Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 http://zoobank.org/ urn:lsid:zoobank.org:pub:66C4E575-ABF5-4B81-9132-0D771B52D68E Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 44 NEARCTIC NEMOURA TRISPINOSA CLAASSEN, 1923 AND N. RICKERI JEWETT, 1971 ARE JUNIOR SYNONYMS OF HOLARCTIC NEMOURA SPECIES (PLECOPTERA: NEMOURIDAE) Scott A. Grubbs1, Richard W. Baumann2, and David K. Burton3,4 1 Department of Biology and Center for Biodiversity Studies, Western Kentucky University, Bowling Green, Kentucky 42101, U.S.A. E-mail: scott.grubbs@wku.edu 2 Department of Biology, Monte L. Bean Life Science Museum, Brigham Young University, Provo, Utah, U.S.A., 84602. E-mail: richard_baumann@byu.edu 3 Faculty of Education, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 E-mail: dburton@uottawa.ca 4 Canadian National Collection, Agriculture Canada, Central Experimental Farm, Ottawa, Ontario, Canada K1A 0C6 ABSTRACT Only five species of the diverse Holarctic stonefly genus Nemoura Latreille, 1796 are known to occur in North America. We used scanning electron microscopy to show that (a) N. trispinosa Claassen, 1923 is a junior synonym of N. arctica Esben-Petersen, 1910, and (b) N. rickeri Jewett, 1971 is a junior synonym of N. sahlbergi Morton, 1896. Four species of Nemoura: N. arctica, N. normani Ricker, 1952, N. sahlbergi, and N. spiniloba Jewett, 1954, and are now recognized from the Nearctic realm. Keywords: Plecoptera, Nemouridae, Nemoura, N. arctica Esben-Petersen, 1910, N. sahlbergi Morton, 1896, Nearctic, Holarctic INTRODUCTION Holarctic Nemoura Latreille, 1796 (Insecta, Nemouridae) is among the speciose stonefly genera, with ca. 190 species distributed mainly across Asia and Europe (DeWalt et al. 2018). In contrast, only five species are recognized from North America: N. arctica Esben-Petersen, 1910, N. normani Ricker, 1952, N. rickeri Jewett, 1971, N. spiniloba Jewett, 1954, and N. trispinosa Claassen, 1923. Nemoura spiniloba is a member of the N. cercispinosa Kawai, 1960 group (sensu Baumann 1975) and distinct from the other four Nearctic species. The main intent of this paper was to access the Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 45 taxonomic status of two Nearctic species: N. rickeri and N. trispinosa. We provide evidence using scanning electron microscopy (SEM) that Nearctic N. trispinosa Claassen, 1923 and Nearctic N. rickeri Jewett, 1971 are junior synonyms of Holarctic N. arctica Esben-Petersen, 1910 and Palearctic N. sahlbergi Morton, 1896, respectively. Systematic notes are also provided for N. normani. Terminology follows that of Baumann (1975). METHODS Material of adult Nemoura were examined from the Monte L. Bean Museum, Brigham Young University, Provo, Utah (BYU), California Academy of Sciences, San Francisco (CASC), Canadian National Collection of Insects, Ottawa (CNCI), Cornell University Insect Collection, Ithaca, New York (CUIC), Illinois Natural History Survey, Champaign (INHS), Zoological Museum, University of Oslo, Norway (NMHO), United States National Museum, Washington, DC (USNM), University of Prince Edward Island, Charlottetown (UPEI), and Western Kentucky University, Bowling Green. Adult male and female terminalia were studied with SEM using a Philips XL30 ESEM FEG scanning electron microscope at Brigham Young University. The following are locality data for specimens that were examined during this study. Records extend geographically across Europe, Asia, and North America: Nemoura arctica NORWAY Buktved Garnvika, rock pools, 17-V-2010, T.E. Krem (NHMO) Finnmark, Kautokeino, Caskijas, 30-VI-1972, A. Lillehammer (NHMO) RUSSIA Siberia, Magadan Oblask, Kontaktovy Creek, Kolyma Water Balance Station, 61°50’ N, 147°40’ E, 17-VI-1995, P.H. Adler (BYU) MONGOLIA Bayan Olgiy Aimag, Tsengel Soum, Khoton Lake, 15 km NW Syrgal, 14-VII-2008, C.R. Nelson (BYU) Hovsgol Aimag, Tsagaan Nuur Soum, stream 16 km NW Tsagaan Nuur Town, 3-VII-2006, C.R. Nelson (BYU) CANADA Manitoba Warkworth Creek, Churchill, 18-VI-1948, F.P. Ide (CNCI) New Brunswick Madawaska Co., Coombs Brook, Hwy 17, E St. Leonard, 16-VI-1993, Baumann & Kondratieff (BYU) Northwest Territories Thelon River, 63˚49’58” N, -104˚06’ 21” W, 1- VII-2002, Giberson & Purcell (UPEI) Tuktoyaktuk, 12-VII-1971, D.R. Oliver (CNCI) Prince Edward Island Queens Co., Balsam Hollow Brook, Cavendish, 6-VI-1997, M.D. Dobrin (UPEI) Saskatchewan stream at Promontory Campground, 15 mi N of La Rouge, junction Hwy 102, 21-VI-1976, L. Dosdall (BYU) UNITED STATES Illinois Kane Co., stream, Elgin Botanical Garden, Elgin, 20-VI-1946, Ross & Sanderson (INHS) Iowa Winneshiek Co., Twin Springs, Twin Springs State Park, Hwy 52, Decorah, 13-IV-1996, Baumann, Kondratieff & Huntsman (BYU) Ohio Greene Co., spring, John Bryan State Park, 7-VI- 1989, Baumann & Clark (BYU) South Dakota Pennington Co., Burnt Fork, Rd 389, E Tigerville, 6-VI-1995, Baumann & Huntsman (BYU) Wisconsin Dunn Co., spring, Paradise Valley Road, 1 mi N Irvington, 23-V-1988, B.C. Poulton (BYU) Wyoming Crook Co., Blacktail Creek, Rd 849, SW Cook Lake, 44°32’32” N, -104°27’02” W, 16-VII-1997, Baumann & Kondratieff (BYU) Nemoura sahlbergi NORWAY Gargiaelva, ved Storeng, 28-VI-2010, L. Boumans (NHMO) Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 46 Figs. 1–8. Nemoura arctica, cerci, distal view. 1, USA, Iowa, Twin Springs, 545X; 2, USA, Illinois, Elgin, 516X; 3, USA, Ohio, John Bryan State Park, 518X; 4, USA, Wisconsin, spring, 1 mile N Irvington, 509X; 5, USA, South Dakota, Burnt Fork, 497X; 6, USA, Wyoming, Blacktail Creek, 584X; 7, Canada, Saskatchewan, Promontory Campground, 605X; 8, Canada, New Brunswick, Coombs Brook, 591X. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 47 Figs. 9–16. Nemoura arctica, cerci, distal view. 9, Canada, Manitoba, Warkworth Creek, 773X; 10, Canada, Northwest Territories, Thelon River, 636X; 11, Canada, Northwest Territories, Tuktoyaktuk, 612X; 12, Russia, Siberia, Magadan Oblask, 486X; 13, Norway, Buktved Garnvika, 443X; 14, Norway, Kautokeino, 431X; 15, Mongolia, Khoton Lake, 675X; 16, Mongolia, Tsagaaan Lake, 646X. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 48 Baukop, bekk fra Vuolit Gealbotjavri, 15-VI- 2010, T.E. Krem (NHMO) Finnmark, Porsaugen, Jagecolas, 2-VII-1968, A. Lillehammer (NHMO) MONGOLIA Khovsgol Aimag, stream above Bul Nai Hot Springs, 18-VIII-2005, C.R. Nelson (BYU) CANADA Manitoba Goose Creek, tributary Churchill River, near Churchill, 7-VI-1976, T.D. Galloway (BYU) Yukon Glacier Creek, Dempster Hwy, 66°38’38”N, 136°19’27”W, 22-VI-1996, Abbott & Stewart (BYU) UNITED STATES Alaska creek, 7 mi E Eureka, Glenn Hwy, 30-VI-1968, S.G. Jewett, Jr. (1♂ paratype) (BYU) Ogotoruk Creek, 21-VI-1960, D.G. Wilson (BYU) RESULTS AND DISCUSSION Nemoura arctica Esben-Petersen, 1910 Arctic Forestfly (Figs. 1–52) http://lsid.speciesfile.org/urn:lsid:Plecoptera.speciesfile.org: TaxonName:6232 Nemoura arctica Esben-Petersen 1910:85. Holotype ♂, Type locality – Karasjok, Norway Nemoura trispinosa Claassen 1923:289. Holotype ♂, Type locality – Mud Creek, Tompkins Co., New York. New synonym (Holotype ♂ examined) Nemoura trispinosa: Needham & Claassen 1925:213. Nemoura arctica: Claassen 1940:50. Nemoura trispinosa: Claassen 1940:64. Nemoura trispinosa: Frison 1942:261 Nemoura arctica: Koponen & Brinck 1949:7. Nemoura trispinosa: Weber 1950:175. Nemoura arctica: Brinck 1952:107. Nemoura trispinosa: Harden & Mickel 1952:19. Nemoura (Nemoura) arctica: Ricker 1952:36. Nemoura arctica: Zhiltzova 1964:187. Nemoura arctica: Illies 1966:194. Nemoura trispinosa: Illies 1966:214. Nemoura arctica: Lillehammer 1972a:163. Nemoura trispinosa: Lillehammer 1972a:163. Nemoura arctica: Zwick 1973a:332. Nemoura trispinosa: Zwick 1973a:342. Nemoura arctica: Lillehammer 1974a:82. Nemoura arctica: Baumann 1975:21. Nemoura trispinosa: Baumann 1975:21. Nemoura arctica: Baumann et al. 1977:34. Nemoura arctica: Lillehammer 1988:113. Nemoura arctica: Zhiltzova 2003:266. Nemoura arctica: Kondratieff & Baumann 2004:114. Nemoura arctica: Stewart & Oswood 2006:78. Nemoura arctica: Judson & Nelson 2012:33. Distribution. Canada: AB, BC, LB, MB, NB, NS, NT, NU, ON, PE, PQ, YK. Europe: Baltic States, Finland, Norway, Sweden. Mongolia. Russia East, Russia North, West Siberia. USA: AK, IA, IL, ME, MI, NY, OH, PA, SD, WI, WY (DeWalt et al. 2018). New Canadian province and USA state records. Canada, Saskatchewan, stream at Promontory Campground, 15 miles north of La Rouge, junction Hwy 102, 21-VI-1976, L.M. Dosdall, 4♂, 2♀; Puskwakau River, Hwy 106, 30-V-1976, L.M. Dosdall, 1♂. USA, Minnesota (Harden & Mickel 1952, their pp. 19–20). New Hampshire, Coös Co., Lakes of the Clouds, White Mountains, 20 June 1951, C.P. Alexander, 1♂ (USNM); Grafton Co., Franconia, A.T. Slosson, no date information, 1♂ (USNM; Ac #26226). West Virginia, Tucker Co., Abe Run, Canaan Valley State Park, 28 May 1993, S.M. Clark, 1♀ (BYU). Diagnosis. Cercus. Highly variable. Adults of N. arctica and N. trispinosa have been previously differentiated by a combination of cercal characteristics (males) and body size and distribution (females) (Ricker 1952). Male cerci are sclerotized laterally and terminate typically in a pair of appressed spines that vary in length and degree of tapering (Figs. 1–16), plus a third unit that is highly variable and has been used for the past ca. 65 years to separate males of N. arctica and N. trispinosa (Ricker 1952). Lillehammer (1972a) later illustrated cerci as either lacking (N. arctica, his Fig. 4b) or possessing a distinct (N. trispinosa, his Fig. 4a) spine. Ricker’s (1952, p. 36) key to N. trispinosa males focused on “…the outer edge of the cercus produced into a slender acute spine… may be forked once or twice at the tip”. This feature is common in North America and shown here clearly for populations from Iowa (Fig. 1), Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 49 Figs. 17–24. Nemoura arctica, epiproct, lateral view. 17, USA, Iowa, Twin Springs, 270X; 18, Canada, New Brunswick, Coombs Brook, 288X; 19, Canada, Northwest Territories, Thelon River, 285X; 20, Canada, Northwest Territories, Tuktoyaktuk, 328X; 21, Russia, Siberia, Magadan Oblask, 271X; 22, Norway, Buktved Garnvika, 286X; 23, Norway, Kautokeino, 316X; 24, Mongolia, Khoton Lake, 276X. AP = apical prong, BC = basal cushion, DS = dorsal sclerite, LA = lateral areas, VS = ventral sclerite. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 50 Figs. 25–32. Nemoura arctica, epiproct, dorsal view. 25, USA, Iowa, Twin Springs, 141X; 26, USA, Illinois, Elgin, 165X; 27, USA, Ohio, spring, John Bryan State Park, 144X; 28, USA, Wisconsin, spring, 1 mile N Irvington, 132X; 29, USA, South Dakota, Burnt Fork, 140X; 30, USA, South Dakota, Burnt Fork, 229X; 31, Canada, Prince Edward Island, Balsam Hollow, 163X; 32, Canada, New Brunswick, Coombs Brook, 168X. AP = apical prong, BC = basal cushion, DS = dorsal sclerite, LA = lateral area, VS = ventral sclerite. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 51 Figs. 33–40. Nemoura arctica, epiproct, dorsal view. 33, Canada, Saskatchewan, Promontory Campground, 187X; 34, Canada, Northwest Territories, Thelon River, 282X; 35, Canada, Northwest Territories, Tuktoyaktuk, 267X; 36, Norway, Buktved Garnvika, 321X; 37, Norway, Kautokeino, 278X; 38, Russia, Siberia, Magadan Oblask, 206X; 39, Mongolia, Khoton Lake, 277X; 40, Mongolia, Tsagaaan Lake, 281X. AP = apical prong, BC = basal cushion, DS = dorsal sclerite, LA = lateral area, VS = ventral sclerite. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 52 Illinois (Fig. 2), Ohio (Fig. 3), Wisconsin (Fig. 4), South Dakota (Fig. 5), Wyoming (Fig. 6), and New Brunswick (Fig. 8), and also from Siberia (Fig. 12), Norway (Fig. 13) and Mongolia (Fig. 16). The spine, however, varies in width and degree of tapering, For example, males from South Dakota have an outer spine that is rectangular, not “slender”, and crenulated distally (Fig. 5). Nemoura arctica was separated out by Ricker (1952) as the “…outer edge of the cercus bordered by a crenulate shelf or ridge”. No form of a spine is evident for populations studied from North America from Saskatchewan (Fig. 7), Manitoba (Fig. 9), and the Northwest Territories (Figs. 10–11) plus Norway (Fig. 14) and Mongolia (Fig. 15). Overall, there is sufficient variability (e.g. forked vs. crenulated; tapered or not) to strongly suggest that the male cercus does not provide objective, diagnostic information to support N. trispinosa as distinct from N. arctica. Epiproct. Males exhibit consistency with epiproct shape and characteristics across the Holarctic with only minor differences between individuals. In lateral aspect, the basal cushion occupies the anterior ca. ½ and is separated from the dorsal sclerite by smooth lateral areas (Figs. 17–24). The lateral areas vary in thickness but are consistently recurved slightly over the distal medial portion of the basal cushion. The dorsal sclerite appears scaly at high magnifications, especially at the distal tips (Figs. 41–52). The dorsal sclerite is open apically, exposing parallel, broad, hatchet-like apical prongs of the ventral sclerite (Figs. 25–40) and prominent, scaly, apical prongs positioned ca. perpendicular to the ridges (Figs. 41–52). The prongs terminate laterally bearing two short, thick, grooved spines (e.g. Figs. 42, 45, 49, 52). Comments. Nemoura trispinosa is placed in synonymy with N. arctica due to consistencies in epiproct characteristics across the Holarctic, particularly the paired apical prongs of the ventral sclerite (Figs. 41–52). In contrast, cercal spine characteristics are highly variable and do not provide objective, diagnostic information. Even males from the same geographic entity (e.g. Mongolia, Figs. 15–16) exhibit different cercal forms. Lillehammer (1972a, his Fig. 25.4) previously illustrated several different cercal forms from Norway. Geographic notes. Holarctic: Scandinavia east across Asia; east to Alaska, Yukon, Northwest Territories and Nunavut. South in Europe to Latvia and in far eastern Asia to Mongolia and Siberia. South in North America to Wyoming and South Dakota east across the Great Lakes region to Atlantic Canada, with relictual southern populations in Ohio, Pennsylvania, and West Virginia. Additional notable references include Ricker (1944, 1964), Brinck (1958), Ulfstrand (1969), Jewett (1971), Lillehammer (1974, 1985, 1986, 1988), Harper (1973), Flannagan & Flannagan (1982), Burton (1984), Stewart et al. (1990), Harper & Ricker (1994), Stewart & Ricker (1997), Huntsman et al. (1999), Teslenko & Bazova (2009), Walters et al. (2009), Zhou et al. (2010), Boumans (2011), Boumans & Brittain (2012), Surenkhorloo et al. (2012), Dosdall & Giberson (2014), Kendrick & Huryn (2014), and Potikha (2015). Nemoura sahlbergi Morton, 1896 (Figs. 53‒84) http://lsid.speciesfile.org/urn:lsid:Plecoptera.speciesfile.org: TaxonName:6326 Nemoura sahlbergi Morton 1896:56. Holotype ♂, Type locality – Utsjoki, Lake Enara, Finland Nemoura sahlbergi: Claassen 1940:63 Nemoura trispinosa: Ricker 1944:177. In part Nemoura sahlbergi: Brinck 1952:104 Nemoura sahlbergi: Zhiltzova 1964:187 Nemoura sahlbergi: Meinander 1965:17 Nemoura sahlbergi: Illies 1966:212. Nemoura rickeri Jewett, 1971:190. Type locality – Cache Creek, 19 mi E Eureka, Glenn Highway, Alaska. New synonym (Paratype ♂ examined) Nemoura sahlbergi: Lillehammer 1972b:157 Nemoura sahlbergi: Benedetto 1973:20 Nemoura sahlbergi: Zwick 1973a:340 Nemoura sahlbergi problematica: Zwick 1973b:162. Type locality – Diamond Range, Kangwon Province, People’s Republic of Korea. Nomen dubium Zwick 2010 Nemoura sahlbergi: Lillehammer 1974a:85 Nemoura rickeri: Dosdall & Lehmkuhl 1979:34 Nemoura rickeri: Stewart & Oswood 2006:78 Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 53 Figs. 41–46. Nemoura arctica, epiproct, dorsal view. 41, USA, Iowa, Twin Springs, 584X; 42, USA, Illinois, Elgin, 519X; 43, USA, South Dakota, Burnt Fork, 669X; 44, Canada, Saskatchewan, Promontory Campground, 1056X; 45, Canada, New Brunswick, Coombs Brook, 770X; 46, Canada, Prince Edward Island, Balsam Hollow, 695X. AP = apical prong. Distribution. Canada: MB, NT, NU, SK, YK. Europe: Baltic States, Finland, Norway, Sweden. Mongolia. Russia East, Russia North. USA: AK (DeWalt et al. 2018). Diagnosis. Cercus. Highly variable. Male cerci are sclerotized laterally and terminate in either one (Figs. 54–57, 59) or two (Figs. 53, 58, 60) produced, curved spines that vary in length, curvature, and degree of tapering, plus a third unit (= outer spine) that tapers little and is typically crenulated distally. Epiproct. Males exhibit consistency with epiproct shape and characteristics across the Holarctic with only minor differences between individuals. In lateral aspect, the basal cushion occupies the anterior ca. ½ and is separated from the dorsal sclerite by smooth lateral areas (Figs. 61–68). The lateral areas are consistently recurved slightly over Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 54 Figs. 47–52. Nemoura arctica, epiproct, dorsal view. 47, Canada, Northwest Territories, Thelon River, 1161X; 48, Russia, Siberia, Magadan Oblask, 1204X; 49, Norway, Buktved Garnvika, 751X; 50, Norway, Kautokeino, 809X; 51, Mongolia, Khoton Lake, 598X; 52, Mongolia, Tsagaaan Lake, 969X. AP = apical prong. the distal medial portion of the basal cushion. The dorsal sclerite is open apically, exposing paired, rounded apical prongs bearing scale-like ridges, terminating laterally into one or two stout, grooved lateral spines (Figs. 69–76). The apical prongs are positioned either ca. parallel (Figs. 82, 84) or ca. diagonal to the ridges (Figs. 77–81, 83). Comments. The synonymy of N. rickeri with N. sahlbergi has been suggested previously (e.g. Lillehammer 1972b; Boumans & Brittain 2012). Jewett (1971) noted in his description of N. rickeri that this species “…is similar to the rare northern European Nemoura sahlbergi…”. Lillehammer (1972a, his Fig. 29.4) illustrated several different cercal forms from Norway, showing variability in the curved and outer spines. The epiproct apical Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 55 Figs. 53–60. Nemoura sahlbergi, cerci, distal view. 53, Canada, Manitoba, Goose Creek, 347X; 54, USA, Alaska, 7 mi E Eureka, 586X; 55, USA, Alaska, 7 mi E Eureka, 397X; 56, USA, Alaska, Ogotoruk Creek, 546X; 57, Norway, Gargiaelva, 740X; 58, Norway, Baukop, 941X; 59, Norway, Finnmark, 610X; 60, Mongolia, Khovsgol Aimag, 568X. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 56 Figs. 61–68. Nemoura sahlbergi, epiproct, lateral view. 61, Canada, Manitoba, Goose Creek, 306X; 62, Canada, Yukon, Glacier Creek, 380X; 63, USA, Alaska, 7 mi E Eureka, 560X; 64, USA, Alaska, Ogotoruk Creek, 324X; 65, Norway, Gargiaelva, 394X; 66, Norway, Baukop, 334X; 67, Norway, Finnmark, 316X; 68, Mongolia, Khovsgol Aimag, 418X. AP = apical prong, BC = basal cushion, DS = dorsal sclerite, LA = lateral area, VS = ventral sclerite. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 57 prongs studied herein from the Northwest Territories (Fig. 78), Alaska (Fig. 80), Norway (Fig. 82), and Mongolia (Fig. 84) are consistent with illustrations or images in Lillehammer (1972a, his Fig. 31.3; Norway), Boumans (2011, his Fig. 2; Norway) and Judson & Nelson (2012, their Fig. 187; Mongolia). Geographic notes. Holarctic: Scandinavia east across Asia; in North America from Alaska east to Nunavut and Manitoba. South in Europe to Latvia and in eastern Asia south to Mongolia and far eastern Siberia. South in North America to the treeline in the Saskatchewan River Basin in Manitoba and Saskatchewan. Additional notable references include Rauser (1968), Lillehammer (1972a, 1974, 1985, 1988), Burton (1984), Teslenko & Bazova (2009), Zhou et al. (2010), Zwick (2010), Boumans (2011), Boumans & Brittain (2012), and Judson & Nelson (2012). Nemoura normani Ricker Alaska Forestfly http://lsid.speciesfile.org/urn:lsid:Plecoptera.speciesfile.org: TaxonName:6350 Nemoura species E: Ricker 1944:177. Nemoura sp. A: Weber 1950:175. Nemoura normani Ricker 1952:37. Type locality – Mackenzie River, Fort Norman, Northwest Territories (Holotype ♀ and Paratype ♀ examined) Nemoura normani: Illies 1966:209. Nemoura normani: Stewart & Oswood 2006:78. Distribution. Canada: NT. USA: AK (DeWalt et al. 2018). Diagnosis. Nemoura normani was described from the holotype female and one paratype female (Ricker 1952) and is still unknown from the male stage. The females were described as “noticeably larger” than both N. arctica and N. trispinosa and exhibit subtle differences in the shape of the subgenital plate (Ricker 1952). Stewart and Oswood (2006) examined the paratype female (Alaska, Anaktuvik Pass, 6 July 1949, preserved in alcohol) during their study of the stoneflies of Alaska and western Canada but were unable to collect additional material. We likewise studied the paratype female and determined that it was indeed a Nemoura female with the correct wing venation, sclerotized cerci, and no cervical gills. The color of the wings are fumose in alcohol. This species is perhaps also absent from the Yukon (Stewart and Ricker 1997). Hence, the two females remain the only specimens of this species collected and none since 1949. Males or molecular data are needed to determine if this is a valid species, another Nemoura species (Ricker, 1964), or a junior synonym of either N. arctica or N. sahlbergi. Conclusions We present morphological evidence with SEM micrographs of the male epiprocts and cerci to propose that Nearctic N. rickeri and Nearctic N. trispinosa are junior synonyms of Holarctic N. arctica and Palearctic N. sahlbergi, respectively. Hence, both N. arctica and N. sahlbergi exhibit Holarctic distributions. On a similar note, Boumans & Baumann (2012) synonymized Amphinemura linda (Ricker, 1952), a species recognized for ca. 65 years, with A. palmeni (Koponen, 1917) using a combination of external reproductive morphology plus mitochondrial COI subunit and nuclear 28S gene sequence data. Amphinemura palmeni likewise is a Holarctic species (DeWalt et al. 2018). ACKNOWLEDGEMENTS Thanks are extended to Boris Kondratieff (Colorado State University, Fort Collins, Colorado, USA) and Peter Zwick (Limnologische Fluβstation Max-Planck_Institut für Limnologie, Schlitz, Germany) for thoughtful reviews and comments that improved the quality of this paper. Several individuals have provided assistance, shared ideas, and provided material across several years that has made this study possible: John Abbott, Department of Biology, University of North Texas, Denton, Texas, USA Peter H. Adler, Division of Entomology, Clemson University, Clemson, South Carolina, USA Louis Boumans, Insect Collection, Department of Zoology, Natural History Museum, University of Oslo, Oslo, Norway Per Brink, Department of Animal Ecology, Zoological Institute, University of Lund, Sweden Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 58 Figs. 69–76. Nemoura sahlbergi, epiproct, dorsal view. 69, Canada, Manitoba, Goose Creek, 312X; 70, Canada, Northwest Territories, Thelon River, 367X; 71, USA, Alaska, Eureka, 344X; 72, USA, Alaska, Ogotoruk Creek, 313X; 73, Norway, Gargiaelva, 424X; 74, Norway, Baukop, 334X; 75, Norway, Finnmark, 419X; 76, Mongolia, Khovsgol Aimag, 365X. AP = apical prong, BC = basal cushion, DS = dorsal sclerite, LA = lateral area, VS = ventral sclerite. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 59 Figa. 77–84. Nemoura sahlbergi, epiproct, dorsal view. 77, Canada, Manitoba, Goose Creek, 1813X; 78, Canada, Northwest Territories, Thelon River, 1778X; 79, Canada, Yukon, Glacier Creek, 1428X; 80, USA, Alaska, 7 mi E Eureka, 1308X; 81, Norway, Gargiaelva, 1106X; 82, Norway, Baukop, 719X; 83, Norway, Finnmark, 1674X; 84, Mongolia, Khovsgol Aimag, 873X. Grubbs, S.A., R.W. Baumann, and D.K. Burton. 2018. Nearctic Nemoura trispinosa Claassen, 1923 and N. rickeri Jewett, 1971 are junior synonyms of Holarctic Nemoura species (Plecoptera: Nemouridae). Illiesia, 14(03):44-64. https://doi.org/10.25031/2018/14.03 Illiesia – http://illiesia.speciesfile.org Volume 14 – Number 3 – Page 60 Sydney Cannings, Canadian Wildlife Service, environment Canada, Whitehorse, Yukon, Canada Shawn M. Clark, Department of Biology, Brigham Young University, Provo, Utah, USA David Donald, Environment Canada, Regina, Saskatchewan, Canada Lloyd M. Dosdall, Biology Department, University of Saskatchewan, Saskatoon, Saskatchewan, Canada George F. Edmunds Jr., Department of Biology, University of Utah, Salt Lake City, Utah, USA Sanaa Enkhtaivan, Ministry of Environment and Tourism, Ulaan Baatar, Mongolia John F. Flannagan, Freshwater Institute, Winnipeg, Manitoba, Canada Oliver S. Flint, Jr., Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington D.C., USA Donna Giberson, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada Peter P. Harper, Department of Biological Sciences, University of Montreal, Quebec, Canada Bret O. Huntsman, Brigham Young University, Provo, Utah, USA H.B.N. Hynes, Department of Biology, University of Waterloo, Waterloo, Ontario, Canada Stanley G. Jewett, Jr., National Marine Fisheries Service, Portland, Oregon, USA Sarah W. Judson, Department of Watershed Sciences, Utah State University, Logan, Utah, USA Boris C. Kondratieff, Department of Entomology, Colorado State University, Fort Collins, Colorado, USA Vincent Lee, Department of Entomology, California Academy of Sciences, San Francisco, California, USA James K. Liebherr, Department of Entomology, Cornell University, Ithaca, New York, USA Albert Lillehammer, Zoological Museum, Sarsgatan 1, Oslo, Norway Carl Lindroth, Department of Entomology, Zoological Institute, University of Lund, Sweden Owen Lonsdale, Canadian National Collection (Entomology), Ottawa, Ontario, Canada Martin Meinander, Division of Entomology, Zoological Museum, Helsinki, Finland David Muranyi, Department of Zoology, Hungarian National Museum, Budapest, Hungary Karen Needham, Spencer Entomological Collection, Department of Zoology, University of British Columbia, Canada C. Riley Nelson, Department of Biology, Brigham Young University, Provo, Utah, USA Robert L. Newell, Flathead Lake, Biological Station, Big Fork, Montana, USA William E. 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Illiesia, 6:75–97. http://illiesia.speciesfile.org/papers/Illiesia06- 09.pdf Submitted 16 January 2018, Accepted 12 February 2018, Published 2 April 2018 Hosted and published at the University of Illinois, Illinois Natural History Survey, Champaign, Illinois, U.S.A.