This article reviews the capniid genus Paracapnia Hanson and describes a new species, P. boris, from males and females collected in northern California, provisionally assigned to the genus. Paracapnia oswegaptera (Jewett) is placed in synonymy with P. ensicala (Jewett), and the first description is provided for the male of P. disala (Jewett). Keys are presented for recognized Palearctic and Nearctic members of the genus. Distribution data are given for specimens examined and for those in the published literature.
Hanson (1946) proposed Paracapnia for Chloroperla opis (Newman 1839) and P. curvata, a newly described species. Later, Hanson (1961) found P. curvata to be a synonym of P. opis, leaving the species that Frison (1942) and Hanson (1946) had mistaken for P. opis without a name. Hanson (1961) renamed this species P. angulata, and the concept of the genus as an eastern Nearctic endemic of 2 species was established.
This concept was expanded when Zhiltzova (1972, 1984) and Zhiltzova and Levanidova (1978) described 3 new species from eastern Russia: P. khorensis, P. recta, and P. sikhotensis. Detailed information shows that these 3 species occur in the Amur River basin and Primorye with the following type localities: P. khorensis at the Khor River, Ussuri drainage, and Amur basin; P. recta at the Kedrovaya River and Kedrovaya Pad National Park; and P. sikhotensis at the Zabolochennaya River and Sikhote Alin National Park (Zhiltzova 2003). Zwick (1973) transferred Capnia oswegaptera Jewett (1965) to the genus. Two other apterous Capnia species described by Jewett (1962)—C. disala from Oregon and C. ensicala from Washington—were assigned to the genus by Nelson and Baumann (1989).
In the current study, adults of several Nearctic Paracapnia populations were examined with scanning electron microscopy in an effort to locate additional characters useful for phylogenetic analysis. Although no characters were revealed, the study confirmed the presence of an undescribed species from Colusa County, California, which is described below and is provisionally placed in Paracapnia. We redescribe P. ensicala (Jewett) from type material, provide the first description of the P. disala (Jewett) male, and place P. oswegaptera (Jewett) as a synonym of P. ensicala. We also present a key to the Holarctic species of Paracapnia, using characters extracted from Zhiltzova (1972, 1984, 2003) and from Zhiltzova and Levanidova (1978) for the Palearctic species.
Specimens observed with scanning electron microscopy were dehydrated in ethanol and hexamethyldisilizane, mounted on specimen stubs, and examined with an 1810D Amray or Phillips XL30 ESEM FEG scanning electron microscope following the procedures of Stark and Kyzar (2001). North American distribution data supplement those listed in Stark (2001).
Specimens examined during this study are deposited in the following museums or collections: Bill P. Stark Collection, Clinton, Mississippi (BPSC); California Academy of Sciences, San Francisco (CASC); Colorado State University, Fort Collins (CSUC); Memorial University of Newfoundland, St. Johns (MUNC); Monte L. Bean Museum, Brigham Young University, Provo, Utah (BYUC); Oregon State University, Corvallis (OSUO); Oxford University Museum, England (OXUM), cited only; United States National Museum, Washington, D.C. (USNM); University of Montreal, Quebec (QMOR); and University of Prince Edward Island, Charlottetown (UPEI).
Type species.—Paracapnia curvata Hanson = Paracapnia opis (Newman), designation by Hanson (1946).
Diagnosis.—Western Nearctic species are apterous (Fig. 1), but those found predominantly in eastern North America (P. angulata, P. opis) and at least 1 Asian species (P. khorensis) are macropterous, micropterous, or brachypterous. Winged specimens have R1 of the forewing “slightly curved cephalad at its base,” according to Hanson (1946), but are “flat” or “straight” at this point, according to Nelson and Baumann (1989) and Stewart and Harper (1996). Figure 4 illustrates the forewing of a female P. opis specimen in which this “slightly curved” R1 base is evident; this is also apparent in Hanson's (1946) figure of an unspecified Paracapnia wing and to a lesser degree in Zhiltzova's (1972) figures of P. khorensis wings.
Hanson (1946) suggested Paracapnia adults differ from other capniids with respect to the relative widths of their glossae and paraglossae. Figure 2 shows the glossae of a Paracapnia female to be somewhat wider than the paraglossae; however, we have not pursued this character as a potential diagnostic feature for the genus. Hanson (1946) also showed that Paracapnia, Isocapnia, and Nemocapnia, among the Nearctic genera recognized at that time, shared the character of “mesothoracic furcasternum, postfurcasternal plates, and spinasternum,” being “closely united.” Figure 3 shows the mesosternum of a female Paracapnia in which this character is evident; however, the new species we describe below has the mesothoracic postfurcasternal plates narrowly separated from the spinasternum, and this is somewhat intermediate between known Paracapnia and other capniid genera. Thus, the male Paracapnia is most readily diagnosed by the distinctive epiproct, with a dorsal, membranous seminal duct that terminates in a frayed apex (Fig. 13). Females have a broadly rounded subgenital plate that is covered with long hairs (Figs. 12, 14). Both sexes exhibit extremely long cerci, which are longer than the abdomen but break off easily.
In the Stewart and Harper (1996) generic key, macropterous Paracapnia with slight curvature to the R1 vein key to Capnia (couplet 53); these specimens may be distinguished from Capnia by either the mesothoracic sternal features or by the epiproct character. Apterous Paracapnia specimens with the mesothoracic postfurcasternal plates separated from the spinasternum also key to Capnia (couplet 53), and these can be reliably distinguished from Capnia only by the epiproct character.
Key to Paracapnia Species
1. Nearctic species2
2. Apterous, known from the Cascade Mountains and coastal ranges of western North America3
Micropterous, brachypterous, or fully winged; ranging from eastern North America west to the Rocky Mountains5
3. Dorsoapical third of epiproct about as wide as subbasal area (Fig. 28); epiproct apex upturned beyond membranous seminal duct (Fig. 25); female subgenital plate deeply recessed mesally (Fig. 29)P. boris, n. sp.
Dorsoapical third of epiproct gradually tapered to a rounded or pointed apex (Fig. 9); epiproct apex slightly downturned or straight beyond seminal duct (Fig. 19); female subgenital plate not recessed mesally (Fig. 14)4
6. Epiproct apex slightly upturned in lateral aspect; dorsal aspect very slenderP. recta
Epiproct apex slightly downturned in lateral aspect; dorsal aspect more robust7
7. Epiproct apex terminating in small, abruptly downturned, toothlike structureP. khorensis
Epiproct apex without tooth-like structureP. sikhotensis
Paracapnia angulata Hanson
Paracapnia angulata Hanson, 1961: 29. Holotype ♂, Pelham, Massachusetts (USNM).
Male.—Micropterous, brachypterous, or macropterous. Body length 4–5 mm. Epiproct ca. 525 μm long and ca. 90 μm wide near base and tapered to a narrowly rounded apex (Fig. 6); lateral aspect with base of epiproct abruptly recurved, producing an angulate curve (Figs. 34–35); unexpanded seminal duct marked by a median and 2 or more lateral sulci (Fig. 7); median sulcus ca. 230 μm long.
Female.—Brachypterous or macropterous. Body length 6–7 mm. Subgenital plate truncate or slightly rounded, with a small, membranous mesal area near the posterior margin.
Diagnosis.—Males can be distinguished by the angulate curve that occurs laterally at the base of the epiproct (Figs. 34–35) and by the dorsal aspect that is broad at the base but becomes gradually narrower toward the apex (Fig. 5). Figures of the dorsal aspect were selected from eastern (Figs. 5–6) and western populations (Figs. 7–8) of the species to show the general consistency of epiproct structure. However, some variations were observed in epiproct shape and length.
Material examined.—Canada: Newfoundland: Upper Ferry Gulch, Gros Morne Mountain, Gros Morne National Park, 21 June 1979, D. & M. Larson, 7♂, 7♀ (MUNC); Three Mile Pond Park, Northern Peninsula, 30 June 1980, Brennan & Larson, 5♂, 30♀ (MUNC); Labrador, Valley River, 20 miles W Churchill Falls, 13 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 1♂, 7♀ (BYUC). USA: Colorado: Grand Co., Blue River, Hwy 9, 10 miles S Kremmling, 8 April 1997, R.W. Baumann, 1♂ (BYUC); Jackson Co., North Platte River, North Gate Canyon, 21 April 1993, R. Durfee, 2♂, 3♀ (CSUC); Jackson Co., Michigan River, Hwy 125, 9 May 1976, ?, 2♂, 2♀ (BYUC); Routt Co., Willow Creek near Hahns Peak, 13 May 1968, B.R. Oblad, 1♂, 1♀ (BYUC). Massachusetts: Worcester Co., Lynde Brook, near Leicester, 28 March 1969, D.S. Potter, 3♂, 8♀ (BYUC). Michigan: Keweenaw Co., Isle Royale, Isle Royale National Park, 12 July 1957, R.W. Hodges, 1♂, 1♀ (BPSC). Missouri: Shannon Co., Loggers Lake, Clark National Forest, 16 March 1972, Palmer & Thewke, 6♂, 4♀ (BYUC); Taney Co., Bull Creek, Hwy 76, 17 March 1972, B.K. Newman, 1♂ (BYUC). New Hampshire: Grafton Co., Hubbard Brook, 5 April 1973, G. Thornton, 3♂, 3♀ (BYUC). New York: Madison Co., Kingsley Creek, Randallsville, 20 March 1990, R.L. Fuller, 2♂, 2♀ (BYUC); Bradley Brook, west of Hamilton, 7 May 1991, R.W. Baumann, S.A. Wells, 1♂ (BYUC); Tompkins Co., Cascadilla Creek, Ithaca, 5 March 2001, M.D. Terry, 1♂ (BYUC). Ohio: Ashtabula Co., Crooked Creek, Callahan Road, 15 March 1990, R.W. Baumann, R.F. Kirchner, 19♂, 34♀ (BYUC). Pennsylvania: Perry Co., Laurel Run, tributary Sherman Creek, 11 April 1992, J.I. Earle, 2♂ (BYUC); Somerset Co., Kooser Run, Kooser State Park, 17 April 1979, R.W. Baumann, O.S. Flint, Jr., 4♂, 4♀ (BYUC); Warren Co., Brokenstraw Creek, 14 April 1994, E.C. Masteller, 2♂ (CSUC); Westmoreland Co., Powder Mill Run, Powder Mill Nature Preserve, 19 March 1975, R.W. Baumann, O.S. Flint, Jr., 19♂, 40♀ (BYUC). South Dakota: Lawrence Co., Spearfish Creek, Hwy 14A, 7 February 1995, R.W. Baumann, B.C. Kondratieff, B.O. Huntsman, 1♂, l♀ (CSUC); Pennington Co., Boxelder Creek, Custer Gap, 22 April 1996, R.W. Baumann, B.O. Huntsman, 14♂, 23♀ (BYUC). Virginia: Giles Co., Stony Creek, Rt. 623, 4 April 1980, B.C. Kondratieff, 2♂, 1♀ (CSUC). West Virginia: Greenbrier Co., Coats Run, Rt. 39, 26 April 1987, B.C. Kondratieff, 1♂, 4♀ (CSUC); Pocahontas Co., East Fork Greenbrier River, FR 51, 26 April 1987, B.C. Kondratieff, 8♂, 7♀ (CSUC). Wisconsin: Bayfield Co., Rocky Island, Apostle Islands, 15 May 1984, S.W. Szczytko, 2♂, 11♀ (BYUC). Wyoming: Crook Co., Beaver Creek, above Cook Lake, Bear Lodge Mountains, 24 April 1996, R.W. Baumann, B.O. Huntsman, 27♂, 44♀ (BYUC).
Distribution.—AR, CO, CT, DE, IL, KY, MA, MB, MD, ME, MI, MO, NC, NF, NH, NY, OH, OK, PA, PQ, SD, SK, TN, VA, WI, WV, WY.
Paracapnia disala (Jewett)
Capnia disala Jewett, 1962: 15. Holotype ♀, Parker Creek, Marys Peak, Benton Co., Oregon (CASC).
Paracapnia disala: Nelson and Baumann, 1989: 290.
Male.—Apterous. Body length 4–5 mm. Epiproct ca. 750 μm long and ca. 90 μm wide near base; margins approximately parallel to apical insertion of seminal duct, then gradually narrowed to apex (Figs. 9–10); lateral aspect gradually narrowed to small terminal knob (Fig. 11).
Female.—Apterous. Body length 5–6 mm. Subgenital plate slightly produced beyond lateral margins; apex truncate or slightly rounded but hairless medially and rather evenly sclerotized along posterior margin (Figs. 12, 14).
Diagnosis.—Among Nearctic Paracapnia this species is the only known species in which the epiproct apex is expanded to a small terminal knob (Fig. 11) and is also the only species in which the female subgenital plate is completely sclerotized and straight or rounded across the posterior margin (Figs. 12, 14). The association of the Lane County specimens with this species is based on similarities of the females in that series and the holotype. No male specimens from the type locality were available to confirm this association.
Material examined.—Oregon: Benton Co., Parker Creek, Marys Peak, 18 May 1958, H.A. Hacker, holotype ♀ (CASC); Parker Creek, Marys Peak, 1.5 miles W FR 3010, 18 May 1982, B.P. Stark, D.D. Ziegler, 1♀ (BPSC); stream, Marys Peak Road, 5 miles below Parker Creek, 28 February 1984, R.W. Baumann, C.R. Nelson, 1♀ (BYUC); Lane Co., H.J. Andrews Experimental Forest, 11 miles NE Blue River, 15 January 1979, G. Cooper, 13♂, 13♀ (BPSC).
Paracapnia ensicala (Jewett)
Capnia ensicala Jewett, 1962: 17. Holotype ♂, Boston Harbor, Thurston Co., Washington (CASC).
Paracapnia ensicala: Nelson and Baumann, 1989: 290.
Paracapnia oswegaptera (Jewett), 1965: 7. Holotype ♂, Osweg Creek, Clatsop Co., Oregon (CASC). New synonymy.
Male.—Apterous. Body length 4–5 mm. Epiproct ca. 658–800 μm long and ca. 90 μm wide near base; margins approximately parallel to midlength, then gradually narrowed to apex (Fig. 15); unexpanded seminal duct marked by obscure median sulcus and numerous lateral grooves (Fig. 16). Median sulcus ca. 310 μm long.
Female.—Apterous. Body length 5–6 mm. Subgenital plate slightly produced beyond lateral margins of sternum 8; posterior margin of plate rounded and sclerotized except for a small, membranous area (Fig. 22).
Diagnosis.—Males of this species have the epiproct apex curved downward near the tip, and females have a small, membranous area near the margin of the subgenital plate. The Wahkeena Falls males have a shorter epiproct than those from other sites (Fig. 21). When a larger series of specimens from several sites is available, the status of specimens from the Columbia River gorge should be reconsidered. The holotype of P. ensicala also differs slightly in epiproct structure from that of the P. oswegaptera holotype (Figs. 19–20). The major difference is due to an asymmetry near the epiproct base, which causes the P. ensicala holotype epiproct to appear more swollen in this area. We consider this to be an abnormality, but should other specimens with this feature become available, our synonymy of these species should be reevaluated.
Material examined.—Oregon: Clatsop Co., Osweg Creek, ca. 2 miles E Elsie, 1 February 1964, S.G. Jewett, Jr., holotype (P. oswegaptera) ♂ (CASC); Multnomah Co., Wahkeena Falls, 28 February 1984, R.W. Baumann, C.R. Nelson, 4♂, 4♀ (BYUC); same location, 27 November 1966, O.S. Flint, Jr., 2♂, 2♀ (USNM). Washington: Cowlitz Co., Kalama Springs, near Merrill Lake, Weyerhaeuser Research Area, 14 November 1974, N.H. Anderson, 3♂, 2♀ (OSUO). Thurston Co., Boston Harbor, 9 miles N Olympia, 3 January 1959, H.A. Hacker, holotype ♂ (CASC).
Paracapnia boris, new species
Adult thoracic sterna.—Mesosternal postfurcasternal plates narrowly separated from spinasternum and furcasternum by membrane; prosternal spinasternum not fused to anterolateral margins of mesosternal basisternum.
Male.—Apterous. Body length 4 mm. General color dark brown. Epiproct slender in dorsal aspect with lateral margins approximately parallel; ventroapical margin narrowed and upturned beyond membranous seminal duct (Figs. 23–25, 27–28).
Female.—Apterous. Body length 5–6 mm. General color dark brown. Dorsum of abdomen with wide, membranous band extending through segment 8; subgenital plate deeply emarginate mesally; sternum 7 with mesal sclerite distinctive (Figs. 26, 29).
Etymology.—This species is named in honor of our colleague, friend, and collecting companion, Boris C. Kondratieff, for his many contributions to the study of stonefly systematics. The species name is used as a noun in apposition.
Types.—Holotype ♂, 5♂, and 5♀ paratypes from California, Colusa Co., Mendocino National Forest, tributary South Fork Stony Creek, 28 January 1992, B.C. Kondratieff, R.W. Baumann, J.T. Zenger (holotype CASC; paratypes: CSUC, BYUC). Additional paratypes: California, Colusa Co., small stream at Letts Lake Picnic Area, 28 January 1992, R.W. Baumann, B.C. Kondratieff, J.T. Zenger, 1♂, 8♀ (BYUC).
Diagnosis.— Males are distinguished from other western Nearctic Paracapnia by the slender, unturned epiproct apex (Figs. 25, 27), and the females are distinguished by the deeply emarginate subgenital plate, completely separated laterally by membranes (Fig. 29). Hanson's (1946) definition of Paracapnia includes 2 thoracic features: “furcasternum of meso- and metathorax transverse and nearly rectangular” and “mesothoracic postfurcasternal plates large and united with the furcasternum and spinasternum.” Both are absent in this species. The latter feature is often used in combination with other characters to identify Paracapnia in keys (for example, Stewart and Harper 1996); however, this character appears in several other capniid genera, including Isocapnia and Nemocapnia (Hanson 1946), and it now appears that the distinctive epiproct character noted by Hanson (1946, 1961)—a dorsal, membranous, expandable “seminal duct” with a frayed apex—is the apomorphy that unites Paracapnia. Due to the mesothoracic character, P. boris keys to couplet 53 (genus Capnia) in Stewart and Harper (1996); however, this species differs from any known Capnia by the epiproct seminal duct character noted above.
Paracapnia opis (Newman)
Male.—Brachypterous or macropterous. Body length 4–5 mm. Epiproct ca. 558 μm long and ca. 73 μm wide near base; margins slightly narrowed at midlength but approximately parallel throughout most of length (Fig. 30); lateral aspect with base of epiproct broadly recurved, forming a smoothly rounded curve (Figs. 36–37); unexpanded seminal duct marked by a median sulcus and obscure lateral grooves (Fig. 31). Median sulcus ca. 240 μm long.
Female.—Macropterous. Body length 6–7 mm. Subgenital plate slightly produced into a rounded structure that does not project beyond lateral margins of sternum 8. Mesal area of plate with a small, membranous area.
Diagnosis.—Males of this species are most easily distinguished from those of the other eastern Nearctic species, P. angulata, by the shape of the epiproct in both dorsal and lateral aspects. The latter species has this structure wide near the base and gradually tapered to the apex dorsally (Figs. 5–7), whereas in P. opis the lateral margins of the epiproct are almost parallel throughout most of the epiproct length (Figs. 30, 32). The lateral recurved portion is short and angulate in P. angulata (Figs. 34–35), whereas in P. opis it is longer and smoothly C-shaped (Figs. 36–37). Females of these species cannot be reliably distinguished. Figures from 2 Canadian populations (Figs. 30–33) were included to indicate the general consistency in epiproct structure. Several specimens from different populations exhibit abnormalities in the seminal duct length, but for every site where this was noted, most of the specimens were of the typical form shown in the figures.
Material examined.—Canada: New Brunswick: Catamaran Brook, tributary Little South Miramichi River, 16 April 1997, D.L. Giberson, 4♂ (UPEI). Newfoundland: Avalon Peninsula, Renews, 13 April 1965, R.F. Morris, 4♂, 4♀ (BYUC); Broad Cove River, near St. Phillips (Benthobservatory), 8 April 1978, D.&M. Larson, 12♂, 21♀ (MUNC); North Harbour River, North Harbour, 9 April 1981, G. Brassard, 1♂ (MUNC); Avalon Peninsula, Big Northern Pond, St. Johns, 30 April 1983, D. & M. Larson, 10♂, 30♀ (MUNC); Labrador, Walsh River, Hwy 500, S of Labrador City, 10 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 4♂, 4♀ (BYUC); Labrador, Miron River, Hwy 500, E of Ross Bay Junction, 12 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 5♂, 26♀ (BYUC, CSUC); Labrador, stream, 4 miles E Churchill Falls, Hwy 500, 13 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 3♂, 3♀ (CSUC); Labrador, Pinware River, Hwy 510, above junction Lost River, 6 June 1998, R.W. Baumann, B.C. Kondratieff, 7♂ (BYUC). Quebec: St. Hippolyte, tributary to Lac Cromwell, 21 April 1967, P.P. Harper, 10♀, 10♀ (QMOR); Riviere Aux Pekans, Hwy 389, S of Fermont, 14 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 1♂ (BYUC); Little Manicouagan River, Hwy 389, km 480, 14 June 1997, R.W. Baumann, B.C. Kondratieff, C.R. Nelson, 20♂, 19♀ (BYUC). USA: Connecticut: Mansfield Co., Gurleyville, 17 March 1959, S.W. Hitchcock, 4♂, 3♀ (USNM). New Jersey: Burlington Co., stream, Mount Misery, ca. 2.5 miles E of junction Hwys 70 and 72, 5 April 1993, J.K. Gelhaus, 3 ♂, 4♀ (BYUC).
Distribution.—CT, ME, MN, NB, NF, NJ, NY, ON, PE, PQ, WI.
We thank O.S. Flint, Jr. (United States National Museum), D.L. Giberson (University of Prince Edward Island), B.C. Kondratieff (Colorado State University), P.P. Harper (University of Montreal), D.L. Larson (Memorial University of Newfoundland), J.A. Lattin (Oregon State University), and N.D. Penny and R. Zuparko (California Academy of Sciences) for lending us material used in this study. We also thank A. Gifford (Mississippi College) and M. Standing (Brigham Young University) for their assistance in scanning electron microscopy. Special thanks are given to K.W. Stewart and B.J. Armitage for allowing us to use on the cover of the reprints the P. angulata habitus illustration from the 2nd edition of Stewart and Stark (2002), which was printed by Caddis Press. The final illustration plates for this article were organized by R. Baker at the Monte L. Bean Life Science Museum, Brigham Young University.