Diura bicaudata

Diura bicaudata (Linnaeus, 1758)

Lapland Springfly http://lsid.speciesfile.org/urn:lsid: Plecoptera.speciesfile.org: TaxonName:934

Figs. 46-60, 76-77

Phryganea bicaudata Linnaeus 1758: 548,

type (s) not designated, Europe

Phryganea bicaudata Linnaeus 1767: 908

Diura bicaudata Billberg 1820: 96

Diura bicaudata Brinck 1949:61

Diura bicaudata Illies 1966: 381

Diura nanseni Raušer 1968: 357

Diura bicaudata Zwick 1973: 227

Diura bicaudata Judson and Nelson, 2012:42

Diura majuscula Judson and Nelson 2012:42

Diura bicaudata DeWalt et al. 2018

Material examined. Photographs of the dorsal aspect of the Linnaean collection pinned specimen of this species are available at the Linnean Society of London (2017). The specimen is macropterous and is likely a female as European males are usually micropterous. Specimens of D. bicaudata examined for this study are consistent with previous descriptions and illustrations of this species (Klapálek 1909, 1912 (as Dictyopterygella recta, Dictyopterygella septentrionis – vide Brinck 1949), Hanson 1940 (as Dictyopterygella hudsonica - vide Brinck 1949), Hynes 1940 (as Dictyopterygella recta – vide Brinck 1949), 1941, Brinck 1949, 1954, Koponen 1949 (as Dictyopterygella recta – vide Brinck 1949), Illies 1955, Raušer 1966, Lillehammer 1974, 1988, Stewart & Oswood 2006). In the following listing macropterous males are indicated, otherwise micropterous: Canada; Nunavut; Baker Lake, 64°N, 95°W, Dutilly, 10 August 1936, 1♂ [Holotype Dictyopterygella hudsonica] (USNM). Germany; Rhön, Upper reaches of Ulster River, P. Zwick, 9 May 1971 (PZC) Isle of Man; Llergyrhemy, Headwaters of Sulby River, N.S. Jones & H.B.N. Hynes, 7 June 1951, 1♂ (USNM). Headwaters of Sulby River, H.B.N. Hynes & N.S. Jones, 26 July 1949 & 7 June 1951, 14 larvae (USNM). Silver Burn, N.S. Jones, 3 May 1951, 1♀ (USNM). River Neb, Glen Hellen, 220, H.B.N. Hynes, 10 April 1949, 3 larvae (USNM). Ballaguine stream, G67, H.B.N. Hynes, 25 July 1949, 2 larvae (USNM). Mongolia; Arkhangay: Bulgan Soum, Gol braid upstream of bridge ~ 63 km SW of Tsetserleg, N47.11192°, E101.01048°, elev. 2066 m, Selenge River Project Team, 13-15 July 2004, 1♂ [macropterous] (BYU) [CRN laboratory photo voucher D11]. Bulgan Soum, Urd Tamir Gol braid upstream of bridge ~ 63 km SW of Tsetserleg, N47.11192°, E101.01048°, elev. 2066 m, Selenge River Project Team, 13-15 July 2004, 1♂ [macropterous] (BYU). Bulgan Soum, Urd Tamir Gol ~ 50 km SW of Tsetserleg, N47.21109°, E101.07947°, elev. 1962 m, Selenge River Project Team, 13 July 2004, 2♀ (BYU) [CRN laboratory photo voucher D22]. Chuluut Soum, Khuurmen/Davaat Gol 15 km SSE of Chuluut/Jargalant N47.42580°, E100.30130°, elev. 2104 m, Selenge River Project Team 15-16 July 2004, 2♀ (BYU), [CRN laboratory photo voucher D21]. Chuluut Soum, Chuluutin Gol ~ 45 km SW of Chuluut/Jargalant N47.21768°, E99.92824°, elev. 2471 m, 16 July 2008, Selenge River Project Team SRP2004071602, 1♀ (BYU) [CRN laboratory photo voucher D14]. Bayankhongor: Gurvanbulag Soum, Khokh Nuur (Blue Lake) N47.53° E 97.53°, 2600m, Yu Marusik, 7-10 June 1997, 2♂, 2♀ (RASC). Bayan Olgiy; Bulgan Soum, “Ulaagchiny Davaa Gol”, unnamed stream, ~ 50 km SSE Deluun N 47.45456° E 90.92342°, 2631 msl, 6 July 2009, S.W. Judson & C.R. Nelson #9234, 2♀, MAIS2009070601, (BYU) [CRN laboratory photo voucher D13]. Bulgan Soum, Khar Nuur (Black Lake), ~ 50 km NNW Bulgan N 47.24133° E 90.75316°, 2563 msl, 7 July 2009, S.W. Judson & C.R. Nelson #9239, 2♂ 4♀, MAIS2009070703, (BYU). [CRN laboratory photo voucher D23]. Bulgan Soum, Bulgan Gol, ~ 15 km N Bulgan N47.03954° E91.03448° elev. 2010 m, 8 & 9 July 2009, S.W. Judson, Mongolian Aquatic Insect Survey, MAIS2009070803, 1♀ (BYU), [CRN laboratory photo voucher D29]. Bulgan Soum, Turgen Gol, ~ 40 km NNW Bulgan, N47.18333° E91.77660° elev. 2492 m, Mongolian Aquatic Insect Survey, 7-8 July 2009, 1♂ 2♀, MAIS2009070705 (BYU), [CRN laboratory photo voucher D17]. Bulgan Soum, Turgen Gol, ~ 40 km NNW Bulgan, N47.18333° E90.77660° elev. 2492 m, S.W. Judson, Mongolian Aquatic Insect Survey, 7-8 July 2009, 5♀ (BYU), [CRN laboratory photo voucher D26]. Deluun Soum, Gantsmodi Gol 27 km S Deluun, N47.66395° E90.7181°, elev. 2196 m, 5 - 6 July 2009, S.W. Judson & C.R. Nelson #9231 & MAIS Team MAIS2009070502, 3♂ 1♀ (BYU), [CRN laboratory photo voucher D15]. Deluun Soum, Gantsmodi Gol 33 km S Deluun, N47.62447°, E90.67194°, elev. 2241, 5 July 2009, S. W. Judson & C.R. Nelson #9230, Mongolian Aquatic Insect Survey, MAIS2009070501, 1♂, 2♀ (BYU), [CRN laboratory photo voucher D18]. Deluun Soum, Gantsmodi Gol 33 km S Deluun, N47.62447° E90.67194°, elev. 2241 m, 5 July 2009, S. Chuluunbat, Mongolia Aquatic Insect Survey MAIS2009070501, 1♀ (BYU), [CRN laboratory photo voucher D25]. Deluun Soum, Buyant Gol 46 km SE Deluun, N47.60915°, E91.13574°, elev. 1947 m, 4 July 2009, S.W. Judson & C.R. Nelson # 9227, Mongolian Aquatic Insect Survey, MAIS2009070404, 1♂ (BYU), [CRN laboratory photo voucher D27]. Tsengel Soum, Syrgali Gol, Bagakhatuugiin Lake junction Ikh Khatuugiin Gol N49.04586° E88.50939° elev. 2385 m, 13 July 2008, C.R. Nelson #8993, 1♀ (BYU), [CRN laboratory photo voucher D3]. Tsengel Soum, Khoton Lake, 15 km NW of Syrgal, N48.66718° E88.29908°, elev. 2090 m, C.R. Nelson, 14 July 2008 1♀ (BYU), [CRN laboratory photo voucher D7]. Tsengel Soum, Khoton Lake, 15 km NW of Syrgal, N48.66718° E88.299908°, elev. 2090 m, C.R. Nelson, 14 July 2008, 1♂, 1♀ (BYU), [CRN laboratory photo voucher D4]. Tsengel Soum, Khoton Lake, 15 km NW of Syrgal, N48.66718° E88.29908°, elev. 2090 m, C.R. Nelson, 14 July 2008 1♀ (BYU), [CRN laboratory photo voucher D5]. Tsengel Soum, Syrgali Gol, bridge over outflow between Khoton Nuur and Khurgen Nuur at Syrgal, N49.59925° E88.43707°, elev. 2095m, 16 July 2008 P. Sigitas, MAIS 2008071603, 2♂ (BYU), [CRN laboratory photo voucher D8]. Tsengel Soum, Syrgali Gol, bridge over outflow between Khoton Nuur and Khurgen Nuur at Syrgal, N49.59925° E88.43707° elev. 2095 m, 16 July 2008, C.R. Nelson #9005, MAIS 2008071603, 1♂, 2♀ (BYU), [CRN laboratory photo voucher D2]. Hovsgol: Ulaan Uul Soum, Gunain Gol, 12 km SW of Ulaan Uul, N 50.61826° E 99.12094°, elev. 1761 m, 29 June 2006, C.R. Nelson #8465, Selenge River Project Team SRP2006062903, 1♂ {macropterous} (BYU), [CRN laboratory photo voucher D12]. Ulaan Uul Soum, Hugin Gol at toll bridge, 46.8km N of Ulaan Uul town, N 51.09845° E 99.32051°, elev. 1557 m, 1 July 2006, C.R. Nelson #8475, Selenge River Project Team SRP 2006070101, 1♂ {macropterous} (BYU), [CRN laboratory photo voucher D28]. Renchinlhumbe Soum, Jarin Gol 32.8 km N of Renchinlhumbe N51.39852°, E99.75011° elev. 1575 m, C.R. Nelson #8481, 3 July 2006, 1♀ (BYU), [CRN laboratory photo voucher D6]. Ovorhangay: Bat-Olziy Soum, Orkhon Gol ~ 34 km W of Khujirt N46.89303°, E102.39457°, elev. 1610 m, Selenge River Project Team, 06 July 2004, 1♀ (BYU) [CRN laboratory photo voucher D19]. Tov: Erdene Soum, Gorkhi Terelj National Park, Gultain Gol at road crossing 19.1 km upstream of Tuul River Bridge, N48.09720°, E107.9199° elev. 1551 m, 1 July 2002, Suvdaa Chuluunbat, E. Sanaa, 1♂ {macropterous} (BYU), [CRN laboratory photo voucher D9]. Erdene Soum, Gorkhi Terelj National Park, Tuul River 10.1 km upstream of Tuul River Bridge N48.09549°, E107.84265°, elev. 1531m, 8 July 2003, Selenge River Basin Insect Survey Team, SRBIS03070801 Gelhaus #903 1♂ {macropterous} 1♀ (BYU), [CRN laboratory photo voucher D10]. Erdene Soum, Gorkhi Terelj National Park, unnamed tributary of Tuul River on its E side 8.5 km downstream of Galtain Gol N48.09720° E107.84928°, elev. 1542m, E. Sanaa., 8 July 2003, 1♀ (BYU), [CRN laboratory photo voucher D 20]. Erdene Soum, Gorkhi Terelj National Park, Terelj River, just above Terelj, N47.99158° E107.46717°, elev. 1516 m, 28 June 2008, C.R. Nelson #8949, 1♀ (BYU), [CRN laboratory photo voucher D24]. Zavkhan; Ider Soum, Dogshin/Nogoon Nuur ~ 21 km SE of Zuummod/Ider N48.06257° E97.55064°, elev. 2054m, Selenge River Project Team, 23= 24 July 2004, 2♀ (BYU), [CRN laboratory photo voucher D16]. Sweden; Torne Träsk, Abisko, H.B.N. Hynes, 30 July 1968, 7♂, 11♀ (USNM). United Kingdom; England; Fisher Gill, 1300 – 1500’ [400 – 461 m], H.B.N. Hynes, 13 May 1940, 1♂, 1♀ (USNM). Cumberland, Whelpside Gill, 2000’ [616 m], T.T. Macon, 20 May 1940, 2♂, 1♀ (USNM). Cumberland, Whelpside Gill, 2000 – 2800’ [616 – 862m], T.T.M. & J.M., May 1940 & May & June 1953, 37 larvae (USNM). Cumberland, Wastwater,

H.B.N. Hynes, 7, 12 May 1940, 2♂, 2♀ (USNM). Cumberland, Ennerdale, H.B.N. Hynes, April 1939, 14♂, 12♀, 11 exuviae (USNM). Cumberland, Ennerdale water, collector unknown, 17 April 1939, 14 larvae (USNM). Cumberland, Stake Pass, 1540’ [474m], W.E. Frost, 4 May 1940, 1♀ (USNM). Cumberland, Derwent Water, 15, H.B.N. Hynes, 2 October 1939, 7 larvae (USNM). Cumberland, Ullswater, H.B.N. Hynes, 1939, 28 larvae (USNM). Westmoreland, Windermere, H.B.N. Hynes, 22 April 1939, 23 May 1940 & 2 June 1941, 26♂, 18♀ (USNM). Westmoreland, Scandale Beck, 1400’ [431m], 71, H.B.N. Hynes, 30 April 1940, 1♂, 1♀ (USNM). Westmoreland, Brothers Water, H.B.N. Hynes, 8 August 1939, 10 larvae (USNM). Westmoreland, Rydal Beck, 2000’ [616m], 102, H.B.N. Hynes, 12 August 1940, 4 larvae (USNM). Scotland; Argyle; L. Triochatan (Pass of Glencoe), W. D.W., 24 May 1959, 1♂, 2♀ (USNM). Caithness, Loch Shurrery, W.E. Frost, 3 May 1939, 1♂, 2♀, 2 exuviae (USNM). Selkirk, St. Mary’ s Loch, 22 March 1955, H.B.N. Hynes, 36 larvae (USNM). Mid Perth, Loch Rannoch, H.B.N. Hynes, 30 March 1955, 29 larvae (USNM). North Sutherland, Allt na a Bhathaich, Quinag, 1500 – 1750’ [461 – 539m], 28 August 1957, 224294, H.B.N. Hynes, 3 larvae (USNM). East Ross, L. Garve, H.B.N. Hynes, 25 March 1955, 16 larvae (USNM). Scotland, South Sutherland, “ L. Assynt & L. Borralan ” or England, South Somerset, H.B.N. Hynes, 28 March 1955, 6 larvae (USNM). Wales; Caernarvon, Llyn Idwal, 225, H.B.N. Hynes, 1 July 1949, 9 larvae (USNM). Merioneth, Afon Hirnant, H.B.N. Hynes, 1955/1956, 132 larvae (USNM).

Adult habitus. General color in alcohol similar to that of D. washingtoniana. Markings on head, pronotum, and meso- and metaeusterna (Figs. 46, 47, 55) similar to D. washingtoniana . However, Brinck (1949) reports that head coloration is variable. A well-developed sternacostal suture (Fig. 47 ss), as observed in D. washingtoniana (Fig. 3) and D. nanseni (Fig. 32), is present in D. bicaudata. Male. Body length (Lillehammer 1974, Stewart and Oswood 2006) similar to that of D. washingtoniana. Typically micropterous (Lillehammer 1974) but Brinck (1949) concluded that several populations with macropterous males are actually this species. In this study Mongolian populations with micropterous males exhibiting wings terminating prior to the 2 nd abdominal segment or reaching the mid-section of the abdomen as well as populations with macropterous males exhibiting wings reaching the abdominal apex or beyond are considered to be this species as well. Tergum 8 (Fig. 48) bearing a narrow, longitudinal, lightly sclerotized median strip; setose but lacking short, stout sensilla basiconica. Tergum 9 similar to that of D. nanseni in that the hind margin (Fig. 48) exhibits a broad, lightly sclerotized, median Ushaped area separated by a short distance from a more anteriorly located narrow, longitudinal, lightly sclerotized median band; presence of mesal patches of short, stout sensilla basiconica similar to D. washingtoniana. Tergum 10 with median, pale, longitudinal lightly sclerotized strip interrupted mesally by darkly sclerotized band connecting the adjacent tergal halves (Fig. 48); distribution of setae and sensilla basiconica similar to that of D. washingtoniana and D. nanseni. Epiproct also absent. Paraproct caudal projections in dorsal and ventral view (Figs. 48, 50, 51, 56) with outer surfaces somewhat flattened, not robustly convex as are those in D. washingtoniana and D. nanseni, setal lengths variable but generally shorter than those of preceding species; in lateral view (Figs. 49, 50, 57, 59, 60) subtriangular, tapering to narrowly rounded apical margins

Female. Body length (Lillehammer 1974) similar to D. washingtoniana. Macropterous, forewing length (Lillehammer 1974) similar to D. washingtoniana. Sternum 9 bearing two oblique brown bands (Figs. 52). Subgenital plate shape variable (Figs. 53, 58) (Brinck 1949, Lillehammer 1974); plate width overlaps that of D. nanseni but can be wider, ca 2.3 – 6.5X wider than long. Vagina and spermatheca membranous; spermatheca (Fig. 54 s) ovoid or eggshaped, nearly as long as wide (1.3x longer than wide); spermathecal duct (sd) 0.5x length of vagina; spermatheca and duct bearing accessory glands (ag).

Larva. Originally described by Hynes (1941), other information provided by Brinck (1949, 1952), Illies (1955), Hynes (1958) and Lillehammer (1988). Closely similar to D. washingtoniana, except that the lateral pronotal margins are lined with a row of short spinulae and a few longer hairs at the posterolateral corners (Fig. 77).

Egg. First illustrated by Lillehammer (1988) and nearly identical to D. washingtoniana and D. nanseni (Fig. 78).