Paracapnia humboldta, Baumann & Lee, 2007

Baumann, Richard W. & Lee, Jonathan J., 2007, Paracapnia Humboldta (Plecoptera: Capniidae), A New Winter Stonefly From Northern California, U. S. A., Illiesia 3 (3), pp. 17-19 : 18-19

Paracapnia humboldta sp.n.

( Figs. 1‐6 )

Material examined. Holotype ♂ from California, Humboldt County, Mason Gulch Creek, January 20, 2007, J.J. Lee. Type deposited at the California Academy of Sciences, San Francisco, California. Paratypes: California, Humboldt Co., Mason Gulch Creek , Hwy 299, mile 29.68, near junction Willow Creek , 19 Jan. 2007, J.J. Lee , 5♂ 1♀; 20 Jan. 2007, J.J. Lee , 23♂ 12♀; 1 Feb. 2007, J.J. Lee , 4♂ 1♀; 14 Feb. 2007, J.J. Lee , 10♂ 9♀; 23 Mar. 2007, J.J. Lee , 1♀ .

Male. Apterous. Body length 4.5‐5.5 mm. Body and appendages dark brown, with light areas laterally at junction of terga and sterna and between segments, light areas medially on terga 7, 8 and 9. Epiproct recurved anteriorly over terminal abdominal segments, long and very thin, width similar from base to apex, extending almost to tergum 7 ( Figs. 1, 3 ); tip rounded dorsally and slightly upturned laterally, bearing elongate feather‐ like structures ( Figs 2, 4 ); curve of epiproct nearly flat laterally, slightly turned to the left dorsally, near apex ( Figs. 1, 3 ). Cerci long, composed of 10‐14 segments.

Female. Apterous. Body length 6.0‐7.0 mm. Body and appendages dark brown, with light areas at junction of segments and in pleural space, with broad, light membranous band dorsally extending from abdominal segments 2‐7. Subgenital plate large and well defined, extending to posterior border of sternum 8, broadly rounded to truncate, sometimes with a tiny median point, with triangle shaped hairless area medially ( Figs 5, 6 ). Cerci long, composed of 14‐16 segments.

Etymology. The species name is taken from Humboldt County, California where this species occurs.

Diagnosis. The male of P. humboldta has the narrowest epiproct of any known species in the genus. It is equally wide from base to apex and slightly upturned at the tip. In addition, it always turns slightly to the left near the apex. Only P. boris has an epiproct that turns up at the apex, however, it is much wider both dorsally and laterally. The feather‐ like projections occur only very near the apex of the epiproct in P. humboldta while they extend to nearly 1/3 the length of the apex in both P. disala and P. ensicala (Jewett) . Females of P. humboldta exhibit a wide dorsal abdominal band that only extends to segment 7. This makes it possible to separate the females of this species from the other Nearctic Paracapnia species since their band extends to segment 8 as it does in the genus Capnia . Generally the females of P. disala and P. ensicala can be hard to distinguish in the absence of males. However, P. humboldta can be separated from them by the above character and also from the females of the odd species C. fialai Nelson and Baumann , which occurs in the Willow Creek drainage ( Nelson and Baumann 1990).

Notes. Paracapaia disala is recorded in the revision of the genus Paracapnia by Stark and Baumann (2004) as occurring only in Benton and Lane County , Oregon. However , recent collecting of winter stoneflies in Humboldt County , California, by the second author, has shown that this species is common in northwestern California. The following are records from five sites: Red Mountain Creek at rd. 10 N 12, 23 November 2005, 12♂ 11♀; 24 February 2006, 36♂ 50♀. Slide Creek at rd. 13 N 01, 14 December 2005, 9♂ 17♀; 23 January 2006, 8♂ 11♀. Upper Willow Creek drainage, Hwy 299: stream, mile 31.23, 7 February 2006, 4♂ 11♀; stream, mile 31.33, 14 February 2007, 10♂ 7♀; stream, mile 32.23, 7 February 2006, 4♀. In addition, 4♀ specimens were collected at Del Norte Co., tributary Middle Fork Smith River , 10 miles upstream from Jedediah Smith State Park, 12 March 1994, G.R. Fiala, that probably belong to this species.

Figures

Figs. 1‐6. Paracapnia humboldta: 1. Male terminalia, epiproct, dorsal. 2. Epiproct tip, dorsal. 3. Male terminalia, epiproct, lateral. 4. Epiproct tip, lateral. 5. Female terminalia, ventral. 6. Female subgenital plate, ventral.