Nemoura arctica Esben-Petersen, 1910

Grubbs, Scott A. & Baumann, Richard W., 2023, The Nemourinae (Insecta, Nemouridae) of the eastern Nearctic, Zootaxa 5306 (1), pp. 1-53 : 6-7

1. Nemoura arctica Esben-Petersen, 1910

Arctic Forestfly

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org:TaxonName:6232

( Figs. 1 , 9–18 )

Nemoura arctica Esben-Petersen 1910:85 . Holotype male (Museum unknown), Karasjok , Norway

Nemoura trispinosa Claassen, 1923:289 . Syn. Grubbs et al., 2018:48

Nemoura trispinosa: Needham & Claassen, 1925:213

Nemoura arctica: Claassen, 1940:50

Nemoura trispinosa: Claassen, 1940:64

Nemoura trispinosa: Frison, 1942:261

Nemoura trispinosa: Harden, 1942:322

Nemoura trispinosa: Ricker, 1944:177

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 (Nemoura) arctica: Harper & Hynes, 1971:1133

Nemoura (Nemoura) trispinosa: Harper & Hynes, 1971:1133

Nemoura arctica: Lillehammer, 1972:163

Nemoura trispinosa: Lillehammer, 1972:163

Nemoura arctica: Zwick, 1973:332

Nemoura trispinosa: Zwick, 1973:342

Nemoura (Nemoura) trispinosa: Hitchcock, 1974:107

Nemoura arctica: Lillehammer, 1974:82

Nemoura arctica: Baumann, 1975:51 , 64 (in part)

Nemoura trispinosa: Baumann, 1975:51

Nemoura arctica: Baumann et al., 1977:34

Nemoura arctica: Lillehammer, 1988:113

Nemoura trispinosa: Stewart & Stark, 1988:169

Nemoura trispinosa: Stewart & Stark, 2002:196

Nemoura arctica: Zhiltzova, 2003:266

Nemoura arctica: Kondratieff & Baumann, 2004:114

Nemoura arctica: Stewart & Oswood, 2006:78

Nemoura arctica: Boumans, 2011:286

Nemoura arctica: Judson & Nelson, 2012:33

Nemoura arctica: Grubbs et al., 2018:48

Distribution (Nearctic only). Canada: AB, BC, LB, MB, NB, NF, NS, NT, NU, ON, PE, PQ, SK, YK; USA: AK, IA, IL, ME, MI, MN, NH, NY, OH, PA, SD, WI, WV, WY ( DeWalt et al. 2022)

Male. Macropterous. Body length 4.7–5.9 mm, forewing length 4.1–6.1 mm (n = 25). Gills absent. Cerci sclerotized laterally and modified, outer edge produced and terminates typically in a pair of appressed spines that vary in length and degree of tapering, plus an outer spine that is variable ( Figs. 9–13 ). The outer spine is distally forked ( Fig. 13 ) or not ( Fig. 12 ). Populations further westward vary from the eastern Nearctic males. For example, males from South Dakota have an outer spine that is rectangular and crenulated distally ( Grubbs et al. 2018, their fig. 5). Paraproct outer lobes straight anteriorly and slightly trilobed posteriorly. The base of the cerci fit between the anterior and medial lobe. Epiproct short and robust, recurved anteriorly over the terminal abdominal segments ( Figs. 9–11 ); in lateral aspect, the basal cushion occupies the anterior ca. ½ and is separated from the dorsal sclerite by smooth lateral areas ( Fig. 14 ). The lateral areas are recurved slightly over the distal medial portion of the basal cushion. The dorsal sclerite appears scaly at high magnifications, especially apically ( Fig. 14 ). The dorsal sclerite is open apically, exposing parallel, broad, hatchet-like apical prongs of the ventral sclerite ( Figs. 11, 15–16 ) and prominent, scaly, apical prongs positioned ca. perpendicular to the ridges ( Figs. 15–16 ). The prongs terminate laterally bearing two short, thick, grooved spines ( Figs. 15–16 ).

Female. Macropterous. Body length 5.4–7.4 mm, forewing length 4.6–7.6 mm (n = 23). Gills absent. The 7 th sternum is produced as a broadly-subtruncate to subtriangular subgenital plate that extends over minimally across ½ of the 8 th sternum ( Figs. 17–18 ).

Larva. Described by Brinck (1949, 1952), Harden & Mickel (1952, as N. trispinosa ), and Harper & Hynes (1971, as N. trispinosa ). A partial illustration was also given in Frison (1942, as N. trispinosa ) and Harper & Stewart (1996). Stewart & Stark (1988, 2002) provided a description and full habitus illustration as N. trispinosa .

Comments. Grubbs et al. (2018) recently provided evidence with scanning electron micrographs that Nearctic N. trispinosa is a junior synonym of Holarctic N. arctica . Nemoura arctica is distributed extensively at mid- to northern latitudes across the Northern Hemisphere ( DeWalt et al. 2022).

Figures

FIGURES 1‒8. Forewing images. 1, Nemoura arctica, USA, Michigan, Silver Creek; 2, Ostrocerca albidipennis, USA, West Virginia, Middle Fork Indian Run; 3, Paranemoura perfecta, USA, West Virginia, headwaters Sugar Creek; 4, Podmosta macdunnoughi, USA, New York, Grampus Brook, dark line at tips of arrows represent the termini of veins A1 and A2; 5, Prostoia completa, USA, Kentucky, Middle Fork Drakes Creek; 6, Shipsa rotunda, USA, Michigan, Montreal River; 7, Soyedina calcarea, USA, Kentucky, tributary Green River; 8, Zapada katahdin, Canada, Labrador, tributary Leg Lake.

FIGURES 9‒16. Nemoura arctica. 9, USA, Wyoming, West Glacier Lake, male abdominal terminalia, lateral view; 10, USA, Wyoming, West Glacier Lake, male abdominal terminalia, dorsal view; 11, USA, Iowa, Twin Springs, epiproct, dorsal view; 12, Canada, New Brunswick, Coombs Brook, male cercus, distal view; 13, USA, Iowa, Twin Springs, male cercus, distal view; 14, Canada, New Brunswick, Coombs Brook, epiproct, lateral view; 15, USA, Iowa, Twin Springs, epiproct apex; 16, Canada, New Brunswick, Coombs Brook, epiproct apex. ap = apical prong, as = appressed spine, bc = basal cushion, c = cercus, ds = dorsal sclerite, la = lateral area, os = outer spine, vs = ventral sclerite.

FIGURES 17‒18. Nemoura arctica. 17, female abdominal terminalia, ventral view; 18, USA, New Hampshire, Lakes of the Clouds, female abdominal terminalia, ventral view. c = cercus, sgp = subgenital plate.