Procladius islandicus ( Goetghebuer, 1931 )

Procladius islandicus ( Goetghebuer, 1931) View in CoL

Trichotanypus islandicus Goetghebuer, 1931 View in CoL — Goetghebuer & Lindroth (1931), Iceland, adult male, adult female, description, illustration.

Procladius islandicus ( Goetghebuer, 1931) View in CoL — Goetghebuer & Lenz (1936a), Iceland, adult male in part, adult female in part, key, description.

Procladius? islandicus View in CoL ( Goetghebuer, 1931 — Brundin (1947), Sweden, adult male, description, illustration.

Procladius fuscus Brundin, 1949 View in CoL — Brundin (1949), Sweden, adult male, key, illustration.

Procladius? islandicus ( Goetghebuer, 1931) View in CoL — Brundin (1949), Sweden, adult male, key.

Procladius vesus Roback, 1971 View in CoL — Roback (1971), Canada, adult male, adult female, description, illustrations.

Procladius vesus Roback, 1971 View in CoL — Roback (1980), Canada, adult male, pupa, larva, keys, description, photos, illustrations.

Procladius vesus Roback, 1971 View in CoL — Fittkau & Murray (1986), pupa, illustration.

Procladius choreus ( Meigen, 1804) View in CoL — Ratnasingham et al. (2024), Germany, adult males.

Procladius islandicus ( Goetghebuer, 1931) View in CoL — Ratnasingham et al. (2024), Iceland and Norway, adult male, photos.

? Procladius desis Roback, 1971 View in CoL — Saether (2010), Canada, adult female, key.

? Procladius View in CoL near vesus Roback, 1971 View in CoL — Langton et al. (2013), pupa, key, illustration.

Material examined (n = 29). BELGIUM, 2 adult males (as Procladius sp. , RBNS), Gand ( Ghent ), 51.05°N 3.72°E, 12 m a.s.l., +10 °C m.a.t., 19.iv.1919, 4.viii.1919, leg. M. Goetghebuer. GoogleMaps — CANADA, 1 adult male (Holotype of P. vesus, CNCC ), Lake Muskox , 64.63°N 108.25°W, 343 m a.s.l., ‒9 °C m.a.t., 25.vii.1953, leg. J.G. Chillcott. GoogleMaps — FAROE ISLANDS, 2 adult males ( NHRS), Lake Leynavatn , 62.12°N 7.03°W, 74 m a.s.l., +5 °C m.a.t., 27.vii.1980, leg. G. Brodin-Lindsten GoogleMaps ; 3 adult males ( NHRS), Lake Eithis , 62.17°N 7.06°W, 135 m a.s.l., +5 °C m.a.t., 15.viii.2002, leg. Y. Brodin GoogleMaps [1 Barcoded ] ; 2 adult males ( NHRS), Lake Toftavatn , 62.10°N 6.72°W, 15 m a.s.l., +5 °C m.a.t., 15.viii.2002, leg., Y. Brodin GoogleMaps .— FINLAND, 1 adult male, Galddoaivi, Sullamintie , 69.9°N 27.0°E, 90 m a.s.l., 0 °C m.a.t., 8.vii.2003, leg. J. Salmela GoogleMaps ; 1 adult male (as P. cf. vesus ), Malax, Rönnskären island , 63.06°N 20.83°E, 5 m a.s.l., +4 °C m.a.t., 30.vii‒5.viii.2018, leg. L. Paasivirta. GoogleMaps — GERMANY, 1 adult male (as P. sagittalis, ZSMG ), Kossau stream, Kossautal , 54.27°N 10.55°E, 13 m a.s.l., +9 °C m.a.t., 1991, leg. Schröder GoogleMaps ; 3 adult males (as P. choreus, ZFMK ), Wersabe, Fleet , meadow, 52.51°N 9.38°E, 37 m a.s.l., +10 °C m.a.t., 6.vii.2017 [Barcode GBOL-2597108, GBOL-2597110 and GBOL-2597112] GoogleMaps .— ICELAND, 1 adult male (Syntype of P. islandicus, RBNS ) Grimsstadir , 65.65°N 16.11°W, 395 m a.s.l., 0 °C m.a.t., 20‒22.vii.1927, leg. C.H. Lindroth GoogleMaps ; 1 adult male ( NHRS), River Laxá , 65.59°N 17.17°W, 253 m a.s.l., +3 °C m.a.t., 12.vii.1978, leg. Y. Brodin. GoogleMaps — NORWAY, 2 adult males ( NTNU), Einarsneset, pond at Risbakk , 58.06°N 6.79°E, 1 m a.s.l., +8 °C m.a.t., 25.viii.2019, 26.vi.2020, leg. E. Stur and P. Dominiak GoogleMaps [ Barcode MMCH050-19 and MMCH222-20 ] .— SWEDEN, 1 adult male ( NHRS), Lake Innaren , 56.98°N 14.97°E, 174 m a.s.l., +6 °C m.a.t., 6.viii.1943, leg. L. Brundin GoogleMaps ; 1 adult male (Syntype of P. fuscus, NHRS ), Lake Grimsberga göl, 56.97°N 14.92°E, 193 m a.s.l., +6 °C m.a.t., 12.vi.1947, leg. L. Brundin. GoogleMaps — UNITED STATES, 3 adult males (as Procladius sp. , NHRS), Crater Lake, Wizard Island , 42.93°N 122.01°W, 1 883 m a.s.l., +7 °C m.a.t., 10.viii.1957, leg. L. Brundin GoogleMaps ; 2 adult males (as Procladius sp. , NHRS), Crowley Lake , 37.62°N 118.74°W, 2 063 m a.s.l., +8 °C m.a.t., 21.viii.1957, leg. L. Brundin GoogleMaps ; 2 adult males (as P. vesus, NDSU ), Alaska, Utqiagvik , tundraponds, 71.3°N 156.8°W, 7‒12 m a.s.l., ‒12 °C m.a.t., vi.1975, vi.1976, leg. M.G. Butler and S. Mozley. GoogleMaps

Diagnostic characters. Figs. 7 View FIGURES 7‒8 , 15 View FIGURES 14‒15 , 38 View FIGURES 36‒39 , 101‒103 View FIGURES 101‒103 , key couplet 20. P. islandicus has a rather short gonostylus process with a GspR that overlaps that of nine other species of Procladius in Europe. Of these, P. nudipennis , P. gemma , P. tenebricosus and P. lugubris are distinctly separated from P. islandicus by more than one other morphological character in the key and the helpdesk.

P. islandicus has a highly variable length of the setae of the front leg tarsi (BR 3‒6.5). When the BR is 4.5 or more, as mostly in the northern colder part of the species geographical distribution, P. islandicus can usually be separated from all other European species of Procladius with overlapping GspR, but for P. exilis . P. islandicus can however be distinguished from P. exilis by a higher number of hind tibia comb spines (10‒13 versus 7‒9) and fewer median anepisternal setae (0‒3 versus 10‒18).

The GspR of P. islandicus partly overlaps that of P. choreus (0.18‒0.24 versus 0.13‒0.20). If overlapping, the species can almost always be separated by a combination of characters. P. islandicus has a higher front leg tarsi BR than that of P. choreus (3‒6.5 versus 1.5‒3), it is usually larger (wing length 2.6‒3.5 mm versus 1.8‒2.8 mm) and with an on average darker posterior colour of tergite II‒IV (brown to dark brown not distinctly contrasting with the anterior part of the tergites versus whitish to light brown contrasting with the clearly darker anterior part of the tergites).

The GspR of P. islandicus substantially overlaps that of P. saeticubitus (0.18‒0.24 versus 0.14‒0.20), but the species can be distinguished by combining other morphological characters. P. islandicus has frequently a higher front leg tarsi BR than that of P. saeticubitus (BR 3‒6.5 versus 2‒4), the gonostylus is on average broader (GsmR 5.3‒6.4 versus 5.9‒6.9), the Cu stem setae usually fewer (0‒14 versus 5‒33) and palpomere five measured as length divided by width usually broader (9.9‒11.9 versus 10.7‒12.3). P. islandicus has an almost uncoloured to slightly greyish wing membrane, whereas the wing membrane of P. saeticubitus is greyish to conspicuously grey.

The GspR of P. islandicus entirely overlaps that of P. culiciformis (0.18‒0.24 versus 0.18‒0.25). The species can be separated by the narrower gonostylus of P. islandicus compared with that of P. culiciformis (GsmR 5.3‒6.4 versus 4.2‒5.2), the on average longer setae of the front leg (BR 3‒6.5 versus 2‒4.5) and an on average lighter mid-section of the front leg tibia (light brown to dark brown versus whitish to light brown).

The GspR of P. islandicus slightly overlaps that of P. pruinosus (0.18‒0.24 versus 0.23‒0.30). If overlapping, P. islandicus can be separated from P. pruinosus by the on average longer front leg tarsi BR (3‒6.5 versus 2‒4.5) and the broader gonostylus process (length/width 0.9‒1.2 versus 1.2‒1.7).

P. islandicus is usually named correctly in literature regarding findings in Europe but named P. vesus in North America. The adult female, pupa and larva have been briefly described. Barcodes of adult males are available.

Geographical distribution and ecology. In Europe , P. islandicus has a latitude range stretching from 48°N in southern Germany to 70°N in northernmost Finland . In Canada and the United States, the range is from 38°N to 71°N. Altitude records in Europe are from 1 m to around 640 m in Iceland , while in North America up to 2 060 m in the United States .

P. islandicus has among the widest climate adaptability of all Procladius species, expressed as a mean annual temperature span of 22 °C ranging from about +10 °C in temperate Germany and Belgium to about ‒12 °C in Arctic Alaska in the United States.

Larvae of P.islandicus inhabit shallow water over bottoms with vegetation such as mosses, Carex and Cladophora in puddles, ponds or lakes in wet meadows or tundra. Bottoms with mud or lava sand without vegetation are also habitats for the larvae. No findings below 4 m water depth are known. A few findings of adults have been made close to slowly running to rather fast running water and one finding is from a natural spring with pH 9.5.

Ice cover on the water bodies containing P. islandicus larvae may remain 6‒8 months per year in northern Europe and 7‒9 months per year in northern North America. Completion of the larval life cycle may take at least four years in the coldest waters.

Oligotrophic to eutrophic conditions prevail in the water bodies with findings. P. islandicus larvae have been observed to prey on other smaller Chironomidae larvae such as first and second instars of Chironomus . Adults have been found from early May to the middle of September.

Countries or autonomous regions with records of P. islandicus in Europe are Belgium, Faroe Islands, Finland, Germany, Iceland, Lithuania, Norway, Russia, Scotland and Sweden. There are also records from Canada and the United States.

References. Böttger & Rudow 1995; Brodin & Wolgast 2019; Brundin 1947; Brundin 1949; Butler 1980; Butler 1982; Butler et al. 1980; Dennis Braegelman 2015; Fittkau & Murray 1986; Goetghebuer & Lenz 1936a; Goetghebuer & Lindroth 1931; Kreiling et al. 2018; Langton 1991; Langton et al. 2013; Lindegaard 1979; Lindegaard 1980; Lindegaard & Jónasson 1975; Lindegaard & Jónasson 1979; Lougheed et al. 2011; Mozley 1978; Paasivirta 2012; Ratnasingham et al. 2024; Roback 1971; Roback 1980; Saether 2010; Shcherbina 1989; Wiederholm 1974.