Triznaka wallowa, Kondratieff & Baumann, 2012

Kondratieff, Boris C. & Baumann, Richard W., 2012, A New Species Of The Western North American Genus Triznaka From Oregon (Plecoptera: Chloroperlidae), Illiesia 8 (2), pp. 10-15 : 10-15

Triznaka wallowa sp. n.

( Figs. 1-12 )

Material examined. Holotype ♂, USA, Oregon, Union County, Fry Meadow Creek , Forest Road 62, above confluence Grand Ronde River, near junction of Wallowa River, 2 July 2011, C. Kerst ( USNM) . Paratypes ( BYUC, CSUC): Same locality as holotype: 2 July 2011, C. Kerst, 4♂, 3♀; 23 July 2011, N. M. Craft, 8♂, 6♀.

Male. Macropterous. Length of forewing 9-11 mm. General color yellow, to light yellow-brown. Head and pronotum with black markings, median pronotal stripe expanded anteriorly and especially posteriorly, with rugosities unmarked ( Fig. 1 ); abdomen with mid-dorsal black stripe, extending from segments 1-8. Hammer present on sternum 7 ( Fig. 9 ). Epiproct widest at base ( Fig. 7 ), rugose at tip, bearing basally expanded scale-like spines anteapical to tip and on lateral edges, also bearing medial and basal setae ( Figs. 7, 8 ). Aedeagus, ventrally with a distinct median band of thick reddish-brown setae arranged in longitudinal rows ( Figs. 3, 4, 5, 6 , 11, 12 ), aedeagal apex with a pair of triangular lobes, surrounded by patches of setae ( Figs. 3, 4 ).

Female. Length of forewing 10-11 mm. Coloration and markings similar to male, black pronotal stripe often wider. Subgenital plate often narrow at apex, lateral margins relatively straight to slightly convex, apical margin shallowly emarginate ( Fig. 2 ) to relatively deeply emarginate ( Fig. 10 ).

Larva. Unknown.

Etymology. The species name is a noun in apposition based on the Wallowa Mountains of northeastern Oregon.

Diagnosis. The males of T. wallowa can be readily separated from the other three described Triznaka species by the distinctive ventral longitudinal band of reddish-brown setae on the aedeagus ( Figs. 3, 4, 5, 6 , 11, 12 ). The aedeagus of T. signata has a ventral broad mushroom shaped patch of golden setae ( Baumann and Kondratieff 2008, figs. 15-17, 23, 24, 31). The aedeagus of T. pintada bears numerous large basal spines and an inverse V-shaped medial patch of golden setae ( Baumann and Kondratieff 2008, figs. 12-14, 29). The basal half of the aedeagus of T. sheldoni in ventral aspect is covered with hair-like setae and a medial elongate patch of spines ( Baumann and Kondratieff 2008, figs. 18-20, 33). The epiproct tips of the four species are similar, with flattened setae basally, and overlapping scales of spine-like setae apically as shown for T. wallowa ( Figs. 7, 8 ). The subgenital plate of T. wallowa is narrower at the apex ( Figs. 2 , 10 ) than either T. sheldoni ( Baumann and Kondratieff 2008, figs. 42-44) or T. pintada ( Baumann and Kondratieff 2008, figs. 37-39), which can also have emarginated apical margins.

REMARKS. Fry Meadow Creek was flowing on July 2 and 23 ( Fig. 13 ) when both adult collections were made, but when Cary Kerst returned to the site on 15 August, the stream was dry ( Fig. 14 ). The Wallowa Mountains are located in the Columbia Plateau of northeastern Oregon, an area often known as the “Alps” of Oregon. Most precipitation in the Wallowa Mountains occurs in the form of snow during the colder months and in the higher elevations, and usually from late July to mid-December there is little additional precipitation ( Hamlet et al. 2005). Drying of streams such as Fry Meadow Creek may also result from decreased snowpack and earlier runoff that this region has recently experienced ( Luce and Holden 2009). The Wallowa Mountains are relatively isolated from the Rocky Mountains to the east and the Cascade Range to the west. However, the stonefly fauna of these mountains is most closely related to the Rocky Mountains ( Baumann et al. 1977). The Quaternary climate fluctuations and topographical variation of the region, including the Wallowa Mountains, may have isolated a clade that gave rise to T. wallowa as has been reported for other faunal elements ( Chavez and Kenagy 2010). Additional adult stoneflies collected by Nadine Craft with T. wallowa included Podmosta decepta (Frison) and Suwallia sp.

Figures

Figures 1-2. Triznaka wallowa, Fry Meadow Creek, Oregon. 1. Head and pronotum. 2. Female, terminalia, ventral.

Figures 3-10. Triznaka wallowa, Fry Meadow Creek, Oregon. 3. Male, aedeagus, ventral. 4. Male, aedeagus, lateral. 5. Male, aedeagus, ventral spine patch. 6. Male, aedeagus, ventral spine patch, magnified. 7. Male, epiproct, dorsal. 8. Male, epiproct, dorsolateral. 9. Male, sternum 7, hammer. 10. Female, subgenital plate, ventral.

Figures 11-12. Triznaka wallowa, Fry Meadow Creek, Oregon. 11. Male, terminalia and aedeagus, lateral. 12. Male, aedeagus, ventral.

Figs. 13-14. Fry Meadow Creek, Forest Road 62, Union County, Oregon. 13. Upstream view, wet, 23 July 2011, Nadine Craft. 14. Downstream view, dry, 15 August 2011, Cary Kerst.