Nemoura arctica Esben-Petersen 1910
- Dataset
- The Nemourinae (Insecta, Nemouridae) of the eastern Nearctic
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Insecta
- order
- Plecoptera
- family
- Nemouridae
- genus
- Nemoura
- species
- Nemoura arctica
description
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.
description
http: // lsid. speciesfile. org / urn: lsid: Plecoptera. speciesfile. org: TaxonName: 6232 (Figs. 1, 9 – 18)
discussion
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).
distribution
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)
vernacular_names
Arctic Forestfly