Paraperla wilsoni Ricker, 1965

Stark, Bill P., Baumann, Richard W., Kondratieff, Boris C. & Stewart, Kenneth W., 2013, Larval And Egg Morphology Of Paraperla Frontalis (Banks, 1902) And P. Wilsoni Ricker, 1965 (Plecoptera: Chloroperlidae), Illiesia 9 (8), pp. 101-108 : 106-108

Paraperla wilsoni Ricker

( Figs. 5-6 , 11-12 , 16-18 )

Paraperla wilsoni Ricker 1965:496 .

Holotype ♂ (Canadian National Collection), Chiliwack River, Vedder Crossing , British Columbia

Paraperla wilsoni: Baumann et al., 1977:188 . Pronotum Paraperla frontalis: Stewart & Stark, 2002:266 . Larval description

Paraperla wilsoni: Zwick, 2006:21 . Notes on male genitalia and larval lacinial structure

Material examined. (Suitable egg and/or larval/exuvial specimens were examined from the following sites): CANADA: BRITISH COLUMBIA: Fry Creek, Fry Creek Trail below bridge, Purcell Mountains , Wilderness Park , 18 May 2010, B. Stark, R . W. Baumann, 1♂, 3♀ (no eggs), 3 exuviae ( BPSC). Davis Creek, Davis Creek Provincial Park , 29 May 2010, B. Stark, R . W. Baumann, 1 exuvium ( BPSC). South Salmo River, Lost Creek Reservoir Area , 2 June 2010, B. Stark, R . W. Baumann, 1 exuvium ( BPSC) . UNITED STATES: ALASKA: Kari Creek, Steamer Bay, Etolin Island, 30 August 1977, T . F. Hanson, 1 larva ( KWSC) . MONTANA: Flathead Co., Jewell Basin, Picnic Lakes outfall, 5 July 1985, K.W. Stewart, B. Poulton, 3♀, 2 larvae, 3 exuviae ( KWSC). Same site, 7 July 1989, K.W. Stewart, 3♂, 11♀ (no eggs), 1 larva, 14 exuviae ( KWSC). Wounded Buck Creek , west side of Hungry Horse Reservoir , 4 June 1996, C. R . Nelson, R . S. Hanson, B. Ward, 6 exuviae ( BYUC). Lake Co., Yellow Bay Creek, Flathead Lake, 6 June 1972, D.S. Potter, exuviae ( BYUC). Yellow Bay Well #4, 22 June 2004, R . L. Newell, 1♂, 2♀ (no eggs), 3 exuviae ( BYUC). Same site, 15 June 2004, R . L. Newell, 9♂, 7♀ (no eggs), 16 exuviae ( KWSC). Missoula Co., Pattee Creek near Missoula , 7 May 1969, M. Poore, A. Dover, exuviae ( BYUC) .

Additional specimens examined: CANADA: ALBERTA: Crows Nest Pass, Kananaskis Highway , 2 August 1971, D.S. Potter, S. Fisher, 1♀ ( BYUC) . BRITISH COLUMBIA: Preacher Creek, Crawford Creek Rd, NE Crawford Bay , 31 May 2010, B. Stark, R . W. Baumann, 1♀ ( BPSC). Tam O’Shanter Creek, Riondel Road, Dutch Harbor Camp , 31 May 2010, B. Stark, R . W. Baumann, 1♀ ( BPSC) . UNITED STATES: CALIFORNIA: Sierra Co., Big Spring, Hwy 49, near Bassetts , 29 May 1991, B. Stark, R . W. Baumann, C. Henderson, 1♀ ( BPSC) . IDAHO: Kootenai Co., stream into Hayden Lake, Hayden Lake Rd , 26 May 2010, B. Stark, R . W. Baumann, 1♀ ( BPSC) . MONTANA: Lincoln Co., Ross Creek , FR 398, 27 April 2008, R . Durfee, 1♂ ( CSUC) . WASHINGTON: Lewis Co., Stevens Creek, below Louise Lake , Mount Rainier National Park , 15 June 1969, R .W. Baumann, 1♀ ( BYUC). Spokane Co., Big Spring , Mt. Spokane State Park, 11 June 1991, B. Stark, R .W. Baumann, C. Henderson, 1♀ ( BPSC) .

Egg. Outline oval. Length ca. 331 μm, equatorial width ca. 241 μm. Collar sessile, surrounded by a smooth circular zone ca. 37 μm wide forming a circular plaque-like structure with diameter of ca. 97 μm ( Figs. 5-6 ). Chorion covered throughout (except smooth collar zone) with shallow, obscure, irregularly sized pits, ca. 2.5 μm in diameter. Micropylar row equatorial.

Larva. Body length pre-emergent specimens 14-16 mm. General color pale brown without distinctive pigment pattern. Body covered with thin clothing hairs and short, thick setae, usually restricted to posterior segmental fringes and lateral clusters. Posterior fringes of abdominal sterna interrupted mesally, except on sternum 10. Lacinia with two teeth, 2 nd much smaller than 1 st, and not reaching mid length of larger tooth ( Figs. 11-12 ); lacinial pecten row absent. Basal, mid and apical cercal segments bear terminal whorls of setae ( Figs. 16-18 ); apical setal whorls composed of longer setae but vertical setal fringe absent. Legs with femoral and tibial swimming fringes absent or sparse.

Discussion

Based on the limited available samples, eggs of the two Nearctic species of Paraperla are similar in shape, size, collar form, micropylar placement and chorionic surface detail ( Figs. 1-6 ).The major difference lies in the relative size of the chorionic punctations which are larger in diameter and deeper on eggs of P. frontalis . All larvae and exuviae of P. frontalis we examined (n= 78) have a well developed vertical setal fringe on the cerci ( Figs. 14-15 ) and a well developed pecten row on the lacinia ( Figs. 9-10 ), and these are lacking on all specimens (n = 53) of P. wilsoni examined ( Figs. 11-12 , 16-18 ).The cercal feature is apparent in Claassen’s (1931) habitus figure of P. frontalis , presumably from Bozeman, Montana, although he describes the setation as “…each segment terminating in a whorl of hairs”, and a “vertical fringe” is not specifically mentioned; the presence of a “…prominent vertical cercal fringe on apical half of cerci…” was noted by Stewart & Stark (1988, 2002) among “some Alaska specimens”. The lacinial pecten feature was noted and illustrated by Claassen (1931), who referred to it as a “…’comb’ of stiff hairs”, and by Zwick (2006). The vertical cercal fringe and lacinial pecten row are absent from Stewart & Stark’s (2002) figures attributed to P. frontalis from a larval specimen collected on the Cedar River, King Co., Washington. In our opinion, these figures and the description in Stewart & Stark (2002) represent P. wilsoni .

Zwick (2006) raised a fundamental issue about the absence of a single shared apomorphic character for P. frontalis and P. wilsoni not also shared by Utaperla . (e.g. male sternum 7 with hairy lobe; mesosternal Y-stem not forked). We suggest this criterion may be met by the unusual egg collar form of these two species. If this character should prove phylogenetically unacceptable for defining the genus Paraperla with only these two species, it might become desirable to place P. wilsoni in a separate monotypic genus.

Figures

Figs. 1-6. Paraperla eggs. 1-4. P. frontalis, Humboldt Co., California. 1. Egg, lateral. 2. Egg collar, lateral, 3. Egg collar, apical. 4. Chorionic detail (M = putative micropyle). 5-6. P. wilsoni, Jewell Basin, Montana. 5. Egg collar, apical (fractured during cleaning). 6. Egg collar, lateral.

Figs. 7-12. Paraperla laciniae. 7, 9. P. frontalis, Lake Josephine, Montana. 8, 10. P. frontalis, Whitewood, South Dakota (lacinial pecten row at arrows). 11. P. wilsoni, Flathead Lake, Montana. 12. P. wilsoni, Pattee Creek, Montana.

Figs. 13-18. Paraperla larval cerci. 13-15. P. frontalis, basal, mid and apical segments, Klamath Basin, Oregon. 16-18. P. wilsoni, basal, mid and apical segments, Jewell Basin, Montana.