Zapada chila ( Ricker, 1952 )

Grubbs, Scott A. & Baumann, Richard W., 2023, The Nemourinae (Insecta, Nemouridae) of the eastern Nearctic, Zootaxa 5306 (1), pp. 1-53 : 45

24. Zapada chila ( Ricker, 1952)

Smokies Forestfly

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org:TaxonName:6008

( Figs. 157–160 )

Nemoura (Zapada) chila Ricker 1952:55 . Holotype male (Illinois Natural History Survey ), Walker ( Camp ) Prong , Great Smoky Mountains National Park, (Sevier Co.), Tennessee, USA

Zapada chila: Illies, 1966:249

Zapada chila: Grubbs et al., 2015:1313

Zapada chila: Stark, 2017:214

Distribution. USA: TN ( DeWalt et al. 2022)

Male. Macropterous. Body length 4.6–4.9 mm, forewing length 6.2–7.1 mm (n = 4). Four unbranched cervical gills are present. The length:maximum width (L:MW) ratio for the outer lateral gills is ca. 9.8 compared to ca. 9.4 for the inner medial gills ( Fig. 159 ; Grubbs et al. 2015). Cerci simple and unmodified ( Fig. 157 ). Paraprocts with two sclerotized lobes; inner lobes short and thin, outer lobe broadly quadrate. Epiproct recurved over 10 th tergite ( Figs. 157–158 ); broadest basally and open dorsally, with a distinct membranous structure that is medially expanded and distally spatulate ( Fig. 157 ); laterally sinuous in shape, showing the hump-shaped membranous structure mesally ( Fig. 158 ); dorsal sclerite larger than the ventral sclerite in lateral view, the two structures run ca. parallel from base nearly to mid-point ( Fig. 158 ).

Female. Macropterous. Body length 5.3 mm, forewing length 7.2–7.7 mm (n = 2). Cervical gills same as male. The 7 th sternum is produced as a broadly-rounded subgenital plate that extends slightly over the anterior margin of the 8 th sternum ( Fig. 160 ); posterior margin of 8 th sternum slightly concave medially.

Larva. Undescribed. Adult gill characteristics of Zapada , however, are identical to those in the larval stage. This should permit positive identification of larva of this species ( Stark 2017).

Comments. Zapada chila is considered a rare species. Only 13 adult specimens have been collected across a 65-year time span from a single stream (Walker Camp Prong) at the eastern Tennessee edge of Great Smoky Mountains National Park ( Grubbs et al. 2015) .

Figures

FIGURES 157‒160. Zapada chila. 157, USA, Tennessee, Little Pigeon River, male terminalia, dorsal view; 158, USA, Tennessee, Little Pigeon River, epiproct, lateral view; 159, USA, Tennessee, Little Pigeon River, cervical gills, ventral view; 160, USA, Tennessee, Little Pigeon River, subgenital plate, ventral view. c = cercus, ds = dorsal sclerite, lg = lateral gill, ma = membranous area, mg = medial gill, sgp = subgenital plate, vs = ventral sclerite.