), usually smaller size (wing length 1.8‒2.6 mm versus 2.4‒3.5 mm, mid leg tibia length 0.7‒1.1 mm versus 1.0‒1.4, body length 3.2‒4.3 mm versus 4.2‒6.0 mm) and frequently also lighter colour of the posterior half of tergite II‒IV (whitish to light brown versus light brown to dark brown).

Neither the adult female, pupa or larva has been described. Pupal exuviae and larval skins from specimens reared to males are kept in NHRS. Barcodes of adult males are available and part of BIN BOLD:AER3360 which has incorrectly been merged into BIN BOLD:AAG5487.

Geographical distribution and ecology. P. tenebricosus is probably a less frequent species in Europe found from southern Greece and Portugal at latitude 37°N in the south to mid Norway at latitude 63°N in the north. Mean annual temperature at the 16 sites with findings range from +18 to +4 °C, thus from almost subtropical to temperate boreal climatic conditions. The altitude of the sites ranges from 40 m to 1 220 m above sea level.

Most of the 15 sites with records of P. tenbricosus are at or close to running water, even torrents in one case. This implies that the species has an overall more lotic habitat choice than other species of Procladius in Europe, but there are also findings of P. tenebricosus at sites with stagnant water of freshwater lakes, lake-like reservoirs and ponds.

Larvae of P. tenebricosus from samples taken at 0.5 m water depth in an exposed zone near a lake shore have been reared to adults. The habitat of the larvae is otherwise unknown. Judging from the findings of adult males, the larvae inhabit water with oligotrophic to eutrophic conditions. Adults have been collected from the middle of April to the middle of November.

Countries with records of P. tenebricosus in Europe are France, Germany, Greece, Norway, Poland, Spain, Sweden and Switzerland. The species is possibly also recorded from Israel.

References. Brodin & Wolgast 2019; Casas & Vilchez-Quero 1980; Goetghebuer & Lenz 1936a; Goetghebuer & Lenz 1936b; Grzybkowska 1985; Kieffer 1924; Kugler 1978; Płóciennik & Karaouzas 2014; Prat 1979; Prat 1980; Ratnasingham et al. 2024; Serra-Tosio & Laville 1991; Thienemann 1954.