Procladius signatus ( Zetterstedt, 1850 )

Procladius signatus ( Zetterstedt, 1850) View in CoL

Tanypus signatus Zetterstedt, 1850 View in CoL — Zetterstedt (1850), Sweden, adult male, description.

Trichotanypus signatus ( Zetterstedt, 1850) — Kieffer (1918a), Lithuania, adult male, key, description.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Goetghebuer (1922), Belgium, description.

Trichotanypus nigriventris Kieffer, 1924 View in CoL — Kieffer (1924), Germany, adult male, key, description.

Trichotanypus signatus ( Zetterstedt, 1850) — Goetghebuer (1927), Finland and France, adult male, key, description.

Procladius nigriventris ( Kieffer, 1924) View in CoL — Goetghebuer & Lenz (1936a), Goetghebuer & Lenz (1936b), Germany and Austria, adult male, key, description, illustration.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Goetghebuer & Lenz (1936a), Goetghebuer & Lenz (1936b), Belgium and Germany, adult male, adult female, key, description, illustration.

Procladius nigriventris ( Kieffer, 1924) View in CoL — Muragina-Koreneva (1957), Russia, adult male, adult female, pupa, larva, keys, descriptions, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Sublette (1964), United States, adult male in part, description, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Roback (1971), Canada and the United States, adult male, adult female, key, description, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Saether (1977), Canada, adult female, key, illustration.

Procladius denticulatus Sublette, 1964 View in CoL — Moore & Moore (1978), Canada, larva, description, illustration.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Pinder (1978), adult male, key, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Roback (1980), Canada and the United States, adult male, pupa, larva, keys, descriptions, photos, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Roback (1984), United States, pupa, description, illustration.

Procladius denticulatus Sublette, 1964 View in CoL — Murray & Fittkau (1989) adult male, illustrations.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Langton (1991), pupa, key, illustration.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Aagaard (1995), Norway, pupa, photo.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Langton & Visser (2003), pupa, key, illustration.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Langton & Pinder (2007), adult male, key, illustrations.

Procladius denticulatus Sublette, 1964 View in CoL — Saether (2010), Canada, adult male, adult female, pupa, larva, keys, descriptions, illustrations.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Langton et al. (2013), pupa, key, illustration.

Procladius denticulatus Sublette, 1964 View in CoL — Ratnasingham et al. (2024), Canada and United States, adult males, adult females, larvae, photos.

Procladius signatus ( Zetterstedt, 1850) View in CoL — Ratnasingham et al. (2024), Finland, Norway, Sweden and Canada, adult males, adult females, pupa, larvae, photos.

Procladius sp. — Ratnasingham et al. (2024), England and Canada, adult males, larvae, photos.

? Trichotanypus imicola Kieffer, 1924 — Kieffer (1924), Germany, adult male, key, description.

? Trichotanypus longilobus Kieffer, 1924 — Kieffer (1924), Germany, adult male, key, description.

? Trichotanypus subaequalis Kieffer, 1924 — Kieffer (1924), Germany, adult male, key, description.

? Procladius imicola ( Kieffer, 1924) View in CoL — Goetghebuer & Lenz (1936a), Germany, adult male, key, description.

? Procladius longilobus ( Kieffer, 1924) — Goetghebuer & Lenz (1936a), Germany, adult male, key, description.

? Procladius subaequalis ( Kieffer, 1924) — Goetghebuer & Lenz (1936a), Germany, adult male, key, description.

Material examined (n = 34). AUSTRIA, 1 adult male ( ZSMG), Lake Gebhartsteich, 48.80°N 15.14°E, 545 m a.s.l., +6 °C m.a.t., 12.vi.1978, leg. H. Malicky.— CANADA, 2 adult males (as P. denticulatus, CNCC ), Lake Muskox, 64.63°N 108.25°W, 343 m a.s.l., ‒9 °C m.a.t., 17‒24.vii.1953, leg. J.G. Chillcott.— ENGLAND, 1 adult male ( UUZM), South Hanningfield, Hanningfield Reservoir, 51.65°N 0.51°E, 53 m a.s.l., +11 °C m.a.t., 23.vii.1982, leg. T. Samman and Y. Brodin.— FINLAND, 1 adult male ( WIFE), Lake Kuusijärvi, 60.31°N 25.12°E, 44 m a.s.l., +5 °C m.a.t., 15.vi.1965, leg. P. Armitage; 4 adult males ( HECH), Lake Vanajavesi, 61.17°N 25.08°E, 79 m a.s.l., +5 °C m.a.t., 21.viii.1978, leg. P.H. Kansanen; 2 adult males ( ZMUO), Lake Pyhäjärvi, Säkylä, 61.00°N 22.28°E, 45 m a.s.l., +5 °C m.a.t., 4.vii.2015, leg. L. Paasivirta [Barcode LEFIJ 3482-16 and LEFIJ 3483-16].— FRANCE, 2 adult males ( NHRS), Lake Remoray, 46.77°N 6.26°E, 849 m a.s.l., +7 °C m.a.t., iv.2017, leg. B. Tissot.— GERMANY, 1 adult male (as P. pectinatus, ZSMG ), south of Wismar, Lake Tanysee, 53.67°N 11.45°E, 35 m a.s.l., +9 °C m.a.t., 1936, leg. A. Thienemann; 1 adult male (as P.? parvulus, ZSMG ), Lake Bodensee, 47.67°N 9.32°E, 394 m a.s.l., +9 °C m.a.t., 12‒17.vii.1961, leg. F. Reiss; 1 adult male ( ZSMG), Lake Bodensee, 47.53°N 9.40°E, 395 m a.s.l., +9 °C m.a.t., 20.vii.1961, leg. F. Reiss; 1 adult male ( ZSMG), Lake Chiemsee, Herrenchiemsee, 47.87°N 12.40°E, 518 m a.s.l., +9 °C m.a.t., 2.vii.1988, leg. C. Orendt.— IRELAND, 4 adult males ( UCDZ), Lake Leane, Castlelough Bay, 52.03°N 9.50°E, 17 m a.s.l., +9 °C m.a.t., 3.ix.1973, leg. D.J. Douglas and D.A. Murray.— NORWAY, 2 adult males ( NTNU), Lebesby, Lake Eastorjavri, outlet to stream, 70.44°N 27.35°E, 258 m a.s.l., ‒2 °C m.a.t., 28.vii.2010, leg. T. Ekrem [Barcode CHRFI 245-10 and CHRFI 246-10].— RUSSIA, 3 adult males ( TUSF), Lake Ladoga, Sorvala, 61.74°N 30.77°E, 4 m a.s.l., +5 °C m.a.t., 4.viii.1991, leg. G. Söderman.— SWEDEN, 1 adult male (Syntype of P. signatus , as Tanypus signatus, ZMLU ), Åreskutan, 63.4°N 13.0°E, 900 m a.s.l., ‒1 °C m.a.t., 31.vii‒4.viii.1840, leg. J.W. Zetterstedt; 1 adult male (as P. lundstroemi, ZSMG ), Lake Torneträsk, 68.4°N 18.8°E, 343 m a.s.l., ‒1 °C m.a.t., 19.vi.1937, leg. A. Thienemann; 2 adult males ( NHRS), Lake Färnebofjärden, Östa, 60.17°N 16.80°E, 60 m a.s.l., +5 °C m.a.t., 1.vi.2007, 7.ix.2007, leg. Y. Brodin; 1 adult male ( NHRS), Lake Färnebofjärden, Edsviken Bay, 60.29°N 16.81°E, 59 m a.s.l., +5 °C m.a.t., 6‒13.vi.2007, leg. Y. Brodin; 1 adult male ( NHRS), Lake Vättern, Motala, 58.53°N 14.98°E, 88 m a.s.l., +6 °C m.a.t., 30.vii.2012, leg. Y. Brodin [Barcode BSCHI 770-17]; 1 adult male ( NHRS), Lake Mälaren, Vårby beach, 59.26°N 17.88°E, 3 m a.s.l., +6 °C m.a.t., 1.viii.2012, leg. Y. Brodin [Barcode BSCHI 727-17].— SWITZERLAND, 1 adult male (as P. cinereus, ZSMG ), Lake Bodensee, Egnach, 47.54°N 9.38°E, 396 m a.s.l., +9 °C m.a.t., 1938, leg. J. Geissbühler.

Diagnostic characters. Figs. 17 View FIGURES 16‒17 , 24 View FIGURES 24‒27 , 59‒61 View FIGURES 59‒61 , key couplet 6. P. signatus is easily distinguished from other species of Procladius in Europe by the form of the medioapodeme, especially its inner apical part with many dents. A similar strongly dented medioapodeme is present in P. wilhmi Roback, 1971 and P. sublettei Roback, 1971 in North America. P. wilhmi has a much shorter gonostylus process. P. sublettei has a similar gonostylus but lacks the bulging inferior volsella present in P. signatus . It is also smaller and has an on the whole more southern geographical distribution compared to that of P. signatus .

P. signatus has a very long curved gonostylus process usually with a distinct net-pattern. Such a net-pattern is only occasionally seen on the gonostylus process of other species of Procladius in Europe.

P. signatus is generally correctly identified in literature regarding occurrences in Europe. It has been known as P. denticulatus in North America. Holotype and paratypes are destroyed, but other studied specimens from Canada and the United States show that P. denticulatus is a synonym of P. signatus .

The adult female, pupal exuvia and larva have been described. Barcodes of adult males, adult females, a pupa and larvae are available.

Geographical distribution and ecology. The latitude range of P. signatus in Europe stretches from France and Hungary at 47°N to the most northern districts of the mainland in Norway and Finland at 70°N. In North America, the species is found near the west coast of the Pacific Ocean of the United States at 41°N to near the Arctic Ocean in northern Canada at 68°N. This means a mean annual temperature range from +11 °C in England, Hungary and the United States to ‒13 °C in northern Canada, thus as much as 24 degrees. Noteworthy is that barcodes of P. signatus from the sites in England and those from the sites in northern Canada only differ by 0.2%.

P. signatus has been found at altitudes in Europe ranging from 3 m near the sea in Sweden to about 850 m above sea level in France , and up to 1 130 m in Canada .

Most of the 80 quality assured findings of P. signatus are from lakes, but it does seem to be frequent also in ponds such as those in peat bogs. Findings from reservoirs, puddles or slowly floating water sections of streams or rivers are less frequent.

Larvae of P. signatus occur mostly in oligotrophic to eutrophic water bodies, sometimes also in ultraoligotrophic ones down to 28 m water depth. Larval habitats can have low to high content of dissolved organic matter such as in polyhumic ponds with pH reaching down to 5.0. This indicates that the larvae have a good ability to withstand low oxygen concentrations. P. signatus larvae are mostly found on bottoms with mud or sand without or with vegetation of various kinds, including Chara , Cladophora , Elodea and Nymphaea .

Animal food items of P. signatus larvae, such as small Chironomidae larvae, Cladocera, Copepoda and Gastrotrichia, seem to be mainly consumed during periods of rapid growth in spring or summer, whereas mostly benthic algae and detritus are found in the larval guts during late autumn, winter and early springs months from November to April. Larvae of P. signatus serve as food for water mites and other aquatic organisms.

Adults of P. signatus appear from early May to late October. Studies from Norway show that adult males can be parasitized by nematodes which cause deformation of the male’s genitalia and other body parts.

Countries or autonomous regions with records of P. signatus in Europe are Austria, Belgium, Czechia, Denmark, England, Estonia, Finland, France, Germany, Hungary, Ireland, Lithuania, Netherlands, Northern Ireland, Norway, Poland, Russia, Scotland, Slovakia, Sweden, Switzerland and Wales. The species has also been found in Canada, Russian Asia and in the United States.

References. Aagaard 1974; Aagaard 1978a; Aagaard 1995; Anikina 2009b; Armitage 1968; 1966; Bista et al. 2017; Bitušík & Brabec 2009; Brodin et al. 2013; Brundin 1949; Cloutier & Harper 1978; Egan & Langton 2018; Frey et al. 1941; Goetghebuer 1922; Goetghebuer 1927; Goetghebuer & Lenz 1936a; Goetghebuer & Lenz 1936b; Kahlert et al. 2024; Kansanen 1985; Kansanen et al. 1990; Kieffer 1924; Langton 1991; Langton 1993; Langton & Pinder 2007; Langton & Visser 2003; Larsen 1993; Mol 1984; Moore & Moore 1978; Moore 1979; Moubayed-Breil et al. 2019; Muragina-Koreneva (1957); Murray & Fittkau 1989; Murray et al. 2018; O´Dell 2018; Orendt 1991; Orendt 1993; Paasivirta 1976; Paasivirta 1985; Paasivirta 2012; Pinder 1978; Poppius et al. 1916; Ratnasingham et al. 2024; Berczik Roback 1971; Roback 1980; Roback 1984; Saether 1977; Saether 2010; Sandberg 1969; Shcherbina 1989; Stasiukynas et al. 2024; Sublette 1964; Takács & Tokeshi 1993; Thienemann 1941; Thienemann & Zavrel 1916; Timm et al. 1994; Tomlin et al. 2024; Vasques et al. 2022; Wiederholm 1974; Zetterstedt 1850; Zilahi-Sebess 1944.