Alloperla clarki, Grubbs & Baumann, 2019

Grubbs, Scott A. & Baumann, Richard W., 2019, Alloperla clarki sp. nov. (Plecoptera: Chloroperlidae), a new species from the eastern Nearctic with discussion of a new species group, Zootaxa 4624 (2), pp. 241-255 : 248-249

Alloperla clarki sp. nov.

http://lsid.speciesfile.org/urn:lsid: Plecoptera .speciesfile.org:TaxonName:506661

( Figs. 31–38 & 40)

Description. Male body length 5.5–6.0 mm, forewing length 6.5–7.0 mm (n = 2). General color in life unknown, pale yellow in alcohol. Head, thorax, and abdomen lacking darkened markings or margins. Lateral pectens present on abdominal segments 8 and 9. Wings macropterous and hyaline.

Male ( Figs. 31–38). Tergum 10 divided mesally by epiproct and reduced cowl into two hemitergal lobes; lobes covered by a dense matting of long setae ( Figs. 31–32). Epiproct length (L) 175 µm, maximum width (MW) 56 µm, L:MW ratio = 3.1. In dorsal view the epiproct is widest in medial ½, tapering both anteriorly and distally ( Figs. 31–32). The dorsal surface is covered by a dense matting of long hairs except for the anterior 1/5, which is entirely bare ( Figs. 31–32). The apical notch is subtriangular and extends anteriorly and ventrally as a groove between paired, serrated apical margins ( Figs. 33–36); 8–9 distinct teeth are present ( Figs. 35–38); the serrated apex is broadly arcuate ventrally ( Figs. 37–38). In lateral view the epiproct stem is broadest basally ( Fig. 37). The stem is slightly longer than the serrated apex and covered by a dense matting of long hairs except for a narrow bare band laterally near the hinge ( Fig. 37). The lateral portion of the serrated apex is bare except for a single line of 5–6 hairs plus a few additional accessory hairs ( Fig. 38).

Female. Unknown.

Egg. Unknown.

Larva. Unknown.

Type material. Holotype male ( BYU): USA, West Virginia, Greenbrier Co., Onemile Run, jct. North Fork Anthony Creek , 3 mi N Neola, 37.97941 -80.13596, 21 May 1990, R.W. Baumann & S.M. Clark . Paratypes: Virginia, Montgomery Co., Craigs Creek, Route 621, 0.5 miles off Route 460, 29 May 1979, B.C. Kondratieff, 3 males ( CHNC) , West Virginia, Greenbrier Co., headwaters of Little Creek , Rt. 16, 15 mi NW of White Sulphur Springs, 38.02371, -80.16601, 21 May 1990, R.W. Baumann & S.M. Clark, 2 males ( BYU) .

Etymology. This species is named for Dr. Shawn Clark, Entomology Collections Manager at the Monte L. Bean Museum, Brigham Young University. His collecting efforts during the 1990s helped form the backbone of an Atlas on Ohio Plecoptera ( DeWalt et al. 2016) and are likewise critical for the current development on an Atlas on West Virginia Plecoptera . The common name “Clark Sallfly” is proposed for this species ( Stark et al. 2012).

Diagnosis. Alloperla clarki sp. nov. is readily differentiated from A. nanina by the presence of the epiproct stem. The stem is distinct on A. clarki sp. nov. ( Fig. 37) and secondarily reduced for A. nanina ( Fig. 21). This is easily deciphered with standard light microscopy. Although seen most easily on SEM micrographs, the secondary loss of dense hair matting on both the epiproct stem and apical serrated margin of A. nanina ( Figs. 19–22) is easily contrasted from A. clarki sp. nov. ( Figs. 32, 37). For A. clarki sp. nov., the only portion of the epiproct lacking matting is dorsoapical surface, the ventral serrated margins, and thin lateral areas near the hinge ( Figs. 37–38).

Alloperla clarki sp. nov. can also be differentiated from A. biserrata by characteristics of the epiproct. For A. biserrata the ratio of total epiproct length to maximum width is 5.1 ( Fig. 11) compared to 3.1 for A. clarki sp. nov. ( Fig. 37). In lateral view the epiproct stem of A. biserrata has a narrower profile basally ( Fig. 9) compared to A. clarki sp. nov. ( Fig. 37). In addition, A. biserrata has a larger glabrous area near the epiproct hinge ( Figs. 9, 11) compared to A. clarki sp. nov. ( Fig. 37).

Alloperla clarki sp. nov. is morphologically similar to A. stipitata but there are three diagnostic, albeit subtle, differences on the epiproct. First, 5-6 distinct teeth are present on the apical serrated margin of A. stipitata ( Figs. 28–30). This is contrasted from the 8-9 teeth present on A. clarki sp. nov. ( Figs. 35–36, 38). Second, the ventral serrated margin of A. stipitata is positioned essentially along one linear, ventral plane ( Figs. 29–30) compared to the ventral arcuate shape of A. clarki sp. nov. ( Figs. 37–38). Third, there is a difference in the total length to maximum width ratio (2.4: A. stipitata vs. 3.1: A. clarki sp. nov.) between the two species.

Remarks. The type locality and the two paratype sites are positioned in southern West Virginia and adjacent southwestern Virginia in EPA Level III Ecoregion 67 (Ridge and Valley; Fig. 40). Twelve and nine Alloperla species are now known from Virginia and West Virginia, respectively ( DeWalt et al. 2018). A collecting effort in early June 2018 to the two West Virginia streams noted above and the vicinity in general failed to produce fresh material of A. clarki sp. nov. for additional study.